DRAFT Environmental Impact Report

Orange County Water District Prado Basin Sediment Management Demonstration Project State Clearinghouse No. 2013111071

Orange County Water District 18700 Ward Street Fountain Valley, CA 92708 Contact: Daniel Bott

March 2014

Table of Contents

Section Page

SECTION 1 INTRODUCTION ...... 1-1 1.1 Purpose and Authority ...... 1-1 1.2 Public Consultation ...... 1-1 1.3 Effects Determined Not Significant ...... 1-4 1.4 Effects Determined To Be Potentially Significant ...... 1-4 1.5 Review of the Draft EIR ...... 1-5 SECTION 2 PROJECT DESCRIPTION ...... 2-1 2.1 Background ...... 2-1 2.2 Project Area Setting ...... 2-1 2.3 Project Activities ...... 2-2 2.4 Project Monitoring Programs ...... 2-9 2.5 Construction Operations ...... 2-12 2.6 CEQA Project Objectives ...... 2-17 2.7 Permits and Approvals ...... 2-18 SECTION 3 ENVIRONMENTAL ANALYSIS ...... 3-1 3.1 AESTHETICS RESOURCES ...... 3-2 3.1.1 Regulatory Framework ...... 3-2 3.1.2 Existing Environmental Setting ...... 3-2 3.1.3 Thresholds of Significance ...... 3-4 3.1.4 Project Impacts...... 3-4 3.2 AIR QUALITY ...... 3-7 3.2.1 Regulatory Framework ...... 3-7 3.2.2 Existing Environmental Setting ...... 3-10 3.2.3 Threshold of Significance ...... 3-13 3.2.4 Project Impacts...... 3-13 3.3 BIOLOGICAL RESOURCES ...... 3-29 3.3.1 Regulatory Framework ...... 3-29 3.3.2 Existing Environmental Setting ...... 3-33 3.3.3 Thresholds of Significance ...... 3-59 3.3.4 Project Impacts...... 3-60 3.3.5 Unavoidable Significant Impacts to Listed Sensitive Species . 3-102 3.3.6 Orange County Water District Prior Mitigation Commitments in Prado Basin ...... 3-102 3.3.7 Proposed Mitigation Concept ...... 3-104 3.4 CULTURAL RESOURCES ...... 3-110 3.4.1 Regulatory Framework ...... 3-110 3.4.2 Existing Environmental Setting ...... 3-111 3.4.3 Threshold of Significance ...... 3-122 3.4.4 Project Impacts...... 3-122 3.5 GEOLOGY ...... 3-126 3.5.1 Regulatory Framework ...... 3-126 3.5.2 Existing Environmental Setting ...... 3-127 3.5.3 Threshold of Significance ...... 3-130 3.5.4 Project Impacts...... 3-130 3.6 GREENHOUSE GAS EMISSIONS ...... 3-136 3.6.1 Regulatory Framework ...... 3-136 3.6.2 Existing Environmental Setting ...... 3-137

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report i Table of Contents

3.6.3 Threshold of Significance ...... 3-139 3.6.4 Project Impacts...... 3-139 3.7 HAZARDS/HAZARDOUS MATERIALS...... 3-142 3.7.1 Regulatory Framework ...... 3-142 3.7.2 Existing Environmental Setting ...... 3-144 3.7.3 Thresholds of Significance ...... 3-145 3.7.4 Project Impacts...... 3-145 3.8 HYDROLOGY/WATER QUALITY ...... 3-148 3.8.1 Regulatory Framework ...... 3-148 3.8.2 Existing Environmental Setting ...... 3-152 3.8.3 Significance Criteria ...... 3-172 3.8.4 Project Impacts...... 3-173 3.9 LAND USE/RELEVANT PLANNING PROGRAMS...... 3-185 3.9.1 Regulatory Framework ...... 3-185 3.9.2 Existing Environmental Setting ...... 3-186 3.9.3 Thresholds of Significance ...... 3-187 3.9.4 Project Impacts...... 3-187 3.10 NOISE 3-192 3.10.1 Regulatory Framework ...... 3-192 3.10.2 Existing Environmental Setting ...... 3-195 3.10.3 Thresholds of Significance ...... 3-198 3.10.4 Project Impacts...... 3-198 3.11 TRANSPORTATION ...... 3-205 3.11.1 Regulatory Framework ...... 3-205 3.11.2 Existing Environmental Setting ...... 3-206 3.11.3 Thresholds of Significance ...... 3-207 3.11.4 Project Impacts...... 3-207 SECTION 4 CUMULATIVE IMPACTS ...... 4-1 4.1 CEQA Analysis Requirements...... 4-1 4.2 Cumulative Analysis Methodology ...... 4-1 4.3 Cumulative Impact Evaluation ...... 4-7 SECTION 5 OTHER CEQA SECTIONS ...... 5-1 5.1 Growth Inducing Impacts ...... 5-1 5.2 Significant Irreversible Changes ...... 5-2 5.3 Summary of Project Impacts ...... 5-3 SECTION 6 ALTERNATIVES TO THE PROPOSED PROJECT ...... 6-1 6.1 Purpose and Scope ...... 6-1 6.2 Project Objectives ...... 6-2 6.3 Planning Criteria ...... 6-2 6.4 Alternatives Eliminated From Further Analysis ...... 6-3 6.5 Project Alternatives Considered and Evaluated ...... 6-5 6.5.1 Alternative 1-No Project Alternative ...... 6-5 6.5.2 Alternative 2- Alternative Sediment Storage Site D ...... 6-8 6.5.3 Alternative 3 - Alternative Sediment Removal Method...... 6-13 6.6 Environmentally Superior Alternative ...... 6-19 SECTION 7 LIST OF PREPARES AND REVIEWERS ...... 7-1 SECTION 8 REFERENCES ...... 8-1

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Table Page

Table 1: IS/NOP Comment Letters ...... 1-2 Table 2: Phasing Plan ...... 2- 12 Table 3: Phase 1: Pre-Construction Monitoring ...... 2-13 Table 4: Phase 2: Site Preparation ...... 2-13 Table 5: Phase 3 Infrastructure Construction ...... 2-14 Table 6: Phase 4 Sediment Removal ...... 2-15 Table 7: Phase 5 Sediment Re-entrainment ...... 2-16 Table 8: Phase 6– Monitoring and Site Restoration ...... 2-16 Table 9: 2010 to 2012 Air Quality Monitoring Summary ...... 3-11 Table 10: South Coast Air Basin Attainment Status ...... 3-12 Table 11: Localized Significance Analysis (Construction) ...... 3-19 Table 12: Regional Construction Air Pollutant Emissions ...... 3-22 Table 13: Mitigated Construction Air Pollutant Emissions ...... 3-23 Table 14: Vegetation/Land Cover (Acres) ...... 3-38 Table 15: Sensitive Plant List ...... 3-41 Table 16: List of Special Status Wildlife Species ...... 3-48 Table 17: Sediment Removal Channel U.S./State Jurisdictional Area ...... 3-59 Table 18: Fish Survey Upstream Prado Dam Point 119 May 30 2013 ...... 3-69 Table 19: Fish Survey Upstream Prado Dam Point 119 May 30 2013 ...... 3-69 Table 20: Fish Survey Prado Dam Approach/Outlet Channel July 1, 2, 2008 ...... 3-70 Table 21: Fish Survey Santa Ana River Green River Golf Course Reach ...... 3-71 Table 22: Native Fish Survey Santa Ana River Green River Golf Course ...... 3-71 Table 23: Native Fish Survey Santa Ana River Weir Canyon to Imperial Highway April, November 2012 ...... 3- 72 Table 24: Summary of Soil Environmental Test Results ...... 3-74 Table 25: Durations to Deplete 500,000 yd³ of Sediment for Six Selected Discharges .... 3-77 Table 26: Vegetation Impacts (Acres) ...... 3-94 Table 27: Vegetation Communities at Different Elevations (Acres) ...... 3-103 Table 28: Riparian Mitigation Sites (Acres) ...... 3-105 Table 29: Coastal Sage Scrub Mitigation Site (Acres) ...... 3-105 Table 30: Regional Active Faults ...... 3-128 Table 31: Construction Greenhouse Gas Emissions ...... 3-139 Table 32: Summary of Soil Environmental Test Results ...... 3-144 Table 33: Summary of Water Quality Data Santa Ana River Below Prado Dam ...... 3-157 Table 34: Summary of Indicator Bacteria Water Quality Data ...... 3-168 Table 35: Beneficial Uses ...... 3-170 Table 36: Beneficial Uses ...... 3-171 Table 37: Water Quality Objectives (mg/L) ...... 3-172 Table 38: Impaired Water Bodies ...... 3-172 Table 39: Basin Plan Turbidity thresholds ...... 3-173 Table 40: Durations to Deplete 500,000 yd³ of Sediment for Six Selected Discharges .. 3-179 Table 41: Riverside County Noise Ordinance Standards ...... 3-193 Table 42: City of Corona Noise Ordinance Standards ...... 3-194 Table 43: Noise Levels and Human Response ...... 3-196 Table 44: Vibration Source Levels for Construction Equipment ...... 3-197 Table 45: Roundtrip Traffic Trips ...... 3-207 Table 46: Vireo Territories/Breeding Pairs Prado Basin ...... 4-10 Table 47: Summary of Environmental Impacts ...... 6-19

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report iii Table of Contents

Figure Page

Figure 1: Regional Vicinity Map ...... 2-3 Figure 2: Proposed Project...... 2-5 Figure 3: Sediment Removal Channel – Typical Cross-section View ...... 2-6 Figure 4: Eligible State Scenic Highways ...... 3-3 Figure 5: USGS Location ...... 3-35 Figure 6: Sediment Removal Channel ...... 3-36 Figure 7: Sediment Management Storage Site E ...... 3-37 Figure 8: Critical Habitat ...... 3-56 Figure 9: Least Bell’s Vireo Locations ...... 3-62 Figure 10: Southwestern Willow Flycatcher Locations ...... 3-63 Figure 11: Incoming Sediment Load Size ...... 3-78 Figure 12: Susceptibility to Sediment Deposition ...... 3-79 Figure 13: Yorba Slaughter Adobe Property Mitigation Site ...... 3-106 Figure 14: Pheasant Field Mitigation Site ...... 3-107 Figure 15: Demonstration Garden Extension Mitigation Site ...... 3-108 Figure 16: Pigeon Hill Property Mitigation Site ...... 3-109 Figure 17: Geological Constraints ...... 3-129 Figure 18: Mitigation Areas within Santa Ana Canyon ...... 4-6

Appendices Page

Appendix A-1: Initial Study/Notice of Preparation, November 2013, Orange County Water District Appendix A-2: Comment Letters Appendix B: Air Quality and Greenhouse Gas Analysis Report, February 2014, First Carbon Solutions Appendix C-1: Biological Conditions Technical Report, July 2013, Orange County Water District Appendix C-2: Native Fish Relocation for ACOE Reach 9 Channel Diversions Field Report, March 2010, Riverside-Corona Resource Conservation District Appendix C-3: Native Fish Relocation for ACOE Reach 9 - Phase 2 Channel Diversions, April/May 2012, Riverside-Corona Resource Conservation District Appendix C-4: Native Fish Survey Lower Santa Ana River Weir Canyon to Imperial Highway, November 2012, Orange County Water District Appendix C-5: Fish Protection Activities Prado Dam, Corona CA, August 2008, San Marino Environmental Associates Appendix D-1: Assessment of Water and Sediment Patterns within Prado Basin, November 2010, Golder Associates Appendix D-2: HEC-RAS Sediment Transport Modeling Santa Ana River, November 2010, Golder Associates

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Appendix D-2A Appendix D-2B Appendix D-2C Appendix D-2D Appendix D-3: Geotechnical Report for Prado Basin Sediment Management Demo Project, November 2010, Golder Associates Appendix D-4: Figures Appendix E: Hazardous Waste Site Search, May 2013, Orange County Water District

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report v Executive Summary

EXECUTIVE SUMMARY Proposed Project The Orange County Water District (OCWD) is proposing a sediment management demonstration project within the Prado Basin that will remove between 250,000 and 500,000 cubic yards of materials from the Prado Basin and re-entrain it into the lower Santa Ana River. OCWD is the Lead Agency for the proposed project. Project Overview The purpose of the Prado Basin Sediment Management Demonstration Project (Project) is to explore practical and beneficial methods to remove approximately 250,000 to 500,000 cubic yards of sediment from Prado Basin and re-entrain the sediment into the lower Santa Ana River, below Prado Dam to help restore sediment migration to habitats and beaches downstream and to help maintain water conservation storage behind Prado Dam. The demonstration project will be implemented over a five year period and involves the following three activities; 1) construction and operation of a sediment removal channel, 2) construction and operation of sediment storage and handling area and a green waste processing area and 3) sediment re-entrainment activities. Sediment Removal Channel The sediment removed from the Prado Basin for re-entrainment will be removed from a sediment removal channel. The sediment removal channel will parallel the alignment of the Santa Ana River in the southeast portion of Prado Basin. The western end of the channel will be located approximately 1,700 feet from the Prado Dam outlet works. The sediment removal channel will have a length of 6,000 feet, a width of 200 feet and a depth of 12 feet. A 30 foot access road will be provided along both sides of the channel alignment. A 300 buffer area is proposed around the perimeter of the sediment channel. The intent of the buffer area is to allow for modifications to the alignment during the detail design phase to minimize impacts to sensitive areas. In order to construct the sediment removal channel all vegetation within the channel will have to be removed. The alignment of the channel to the maximum extent possible will extend through areas that contain arundo or other non-native vegetation. The vegetation removal will occur outside of nesting season. The removed vegetation will be trucked to a green waste area where it will be processed and converted to mulch and/or firewood. The sediment will be removed from the sediment removal channel with hydraulic dredge operating in the wetted channel. A dredging barge will travel up and down the sediment removal channel by anchoring spuds into the ground. The collected

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-1 Executive Summary

sediment slurry will be conveyed by booster pumps to a sediment storage site through a temporary above ground discharge pipeline. Sediment Storage and Handling Area/Green Waste Processing Area The project includes sediment storage and handling area and green waste area to process the vegetation removed from the site and to prepare the sediment for re-entrainment. The vegetation removed from the sediment removal channel and sediment storage site will be processed at the green waste area. In order to remove and re-entrain sediments back into the Santa Ana River to achieve an adequate sediment concentration, the sediment will need to be re- entrained under flow conditions of 500 cfs and greater. Therefore, it will be necessary to store the removed sediments for a period of time until adequate releases are occurring from Prado Dam. The slurry collected from the hydraulic dredging will be processed at a sediment storage site to prepare it for re- entrainment back into the river. Once the slurry is processed it will be pumped into the first de-watering basin to begin the drying process. Once the sediment is dry it will be temporarily stockpiled for re-entrainment. Sediment Re-entrainment When Santa Ana River flows are at a sufficient rate, the sediment will be re- mixed into a slurry using water from the Santa Ana River and then pumped through an above ground temporary discharge pipeline to a sediment re- entrainment area. A crane will be positioned on the levee to secure the discharge end of the re-entrainment pipeline to insure even distribution of sediment into the river. Project Objectives The following project objectives have been established for the Prado Basin Sediment Management Demonstration Project to assist public agencies and decision makers in their review of potential impacts associated with the Project and Project Alternatives. • Remove between 250,000 and 500,000 cubic yards of sediment material from Prado Basin to prevent further loss of storage capacity and to enhance water storage conservation capabilities. • Prevent further degradation of the Santa Ana River due to sediment- starved stream flows. • Allow operation of Prado Dam to take place to maximize water diversion and infiltration between Imperial Highway and the 22 Freeway.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-2 Executive Summary

• Enhance and restore habitat in the Santa Ana River by preventing further degradation of certain areas of the river through sediment transport processes. • Increase recharge rates in the Santa Ana River by reducing the armoring and incising of the river bed. • Reduce coastal erosion processes by providing sediment to the Santa Ana River that will reach the Pacific Ocean. • Enhance and restore high value habitat in Prado basin by preventing further accumulation of sediments in Prado basin. • Minimize impacts to native vegetation within the Prado Basin. • Collect data and monitor project effects. Significant Unavoidable Adverse Impacts • The Project will have the potential to generate temporary construction noise impacts that could disrupt the breeding patterns of the Federal and State Listed Least Bells Vireo if it occurs within construction activity noise impact area. • The Project will have the potential for native fish to occur within the project area and require physical relocation. • The Project will have the potential to generate temporary construction noise impacts that could disrupt breeding patterns of nesting migratory birds. • The Project during sediment re-entrainment activities could temporary exceeds the Regional Water Quality Control Board Basin Plan threshold for turbidity. Environmental Issues Not Considered The following environmental issues were determined to be less than significant in the Initial Study/Notice of Preparation prepared for the Prado Basin Sediment Management Demonstration Project. The Initial Study/Notice of Preparation is presented in Appendix A. In accordance with section 15063(C) of the CEQA Guidelines these issues do not require further evaluation in the Draft EIR. Agriculture/Forest Resources • Mineral Resources • Population/Housing • Public Services • Utilities/Service Systems

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-3 Executive Summary

Project Impacts Table ES-1 provides a summary of project impacts and mitigation measures and a determination on the level of project impacts after the incorporation of mitigation measures. Summary of Project Alternatives The Draft EIR evaluates three alternatives to the Project. Alternative 1 – No Project Alternative Under the No Project Alternative, the proposed sediment management demonstration project will not be implemented. No activities will occur to remove between 250,000 and 500,000 cubic yards of material from Prado Basin. There will be no change to the existing conditions at the Prado Basin, sediment will continue to build up in the Prado Basin reducing storage for water conservation and continuing to degrade existing riparian habitat in Prado Basin. The lower Santa Ana River will continue to be starved of sediment. Alternative 2 Sediment Storage Site/Green Waste Site Alternative Location Under Alternative 2, between 250,000 and 500,000 cubic yards of sediment will be dredged and removed from the sediment removal channel. . The sediment will be removed from the sediment removal channel by a hydraulic dredging method. Under Alternative 2 the sediment would be removed and conveyed to the sediment storage site with the same method as the Project and will require same mix of construction equipment. However, under Alternative 2 the green waste processing and sediment storage and handling activities will occur at an alternative sediment storage site and green waste site. At the sediment storage site the sediment will be re-mixed with water into slurry and conveyed by an above ground discharge pipeline to the sediment re-entrainment area, downstream of the highway 71 crossing. Alternative 3 Alternative Sediment Removal Method Under Alternative 3 the sediment removal channel will be excavated along the alignment of the Santa Ana River. Between 250,000 and 500,000 cubic yards of sediment will be removed from the channel with heavy construction equipment. The removed sediment will be transported by heavy equipment to an alternative sediment storage site. The sediment will be re-mixed into slurry and conveyed by an above ground discharge pipeline to the sediment with water re-entrainment area. Environmentally Superior Alternative The Project will result in the least amount of significant adverse impacts to the environment and will better achieve the project objective of minimizing impacts to

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-4 Executive Summary

native vegetation within the Prado Basin. Therefore, the Project is considered to be the environmentally superior alternative. Areas of Controversy There are no controversy issues associated with the project. Public Review of Draft EIR The Draft EIR and its appendices are available for public review at the following location. Orange County Water District 18700 Ward Street Fountain Valley, CA 92708 http://www.ocwd.com/News/Publicnotices

Anaheim Public Library 500 W. Broadway Anaheim, CA, 92805

Corona Public Library 650 South Main Street Corona, CA 92882 Comments and questions regarding this Draft EIR should be directed to: Daniel Bott, Principal Planner Orange County Water District 18700 Ward Street Fountain Valley, CA 92708 E-Mail [email protected]

Upon the completion of the 45-day public review period, written responses to all substantive environmental issues raised will be prepared and available for review at least 10 days prior to the public hearing before OCWD Board of Directors at which time the certification of the Final EIR would be considered. These environmental comments and their responses will be included as part of the environmental record for consideration by the Orange County Board of Directors.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-5 Executive Summary

Table ES-1: Executive Summary of Impacts and Mitigation Measures

Impact Mitigation Measures Level of Impact After Mitigation

Aesthetics

The Project activities will have the potential to A-1: After the Project is completed OCWD will return all Less than Significant replace existing views into Prado Basin with areas impacted by the Project to their pre-project construction equipment which will result in a condition. short-term change to the existing aesthetic character of the project area.

The Project will involve night time lighting A-2: Construction lighting fixtures will be shielded by Less than Significant which could have the potential to result in light providing side flap on lights. Onsite construction lighting and glare impacts on nearby land uses. will be arranged so that direct rays shall not shine in or produce glares to nearby residential uses. A-3: If the onsite construction lighting creates a lighting or glare problem for residential properties, OCWD will implement corrective measures to resolve the problem. Such corrective measures would include raising the height of temporary construction walls or other shielding for lighting, providing additional shielding on the light fixtures, and relocating light fixtures.

Air Quality

The Project will have the potential to be in AIR-1: One of the following options will be adhered to Less than Significant conflict with or obstruct implementation of during Phase 2 Clearing and Grubbing, Phase 5 Re- South Coast Air Quality Management District entrainment, and Phase 6 Mitigation. Air Quality Management Plan. Option 1: Tier 3 engines will be used for all of the following equipment; Bulldozers, Off-road Trucks (Work Trucks, Dump

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-6 Executive Summary

Trucks, Water Trucks), Rubber Tired Loaders, and Pumps. Option 2: If construction activity is substantially modified from the assumptions utilized in this analysis, then the following measure will be implemented. Prepare an air quality emission analysis for construction activity with project-specific information prior to start of construction for Phase 2 Clearing and Grubbing, Phase 5 Re-entrainment, and Phase 6 Mitigation. Emissions analysis will detail the off-road equipment list (including type of equipment, horsepower, and hours of operation), any emission control devices added onto off-road equipment, and engine tiers (if known). The analysis will demonstrate that construction will not exceed the South Coast Air Quality Management District’s mass emissions thresholds of significance. If emissions could exceed any threshold, OCWD will decrease the amount of construction activity in a day, use additional emission control devices, or use higher tiered engines. The OCWD will ensure that construction managers adhere to the equipment and trip data utilized within the emissions analysis

The Project will not result in significant adverse No mitigation measures are required. Less than Significant localized air quality impacts.

The Project has the potential to result in Mitigation Measure AIR-1 is required Less than Significant significant cumulative air quality impacts.

The Project will not generate significant No mitigation measures are required. Less than Significant adverse odor impacts.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-7 Executive Summary

Biological Resources

The Project will have the potential to generate BIO-1: All vegetation removal and clearing activities at Significant Adverse temporary construction noise impacts that the sediment removal channel and sediment storage Impact could disrupt the breeding patterns of the site and green waste processing activities will be Federal and State Listed Least Bells Vireo if it conducted outside of the migratory bird season from occurs within construction activity noise impact March 15 to September 15. Biological monitoring of the area. sediment removal channel and sediment storage site will begin in February to determine if active nests are The Project will have the potential for native present. If active nests are present vegetation clearing fish to occur within the project area and activities near the nests will not occur within 500 feet of potentially require physical relocation. an active nest. The Project will have the potential to generate BIO-2: During vegetation removal activities, trees that temporary construction noise impacts that are removed from the area will be inspected to could disrupt breeding patterns of nesting determine if any nests are present. If nests are migratory birds. encountered they will either be relocated and if not feasible to be relocated a new substitute nest will be created and located outside of the construction activity impact area. BIO-3: After the sediment demonstration project is completed, OCWD will manage the alignment area of the sediment removal channel for five years to keep all disturbed areas free of exotic vegetation and to re- established native vegetation. A 10-foot edge along the service road of the sediment removal channel will be maintained. OCWD will plant pole cuttings and remove all non-native vegetation that occurs with the 10-foot edge area BIO-4: To compensate for temporary loss of 8.27 acres of native riparian habitat OCWD will restore native riparian vegetation on a 1:1 ratio and manage the area for duration of the project. To compensate for the temporary loss of 2.3 acres of coastal sage scrub

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-8 Executive Summary

habitat OCWD will restore and manage coastal sage scrub vegetation at a 1:1 ratio. The proposed mitigation will also involve removing 12 acres of arundo from the project area and restoring it with native vegetation. The removal and restoration of 12 acres of arundo with the restoration of 8.27 acres of riparian vegetation and 2.3 acres of coastal sage scrub will provide a total of 22.73 acres of compensatory mitigation and mitigation to temporary impact ratio of 2.15 to 1. BIO-5: To ensure that significant construction noise impacts do not occur to active nests of special status species located within the 500 foot construction activity noise impact area, a construction noise mitigation program will be implemented, and will include the following measures. • During the nesting season portable acoustical panels will be placed along the perimeter of the sediment removal channel where the floating dredge and/or heavy equipment is operating to reduce construction levels to less than 60 dBA at the closest active nest of special status species. The acoustical panels will be a minimum of 10 foot by 8 foot with a 2 foot cantilevered top with a STC rating of 25 or greater • During the nesting season portable acoustic panels will be installed as close as possible to the perimeter of the work area of the sediment storage site and sediment re-entrainment work area to reduce construction levels to less than 60dBA at the closest active nest of a special status species. The acoustical panels will be a minimum of 10 foot by 8 foot with a 2 foot cantilevered top with a STC rating of 25 or

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-9 Executive Summary

greater. • All construction equipment will be equipped with noise reduction features, such as mufflers and engine shrouds. • Onsite generators and booster pumps will be enclosed entirely. • During the nesting season a noise monitoring program will be implemented to ensure that construction noise levels are less than 60 dBA at the closest active nest of a special status species • During the nesting season weekly surveys will be conducted by a qualified biologist approved by CDFW within 500 feet of active construction areas. The purpose of the survey is to determine presence of active nests of special status species and breeding status of individuals. • A qualified biologist approved by CDFW will monitor construction activities to determine if the construction activities would disrupt nesting of special status species that are present within 500 feet of an active work area. If it is determined that the construction activity is disrupting the nesting behavior of a special status species, additional mitigation will be provided. If additional mitigation is not feasible construction in that area will cease and be redirected until the nests of special status species are no longer active or until it is determined that the activity will not disrupt nesting behavior.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-10 Executive Summary

BIO-6: To avoid impacts to special status wildlife species, prior to any ground disturbing activities, during operation and during demobilization of construction equipment, a qualified biologist approved by CDFW will conduct a pre-construction sweep of the project site for special status wildlife species. During these surveys the biologist will 1) inspect the project site for any special status wildlife species and prepare a list of species observed and record their activity during construction and operation of the project, 2) ensure that habitats within the construction activity impact area are not occupied by special status species and that the quality of that habitat is maintained, 3) in the event of the discovery of a special status species determining if the construction activity would cause adverse impacts and 4) if it is determined that the project activity would have the potential to adversely affect special status species and no other measures are available to avoid adverse impacts the biologist will require the project activity to cease in the area until the species is no longer in harm’s way or is relocated outside of the construction activity impact area. BIO-7: Prior to construction activities, a qualified biologist approved by CDFW will conduct a pre- construction training for all construction crew members. The training will focus on required mitigation measures and conditions of regulatory agency permits and approvals. The training will also include a summary of special status species and habitats potentially present within and adjacent to the project area. BIO-8: During the operation of the project, a qualified biologist approved by CDFW will monitor the construction activity impact area of the sediment removal channel and sediment storage site for active

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-11 Executive Summary

nests. The focus of monitoring will be to identify the presence or absence of special status species nesting within the construction activity impact area. If nesting birds are present the biological monitor will determine if the construction activity will cause them to abandon their nests. If the biological monitor determines that the construction activity will not cause nest abandonment then the construction activities will proceed. If it is determined that the construction activity is causing nest abandonment and additional noise measures cannot be implemented to prevent nest abandonment, then construction activity shall be re-directed or ceased until it is determined by the biologist that the activity would not cause nest abandonment or the nest is no longer active. BIO-9: At the end of each work day a qualified biologist approved by CDFW will inspect the work area to ensure there are no components of the Project that could trap or injure wildlife. BIO-10: Prior to sediment handling activities each day a qualified biologist approved by CDFW will inspect the sediment storage site to ensure wildlife will not be adversely impacted by construction equipment. BIO-11: To minimize entrapment of fish during dredging, prior to start of sediment removal activities a 1/8 mesh net inch fish screen will be secured to a temporary gated pipe that would extend through the diversion berm to divert Santa Ana River flows into the sediment removal channel. A 1/8 inch blocking net will also be installed along the Santa Ana River upstream of the diversion berm. The blocking will be secured with rebar or T-posts that are hammered in at the water’s edge and across the channel. The number of posts used will depend on the width and flow of the channel.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-12 Executive Summary

The segment of the river between blocking net and the diversion berm will be surveyed daily for fish. Non- native fish captured will be removed from the site and destroyed. Native fish captured will be relocated to suitable locations outside of the project area. BIO-12: To avoid and minimize potential impacts to native fish and critical habitat a native fish impact mitigation program will be implemented and will include the following measures. • Prior to surveys or construction activity, OCWD will submit the name and resumes of the qualified biologist conducting surveys. A qualified biologist to CDFW in regards to Santa Ana Suckers includes those individuals that hold a section 10(a) (1) (A) Recovery Permit. In regards to Arroyo Chubs a biologist is considered qualified if they have conducted a minimum of 40 hours of field activities with Arroyo Chubs under the supervision of a qualified biologist. • Prior to construction activities within the wetted channel, a qualified biologist will conduct a preliminary survey of the affected water body noting habitat and any fish that are present. If native fish are present seining will be conducted to remove and relocate native fish. • All captured native fish will be kept placed in ice chests filled with Santa Ana River water and aerated. The ice chests will be kept shaded at all times. Any native fish removed from the site will be relocated in suitable habitat upstream of the project area, as determined by a qualified biologist.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-13 Executive Summary

• If capture and relocation of native fish is necessary, such capture will be achieved through use of one or more of the following methods; fine mesh (0.08 to 0.16 inch), knot- less seine nets, fine mesh (0.16 to 0.24 inch) knot-less hoop nets, modified hoop nets, or similar traps or dip nets of 0.20 inch or finer mesh. The survey methods will be selected so as to minimize potential injury or mortality to native fish. Care will be taken to keep native fish in water as much as possible. Larval fishes will be kept submerged in a dip net until species is identified and released. • Prior to activities that may involve handling of native fish, the qualified biologist will ensure that the hands of all participants are free of sunscreen, lotion or insect repellent. • The qualified biologist will be present during the construction of the earthen berm to split flows between the Santa Ana River and the sediment removal channel. • The qualified biologist will submit a report to USFWS and CDFW identifying the number of any native fish species that were relocated and other measures that were taken to minimize impacts to native fish. The report will be submitted to USFWS and CDFW no more than 60 days following capture and relocation activities. BIO-13: The construction contractor will be required to implement a water quality monitoring program throughout the construction and operation period of the Project and where needed make adjustments to ensure

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-14 Executive Summary

water quality levels are maintained at acceptable levels. BIO-14: Prior to the start of ground disturbing activities, OCWD will prepare and implement a Storm Water Pollution Prevention Plan (SWPPP). The SWPPP will contain structural and non-structural Best Management Practices to manage storm water runoff, erosion and sedimentation to maintain water quality. BIO-15: Spoil sites will not be located within areas where spoil could be washed into the active stream channel, or where it will cover aquatic or riparian vegetation. BIO-16: To the extent possible equipment maintenance will occur in upland areas. In instances where equipment maintenance may need to occur near a water body primary and secondary containment measures will be employed to maintain water quality. BIO-17: OCWD construction contractor will prepare a Spill Prevention and Contingency Plan. The Plan shall be implemented prior to and during site disturbance and construction activities. The Plan will include measures to prevent or avoid an incidental leak or spill, including identification of materials necessary for containment and clean-up and contact information. The Plan and necessary containment and clean-up materials shall be kept within the construction area during all construction activities. Workers shall be educated on measures included in the plan at the pre- construction meeting or prior to beginning work on the project. BIO-18: Speed limits of 15 miles per hour or less will be required at all times to avoid potential injury to wildfire in the area. BIO-19: A qualified biologist will monitor access roads

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-15 Executive Summary

to ensure wildlife is not impacted by construction equipment. BIO-20: Prior to the start of construction of the sediment removal channel and prior to dredging each day a qualified biologist, approved by CDFW will survey the sediment removal channel to ensure there are no Southwestern Pond Turtles present. If Southwestern Pond Turtles are present they will be relocated to outside of the work area. Additionally, the biologist shall ensure that sediment removal channel is adequately screened to prevent access.

The Project will have the potential to result Mitigation Measures BIO-3 and BIO-4 are required. Less than Significant adverse impacts to sensitive native vegetation BIO-21: Unpaved areas will be watered as needed to communities. control dust on a continual basis. BIO-22: During the detailed design and construction phases of the project, OCWD will continue to minimize impacts to native vegetation and wildlife habitat whenever possible. This includes shifting footprints or alignment where necessary and possible. BIO-23: Upon development of final construction plans and prior to site disturbance, OCWD will clearly delineate limits of construction on project plans. All construction, site disturbance and vegetation removal will be located within the delineated construction boundaries. The storage of equipment and materials, and temporary stockpiling of soil will be located within designated areas only, and outside of habitat areas. BIO-24: OCWD shall monitor construction activities to assure that vegetation is removed only in designated areas. Riparian areas not to be disturbed shall be flagged. The perimeter of the work site shall be

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-16 Executive Summary

adequately flagged and fenced to prevent damage to adjacent habitat. BIO-25: During construction, adjacent vegetation will be monitored by OCWD for signs of plant stress. BIO-26: OCWD will have an onsite biologist to review grading plans, monitor all grading, excavation and ground disturbing activities in the streambed associated riparian habitat and monitor all aspects of construction monitoring that pertain to biological resource protection.

The implementation of the Project will result in Mitigation Measures BIO-3 and BIO-4. Less than Significant 34.46 acres of temporary impacts to Wetland BIO-27: Prior to start of construction activity OCWD will Waters of U.S./State and 3.58 acres temporary prepare a Habitat Management Plan to implement the impacts to Waters of the U.S./State. project compensatory mitigation requirements and will receive permit approval from the US Army Corps of Engineers, Regional Water Quality Control Board and the California Department of Fish and Wildlife. The HMP will be approved by CDFW prior to the start of construction activity.

The Project will have the potential adversely Mitigation Measures Bio-4, BIO-8, BIO-18, BIO-19, and Less than Significant affect wildlife movement. BIO-21. BIO-28: Construction lighting at the sediment re- entrainment area will focus on the work site to prevent off site spill-over lighting impacts to wildlife. Construction lighting fixtures will be shielded by providing a side flap on the lights BIO-29: A litter control program will be implemented during construction to eliminate the accumulation of trash. Trash shall be removed from trash receptacles at the end of each work day to discourage wildlife movement into work areas. BIO-30: The configuration of the work area at the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-17 Executive Summary

sediment storage site will be designed so when it is not in operation it would allow for wildlife movement. Such design measures will include reducing the slope and height of stockpiled sediment and providing adequate spacing between sediment stockpiles and settling ponds.

The Project has the potential to result in Mitigation Measures BIO-2, BIO-3 and BIO-27 are Less than Significant conflicts with Western Riverside County required. Multiple Species Habitat Management Plan.

Cultural Resources

The Project will have the potential to result in CR-1 Prior to the start of earthwork activities OCWD Less than Significant. adverse impacts to unknown historical and will be required to comply with Section 106 of the archaeological resources. National Historic Preservation Action and receive concurrence from the State Historic Preservation Office

(SHPO) that implementation of the Project will not result in significant adverse impacts to cultural resources. CR-2: In the event previously unknown resources are uncovered during implementation of the Project, OCWD will be required to comply with 36 CFR *00.11, Properties Discovered during Implementation of an Undertaking. In such an event, additional mitigation measures will be required. These additional mitigation measures will be developed in consultation with the SHPO and the Advisory Council on Historic Preservation.

The Project has the potential to result in CR-3: As part of the Project compliance with Section Less than Significant. adverse impacts to unknown Native American 106 of the Historic Preservation Act and prior to the sacred lands. start of earthwork activities the Corps and OCWD will conduct coordination with local Native American Tribes to determine if known Native American cultural

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-18 Executive Summary

resources are present within the project area.

The project area has been determined to have No mitigation measures are required. Less than Significant low sensitivity for the discovery of paleontological resources.

Geology/Soils

The project area is located in a seismically No mitigation measures required. Less than Significant active area and subject to potential seismic shaking impacts.

The Project will uncover soils that could be GEO-1: Prior to the start of construction OCWD will Less than Significant. subject to erosion caused by water and wind. obtain coverage under the General Construction Permit by the Regional Water Quality Control Board and in compliance with the permit shall file a Notice of Intent with the Regional Water Quality Control Board and prepare and implement Storm Water Pollution Prevention Plan.

Greenhouse Gas

The Project emissions will be less than the No mitigation measures are required. Less than Significant SCAQMD draft significance threshold.

There is no greenhouse gas reduction plan No mitigation measures are required. Less than Significant applicable to the Project.

Hydrology/Water Quality

Sediment re-entrainment activities will occur HWQ-1: To minimize turbidity impacts sediment re- Significant Adverse under high flows when there is a high level of entrainment will be done in a manner to recreate Impact turbidity in the water. During sediment re- natural storm glow conditions to the extent practicable, entrainment activities the Project could by pulsing the re-entrainment over a 24 to 72 hour temporarily exceed the Regional Water Quality period with 24 hours of no re-entrainment. The project

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-19 Executive Summary

Control Board Basin Plan threshold for will implement a water quality monitoring program to turbidity. monitor turbidity levels to ensure and where feasible to adjust rates of sediment re-entrainment to minimize

turbidity impacts. If levels of turbidity are below the Basin Plan threshold, the pause period could be reduced and/or concentration of solids in the slurry could be increased providing turbidity levels are below the Basin Plan threshold.

The construction and operation activities of the HWQ-2: The project will implement a water quality Less than Significant Project will have the potential degrade water monitoring program that will include procedures to quality. monitor for organic chemicals including pesticides, Polychlorinated biphenyls (PCBs), Polynuclear aromatic hydrocarbons (PAHs) and hydrocarbons, metals, total dissolved solids, indicator bacteria and dissolved oxygen upstream in the Prado Basin reservoir pool and downstream within the waters where sediment re-entrainment would occur. The monitoring program will be implemented before construction of the Project, during operation of the Project and after the Project is completed. If significant differences between upstream and downstream samples are observed during sediment re-entrainment activities, the rate of sediment re-entrainment would be adjusted to ensure they are within acceptable thresholds of the Regional Water Quality Control Board Basin Plain. The water quality monitoring plan will be coordinated with and approved by the Regional Water Quality Control Board as part of the 401 Water Quality Certification for the Project.

The Project will not extract underground water No mitigation measures are required. Less than Significant supplies. Therefore, the Project will not contribute to the depletion of existing ground water supplies.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-20 Executive Summary

The Project has the potential to increase HWQ-3: During the operation of the Project OCWD will Less than Significant sediment deposition along the lower Santa re-grade and redistribute the re-entrained sediment in Ana River. recharge area to maintain adequate freeboard along the river. HWQ-4: Prior to the start of the Project OCWD will coordinate with the Orange County Flood Control District on fair share responsibility to remove sediment that builds up near the Santa Ana River Tidal Prism.

The Project construction activities will increase Mitigation Measure GEO-1 and HWQ-2 is required. Less than Significant the potential for degraded surface water impacts.

The Project has the potential to expose HWQ-5: During the construction and operation of the Less than Significant structures to flood risks. project OCWD will coordinate with the Corps on weather forecasts for the project area. In the event a storm of sufficient magnitude is predicted that could jeopardize the safety of the area, OCWD will de- mobilize and remove all construction equipment from the project area.

Land Use/Relevant Planning

The Project has the potential to result in land L-1: During final design, construction and operation of Less than Significant use conflicts with the Santa Ana River Trail. the Project OCWD will coordinate with Riverside County Parks and Open Space District and Orange County Parks on the construction and operation of the project.

The Project has the potential to result in Mitigation Measures BIO-3 and BIO-4 are required. Less then Significant. conflicts with biological resource policies of the

Riverside County General Plan.

The Project has the potential to result in L-2: After completion of the Project, OCWD will Less then Significant.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-21 Executive Summary conflicts City of Corona future park plans for coordinate with the City of Corona on activities to return the sediment storage site. the sediment storage site to its pre-project condition.

The Project has the potential to be in conflict Mitigation Measures BIO-3 and BIO-4 are required. Less than Significant with West Riverside County Multiple Species

Habitat Conservation Plan.

Noise

The Project has the potential to expose N-1: The Project will ensure that all booster pumps and Less than Significant persons to noise levels in excess of local noise generators are contained in sound attenuation standards. enclosures. N-2: The Project will require construction contractors to use only construction equipment that have noise- reduction features, such as mufflers and engine shrouds. N-3: The Project will ensure that during sediment re- entrainment activities a sound attenuation enclosure is provided around the operating crane. N-4: OCWD will demonstrate that Mitigation Measure N-3 adequately reduces noise levels to meet City of Corona night time noise standards. During operation, noise measurements will be taken. If the noise measurements are above the night time standard additional sound attenuation measures shall be implemented to meet the noise standard.

The Project has the potential to cause a Mitigation Measures N-1, N-2, N-3 and N-4 are Less than Significant temporary increase in ambient noise levels. required.

The Project will result in less than significant No mitigation measures are required. Less than Significant. vibration impacts.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-22 Executive Summary

Transportation/Traffic

The Project mobilization and demobilization of T-1: Construction equipment mobilization and Less than Significant construction equipment and will have the demobilization activities will not occur during peak potential to result in traffic congestion at offsite traffic periods on public roadways. roadways and intersections and Project T-2: Prior to the start of mobilization and demobilization construction activities could result in onsite activities OCWD will coordinate with City of Corona on traffic conflicts. the availability of project access along Auto Center Drive, the need for preparation of traffic control plans and truck hauling permit requirements. T-3: Prior to the start of construction and operation of the Project OCWD will coordinate with the Corps on the preparation of traffic control plans that coordinates onsite construction traffic within the project area.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report ES-23 Section 1 Introduction

SECTION 1 INTRODUCTION

1.1 Purpose and Authority This Draft Environmental Impact Report (Draft EIR) has been prepared in accordance with the California Environmental Quality Act (CEQA) to evaluate the potential environmental impacts associated with the implementation of the Orange County Water District Prado Basin Sediment Management Demonstration Project (Project). This Draft EIR has been prepared in accordance with the California Environmental Regulations, Title 14, Section (§) 15000 et seq. and the rules, regulations and procedures for implementing CEQA as adopted by the Orange County Water District (OCWD). This document is a Project EIR, in conformance with § 15161 of CEQA Guidelines and examines the short-term construction impacts and operational impacts to the environment associated with the implementation of the Project. As the Lead Agency for the Project, OCWD must complete the environmental review to determine if the Project will create significant adverse environmental impacts. This Draft EIR is intended to serve as an informational document for public agency decision-makers and the public, allowing decisions to be informed regarding the objectives and components associated with the implementation of the Project. This Draft EIR will address the potential adverse impacts associated with implementation of the Project, as well as identify feasible mitigation measures and alternatives that may be adopted to reduce or eliminate these impacts. This Draft EIR is the primary reference document for the formulation and implementation of a mitigation monitoring program for the Project. This Draft EIR document analyzes the environmental effects of the Project to the degree of specificity appropriate to the current proposed actions, as required by §15146 of the CEQA Guidelines. This analysis considers the issues associated with the discretionary actions required for project implementation to determine the potential short-term and long-term effects. Additionally, this Draft EIR discusses both the direct and indirect impacts of this Project, as well as the cumulative impacts associated with planned and foreseeable future development within the project area. 1.2 Public Consultation The scope of this Draft EIR includes issues identified by OCWD during preparation of the Notice of Preparation of EIR (NOP) and Initial Study (IS) for the Project, and issues raised by other agencies and the public in response to

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 1-1 Section 1 Introduction the IS/NOP. The IS/NOP was circulated for the mandated 30-day review period that ended January 3, 2014 and was circulated to various federal, State, regional and local governmental agencies and other interested parties who were contacted to inform them of the Project and to solicit comments regarding project implementation. Additionally, on December 2, 2013 OCWD conducted two Scoping Meetings to discuss the Project with stakeholders in the area. Stakeholders were encouraged to submit in writing comments and concerns about the Project. Comment letters that were received during the public review period are summarized below in Table 1. The IS/NOP, along with comment letters received, are included in Appendix A of this Draft EIR.

Table 1: IS/NOP Comment Letters Location In DEIR Agency/Organization Key Issues Identified Where Addressed Orange County Provide description of project characteristics Section 3.8.2- Santa Public Works with respect to water quality issues Ana River Basin Plan Identify receiving waters that might receive Section 3.8.2-Existing runoff from project site Environmental Setting Describe sensitivity of receiving waters Section 3.8.2- Santa Ana River Basin plan Characterization of potential water quality Section 3.8.4-Impact Impacts. HWQ-1 Identification of downstream hydrologic Section 3.8.4 Impact conditions of concern affected by project. HWQ- 3, HWQ-4 Identify thresholds of significance. Section 3.8.3 Assessment of project impact significance to Section 3.8.4 Impact water quality HWQ-6 Identify if project has potential to create new Section 3.8.4-Impact storm water discharge to water body with HWQ-1 TMDL. Provide cumulative analysis of water quality Section 4.0 impacts. Address project compliance with California The Project does not Surface Mining and Reclamation Act involve the sale or exchange of sediment extracted from Prado Basin. All extracted material will be re-entrained into the Santa Ana River or be transported offsite to an appropriate disposal facility. Therefore the California Surface Mining and Reclamation Act will not apply to the project.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 1-2 Section 1 Introduction

Address issues related to the Section 3.8.4 Impact placement/storage of dredged material HWQ-5 Coordinate with U.S. Army Corps of Section 3.4 Engineers on unknown cultural resources within the Study area. Provide analysis of downstream impacts on Section 3.8.4 Impacts the lower Santa Ana River below Prado HWQ-3, HWQ-4 Dam. The study area should extend from Prado Section 3.8.2 Existing Dam to sediment re-entrainment area. Environmental Setting Santa Ana River California Document existing biological conditions, Section 3.3.4 Impact Department Fish and special status plants and wildlife species and BIO-1 Wildlife identify measures to minimize impacts to sensitive biological resources. Discuss project consistency with Western Section 3.3.4 Impact Riverside County Multiple Species Habitat BIO-5 Conservation Plan. Evaluate cumulative impacts to biological Section 4.4 resources. Evaluate alternatives to the project. Section 6.0 Characterize use of extracted sediments and Section 3.3.4 Impact materials BIO-1Santa Ana Sucker Identify scope of methods to restore Section 3.3.4 impacted areas. Proposed Mitigation Concept Provide analysis of en-entrained sediments Section 3.3.4 Impact including grain size, depth and quantification BIO-1Santa Ana of potential contamination Sucker Orange County Project effects on aesthetic resources Section 3.1.4 Coast Keeper Project effects on biological resources Section 3.3.4 Analysis of potential geologic and soil Section 3.5.4 constraints and project impacts. Project effects on hydrology and water Section 3.8.4 quality of Santa Ana River Project traffic impacts Section 3.11.4 Project noise impacts Section 3.10.4 and 3.3.4 Consideration of Alternatives Section 6.0 South Coast Air Identify all potential adverse regional and Section 3.2.4 Impact Quality Management local air quality impacts from construction AIR-2, AIR-3, AIR-4 District and operation of project. Endangered Habitat Letter of Support Appendix A League California Native Project impacts in Native American Sacred Section 3.4.4 Impact American Heritage Lands C-3 Commission Yorba Linda Water Define criteria for “higher flow conditions” Section 2.3 and District Section 2.5

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 1-3 Section 1 Introduction

1.3 Effects Determined Not Significant In accordance with Section 15063 (c) of the CEQA guidelines, based on the evaluations and findings in the IS/NOP certain environmental issues were determined to be less than significant or less than significant with the incorporation of mitigation measures, and therefore do not require further evaluation in this Draft EIR. The IS/NOP located in Appendix A of this Draft EIR provides the evaluations and findings that determined these issues to be less than significant or less than significant with the incorporation of mitigation measures. These issues include: • Mineral Resources • Population/Housing • Public Services • Utilities 1.4 Effects Determined To Be Potentially Significant Based on the findings in the IS/NOP, a determination was made that a Draft EIR was required to address potential significant environmental effects of the Project. The scope of this Draft EIR includes issues identified by the OCWD during the preparation of the IS/NOP for the Project, as well as environmental issues identified by agencies (see Table 1) and the public in response to the IS/NOP. The following issues were determined to be potentially significant and are addressed in this Draft EIR: • Air Quality • Biological Resources • Cultural Resources • Geology/Soils • Greenhouse Gas Emissions • Hydrology and Water Quality • Hazards • Noise • Aesthetics • Traffic/Transportation

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 1-4 Section 1 Introduction

1.5 Review of the Draft EIR Upon completion of this Draft EIR, OCWD has filed a Notice of Completion (NOC) with the State Office of Planning and Research to begin the public review period (Public Resources Code, Section 21161). Concurrent with the NOC, OCWD distributed a Notice of Availability (NOA) in accordance with § 15087 of the CEQA Guidelines. This Draft EIR has been distributed to responsible and trustee agencies, other affected agencies, surrounding cities and municipalities, and all interested parties requesting a copy of this Draft EIR in accordance with Public Resources Code 21092(b)(3). During the public review period, this Draft EIR, including the technical appendices, will be available for review at the following location: Orange County Water District 18700 Ward Street Fountain Valley, CA 92708

Anaheim Public Library 500 W. Broadway Anaheim, CA, 92805

Corona Public Library 650 South Main Street Corona, CA 92882

Agencies, organizations, and interested parties not previously contacted, or who did not respond to the NOP, currently have the opportunity to comment on this Draft EIR during the 45-day public review period. Written comments on this Draft EIR should be addressed to:

Daniel Bott, Principal Planner Orange County Water District 18700 Ward Street Fountain Valley, CA 92728 Comments may also be sent by email to Daniel Bott at [email protected]

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 1-5 Section 2 Project Description

SECTION 2 PROJECT DESCRIPTION 2.1 Background Prado Dam is an existing earth-filled dam that was constructed by the U.S. Army Corps of Engineers (Corps) in 1941 to control floods occurring in the Santa Ana River Watershed. Prado Dam’s primary purpose and beneficial use is flood control and the secondary beneficial use is water conservation. Through a joint agreement with OCWD and the Corps, the Corps temporarily stores water at Prado Dam for groundwater recharge purposes. Since commencement of operations at Prado Dam, sedimentation has occurred behind Prado Dam restricting the amount of sediment transported to the lower Santa Ana River and the beaches near the outlet of the river. Over time the sediment has accumulated in the Prado Dam reservoir area which is referred to as the Prado Basin. The accumulation of sediment in Prado Basin has reduced the amount of water conservation storage available for OCWD groundwater recharge operations. Since 1941, data suggests that at least 25,000 acre feet of storage has been lost below the 505 foot elevation due to sediment accumulation behind the dam. If the storage loss continues unabated at this rate of about 360 acre feet per year, ultimately all water conservation storage will be lost. Without sediment management, Prado Basin will continue to accumulate sediment and reduce water conservation storage. In addition to reduced storage below the dam is potentially associated with a number of downstream impacts, such as increased erosion and incising of the river bottom, reduced riparian habitat along the banks of the river, armoring of the river and lower groundwater infiltration rates. In response for the need for sediment management at Prado Basin, OCWD is proposing a sediment management demonstration project that will remove between 250,000 and 500,000 cubic yards of material from the Prado Basin and re-entrain it in a controlled manner back into the lower Santa Ana River, downstream of Prado Dam. When completed the sediment management demonstration project will provide data, conclusions and recommendations to assess whether to implement a long-term sediment management program at Prado Basin and if so to help design and implement that program. Any future long term sediment management program proposed in the Prado Basin would need to have subsequent CEQA environmental documentation prepared. 2.2 Project Area Setting The project area is situated within the Prado Basin in western Riverside County. As shown in Figure 1 Prado Basin is bordered to the south by State Route 91 and to the west by State Route 71. The most significant structure in the Prado

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-1 Section 2 Project Description

Basin is Prado Dam. The dam provides flood control for 2,225 square miles of the 2,650 square mile Santa Ana River Watershed. There are four major water bodies that drain into the Prado Basin; Santa Ana River, Chino Creek, Cucamonga Creek/Mill Creek and Temescal Creek. All of these water bodies converge and are impounded behind Prado Dam in a flood control pool during storm flow conditions. Depending on the elevation of the impounded water, the Corps operates Prado Dam by providing controlled condition releases from the flood control pool to the Santa Ana River for use use by OCWD to replenish the Orange County Groundwater Basin. The water surface elevation of the impounded pool in Prado Basin varies depending on the time of year, basin inflow and basin outflow, while taking into account flood control, water conservation and natural resource objectives. The flood control activities at Prado Dam require that vast portions of Prado Basin be inundated with water for periods of time. These periods of inundation influence vegetation and wildlife at Prado Basin and has created the largest riparian forest in southern California. The periods of inundation also significantly restricts access and activities occurring in the Prado Basin. From May to September there is typically no impoundment of water behind Prado Dam. The Corps temporarily captures storm water to elevation 498 feet during the flood season and to elevation 505 feet during the non-flood season 2.3 Project Activities The OCWD is proposing a sediment management demonstration project that will remove between 250,000 and 500,000 cubic yards of sediment from the Prado Basin and re-entrain it in a controlled manner back into the lower Santa Ana River, downstream of Prado Dam. The Project will be implemented behind Prado Dam within the Prado Basin reservoir area. As part of the planning process for the Project, OCWD evaluated a series of alternative sediment removal channel locations along the Santa Ana River, Chino Creek and Temescal Wash. Through this process, the Santa Ana River was identified as the most feasible water body to remove sediment, in terms of quantity of sediment removed and least amount of potential impacts to sensitive biological resources. In comparison to the other water bodies, the Santa Ana River provides significantly more favorable sediments (more sands and less silts) for downstream re-entrainment as well as constant source of sediment replenishment. Because of its more favorable conditions, the Santa Ana River is the only water body proposed for sediment removal activities.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-2 Mill Creek

ChinoCreek

OCWD Wetlands

A« Santa Ana River

Temescal Wash

Sediment Removal Channel

Corona Airport

Sediment Storage Site E & Green Waste Site Corona Wastewater Prado Dam Treatment Plant

Sediment Re-entrainment Area AÆ ?»

K:\Prado\SedimentManagementPlan\MXD\EIR2014\F1_PradoRegional.mxd

0 750 1,500 Proposed Project Areas Prado Basin SMDP Feet Regional Vicinity Map

Aerial Imagery Eagle Aerial Spring 2012 Figure 1 Section 2 Project Description

The Project involves three primary activities; the construction and operation of a sediment removal channel, the construction and operation of sediment storage and handling areas and green waste processing area, and sediment re- entrainment. The components of the Project are shown on Figure 2. Sediment Removal Channel The sediment removed from Prado Basin for re-entrainment will be removed from a sediment removal channel. The sediment removal channel will parallel the alignment of the Santa Ana River in the southeast portion of Prado Basin. Portions of the lands where the sediment removal channel will be located are owned by The U.S. Army Corps of Engineers and OCWD. The western end of the sediment removal channel is located approximately 1,700 feet from the Prado Dam outlet works structure. As shown in Figure 3 the sediment removal channel has a length of 6,000 feet, a width of 200 feet and a depth of 12 feet. A 30 foot wide dirt access road will be provided along both sides of the channel alignment and between the sediment removal channel and the sediment storage site. The access road along the sediment removal channel will provide a buffer between the sediment removal activities and adjacent habitat areas. To minimize potential erosion of the sediment removal channel, the top of the side slopes of the channel will periodically be re-shaped. Additionally the access roads along the channel will be maintained and repaired when needed. The access roads will be maintained during the operation of the Project and during the post-operation site restoration and monitoring periods. After the monitoring period, OCWD will re- establish the access roads with native vegetation. A 300 foot buffer area is also proposed around the perimeter of the sediment channel. The intent of the buffer area is to allow for modifications to the alignment during the detail design phase to minimize impacts to sensitive biological resources. Additionally, the sediment removal channel will include a 300 foot vegetation buffer at the downstream end of the channel to decrease potential impacts from floating debris to the Prado Dam outlet structure. In order to construct the sediment removal channel all vegetation within the alignment of the channel will have to be removed. The alignment of the channel to the maximum extent possible will extend through areas that contain arundo or other non-native vegetation. The vegetation removal will occur outside of nesting season. The vegetation removal and clearing activities will be conducted when the water elevation behind Prado Dam is lowered enough to expose the base of the vegetation. The above-ground vegetation will be cleared, followed by removal of the vegetation root system. The removed vegetation will be trucked to the green waste processing area, shown on Figure 2 to be processed and converted to mulch and/or firewood.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-4 Sediment Removal A« Channel

Green Waste Site

Sediment Storage Site E

Sediment Re-entrainment Area AÆ

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0 750 1,500 Proposed Access Roads Above Ground Pipeline Prado Basin SMDP Feet Proposed Project

Aerial Imagery Eagle Aerial Spring 2012 Figure 2 Existing Vegetation Existing Vegetation

to Remain to Remain ! Approximate Clearing and Grubbing Limits !

Approximate Sediment Removal Limits ôóõ Access / Haul Route Access / Haul Route ôóõ 2 2 1 12' 1

200'

30' 24' 152' 24' 30'

260' Path: K:\Prado\SedimentManagementPlan\MXD\EIR2013\SeptFigures\Fig3_ChannelCrossSection.mxd

Prado Basin SMDP Sediment Removal Channel - Typical Cross-section View *Figure not to scale Figure 3 Section 2 Project Description

Once the vegetation is removed from the alignment of the sediment removal channel heavy equipment will begin the excavation of sediment removal channel, outside of the river channel, to create a pool for hydraulic dredging of the sediment material. The material removed from the basin will be used to create a diversion berm between the river and the sediment removal channel. An area approximately 200 feet in length, 200 feet width and 12 feet in depth will be excavated to create a pool to place the dredge in. A portion of the Santa Ana River flows will be diverted into the sediment removal channel. A temporary, gated pipe will be placed through the diversion berm into the sediment removal channel to control the flow of water into the dredging pool. A 1/8 inch fish screen will be secured to the gated pipe and a 1/8 inch blocking net will be installed along the river, upstream of the diversion berm. The fish screen and blocking net will prevent both native and non-native fish from entering into the sediment removal channel. Prior to the start of dredging, the segment of the river between the diversion berm and the upstream blocking net will be seined daily and non-native fish and if present native fish will be removed. The native fish will be relocated to a suitable location outside of the project area. Any flow that is not diverted into the sediment removal channel will be allowed to flow around channel and through the Prado Basin as usual. When dredging is not occurring, the gated inlet pipe into the sediment removal channel would be closed to prevent incoming flows. The water levels in the dredging pool will be lowered by a combination of the water infiltrating into the ground and water drained through a screened outlet pipe. The dredging barge will travel up and down the sediment removal channel by anchoring spuds into the ground. As the suction pipeline operates one of the spuds is lifted while the other remains anchored. The barge will then pivot around the anchored spud causing the barge to rotate. This process is known as walking and is repeated along the entire sediment removal channel while drawing in slurry. As the barge walks along the sediment removal channel, a discharge pipeline will trail behind the hydraulic dredger while floating on top of the water surface. The channel will have slight downward slope, pending on where the dredging is occurring the water depth within the channel could range from zero to 12 feet. The collected sediment slurry will be conveyed to a sediment storage site through a temporary above ground 12 inch to 18 diameter inch discharge pipeline with the assistance of booster pumps. Pending on climate conditions, river flows will be diverted for three years into the sediment removal channel. After the third year, dredging within the sediment removal channel would cease and the diversion berm will be removed to allow the channel to fill up with river

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-7 Section 2 Project Description

water and sediment. The rate of re-filling will depend upon rainfall conditions. It is anticipated that after dredging has ceased the channel will re-fill with sediment in approximately 2 years. It is anticipated that storm events could occur which could damage or wash away the diversion berm. In the event a significant storm event occurs that threatens the safety of personnel or equipment, the dredging barge and other heavy equipment would be demobilized and staged in an upland location approved by the Corps. In the event demobilization occurs, most likely the re-mobilization of construction equipment and reconstruction of the sediment removal channel and diversion berm will occur after the storm season. If the depth of the water in the basin is not high enough to require de mobilization of the construction equipment, the diversion berm will be reconstructed. Prior to re-construction of the diversion berm the water in the sediment channel will be lowered by a combination of letting the infiltrate into the ground and draining the water through a gated outlet pipe or by pumping the water out of the channel into the Santa Ana River. Once the water is low enough the sediment removal channel both native fish and non- native fish will be removed. Any native fish removed will be relocated to suitable habitat upstream of the project area. Sediment Storage and Handling Area and Green Waste Processing Area The vegetation and sediment removed from the sediment removal channel will be processed at a 45.75 acre site located south of the sediment removal channel. The site is owned by the U.S. Army Corps of Engineers. Currently, the City of Corona has a lease with the Corps for potential parks uses of the site. The vegetation from the sediment removal channel will be processed into mulch. The slurry collected from the hydraulic dredging will be dried out and processed at the sediment storage site to prepare it for re-entrainment into the river. Once adequate flows occur the sediment will remixed with water and the slurry will be conveyed to the sediment re-entrainment area. Sediment Re-entrainment Activities The sediment re-entrainment activities will occur along the Prado dam outlet channel. The outlet channel is on lands owned by the U.S. Army Corps of Engineers. When flows of 500 cfs and greater are released from Prado Dam, the dried out sediment will be re-mixed into a slurry using water from the flood control basin. A suction/discharge line with the assistance of a portable pump will pump water from the flood control basin to the sediment storage site for re-mixing. Once the slurry is re-mixed it will be pumped from the storage site through a temporary above ground 12-inch to 18-diameter inch pipeline to the sediment re- entrainment area. The discharge pipeline will be located along the levee of the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-8 Section 2 Project Description outlet channel. A crane will be position on the levee to secure the discharge end of the re-entrainment pipeline to insure even distribution of sediment into the Santa Ana River. 2.4 Project Monitoring Programs One of the purposes of the Project is to provide data, conclusions and recommendations to help design and implement a long-term sediment management program at Prado Basin. A series of monitoring plans have been incorporated into the Project to measure the effects to water quality, wildlife and aquatic species, riparian habitat and to the substrate of the Sana Ana River. The following is a summary of the project monitoring programs. Sensitive Species Monitoring Program The Project will implement Sensitive Species Monitoring Program to monitor the presence of special status species occurring in the project area and the quantity and quality of habitat during the duration of the Project. The focus of the program will be onsite monitoring conducted by qualified biologist, approved by CDFW to help direct project activities to avoid and/or minimize impacts to sensitive biological resources. The onsite biologist will 1) inspect the project site for any special status wildlife species and prepare a list of species observed and record their activity during construction and operation of the project, 2) ensure that habitats within the construction activity impact area are not occupied by special status species and the quality of that habitat is maintained, 3) in the event of the discovery of a special status species the biologist will determine if the project activity will cause adverse impacts and 4) if it is determined that the project activity will have the potential to adversely affect special status species and no other measures are available to avoid adverse impacts, the biologist will require the project activity to cease in that area until the species is no longer in harm’s way or is relocated outside of the construction activity impact area. Riparian Habitat Monitoring Program The Project will implement a Riparian Habitat Monitoring Program to determine project effects in the lower Santa Ana River riparian habitat. Baseline surveys will be conducted in the soft bottom portions of the lower Santa Ana River to document existing habitat conditions and changes to riparian habitat after the Project is completed. A combination of aerial photography of before and after conditions and will be conducted. The monitoring plan will be implemented annually for 5 years following conclusion of the Project.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-9 Section 2 Project Description

Water Quality Monitoring Program The Project will implement a water quality monitoring plan that will monitor for a wide range of constituents. The monitoring program will include testing water quality for organic chemicals including pesticides, PCBs, PAHs and hydrocarbons, metals, turbidity, total dissolved solids, major ions, nutrients, and indicator bacteria. Water quality samples will be collected at multiple locations, including in the Prado Basin reservoir pool, at the below Prado Dam sampling location, and downstream within the waters where sediment re-entrainment will occur. The monitoring program will be implemented before construction of the project, during operation of the Project and after the Project is completed. The pre-project evaluation will include additional sampling of the sediment from the alignment along where sediment removal is to occur. Samples will be collected from bores advanced to the anticipated bottom of the dredge. Approximately 20 bores will be conducted. Sediment samples from the bores will be analyzed for grain size, metals, pesticides, PCBs, ammonia, and indicator bacteria. Aliquots of sediment samples from the bores will be used to further evaluate potential water quality impacts from the project by mixing the sediment with water to create a slurry similar to the slurry anticipated from the dredging. The supernatant from the sediment/water mixture will be tested for a range of constituents including metals, boron, oil and grease, pesticides, PCBs, ammonia, bacterial indicators, TDS, field parameters including dissolved oxygen, sulfides, MBAS, and turbidity. These analyses will be completed before sediment is dredged from the area of the corresponding bore and the data will be used to determine if any sediment should be left in place and not dredged. During re-entrainment of sediment, water quality sampling will be conducted at below Prado Dam (upstream of the re-entrainment site) and at a location immediately down gradient of the re-entrainment site. Comparison of the water quality data from these two sites will be used to assess water quality changes during the project. If significant differences between upstream and downstream samples are observed during sediment re-entrainment activities, the rate of sediment re-entrainment will be adjusted to ensure they are within acceptable threshold ranges that are provided in the Regional Water Quality Control Board’s Basin Plan. However, because sediment re-entrainment will occur under high flow with elevated levels turbidity, there could be a temporary increase over the turbidity threshold level. The water quality sampling methodologies, sample frequency, and locations will be coordinated with and approved by Regional Water Quality Control Board prior to the start of any construction activity.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-10 Section 2 Project Description

Dam Operations and Structures Monitoring Program The Project will implement a Dam Operations and Structures Monitoring Program to determine if removal of sediments from Prado Basin affects dam seepage. The monitoring program will monitor and evaluate pre-project and post-project condition water levels near the dam. Water levels will be monitored with use of piezometers, boring samples or other approaches approved by the Corps. Sediment Movement Monitoring Program The Project will implement a Sediment Movement Monitoring Program to determine sediment profile changes in the Prado Basin and along segments of the lower Santa Ana River and upstream of sediment removal channel. The purpose of the monitoring plan to monitor changes to sediment deposition and erosion patterns along the lower Santa Ana River and head cutting and migration of sediments into the Prado Basin. The monitoring program will calculate volumes removed by dredging, volumes that accumulate after dredging, volumes that erode after dredging, areas of disposition and erosion. Sediment elevations will be surveyed and mapped at 0.15 meter contours throughout the lower Santa Ana River and upstream of the sediment removal channel within the Prado Basin. Airborne LiDar Bathymetry (ALB) will be used to conduct the surveys. The technique will involve the following methodology; • A flight zone will be established with the appropriate sounding density for the LiDAR. A 1 meter by 1 meter would be appropriate for the lower Santa Ana River and upstream of the sediment removal channel. • The flight elevation and number of paths are established for soundings. • The aircraft is selected based on the sounding density, flight elevation, and number of paths. • GPS base stations are established at a minimum of locations based on the total area to be surveyed. These stations will be used to tie the LiDAR results into a map grid and to verify LiDAR elevations. • The survey is conducted • The data is processed digitally and visually inspected by a photogrammetrist. • Maps are plotted. Plots are verified by the GPS base station points and adjustments made as necessary. Within the Prado Basin, where ALP is not feasible due to water depths, surveys would be conducted with standard bathymetric methods with vessels utilizing ground positioning satellite equipment and depth sounding equipment such as

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-11 Section 2 Project Description

sonar or mechanical sounding equipment. The bathymetric sediment profiles would be to the same precision as sediment profile contours elsewhere. 2.5 Construction Operations Site Access Regional access to the project area will be provided from State Route 91 and State Route 71. Local access into the project area will be provided from a combination of existing access roads. Potential access routes into the project area could include Serfas Club Drive to Auto Center Drive, Lincoln Avenue to Railroad Street and on an existing dirt service road located along the shoulder of the north side of the Santa Ana River. Pre-Construction Phasing Plan The Project will be implemented in several phases over a period of up to five years beginning in winter of 2014. The schedule of the Project is largely driven by environmental and climate conditions. As shown in Table 2 the Project will be performed in 6 distinct phases. Table 2: Phasing Plan Phase Activity Phase 1 Pre-Construction Monitoring Phase 2 Site Preparation Phase 3 Infrastructure Construction Phase 4 Sediment Removal Phase 5 Sediment Re-entrainment Phase 6 Monitoring, Mitigation and Site Restoration

Phase 1: Construction Monitoring Phase 1 involves monitoring and data collection to establish baseline conditions in Prado Basin, in the area around Prado Dam and in the lower Santa Ana River from Prado Dam to the Pacific Ocean, prior to beginning construction activities. Wildlife and habitat in these areas will be monitored and surveyed to identify the presence of special status species and the quantity and quality of habitat. Additional studies will be performed to identify the physical characteristics of the project area, such as sediment quantities/locations, basin and river geometry and water quality parameters. Field activities for this phase of the Project include surveys and data collection. Vehicle access to the project area will occur along existing service roads. If existing service roads are not available, then access to the project area will occur by foot travel. The construction monitoring activities will occur before construction, during operation of the Project and after the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-12 Section 2 Project Description

Project is completed. The construction activity time frames and construction equipment mix for Phase 1 is shown in Table 3.

Table 3: Phase 1: Pre-Construction Monitoring Activity Equipment Equipment Hours Total Hours HP Start Description Quantity Per Day Days (Total) Rating Date Water Quality Pickup Truck 1 4 20 80 300 Dec. Data Collection 2014 Wildlife/Habitat Pickup Truck 2 6 30 360 300 Feb. Monitoring 2015 Sediment Pickup Truck 2 4 10 80 300 May Surveys 2015

Phase 2: Site Preparation Phase 2 involves the clearing, grubbing and rough grading of the sediment removal channel, access roads and the sediment storage site. A portion of the sediment storage site will be used to process the green waste from the vegetation clearing activities. Approximately 500 truck trips will be required to transport the removed vegetation from the sediment removal channel to the green waste processing site. Minor grading will also be performed to level the area for access roads and for the placement of above ground pipeline alignments. Geotechnical borings will also be performed during this phase along the alignment of the sediment removal channel. The site preparation activities will begin in September of 2015 and is anticipated to end January of 2016. The construction activity time frames and construction equipment mix for Phase 2 is shown in Table 4. Table 4: Phase 2: Site Preparation

Activity Equipment Equipment Hours Total Hours HP Start Description Quantity Per Day Days (Total) Rating Date Clearing and Bulldozer 2 8 25 400 250 Sep. 2015 Grubbing Clearing and Tracked 2 8 40 640 200 Sep. 2015 Grubbing Excavator Clearing and Skidder 2 8 30 480 200 Sep. 2015 Grubbing Clearing and Off-Road Haul 2 8 15 240 350 Oct. 2015 Grubbing Truck Clearing and Dump Truck 5 8 25 1,000 350 Oct. 2015 Grubbing Clearing and Tub Grinder 1 8 40 320 300 Sep. 2015 Grubbing Clearing and Wheel Loader 1 8 25 200 250 Oct. 2015 Grubbing Clearing and Water Truck 1 8 80 640 350 Oct. 2015 Grubbing Clearing and Work Truck 2 8 80 1,280 300 Sep. 2015 Grubbing

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-13 Section 2 Project Description

Grading Bulldozer 1 8 10 80 250 Oct. 2015 Grading Tracked Skid 1 8 10 80 90 Oct. 2015 Loader Grading Water Truck 1 8 10 80 350 Oct. 2015 Grading Work Truck 2 8 10 160 300 Oct. 2015 Geotech Drill Rig 1 8 8 64 300 Nov. 2015 Borings (Truck Mounted) Geotech Bulldozer 1 8 8 64 250 Nov. 2015 Borings Geotech Work Truck 1 8 8 64 300 Nov. 2015 Borings

Phase 3 Infrastructure Construction Phase 3 involves the construction of the temporary above ground pipelines, sediment storage area and re-entrainment facility. The Phase 3 infrastructure construction activity will begin in November of 2015 and will be anticipated to end in January of 2016. The construction activity and construction equipment mix for Phase 3 is shown in Table 5.

Table 5: Phase 3 Infrastructure Construction Activity Equipment Equipment Hours Total Hours HP Start Description Quantity Per Day Days (Total) Rating Date Pipelines Bulldozer 1 8 10 80 250 Nov. 2015 Pipelines Tracked 1 8 5 40 200 Nov. 2015 Excavator Pipelines All Terrain 2 8 20 320 120 Nov. 2015 Forklift Pipelines Tracked Skid 1 8 20 160 90 Nov. 2015 Loader Pipelines Work Truck 1 8 20 160 300 Nov. 2015 Grading Bulldozer 2 8 20 320 250 Oct. 2015 Grading Tracked Skid 1 8 30 240 90 Oct. 2015 Loader Grading Scraper 2 8 30 480 490 Oct. 2015 Grading Compactor 1 8 30 240 200 Oct. 2015 Grading Water Truck 1 8 30 240 350 Oct. 2015 Grading Work Truck 1 8 30 240 300 Oct. 2015 Re- Crane 1 8 10 80 300 Dec. 2015 entrainment Facility Re- Backhoe 1 8 10 80 150 Dec. 2015 entrainment Loader Facility Re- Work Truck 1 8 10 80 300 Dec. 2015 entrainment Facility

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-14 Section 2 Project Description

Phase 4 Sediment Removal Phase 4 involves the activities in Prado Basin to remove the sediment from the sediment removal channel and transport it to the sediment storage site. A hydraulic dredge will be used to remove the sediment from the sediment removal channel. The removed sediment will be pumped along an above ground pipeline to the sediment storage site. Booster pumps will be required along the discharge line to transport the material. Once the sediment reaches the sediment storage site the water/sediment mixture will be separated in settling basins to remove the water. Once the water has been removed the sediment will be stockpiled to await re-entrainment. If excessive amount of debris are encountered, some of the sediment could be excavated with heavy equipment and loaded onto off-road haul trucks or scrapers and hauled to the storage site and stockpiled to await re- entrainment. The dredging activities will begin November of 2015 and will occur for 188 days over a three year period. The construction activity timeframes and construction equipment mix for Phase 4 is shown in Table 6.

Table 6: Phase 4 Sediment Removal Activity Equipment Equipment Hours Total Hours HP Start Description Quantity Per Day Days (Total) Rating Date Dredge Hydraulic 2 8 188 3,008 325 Jan. Dredge 2016 Dredge Workboat 2 8 188 3,008 20 Jan. 2016 Dredge Wheel Loader 1 4 188 1,504 250 Jan. 2016 Dredge Scraper 1 4 188 1,504 490 Jan. 2016 Dredge Booster Pump 8 8 188 12,032 150 Jan. 2016 Dredge Work Truck 1 4 188 752 300 Jan. 2016

Phase 5 Sediment Re-entrainment Phase 5 involves activities for the re-entrainment of sediment when high flow releases, 500 cfs and greater are occurring from Prado Dam. This will be accomplished by mixing the dry sediment with water in the storage area and pumping the resulting “slurry” into the lower Santa Ana River immediately downstream of the concrete outlet channel. An above ground discharge line and booster pumps will transport the slurry to the outlet channel. At the outlet channel a crane will be used to position and rotate the discharge line to ensure the sediment is discharged evenly in the sediment re-entrainment area. The sediment re-entrainment will begin in January of 2016 and occur for 43 days over

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-15 Section 2 Project Description a four year period. The construction activity time frames and construction equipment mix for Phase 5 is shown in Table 7.

Table 7: Phase 5 Sediment Re-entrainment Activity Equipment Equipment Hours Total Hours HP Start Description Quantity Per Day Days (Total) Rating Date Re-entrainment Hydraulic 1 24 43 720 350 Nov. Feed Pump 2016 Re-entrainment Water Make- 1 24 43 720 100 Nov. up Pump 2016 Re-entrainment Wheel 2 24 43 1,440 250 Nov. Loader 2016 Re-entrainment Bulldozer 1 12 43 360 250 Nov. 2016 Re-entrainment Booster 3 24 43 2,160 150 Nov. Pump 2016 Re-entrainment Work Truck 1 8 43 240 300 Nov. 2016 Re-entrainment Crane 1 12 43 360 300 Nov. 2016

Phase 6 – Monitoring and Site Restoration Phase 6 activities include those required to monitor and collect data for the Project as well as to restore portions of the site disturbed by the project. The monitoring/data collection will include light vehicle traffic to different areas to assess wildlife/habitat conditions and to measure sediment transport rates. Site restoration will include removal of all equipment from the project site and re- grading the sediment storage area to pre-project conditions. The monitoring and site restoration actives will begin in November of 2016 and will extend up to five years after the Project is completed. The construction activity and construction equipment mix for Phase 6 is shown in Table 8.

Table 8: Phase 6– Monitoring and Site Restoration Activity Equipment Equipment Hours Total Hours HP Start Description Quantity Per Day Days (Total) Rating Date Monitoring Work Truck 2 4 120 960 300 Nov. 2016 Monitoring Workboat 1 4 120 480 20 Nov. 2016 Monitoring Airplane 1 8 8 64 300 Nov. 2016 Mitigation Bulldozer 1 8 120 960 250 Jan. 2017 Site Wheel 1 8 120 960 250 Jan. Restoration Loader 2017 Site Dump Truck 14 8 120 13,440 350 Jan. Restoration 2017

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-16 Section 2 Project Description

Site Work Truck 2 4 90 720 300 Jan. Restoration 2017 Site Bulldozer 2 8 30 480 250 Mar. Restoration 2017 Site Tracked 2 8 30 480 200 Mar. Restoration Excavator 2017 Site Crane 1 8 5 40 300 Mar. Restoration 2017 Site Wheel 1 8 30 240 250 Mar. Restoration Loader 2017 Site Water Truck 1 8 15 120 350 Mar. Restoration 2017 Site Work Truck 2 8 30 480 300 Mar. Restoration 2017

2.6 CEQA Project Objectives Section 15124 of CEQA Guidelines requires the Lead Agency to identify project objectives to help identify a reasonable range of alternatives to the project to evaluate in the EIR and to aid decision makers in preparing findings or a statement of overriding considerations if necessary. Below are the CEQA objectives for the Prado Basin Sediment Management Demonstration Project. • Remove between 250,000 and 500,000 cubic yards of sediment material from Prado Basin to prevent further loss of storage capacity and to enhance water storage conservation capabilities. • Prevent further degradation of the Santa Ana River due to sediment- starved stream flows. • Allow operation of Prado Dam to take place to maximize water diversion and infiltration between Imperial Highway and the 22 Freeway. • Enhance and restore habitat in the Santa Ana River by preventing further degradation of certain areas of the river through sediment transport processes. • Increase recharge rates in the Santa Ana River by reducing the armoring and incising of the river bed. • Reduce coastal erosion processes by providing sediment to the Santa Ana River that will reach the Pacific Ocean. • Enhance and restore high value habitat in Prado basin by preventing further accumulation of sediments in Prado basin. • Minimize impacts to native vegetation within the Prado Basin. • Collect data and monitor project effects.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-17 Section 2 Project Description

2.7 Permits and Approvals The EIR prepared for the Sediment Management Demonstration Project will be used as the supporting CEQA documentation for the following approvals and permits. • Orange County Water District Approval • Army Corps of Engineers Section 404 Permit • Regional Water Quality Control Board 401 Water Quality Certification • Regional Water Quality Control Board General Construction Storm Water NPDES permit • California Department Fish and Game Streambed Alteration Agreement • County of Orange County Encroachment Permit • California Department of Transportation Encroachment Permit • City of Corona Haul Permit

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 2-18 Section 3 Environmental Analysis

SECTION 3 ENVIRONMENTAL ANALYSIS Sections 3.1 through 3.11 of this Draft EIR contain discussions of the potential environmental impacts associated with implementation of the Orange County Water District Prado Basin Sediment Management Demonstration Project (Project). Environmental Issues The following environmental issues are addressed in this Draft EIR. • Aesthetics, Air Quality, Biological Resources, Cultural Resources, Geology/Soils, Greenhouse Gas Emissions, Hazards, Hydrology and Water Quality, Noise, and Transportation/Traffic.

Impact Analysis Format The Draft EIR analysis section contains the following components: • Regulatory Framework provides an understanding of the regulatory environment associated with the Project. • Existing Environmental Setting identifies and describes the existing onsite physical environmental conditions associated with each of the impact sections. • The Thresholds of Significance is the thresholds to determine if an impact is significant. Unless specifically identified within each environmental issue section of this document, the thresholds of significance used are those contained in Appendix G of the CEQA Guidelines. • Project Impacts describe environmental changes to the existing physical conditions that may occur if the proposed project is implemented, and evaluates these changes with respect to the thresholds of significance. • Mitigation Measures are those specific measures that may be required of the Project by the Lead Agency in order to: (1) avoid an impact; (2) minimize an impact; (3) rectify an impact by restoration; (4) reduce or eliminate an impact over time by preservation and maintenance operations; or (5) compensate for the impact by replacing or providing substitute resources. • Level of Significance after Mitigation describes the level of impact significance remaining after mitigation measures have been incorporated into the Project and implemented.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-1 Section 3 Environmental Analysis

3.1 AESTHETICS RESOURCES This section addresses the aesthetic and visual quality of the region and the local project area and evaluates potential aesthetic effects on visual resources and public views. 3.1.1 Regulatory Framework State Scenic Highway The State Scenic Highway Program was established to preserve and protect scenic highway corridors from change that will diminish the aesthetic value of lands adjacent to State highways. A scenic highway is designated under this program when a local jurisdiction adopts a scenic corridor protection program, applies to the California Department of Transportation for scenic highway approval and receives notification from California Department of Transportation that the highway has been designated as a Scenic Highway. According to the California Department of Transportation Scenic Highways Program, within the vicinity of the project area both State Route 71 and State Route 91 are Eligible State Scenic Highways. The location of both Eligible State Scenic Highways is relation to the project area is shown in Figure 4. Riverside County General Plan The Riverside County General Plan also identifies State Route 71 and State Route 91 as Eligible State Scenic Highways within the vicinity of the project area. The General Plan includes policies to provide for the protection of views from scenic highways. 3.1.2 Existing Environmental Setting The Prado Basin is the largest riparian forest in southern California. The basin is situated within the Santa Ana Canyon against the backdrop of the Chino Hills to the west. The southeast area of the basin contains Prado Dam which is the most significant structure in the basin. The aesthetic character of Prado Basin is natural open space. The open space aesthetic resources in the basin are influenced by the operation of Prado Dam. The dominate visual element in the basin is open water when the water level in the reservoir area is high. The dominate visual element in the basin is riparian forest lands when the water level in reservoir area is low. Other scenic resources in Prado Basin include; the Santa Ana River, Chino Creek and Mills Creek. The area contains large expanses of open space which provides visual relief to a predominately urbanized area.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-2 Sediment Removal A« Channel

Green Waste Site

Sediment Storage Site E

Sediment Re-entrainment Area AÆ

K:\Prado\SedimentManagementPlan\MXD\EIR2014\F4_ScenicHighways.mxd

0 750 1,500 Eligible Scenic Highways Prado Basin SMDP Feet Eligible State Scenic Highways

Aerial Imagery Eagle Aerial Spring 2012 Figure 4 Section 3 Environmental Analysis

Sweeping views of the Prado Basin is provided off of State Route 71, which is significantly higher in elevation. Other public scenic vistas into Prado Basin are provided from Chino Hills State Park, State Route 91 and from the Santa Ana River Trail. The interior of basin is natural open space and generally free of night time lighting and glare. The southwestern area of the basin near State Route 71 and State Route 91 is impacted with lighting from vehicle traffic. The closest sensitive receptor to the project area is existing residential land uses located approximately ½ mile west of the sediment re-entrainment area. 3.1.3 Thresholds of Significance • Will the Project result in a substantial and permanent modification of a scenic vista? • Will the Project damage scenic resources, including but limited to trees, rock outpourings, and historic buildings within a State Highway? • Will the Project cause a substantial change to the aesthetic character of the project area? • Will the Project create new sources of light and glare? 3.1.4 Project Impacts IMPACT AR-1: Will the Project result in a substantial and permanent modification of a scenic vista? Public views into Prado Basin are provided from Chino Hills State Park, State Route 71 and State Route 91, and the Santa Ana River Trail. During construction and operation of the Project public views into portions of Prado Basin may be interrupted with construction equipment and construction activity. The aesthetic impacts will be confined to specific locations in Prado Basin where project construction and operational activities will occur and will not reduce the overall scenic value of the Prado Basin. The Santa Ana River Trail is proposed to extend along the perimeter of the sediment storage site and green waste processing site. The sediment storage and processing and green waste processing activities will be within the view shed of trail users along the Santa Ana River Trail. The impacts will be short term and once the Project is completed, all construction activity will cease and scenic views into Prado Basin will return to its pre-project condition. The short term adverse changes to existing scenic vistas within the project area will not be significant. Level of Impact before Mitigation Less than significant impact.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-4 Section 3 Environmental Analysis

Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than significant impact. IMPACT AR-2: Will the Project damage scenic resources, including but limited to trees, rock outpourings, and historic buildings within a State Highway? According to the California Department of Transportation Scenic Highways Program, both State Route 71 and State Route 91 are designated Eligible State Scenic Highways. During the construction and operation of the Project some activities may be within the view shed of motorist along State Route 91 and State Route 71. Existing views into Prado Basin will temporarily be replaced with construction equipment and construction activity. However, the impact will be short term and once the project is completed all construction activity will cease and existing views from State Route 91 and State Route 71 will return to their pre-project condition. With the implementation of Mitigation Measure A-1 potential significant impacts to scenic resources along a State Scenic Highway will be reduced to a less than significant level. Level of Impact before Mitigation Potential significant impact. Mitigation Measures A-1: After the Project is completed OCWD will return all areas impacted by the project to their pre-project condition to the maximum extent feasible. Level of Impact after Mitigation Less than significant impact. IMPACT AR-3: Will the Project cause a substantial change to the aesthetic character of the project area? The majority of the project area is undisturbed open space consisting of a mix riparian forest lands and upland vegetation. The construction and operation of the Project will result in short term aesthetic changes to the project area. The aesthetic changes to the project area will occur from the removal vegetation from the sediment removal channel and from the sediment storage site and from the onsite sediment processing activities. However, views of the project activities will most likely be obstructed because of the distances between the project activities and the public vistas and from the presence of dense vegetation. Once the Project is completed the portions of the project area disturbed by the Project will

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-5 Section 3 Environmental Analysis be returned to its pre-project condition. With the implementation of Mitigation Measure A-1 potential adverse changes to aesthetic character of the project area will be reduced to a less than significant level. Level of Impact before Mitigation Potential significant impact. Mitigation Measure Mitigation Measure A-1 is required. Level of Impact after Mitigation Less than significant impact. IMPACT AR-4: Will the Project create new sources of light and glare? When adequate flows are available the sediment re-entrainment activities at the sediment re-entrainment area could operate up to 24 hours a day until the surface water flows are reduced below the required flow rate. To insure safe working conditions at the work site, night time lighting will be required. Within approximately ½ mile of the sediment re-entrainment area there are existing residential uses. There is some potential that existing residential uses within the line of sight of the flood lights could be adversely affected by spill over lighting. With the implementation of Mitigation Measure A-2 and A-3 potential adverse light and glare impacts will be reduced to a less than significant level. Level of Impact before Mitigation Potential significant impact. Mitigation Measures A-2: Construction lighting fixtures will be shielded by providing side flap on lights. Onsite construction lighting will be arranged so that direct rays will not shine in or produce glares to nearby residential uses. A-3: If the onsite construction lighting creates a lighting or glare problem for residential properties, OCWD will implement corrective measures to resolve the problem. Such corrective measures would include raising height of temporary construction walls or other shielding for lighting, providing additional shielding on the light fixtures, and relocating light fixtures. Level of Impact after Mitigation Less than significant impact.

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3.2 AIR QUALITY The following analysis is based on Air Quality Impact Report prepared by First Carbon Solutions in October of 2013 and updated in January 2014. The report is presented in Appendix B. 3.2.1 Regulatory Framework Air pollutants are regulated at the national, state and air basin level. Each agency has a different level of regulatory responsibility. The United States Environmental Protection Agency (EPA) regulates at the national level. The California Air Resources Board (ARB) regulates at the state level and the South Coast Air Quality Management District regulates at the air basin level. Federal Regulation The EPA handles global, international, national and interstate air pollution issues and policies. The EPA sets national vehicle and stationary source emission standards, oversees approval of all State Implementation Plans, conducts research, and provides guidance in air pollution programs and sets National Ambient Air Quality Standards (NAAQS), also known as federal standards. There are six common air pollutants, called criteria air pollutants, which were identified resulting from provisions of the Clean Air Act of 1970. The six criteria pollutants are Ozone, Particulate Matter (PM10 and PM 2.5), Nitrogen Dioxide, Carbon Monoxide, Lead and Sulfur Dioxide. The NAAQS were set to protect public health, including that of sensitive individuals. State Regulation A State Implementation Plan (SIP) is a document prepared by each state describing air quality conditions and measures that will be followed to attain and maintain NAAQS. The SIP for the State of California is administered by the ARB, who has overall responsibility for statewide air quality maintenance and air pollution prevention. The ARB also administers California Ambient Air Quality Standards (CAAQS), for the ten air pollutants designated in the California Clean Air Act (CCAA). The ten state air pollutants include the six national criteria pollutants and visibility reducing particulates, hydrogen sulfide, sulfates and vinyl chloride. South Coast Air Quality Management District The project area is located within the South Coast Air Basin (Basin). The air pollution control agency for the basin is the South Coast Air Quality Management District (SCAQMD). The SCAQMD is responsible for controlling emissions primarily from stationary sources. Additionally, SCAQMD in coordination with the Southern California Association of Governments (SCAG) is also responsible for

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developing, updating and implementing the Air Quality Management Plan (AQMP) for the basin. An AQMP is a plan prepared by an air pollution control district for a county or region designated as non-attainment of the national and/or California ambient air quality standards. The term non-attainment area is used to refer to an air basin where one or more ambient air quality standards are exceeded. Presently, the basin has a National non-attainment status for Ozone, PM10 and PM2.5 and a State non-attainment status for PM10 and PM2.5. 2007 AQMP The 2007 AQMP outlines a detailed strategy for meeting the federal health-based standards for PM2.5 by 2015 and 8-hour ozone by 2024 while accounting for and accommodating future expected growth. The 2007 AQMP incorporates significant new emissions inventories, ambient measurements, scientific data, control strategies, and air quality modeling. Most of the reductions will be from mobile sources, which are currently responsible for about 75 percent of all smog and particulate forming emissions. The 2007 AQMP includes 37 control measures proposed for adoption by the SCAQMD, including measures to reduce emissions from new commercial and residential developments, more reductions from industrial facilities, and reductions from wood burning fireplaces and restaurant charbroilers. 2012 AQMP The 2012 AQMP proposes Basin-wide PM2.5 measures that will be implemented by the 2014 attainment date, episodic control measures and transportation control measures to achieve air quality improvements that will only apply during high PM2.5 days. Most of the control measures focus on incentives, outreach, and education. There are multiple VOC and NOx reductions in the 2012 AQMP to attempt to reduce ozone formation, including further VOC reductions from architectural coatings, miscellaneous coatings, adhesives, solvents, lubricants, mold release products, consumer products. The 2012 also contains proposed mobile source implementation measures for the deployment of zero- and near-zero emission on-road heavy-duty vehicles, locomotives, and cargo handling equipment. There are measures for the deployment of cleaner commercial harborcraft, cleaner ocean-going marine vessels, cleaner off-road equipment, and cleaner aircraft engines. The 2012 AQMP also relies upon the Southern California Association of Governments regional transportation strategy, which is in its adopted 2012- 2035 Regional Transportation Plan/Sustainable Communities Strategy and 2011 Federal Transportation Improvement Program. The rules and regulations that apply to the Project include the following:

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SCAQMD Rule 402 prohibits a person from discharging from any source whatsoever such quantities of air contaminants or other material which cause injury, detriment, nuisance, or annoyance to any considerable number of persons or to the public, or which endanger the comfort, repose, health or safety of any such persons or the public, or which cause, or have a natural tendency to cause, injury or damage to business or property. SCAQMD Rule 403 governs emissions of fugitive dust during construction and operation activities. Compliance with this rule is achieved through application of standard Best Management Practices, such as application of water or chemical stabilizers to disturbed soils, covering haul vehicles, restricting vehicle speeds on unpaved roads to 15 miles per hour, sweeping loose dirt from paved site access roadways, cessation of construction activity when winds exceed 25 mph, and establishing a permanent ground cover on finished sites. SCAQMD Rule 1108 governs the sale, use, and manufacturing of asphalt and limits the volatile organic compound (VOC) content in asphalt used in the South Coast Air Basin. This rule will regulate the VOC content of asphalt used during construction. Therefore, all asphalt used during construction of the Project must comply with SCAQMD Rule 1108. SCAQMD Rule 1186 limits the presence of fugitive dust on paved and unpaved roads and sets certification protocols and requirements for street sweepers that are under contract to provide sweeping services to any federal, state, county, agency or special district such as water, air, sanitation, transit, or school district. State of California Airborne Toxic Control Measure for Diesel Particulate Matter from Portable Engines Rated at 50 horsepower and Greater. Portable engines rated at 50m horsepower and greater will comply with weighted reduced particulate matter emission fleet averages by compliance dates listed in the regulation. ARB Final Regulation Order, Requirements to Reduce Idling Emissions from New and In-Use Trucks requires that new 2008 and subsequent model- year heavy-duty diesel engines be equipped with an engine shutdown system that automatically shuts down the engine after 300 seconds of continuous idling operation once the vehicle is stopped, the transmission is set to “neutral” or “park,” and the parking brake is engaged. If the parking brake is not engaged, then the engine shutdown system shall shut down the engine after 900 seconds of continuous idling operation once the vehicle is stopped and the transmission is set to “neutral” or “park.” Any project trucks manufactured after 2008 will be consistent with this rule, which will ultimately reduce air emissions.

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ARB Regulation for In-Use Off-Road Diesel Vehicles On July 26, 2007, the ARB adopted a regulation to reduce diesel particulate matter and NOX emissions from in-use (existing) off-road heavy-duty diesel vehicles in California. Such vehicles are used in construction, mining, and industrial operations. The regulation limits idling to no more than five consecutive minutes, requires reporting and labeling, and requires disclosure of the regulation upon vehicle sale. The ARB is enforcing that part of the rule with fines up to $10,000 per day for each vehicle in violation. Performance requirements of the rule are based on a fleet’s average NOX emissions, which can be met by replacing older vehicles with newer, cleaner vehicles or by applying exhaust retrofits. The regulation was amended in 2010 to delay the original timeline of the performance requirements making the first compliance deadline January 1, 2014 for large fleets (over 5,000 horsepower), 2017 for medium fleets (2,501-5,000 horsepower), and 2019 for small fleets (2,500 horsepower or less). ARB Airborne Toxic Control Measure The ARB approved an Air Toxic Control Measure for construction, grading, quarrying and surface mining operations to minimize emissions of naturally occurring asbestos. The regulation requires application of best management practices to control fugitive dust in areas known to have naturally occurring asbestos and requires notification to the local air district prior to commencement of ground-disturbing activities. The measure establishes specific testing, notification and engineering controls prior to grading, quarrying or surface mining in construction zones where naturally occurring asbestos is located on projects of any size. There are additional notification and engineering controls at work sites larger than one acre in size. These projects require the submittal of a “Dust Mitigation Plan” and approval by the air district prior to the start of a project. 3.2.2 Existing Environmental Setting The project area is located in the County of Riverside and is within the South Coast Air Basin (basin). The basin consists of Orange County, all of Los Angeles County except for the Antelope Valley, the non-desert portion of western San Bernardino County, and the western and Coachella Valley portions of Riverside County. The basin is divided into 36 Source Receptor Areas with Basin operating monitoring stations in most of the areas. These Source Receptor Areas are designated to provide a general representation of the local meteorological, terrain, and air quality conditions within the particular geographical area. The project is within Source Receptor Area 22, and the nearest basin operated monitoring station is located in Norco, California. Table 9 summarizes 2010 through 2012 published monitoring data, which is the most recent 3-year period

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-10 Section 3 Environmental Analysis available. The data shows that during the past few years, the project area has exceeded the ozone, PM10, and PM2.5 standards.

Table 9: 2010 to 2012 Air Quality Monitoring Summary

Air Averaging Pollutant Time Item 2010 2011 2012 Ozone 1 1 Hour Max 1 Hour (ppm) 0.121 0.126 0.124 Days > State Standard (0.09 ppm) 22 32 31 8 Hour Max 8 Hour (ppm) 0.094 0.104 0.102 Days > State Standard (0.07 ppm) 59 63 72 Days > National Standard (0.075 38 36 47 ppm) Carbon 1 Hour 4 Max 1 Hour (ppm) 3 ND ND monoxide Days > State Standard (20 ppm) 0 0 ND Days > National Standard (35 ppm) 0 0 ND 8 Hour 1 Max 8 Hour (ppm) 1.94 1.87 1.95 Days > State Standard (9.0 ppm) 0 0 0 Days > National Standard (9 ppm) 0 0 0 Nitrogen Annual 1 Annual Average (ppm) 0.015 ID ID dioxide 1 Hour 4 98th percentile (ppm) 0.057 0.057 ND 1 Hour 1 Max 1 Hour (ppm) 0.062 0.058 0.061 Days > State Standard (0.18 ppm) 0 0 0 Sulfur Annual Annual Average (ppm) 0.001 0.000 ID dioxide 2 24 Hour Max 24 Hour (ppm) 0.005 ID ID Days > State Standard (0.04 ppm) 0 0 ID 1 Hour Max 1 Hour (ppm) ID ID ID Days > State Standard (0.25 ppm) ID ID ID Days > National Standard (0.075 ID ID ID ppm) Inhalable Annual Annual Average (µg/m3) 27.2 27.6 ND coarse particles 24 hour 24 Hour (µg/m3) 50.0 60.0 ND (PM10) 3 Days > State Standard (50 µg/m3) 0 2 ND Days > National Standard (150 0 0 ND µg/m3) Fine Annual Annual Average (µg/m3) 15.5 15.9 15.2 particulate 24 Hour 24 Hour (µg/m3) 54.2 56.3 39.3

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-11 Section 3 Environmental Analysis matter Days > National Standard (35 8 13 7 (PM2.5) 1 µg/m3) Notes and Abbreviations: > = exceed ppm = parts per million µg/m3 = micrograms per cubic meter ID = insufficient data ND = no data max = maximum State Standard = California Ambient Air Quality Standard National Standard = National Ambient Air Quality Standard 1 From the Mira Loma-Van Buren monitoring station 2 From the Riverside-Rubidoux monitoring station 3 From the SCAQMD monitoring station No. 4155 4 From the SCAQMD monitoring station No. 4144 Sources: California Air Resources Board 2013a; South Coast Air Quality Management District 2013a.

Attainment Status The EPA and the ARB designate air basins where ambient air quality standards are exceeded as “nonattainment” areas. If standards are met, the area is designated as an “attainment” area. If there is inadequate or inconclusive data to make a definitive attainment designation, they are considered “unclassified.” National nonattainment areas are further designated as marginal, moderate, serious, severe, or extreme as a function of deviation from standards. Each standard has a different definition, or ‘form’ of what constitutes attainment, based on specific air quality statistics. For example, the Federal 8-hour CO standard is not to be exceeded more than once per year; therefore, an area is in attainment of the CO standard if no more than one 8-hour ambient air monitoring values exceeds the threshold per year. In contrast, the Federal annual PM2.5 standard is met if the three-year average of the annual average PM2.5 concentration is less than or equal to the standard. The current attainment designations for the basin are shown in Table 10. The basin is designated as nonattainment for the state and federal ozone, PM10, and PM2.5, standards. The basin is also in nonattainment for the state nitrogen dioxide annual standard, based on the 2006 - 2008 data. Based on more recent data (2007 - 2009), the basin will be in attainment for nitrogen dioxide; however, the State has not officially designated the basin as in attainment. The Los Angeles County portion of the basin is in nonattainment for lead. However, the project area is in attainment for lead.

Table 10: South Coast Air Basin Attainment Status

Pollutant State Status National Status Ozone Nonattainment Nonattainment Carbon monoxide Attainment Maintenance Nitrogen dioxide (annual) Nonattainment Attainment Nitrogen dioxide (1-hour) Attainment Maintenance

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Pollutant State Status National Status Sulfur dioxide Attainment Attainment PM10 Nonattainment Nonattainment PM2.5 Nonattainment Nonattainment Lead (Los Angeles Nonattainment Nonattainment County) Lead (other parts of Basin, Attainment Attainment including the project area)

Source of State status: California Air Resources Board 2013b. Source of National status: U.S. Environmental Protection Agency 2012.

3.2.3 Threshold of Significance The following air quality significance thresholds are contained in Appendix G of the CEQA Guidelines. A significant impact would occur if the project will: • Will the Project conflict with or obstruct implementation of the applicable air quality plan? • Will the Project violate any air quality standard or contribute substantially to an existing or projected air quality violation? • Will the Project result in a cumulatively considerable net increase of any criteria pollutant for which the project region is nonattainment under an applicable national or state ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors)? • Will the Project expose sensitive receptors to substantial pollutant concentrations? • Will the project create objectionable odors affecting a substantial number of people? 3.2.4 Project Impacts IMPACT AIR-1: Will the Project conflict with or obstruct implementation of the applicable air quality plan? According to the 1993 SCAQMD Handbook, there are two key indicators that demonstrate consistency with the AQMP:

Indicator 1: Whether the project will not result in an increase in the frequency or severity of existing air quality violations or cause or contribute to new violations, or delay timely attainment of air quality standards or the

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interim emission reductions specified in the AQMP. This indicator is applicable to the Project and assessed below. Indicator 2: A project will conflict with the AQMP if it will exceed the assumptions in the AQMP in 2010 or increments based on the year of project build-out and phase. The Handbook indicates that key assumptions to use in this analysis are population number and location and a regional housing needs assessment. The parcel-based land use and growth assumptions and inputs used in the Regional Transportation Model run by the Southern California Association of Governments that generated the mobile inventory used by the SCAQMD for AQMP are not available. Therefore, this indicator is not applicable to the Project and is not assessed. The Indicator 1 analysis considers the recommended criteria in the SCAQMD’s 1993 Handbook and utilizes the following criteria to address potential air quality impact and consistency with the AQMP.

Step 1: Project’s contribution to air quality violations Step 2: Assumptions in AQMP (SCAQMD’s second indictor) Step 3: Compliance with applicable emission control measures in the AQMPs

Step 1: Project’s Contribution to Air Quality Violations According to the SCAQMD, a project is consistent with the AQMP if the project will not result in an increase in the frequency or severity of existing air quality violations or cause or contribute to new violations, or delay timely attainment of air quality standards or the interim emission reductions specified in the AQMP.

If a project’s emissions exceed the SCAQMD regional thresholds for NOX, VOC, PM10, or PM2.5, it follows that the emissions could cumulatively contribute to an exceedance of a pollutant for which the basin is in nonattainment (ozone,

nitrogen dioxide, PM10, PM2.5) at a monitoring station in the basin. An exceedance of a nonattainment pollutant at a monitoring station will not be consistent with the goals of the AQMP to achieve attainment of pollutants. As shown in Table 12 the Project will exceed the regional significance threshold

for NOX. This means that without mitigation, project emissions of NOX could combine with other sources and create ozone. This could result in an ozone exceedance at a nearby monitoring station. The air basin in which the Project is located is in nonattainment for ozone; therefore, the Project will not be consistent with the AQMP. The Project does not meet this criterion. However, as shown in Table 13 with implementation of Mitigation Measure AIR-1 this impact will be reduced to less than significant.

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Step 2: Assumptions in AQMP According to the SCAQMD’s CEQA Air Quality Handbook, the purpose of the consistency finding is to determine whether a project is inconsistent with the assumptions and objectives of the regional air quality plans, and thus whether it will interfere with the region’s ability to comply with federal and State air quality standards. If a project is inconsistent, the local government needs to consider project modifications or inclusion of mitigation to eliminate the inconsistency. Consistency with the AQMP implies that a project is consistent with the goals, objectives, and assumptions in the respective plan to achieve the national and State air quality standards. To assess the environmental impacts of new or renovated developments accurately, environmental pollution and population growth are projected for future scenarios. Since the AQMP are intended to be based on local general plans, projects that are deemed consistent with the general plan are found to be consistent with the AQMP. The Riverside County General Plan has designated the project area as Open Space-Conservation and Open Space -Water. Since the project’s intended actions are consistent with the current General Plan, implementation of the Project will not require any amendments to the County’s General Plan designations for the project site. Therefore, the Project will be within the County’s General Plan designation and is consistent with the adopted SCAQMD AQMP according to this criterion. Step 3: Control Measures This step involves assessing the Project’s compliance with the control measures in the AQMPs. 2003 AQMP: The 2003 AQMP contains a number of land use and transportation control measures including the following: the District’s Stationary and Mobile Source Control Measures; State Control Measures proposed by ARB; and Transportation Control Measures provided by Southern California Association of Governments. The Project indirectly will comply with the control measures set by ARB and Southern California Association of Governments. 2007 AQMP: The focus of the 2007 AQMP is to demonstrate attainment of the federal PM2.5 ambient air quality standard by 2015 and the federal 8-hour ozone standard by 2024, while making expeditious progress toward attainment of state standards. This is to be accomplished by building upon improvements from the previous plans and incorporating all feasible control measures while balancing costs and socioeconomic impacts. The 2007 AQMP indicates that PM2.5 is formed mainly by secondary reactions or sources. Therefore, instead of reducing

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fugitive dust, the strategy for reducing PM2.5 focuses on reducing precursor emissions of SOX, directly emitted PM2.5, NOX, and VOC. The Final 2007 AQMP control measures consist of four components. The first component is SCAQMD’s Stationary and Mobile Source Control Measures. The Final 2007 AQMP includes 30 short-term and mid-term stationary and seven mobile source control measures for SCAQMD implementation. Some of the measures will become new rules and some will be amendments to existing rules. When the rules pass, the owner-operator will follow the applicable rules. The second component is ARB’s Proposed State Strategy, which includes short- and mid-term control measures aimed at reducing emissions from sources that are primarily under state jurisdiction, including on-road and off-road mobile sources, and consumer products. These measures are required in order to achieve the remaining emission reductions necessary for PM2.5 attainment. When these measures are implemented by the ARB, the Project will be required to follow them. The third component is SCAQMD Staff’s Proposed Policy Options to Supplement ARB’s Control Strategy. This strategy does not apply to the Project. The fourth component consists of Regional Transportation Strategy and Control Measures provided by Southern California Association of Governments. Transportation plans within the basin are statutorily required to conform to air quality plans in the region, as established by the 1990 Federal Clean Air Act and reinforced by other Acts. In general, Transportation Control Measures are those projects that provide emission reductions from on-road mobile sources, based on changes in the patterns and modes by which the regional transportation system is used. Strategies are grouped into three categories; high occupancy vehicle strategy, transit and systems management, and information-based technology (traveling during a less congested time of day). Southern California Association of Governments approved the transportation measures in the Regional Transportation Plan, which have been included in the region’s air quality plans. The Transportation Control Measures will be implemented and will subsequently reduce emissions in the Basin. 2012 AQMP: The 2012 AQMP was adopted December 7, 2012. The purpose of the 2012 AQMP for the Basin is to set forth a comprehensive and integrated program that will lead the Basin into compliance with the federal 24-hour PM2.5 air quality standard, and to provide an update of the Basin’s projections in meeting the federal 8-hour ozone standards. Similarly to the prior AQMPs, the Project will comply with all applicable rules and regulations enacted as part of the AQMP.

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SIPs: Geographical areas in the state that exceed the federal air quality standards are called nonattainment areas. The project area is in nonattainment for ozone, PM10, PM2.5, and nitrogen dioxide. State Implementation Plans (SIPs) show how each area will attain the federal standards. To do this, the SIPs identify the amount of pollutant emissions that must be reduced in each area to meet the standard and the emission controls needed to reduce the necessary emissions. The SCAQMD is currently 94 percent of the way towards achieving

the 2014 emissions levels identified in its PM2.5 SIP. The SIP takes into account ARB rules and regulations. The Project will comply with applicable rules and regulations. Summary Analysis Step 1: The Project will potentially contribute to air quality violations because its construction emissions exceed the SCAQMD regional significance

threshold for NOX. However, as shown in Table 13, the construction emissions will be reduced to less than significant with implementation of Mitigation Measure AIR-1. Therefore, the Project is consistent with this criterion with mitigation. Analysis Step 2: The Project will be within the County’s General Plan designation and is consistent with the adopted SCAQMD AQMP. Therefore, the Project is consistent with this criterion. Analysis Step 3: The Project will comply with all applicable rules and regulations. Therefore, the Project is consistent with this criterion. Level of Significance before Mitigation Potential significant impact. Mitigation Measures MM AIR-1: One of the following options will be adhered to during Phase 2 Clearing and Grubbing, Phase 5 Re-entrainment, and Phase 6 Mitigation. Mitigation Option 1.A: Tier 3 engines will be used for all of the following equipment; • Bulldozers, • Off-road Trucks (Work Trucks, Dump Trucks, Water Trucks), • Rubber Tired Loaders, and • Pumps Mitigation Option 1.B: If construction activity is substantially modified from the assumptions utilized in this analysis, then the following measure will be implemented.

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Prepare air quality emissions analysis for construction activity with project- specific information prior to start of construction for Phase 2 Clearing and Grubbing, Phase 5 Re-entrainment, and Phase 6 Mitigation. Emissions analysis will detail the off-road equipment list (including type of equipment, horsepower, and hours of operation), any emission control devices added onto off-road equipment, and engine tiers (if known). The analysis will demonstrate that construction will not exceed the South Coast Air Quality Management District’s mass emissions thresholds of significance. If emissions could exceed any threshold, OCWD will decrease the amount of construction activity in a day, use additional emission control devices, or use higher tiered engines. The OCWD will ensure that construction managers adhere to the equipment and trip data utilized within the emissions analysis. Level of Significance after Mitigation Less than significant impact. IMPACT AIR-2: Will the Project violate any air quality standard or contribute substantially to an existing or projected air quality violation? Two criteria are used to assess the significance of this impact: (1) the localized construction analysis and (2) the CO hot spot analysis. Localized Construction Analysis The SCAQMD Governing Board adopted a methodology for calculating localized air quality impacts through localized significance thresholds. Localized significance thresholds represent the maximum emissions from a project that will not cause or contribute to an exceedance of the most stringent applicable state or federal ambient air quality standard. Localized significance thresholds were

developed in recognition of the fact that criteria pollutants such as CO, NOX, and PM10 and PM2.5 in particular, can have local impacts at nearby sensitive receptors as well as regional impacts. The localized significance thresholds are developed

for each source receptor area and are applicable to NOX, CO, PM10, and PM2.5. The localized assessment methodology limits the emissions in the analysis to those generated from onsite activities. The onsite emissions during construction are compared with the localized significance thresholds and are summarized in Table 11. Onsite emissions are from fugitive dust during grading and off-road diesel emissions. As shown in Table 11, unmitigated emissions during construction will not exceed the localized significance thresholds. As shown in Table 11, Phase 5 Sediment Re-entrainment is anticipated to generate the

highest maximum daily emissions of NOX, CO, and PM2.5. Phase 2 - Site

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Preparation: Clearing and Grubbing is estimated to generate the highest maximum daily emissions of PM10.

Table 11: Localized Significance Analysis (Construction)

Activity (year) Onsite Emissions (pounds per day)

NOX CO PM10 PM2.5 Phase 1 - Preconstruction Monitoring Water Quality 3.74 1.33 0.13 0.13 Wildlife 10.02 3.86 0.36 0.36 Sediment 6.68 2.57 0.24 0.24 Phase 2 - Site Preparation Clearing and Grubbing 120.08 43.98 14.84 6.93 Grading 34.17 13.85 6.6 2.65 Geotech Boring 26.71 11.57 3.56 2.29 Phase 3 - Infrastructure Construction Grading 76.44 31.49 8.98 5.62 Pipeline 33.17 16.55 1.73 1.73 Re-entrainment 16.04 7.48 0.63 0.63 Phase 4 - Sediment Removal Option 1: Dredge 90.39 49.01 3.73 3.73 Phase 5 - Sediment Re-entrainment Sediment Re-entrainment 134.22 64.50 9.20 7.44 Phase 6 Monitoring, Mitigation and Site Restoration Monitoring 17.76 7.51 0.61 0.61 Mitigation 101.91 47.34 6.31 5.04 Site Restoration 45.84 18.48 12.22 4.31 Maximum Daily Emissions 134.221 64.501 14.842 7.441 Localized Significance 378 5,183 81 25 Threshold Exceed Threshold? No No No No Notes: 1. From Phase 5- Sediment Re-entrainment: Sediment Re-entrainment (2015) 2. From Phase 2 - Site Preparation: Clearing and Grubbing (2014) NOX = nitrogen oxides CO = carbon monoxide PM10 and PM2.5 = particulate matter Phases are assumed to not overlap; therefore, the maximum daily emissions are from the highest representative phase. Source of emissions: FCS 2013. Source of thresholds: South Coast Air Quality Management District 2009, for SRA 22, 200 meters, 2-acre site.

The localized construction analysis uses thresholds that represent the maximum project emissions that will not cause or contribute to an exceedance of the most

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-19 Section 3 Environmental Analysis stringent applicable federal or state ambient air quality standard. If the project results in emissions that do not exceed the localized significance thresholds, it follows that those emissions will not cause or contribute to a local exceedance of the appropriate ambient air quality standard. The localized construction analysis demonstrates that the Project will not exceed the localized significance thresholds for CO, nitrogen dioxide, PM10, or PM2.5. Therefore, the Project will not violate any air quality standard or contribute substantially to an existing or projected air quality violation during construction. Carbon Monoxide Hot Spot Analysis Carbon monoxide (CO) “hot spot” thresholds ensure that emissions of CO associated with traffic impacts from a project in combination with CO emissions from existing and forecasted regional traffic do not exceed state or federal standards for CO at any traffic intersection impacted by the project. Project concentrations may be considered significant if a CO hot spot intersection analysis determines that project generated CO concentrations cause a localized violation of the state CO 1-hour standard of 20 ppm, state CO 8-hour standard of 9 ppm, federal CO 1-hour standard of 35 ppm, or federal CO 8-hour standard of 9 ppm. Localized high levels of CO are associated with traffic congestion and idling or slow-moving vehicles. To provide a worst-case scenario, CO concentrations are estimated at project-impacted intersections, where the concentrations will be the greatest. The Project consists of construction and monitoring activities for a short-term sediment management demonstration project. The majority of soils and material hauling will occur within the project site and will not contribute to on- road vehicular traffic. In addition, the Project will not generate operational vehicular trips. On-road trips associated with the Project will be primarily generated by construction employees. This analysis follows the recommended CO Protocol guideline of the SCAQMD. According to the CO Protocol, intersections with Level of Service (LOS) E or F require detailed analysis. In addition, intersections that operate under LOS D conditions in areas that experience meteorological conditions favorable to CO accumulation require a detailed analysis. The SCAQMD recommends that a local CO hot spot analysis be conducted if the intersection meets one of the following criteria: 1) the intersection is at LOS D or worse and where the project increases the volume to capacity ratio by 2 percent or 2) the project decreases LOS at an intersection from C to D. The Project will not affect the LOS of intersections in the project area. Therefore, the Project will not significantly contribute to a CO hotspot.

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Level of significance before mitigation Less than significant impact. Mitigation Measures No mitigation is required. Level of significance after mitigation Less than significant impact. IMPACT AIR-3: Will the Project result in a cumulatively considerable net increase of any criteria pollutant for which the project region is nonattainment under an applicable national or state ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors)? To result in a less than significant impact, the following criteria must be true: 1. Regional analysis: emissions of nonattainment pollutants must be below the regional significance thresholds. 2. Summary of projections: the project must be consistent with current air quality attainment plans including control measures and regulations. 3. Cumulative health impacts: the project must result in less than significant cumulative health effects from the nonattainment pollutants. Step 1: Regional Analysis If an area is in nonattainment for a criteria pollutant, then the background concentration of that pollutant has historically exceeded the ambient air quality standard. It follows that if a project exceeds the regional threshold for that nonattainment pollutant, then it will result in a cumulatively considerable net increase of that pollutant and result in a significant cumulative impact.

The South Coast Air Basin is in nonattainment for PM10, PM2.5, nitrogen dioxide, and ozone. Therefore, if the project exceeds the regional thresholds for PM10, or PM2.5, then it contributes to a cumulatively considerable impact for those pollutants. If the project exceeds the regional threshold for NOX or VOC, then it follows that the project will contribute to a cumulatively considerable impact for

ozone. If the project exceeds the NOX threshold, it could contribute cumulatively to nitrogen dioxide concentrations. Regional emissions include those generated from all onsite and offsite activities. Regional significance thresholds have been established by the SCAQMD

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because emissions from projects in the Basin can potentially contribute to the existing emission burden and possibly affect the attainment and maintenance of ambient air quality standards. Projects within the South Coast Air Basin region with regional emissions in excess of any of the thresholds presented in Table 12 (for construction) are considered to have a significant regional air quality impact. Construction Regional Emissions Table 12 summarizes construction-related emissions without mitigation. The information shown in Table 12 indicates that the SCAQMD regional emission

thresholds will be exceeded for NOX emissions during 3 separate phases of construction. Specifically, the NOX threshold will be exceeded during: Phase 2 - Site Preparation Phase 5 - Sediment Re-entrainment Phase 6I – Monitoring and Site Restoration Therefore, without mitigation, the short-term construction emissions are considered to have a potentially significant regional impact.

Table 12: Regional Construction Air Pollutant Emissions

Source Emissions (pounds per day)

VOC NOX CO SOX PM10 PM2.5 Phase 1- Preconstruction Monitoring Water Quality 0.48 3.78 1.76 0.01 0.21 0.14 Wildlife 1.38 10.13 5.18 0.02 0.89 0.38 Sediment 0.91 6.74 3.23 0.01 0.38 0.25 Phase 2- Site Preparation Clearing and Grubbing 15.30 120.58 49.93 0.18 16.09 7.03 Grading 4.41 34.31 15.57 0.05 6.96 2.68 Geotech Boring 3.36 26.8 12.63 0.03 3.78 2.31 Phase 3- Infrastructure Construction Grading 9.32 76.66 34.13 0.09 9.54 5.66 Pipeline 4.47 33.34 18.53 0.04 2.15 1.76 Re-entrainment 2.04 16.13 8.54 0.02 0.85 0.65 Phase 4 Sediment Removal Option 1: Dredge 10.62 90.77 53.60 0.14 4.79 3.81 Phase 5 Sediment Re-entrainment Sediment Re- 15.13 134.47 67.52 0.20 9.89 7.49 entrainment

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Phase 6 Monitoring and Site Restoration Monitoring 2.15 17.76 7.51 0.06 0.61 0.61 Site Restoration 15.47 102.32 52.44 0.20 7.56 5.14 Site Restoration 6.20 46.05 21.09 0.08 12.86 4.36 Maximum Daily 15.47 134.47 67.52 0.20 16.09 7.49 Emissions Significance Threshold 75 100 550 150 150 55 Significant Impact? No Yes No No No No

Notes: Activities within each phase are assumed to not overlap; therefore, the maximum daily emissions are from the highest representative Activity. VOC = volatile organic compoundsNOX = nitrogen oxides CO = carbon monoxide SOX = sulfur oxides PM10 and PM2.5 = particulate matter Source of emissions: Appendix A: CalEEMod Output. Table 13 provides the project’s emissions after application of Mitigation Measure AIR-1. Table 13 contains only those construction phases that were identified as having a potentially significant impact.

Table 13: Mitigated Construction Air Pollutant Emissions

Source Emissions (pounds per day)

VOC NOX CO SOX PM10 PM2.5 Phase 2- Site Preparation Clearing and Grubbing 13.43 90.14 83.66 0.18 16.47 7.41 Phase 5 - Sediment Re-entrainment Sediment Re- 13.91 91.42 100.84 0.2 10.04 7.82 entrainment Phase 6- Monitoring, Mitigation and Site Restoration Site Restoration 15.9 97.11 101.71 0.2 9.39 6.97 Maximum Daily 15.9 97.11 101.71 0.2 10.04 7.82 Emissions Significance Threshold 75 100 550 150 150 55 Significant Impact? No No No No No No The maximum daily emissions refer to the maximum emissions that would occur in one day; therefore, their emissions are not summed. VOC = volatile organic compounds NOX = nitrogen oxides CO = carbon monoxide SOX = sulfur oxides PM10 and PM2.5 = particulate matter Source of emissions: Appendix A: CalEEMod Output. Source of thresholds: South Coast Air Quality Management District 2011a.

Step 2: Plan Approach In accordance with CEQA Guidelines 15130(b), this analysis of cumulative impacts is based on a summary of projections analysis. This analysis considers the current CEQA Guidelines, which includes the recent amendments approved

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by the Natural Resources Agency and effective on March 18, 2010. This analysis is based on the 2003 and 2007 AQMPs. The South Coast Air Basin is in

nonattainment for ozone, particulate matter (PM10 and PM2.5), and nitrogen dioxide, which means that concentrations of those pollutants currently exceed the ambient air quality standards for those pollutants. When concentrations of ozone,

PM10, PM2.5, and nitrogen dioxide exceed the ambient air quality standard, then those sensitive to air pollution (i.e., children, elderly, sick) could experience adverse health effects. Under the amended CEQA Guidelines, cumulative impacts may be analyzed using other plans that evaluate relevant cumulative effects. The AQMPs describe and evaluate the future projected emissions sources in the South Coast Air Basin and sets forth a strategy to meet both state and federal Clean Air Act planning requirements and federal ambient air quality standards. Therefore, the AQMPs are relevant plans for a CEQA cumulative impacts analysis. The 2003 AQMP updates the attainment demonstration for the federal standards for ozone

and PM10; replaces the 1997 attainment demonstration for the federal CO standard and provides a basis for a maintenance plan for CO for the future; and updates the maintenance plan for the federal nitrogen dioxide standard that the South Coast Air Basin has met since 1992. The 2007 AQMP focuses on ozone

and PM2.5. The AQMP also incorporates significant new scientific data, emission inventories, ambient measurements, control strategies, and air quality modeling. The geographic scope for cumulative criteria pollution from air quality impacts is the South Coast Air Basin, because that is the area in which the air pollutants generated by the sources within the basin circulate and are often trapped. The SCAQMD is required to prepare and maintain an AQMP and a State Implementation Plan to document the strategies and measures to be undertaken to reach attainment of ambient air quality standards. While the SCAQMD does not have direct authority over land use decisions, it is recognized that changes in land use and circulation planning are necessary to maintain clean air. The SCAQMD evaluated the entire Basin when it developed the AQMP. In accordance with CEQA Guidelines section 15064, subdivision (h) (3), a lead agency may determine that a project’s incremental contribution to a cumulative effect is not cumulatively considerable if the project complies with the requirements in a previously approved plan or mitigation program. The Project will comply with the control measures in the 2003 and the 2007 AQMP and all of the SCAQMD’s applicable rules and regulations. However, because the Project exceeds the SCAQMD’s CEQA significance thresholds, the analysis contained in Impact AIR-1 demonstrates that the Project is not consistent with the most recent AQMP and State Implementation Plan without mitigation. Therefore, the Project

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presents a significant impact according to this criterion. Implementation of Mitigation Measure AIR-1 is required to reduce the impact to less than significant. Step 3: Cumulative Health Impacts

The Basin is in nonattainment for ozone, nitrogen dioxide, PM10, and PM2.5, which means that the background levels of those pollutants are at times higher than the ambient air quality standards. The air quality standards were set to protect public health, including the health of sensitive individuals (such as the elderly, children, and the sick). Therefore, when the concentration of those pollutants exceeds the standard, it is likely that some sensitive individuals in the population will experience health effects. However, the health effects are a factor of the dose-response curve. Concentration of the pollutant in the air (dose), the length of time exposed, and the response of the individual are factors involved in the severity and nature of health impacts. If a significant health impact results from project emissions, it does not mean that 100 percent of the population would experience health effects. The regional analysis indicates that without mitigation, the Project will exceed the

SCAQMD regional significance thresholds for NOx (an ozone precursor). Because ozone is a secondary pollutant (it is not emitted directly but formed by chemical reactions in the air), it can be formed miles downwind of the project site.

Project emissions of VOC and NOx may contribute to the background concentration of ozone and cumulatively cause health effects. Implementation of Mitigation Measure AIR-1 is required to reduce the impact to less than significant. Level of significance before mitigation Potential significant impact. Mitigation Measures Mitigation Measure AIR-1 is required. Level of Significance after Mitigation Less than significant impact. IMPACT AIR-4: Will the Project expose sensitive receptors to substantial pollutant concentrations? For purposes of CEQA, the SCAQMD considers a sensitive receptor to be a location where a sensitive individual could remain for 24 hours, such as residences, hospitals, or convalescent facilities. Commercial and industrial facilities are not included in the definition because employees do not typically remain onsite for 24 hours. However, when assessing the impact of pollutants with 1-hour or 8-hour standards (such as nitrogen dioxide and carbon monoxide),

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commercial and/or industrial facilities will be considered sensitive receptors for those purposes. Localized Significance Threshold Analysis The localized construction analysis demonstrated that the Project will not exceed

the localized thresholds for CO, nitrogen dioxide, PM10, or PM2.5. Therefore, during construction, the Project will not expose sensitive receptors to substantial

pollutant concentrations of CO, nitrogen dioxide, PM10, or PM2.5. Criteria Pollutant Analysis

Emissions of NOX and VOC (ozone precursors) during construction from only the Project will not expose sensitive receptors to substantial pollutant concentrations. CO analysis The CO hotspot analysis demonstrated that emissions of CO during operation of the Project will not result in an exceedance of the most stringent ambient air quality standards for CO. The standards are set to protect the health of sensitive individuals. If the standards are not exceeded, then the sensitive individuals will not be significantly impacted. The Project will not generate or substantially contribute to a CO hotspot. Therefore, according to this criterion, air pollutant emissions during operation will result in a less than significant impact. Toxic Air Pollutants - Onsite Workers There are a variety of state and national programs that protect workers from safety hazards, including high air pollutant concentrations. Onsite workers are not required to be addressed through this health risk assessment process. A document published by the California Air Pollution Control Officers Association (CAPCOA, 2009), Health Risk Assessments for Proposed Land Use Projects, indicates that onsite receptors are included in risk assessments if they are persons not employed by the project. Persons not employed by the project will not remain onsite for any significant period. Therefore, a health risk assessment for onsite workers is not required or recommended. Toxic Air Pollutants - Construction The construction equipment will emit diesel particulate matter, which is a carcinogen. However, the diesel particulate matter emissions are short-term in nature. Determination of risk from diesel particulate matter is considered over a 70-year exposure time. Guidance published by the CAPCOA (2009), Health Risk Assessments for Proposed Land Use Projects, does not include guidance for health risks from construction projects addressed in CEQA; risks near

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construction projects are expected to be included later when the toxic emissions from construction activities are better understood. Additionally, the nearest sensitive receptors (residences) will be located approximately 400 meters from the project site. Therefore, considering the dispersion of the emissions and the short time frame, exposure to diesel particulate matter is anticipated to be less than significant. Level of significance before mitigation Less than significant impact. Mitigation Measures No mitigation is required. Level of Significance after Mitigation Less than significant impact. IMPACT AIR-5: Will the project create objectionable odors affecting a substantial number of people? Odors can cause a variety of responses. The impact of an odor results from interacting factors such as frequency (how often), intensity (strength), duration (in time), offensiveness (unpleasantness), location, and sensory perception. Odor is typically a warning system that prevents animals and humans from consuming spoiled food or toxic materials. Odor-related symptoms reported in a number of studies include nervousness, headache, sleeplessness, fatigue, dizziness, nausea, loss of appetite, stomach ache, sinus congestion, eye irritation, nose irritation, runny nose, sore throat, cough, and asthma exacerbation. The SCAQMD’s role is to protect the public’s health from air pollution by overseeing and enforcing regulations. The SCAQMD’s resolution activity for odor compliance is mandated under California Health & Safety Code Section 41700, and falls under SCAQMD Rule 402. This rule on Public Nuisance Regulation states: “A person shall not discharge from any source whatsoever such quantities of air contaminants or other material which cause injury, detriment, nuisance, or annoyance to any considerable number of persons or to the public, or which endanger the comfort, repose, health or safety of any such persons or the public, or which cause, or have a natural tendency to cause, injury or damage to business or property. The provisions of this rule shall not apply to odors emanating from agricultural operations necessary for the growing of crops or the raising of fowl or animals.”

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Project Analysis The SCAQMD recommends that odor impacts be addressed in a qualitative manner. Such an analysis will determine whether the project will result in excessive nuisance odors, as defined under the California Code of Regulations and Section 41700 of the California Health and Safety Code, and thus will constitute a public nuisance related to air quality. Land uses typically considered associated with odors include wastewater treatment facilities, waste-disposal facilities, or agricultural operations. The Project does not contain land uses typically associated with emitting objectionable odors. Diesel exhaust and VOCs will be emitted during construction of the Project, which can be objectionable to some individuals; however, emissions will disperse rapidly from the project site and therefore should not reach an objectionable level at the nearest sensitive receptors. Level of significance before mitigation Less than significant impact. Mitigation Measures No mitigation is required. Level of significance after mitigation Less than significant impact.

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3.3 BIOLOGICAL RESOURCES The following analysis is based on an Existing Biological Conditions Report prepared for the Prado Basin Sediment Management Demonstration Project by the Orange County Water District Natural Resource Department in January of 2013. The Existing Biological Conditions Report is presented in Appendix C. 3.3.1 Regulatory Framework The following federal, state and regional regulatory programs are applicable to the Project. Federal Regulations Federal Endangered Species Act The Federal Endangered Species Act (FESA) designates threatened and endangered animals and plants and provides measures for their protection and recovery. The Take of listed animal and plant species in areas under the federal jurisdiction is prohibited without obtaining a federal permit. A Take is defined as to harass, harm, pursue, hunt, shot, wound, kill, trap, capture or collect or attempt to engage in any such conduct. Harm includes any act which kills or injures fish or wildlife, including significant habitat modification or degradation that significantly impairs essential behavioral patterns of fish or wildlife. Activities that damage the habitat of listed species require approval from U.S. Fish and Wildlife Service (USFWS) for terrestrial species or from National Marine Fisheries Service (NMFS) for marine species. FESA also requires determination of critical habitat for listed species and impacts to the critical habitat is prohibited. ESA contains two pathways for obtaining permission to take listed species. Under Section 7 of FESA, a federal agency that authorizes, funds or carries out a project that may affect a listed species or its critical habitat must consult with USFWS or NMFS, to ensure that their actions do not jeopardize the continued existence of endangered or threatened species or result in the destruction or modification of the critical habitat of these species. A Biological Opinion (BO) will be prepared by USFWS or NMFS to determine if the activity will jeopardize the continued existence of the listed species. If the BO determines that the activity will not threaten the existence of the listed species and a no jeopardy opinion is provided, then the project may proceed. If the BO finds that the project will result in jeopardy to the listed species (jeopardy opinion), then reasonable and prudent measures will need to be incorporated into the project to reduce potential effects to a level that will not be likely to jeopardize the continued existence of the species. Under Section 10 of FESA private parties with no federal nexus may obtain an Incidental Take Permit to harm listed wildlife species incidental to the lawful

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operation of a project. To obtain an Incidental Take Permit, the applicant must develop a habitat conservation plan that specifies impacts to listed species, provides minimization and mitigation measures and alternatives to minimize impacts. If USFWS finds that the habitat conservation will not appreciably reduce the likelihood of the survival and recovery of the species, USFWS will issue an incidental take permit. Critical Habitat The Federal Endangered Species Act (FESA) requires the federal government to designate “critical habitat” for any species it lists under the FESA. “Critical habitat” is defined as: (1) specific areas within the geographical area occupied by the species at the time of listing, if they contain physical or biological features essential to conservation, and those features may require special management considerations or protection; and (2) specific areas outside the geographical area occupied by the species if the agency determines that the area itself is essential for conservation. Critical habitat designations must be based on the best scientific information available, in an open public process, within specific timeframes. Before designating critical habitat, careful consideration must be given to the economic impacts, impacts on national security, and other relevant impacts of specifying any particular area as critical habitat. The Secretary of Commerce may exclude an area from critical habitat if the benefits of exclusion outweigh the benefits of designation, unless excluding the area will result in the extinction of the species concerned. The FESA protects threatened and endangered species in several ways. Under Section 7, all federal agencies must ensure that any actions they authorize, fund, or carry out are not likely to jeopardize the continued existence of a listed species, or destroy or adversely modify its designated critical habitat. These complementary requirements apply only to federal agency actions, and the latter only to habitat that has been designated. A critical habitat designation does not set up a preserve or refuge, and applies only when federal funding, permits, or projects are involved. Critical habitat requirements do not apply to citizens engaged in activities on private land that do not involve a federal agency. Federal Clean Water Act The Clean Water Act is intended to restore and maintain the quality and biological integrity of Waters of the United States (U.S.) According to Section 404 of the Clean Water Act, any activity that involves the discharge of dredged or fill material into Waters of the United States is subject to approval of a 404 Permit from the U.S. Army Corps of Engineers (Corps). Depending on the level of

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-30 Section 3 Environmental Analysis impacts occurring, an activity affecting waters of the U.S. could qualify for one of fifty two separate Nationwide Permits or requires approval of an individual permit. Section 401 of the Clean Water Act requires that an applicant for a federal license or permit to discharge into navigable waters must provide the federal agency with a water quality certification, declaring that the discharge will comply with water quality standards requirements of the Clean Water Act. The issuance of a 404 permit triggers the requirement that a section 401 certification must also be obtained from the Regional Water Quality Control Board (RWQCB). Migratory Bird Treaty Act The Migratory Bird Treaty Act implements international treaties between the United States and other nations that protect migratory birds, including their nests and eggs, from killing, hunting, pursuing, capturing, selling and shipping unless expressly authorized or permitted. State Regulations California Environmental Quality Act The California Environmental Quality Act (CEQA) was enacted in 1970 to provide for full disclosure of environmental impacts before issuance of a permit by a state or local public agency. In addition to state and federally listed species, sensitive plants and animals receive consideration under CEQA. Sensitive species include Wildlife Species of Special Concern listed by CDFG and plant species on the California Native Plant Society list 1A, 1B or 2. California Endangered Species Act The California Endangered Species Act (CESA) provides protection and prohibits the take of plant, fish and wildlife species listed by the State of California. Unlike FESA, state-listed plants have the same degree of protection as wildlife. A Take is defined similarly to FESA and it is prohibited for both listed and candidate species. Take authorization may be obtained from the California Department of Fish and Wildlife (CDFW) under Section 2091 and 2081 of CESA. Section 2091 of CESA, similar to Section 7 of FESA provides for consultation between a state lead agency under the California Environmental Quality Act and CDFW, with issuance of take authorization if the project does not jeopardize the listed species. Section 2081 of CESA allows take of a listed species for educational, scientific or management purposes. California Fish and Game Code Section 1600 The State of California defines Waters of the State as any surface water or groundwater, including saline waters within the boundaries of the State. In

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accordance with Section 1600 of the Fish and Game Code, CDFW must be notified prior to beginning any activity that will obstruct or divert the natural flow of, use material from or deposit or dispose of material into a river, stream, or lake, whether permanent, intermittent or ephemeral water bodies. The notification occurs through the issuance of a Streambed Alteration Agreement. CDFW has 60 days to review the proposed actions and propose measures to protect affected fish and wildlife resources. The final proposal that is mutually agreed upon by CDFW and the applicant is the Streambed Alteration Agreement. California Fish and Game Code Fully Protected Species The legislature of the State of California designated species as fully protected prior to the creation of the California Endangered Species Act. Most fully protected species have since been listed as threatened or endangered under California Endangered Species Act and/or the Federal Endangered Species Act. These species may not be taken or possessed at any time, with the only exception being permits issued for limited scientific study. California Fish and Game Code Sections 3503, 2505, 3513, 3800, 3801 These California Fish and Game Code Sections protect all birds, birds of prey and all non-game birds, as well as their eggs and nests, for species that are not already listed as fully protected and that occur naturally within the State. Specifically, it is unlawful to take any raptors or their nests and eggs. Regional Resource Planning Programs Natural Community Conservation Planning Act (NCCP) The Natural Community Conservation Planning Act (NCCP) Act of 1991, codified in Fish and Game Code Sections 2800-2840, authorizes the preparation of Natural Community Conservation Plans. The NCCP Act provides for regional planning to conserve listed and candidate species, their habitats and natural communities through habitat-based conservation measures while allowing economic growth and development. Under the NCCP Act, CDFW is responsible for implementing conservation guidelines for NCCP Programs. Local governments and landowners may then prepare the NCCP so they can comply with both the Federal and State Endangered Species Acts. The applicable Natural Community Conservation Planning Program that will apply to the project area is the Western Riverside County Multiple Species Habitat Conservation Plan.

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3.3.2 Existing Environmental Setting Regional Setting The project area is located within the Santa Ana River Watershed. The Santa Ana River Watershed encompasses over 2,650 square miles of varying terrain, which includes portions of San Bernardino, Riverside, and Orange Counties. The primary water body in the watershed is the Santa Ana River which extends over 100 miles long and consists of over 50 contributing tributaries. The headwaters for the Santa Ana River and its tributaries originate in the San Gabriel and San Bernardino Mountains to the north and the San Gorgonio and San Jacinto Mountains to the east. The river drains southwest into the Prado Basin, where it is impounded for flood control and water conservation purposes. The impounded water at the dam is released to downstream segments of the Santa Ana River, where it is used to help replenish the Orange County Groundwater Basin. The proposed Sediment Management Demonstration Project will be implemented within the Prado Basin. The biological setting in the Prado Basin is significantly influenced by the presence of Prado Dam. Prado Dam is situated where Chino Creek, Mill Creeks and Temescal Wash meet with the Santa Ana River. As a result of a combination of high groundwater, storm flow accumulation held in the reservoir, ongoing sewage treatment plant effluent and irrigation runoff, perennial flows occur throughout much of the Prado Basin. The presence of the dam has caused vast potions of the Prado Basin to remain inundated with water for long periods of time. The extended periods of inundation has significantly influenced the type of vegetation and wildlife that occurs in the Prado Basin. The presence of the dam has also caused a buildup of sediment in the basin and has converted a once rock cobble substrate of the Santa Ana River to an almost entirely sandy bottom substrate. Additionally, the buildup of sediment has been consistent with an increase in the amount of non-native vegetation and has reduced the quality of existing native aquatic habitat in the Prado Basin. Prado Basin consists of a wide mixture of biological resources and habitats, including; cottonwood/willow riparian forest, riparian scrub, herbaceous riparian, freshwater ponds, freshwater marsh, and riverine. Riparian forest is the most dominant wetland habitat in the Prado Basin. The dominant plant species within the riparian forest are black willow, (Salix goodingii), arroyo willow (Salix lasiolepis), Freemont cottonwood, (Populus fremontii) eucalyptus, sycamore (Platanus recemosa), and mulefat (Baccharis salicifolia). The riparian habitat within Prado Basin is a dynamic community that is dependent upon periodic flooding. Winter flows create areas of scour and sedimentation that cycle the community back to earlier successional stages. Periodic floods of large magnitude and migration of the river channel lay down

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-33 Section 3 Environmental Analysis fresh alluvial deposits where seeds can germinate and plant roots can take hold. The basin contains an expansive riparian forest. At lower elevations in the basin, the riparian forest coverage is nearly complete with an overstory of trees reaching as high as 50 feet and an understory of both native vegetation and non- native vegetation. At the higher elevations in the basin the forest is patchier and the understory consists of more non-native vegetation. The riparian forest in the Prado Basin contains an abundance and diversity of bird species. Neotropical migrants depend on deciduous trees and shrubs for foraging during migration. The mature trees provide numerous cavities for cavity dependent wildlife and the taller trees are used by nesting raptors. The emergent vegetation at the water’s edge provides escape cover, shade and a source of food for fish. The basin supports a wide variety of mammal, amphibian and reptile species, several of which are biologically significant. Additionally, the Santa Ana River and the Prado Basin function as a wildlife movement corridor to and from the Chino Hills. Biological Resources Vegetation Communities As shown in Figure 5 the project area is located on USGS Quadrangle maps for the Prado Dam and North Corona. The project area contains a diverse assemblage of vegetation communities. For mapping purposes similar vegetation types were grouped together under one classification. The vegetation classifications identified within the project area include: Cottonwood/Willow, Mixed Riparian, Coastal Sage Scrub, Mixed Coastal Sage Scrub, Non-Native Grasslands/Weeds, Arundo, Eucalyptus, and Open Water. To further define Cottonwood/Willow area, the classification distinguishes if it has either native vegetation understory or non-native vegetation understory.

The vegetation communities at the sediment removal channel alignment and sediment storage sites are shown on Figure 6 and Figure 7. A statistical summary of vegetation communities at the sediment removal channel and sediment storage site is shown in Table 14. The description of each vegetation classification and a listing of the plant species that can be found in each vegetation community are presented in Table 14.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-34 117°39'0"W 117°38'30"W 117°38'0"W 117°37'30"W 117°37'0"W

A« 33°54'0"N 33°54'0"N Sediment Removal Channel

Green Waste Site

33°53'30"N Sediment Storage 33°53'30"N Site E

K:\Prado\SedimentManagementPlan\MXD\EIR2014\F5_USGS_Topo.mxd Sediment AÆ Re-entrainment Area

33°53'0"N 33°53'0"N

117°39'0"W 117°38'30"W 117°38'0"W 117°37'30"W 117°37'0"W Prado Basin SMDP 0 800 1,600 Proposed Project Areas Proposed Access Roads Feet USGS Location Figure 5 Santa Ana River

498

505

8 9 490 4 498 494 498 498

K:\Prado\SedimentManagementPlan\MXD\EIR2014\F6_SAR_Align_Habitat.mxd

Buffer Area Eucalyptus Arundo Aquatic 0 300 600 Prado Basin SMDP Cottonwood / Willow Cottonwood / Willow Feet Mixed Riparian Area of Impact with Native Understory with Non-Native Understory Sediment Removal Channel

Water Conservation Elevations data source: Army Corp of Engineers 2008 Elevations are referenced to Vertical Datum NGVD 29 Aerial Imagery Eagle Aerial Spring 2012 Figure 6 Sediment Removal Channel

Sediment Storage Site E / Green Waste Site

?£

Sediment Re-entrainment Area

AÆ

K:\Prado\SedimentManagementPlan\MXD\EIR2014\F7_StorageArea_Habitat.mxd Sediment Storage/ Cottonwood / Willow Green Waste Sites with Native Understory Aquatic Disturbed Oak Tree Prado Basin SMDP 0 300 600 Coastal Sage Non-Native Mixed Sediment Management Storage Eucalyptus Feet Scrub Restoration Grasses / Weeds Riparian 50/50 Arundo Site E Aerial Imagery Eagle Aerial Spring 2012 Figure 7 Section 3 Environmental Analysis

Table 14: Vegetation/Land Cover (Acres) SAR Sediment Storage Site E Channel Alignment Cottonwood/Willow-Native Understory 11.45(1) 0 Cottonwood/Willow-Non-Native Understory 10.85(1) 0 Mixed Riparian 0 3.64 Coastal Sage Scrub 0 0 Mixed Coastal Sage Scrub /Non-Native 0 4.61 Grasses/Weeds Non-Native Grasslands/Weeds 0 37.50 Arundo 12.16 0 Eucalyptus 1.25 0 Open Water 3.58 0 Total 39.31 45.75 (1)Includes 1.75 acres Impacts for access roads

Cottonwood/Willow-Native Understory: The Cottonwood/Willow classification has been designated on lands that consist predominately of Fremont cottonwood (Populus fremontii), black willow (Salix gooddingii), with minor components of arroyo willow (Salix lasiolepis), narrow-leaf willow (Salix exigua) and western sycamore (Platanus racemosa). This classification includes an understory that consists of 50 percent of cover or greater of native vegetation. Native vegetation understory includes: cocklebur (Xanthium strumarium), wild grape (Vitis girdiana), Beggar’s Ticks (Bidens frondosa) and mulefat (Baccharis salicifolia). Cottonwood/Willow-Non-Native Understory: The Cottonwood/Willow classification has been designated on lands that consist predominately of Fremont cottonwood (Populus fremontii), black willow (Salix gooddingii), with minor components of arroyo willow (Salix lasiolepis), narrow-leaf willow (Salix exigua) and western sycamore (Platanus racemosa). This classification includes an understory that consists of 50% of cover or greater of non-native vegetation. Non-native vegetation understory includes: Arundo (Arundo donax), Pepperweed (Lepidium latifolium) and Tamarisk (Tamarix ramossima). Mixed Riparian: The Riparian Mixed classification has been applied to lands that consist of a mixture of riparian vegetation. Riparian Mixed vegetation within the project area consists of mulefat (Baccharis salicifolia), elderberry (Sambucus mexicana), cocklebur (Xanthium) and strands of black willow and arroyo willow. Coastal Sage Scrub: The Coastal Sage Scrub classification has been applied to areas that consist of 90% of cover or greater of coastal sage scrub vegetation. The Coastal Sage Scrub Series includes California sagebrush (Artemisia californica), California bush sunflower (Encelia californica), California buckwheat (erigonum fasciculatum), black sage (Salvia mellifera) and white sage (Salvia apiana).

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Mixed Coastal Sage Scrub /Non-Native Grasses/Weeds: The Mixed Coastal Sage Scrub /Non-Native Grasses/Weeds have been applied to areas that consist of approximately 50% cover of coastal sage scrub and 50% cover non-native grasses and weeds. The Coastal Sage Scrub Series includes California sagebrush (Artemisia californica), California bush sunflower (Encelia californica), California buckwheat (erigonum fasciculatum), black sage (Salvia mellifera) and white sage (Salvia apiana). Non-native grasses and non-native weeds includes; black mustard (Brassica nigra), poison hemlock (Conium maculatum), starthistle (Centaurea spp.), and castor bean (Ricinus communis). Non-Native Grasses/Weeds: The Non-native grasslands and weeds classification has been designated on lands that consist of 90% cover or more of non-native grasses and non-native weeds. Non-native grasses and non-native weeds include; black mustard (Brassica nigra), poison hemlock (Conium maculatum), starthistle (Centaurea spp.), and castor bean (Ricinus communis). Eucalyptus: The Eucalyptus classification has been applied to lands that consist predominantly of Eucalyptus Trees, with less than 10% cover of other vegetation.

Arundo: The Arundo (Arundo donax) classification has been applied to lands that consist predominantly of Arundo, with less than 10 % cover of other vegetation. Open Water: The open water classification represents portion of the project area that consists of water bodies, including stream systems, pools and ponds with no significant emerging floating vegetation except along the edges where species such as cattail (Typha latifolia), bulrush (Scirpus), and smartweed (Polygonum lapathifolium) occur. Sensitive Communities/Special Status Plants A literature search conducted of the California Department of Fish and Wildlife Natural Diversity Database identified that there are two sensitive communities known to occur within the project area. These communities include; Southern Cottonwood Willow Riparian Forest and California Arroyo Chub/Santa Ana Sucker Stream. Below is a description of the sensitive vegetation communities and where they have been identified in the project area. Southern Cottonwood Willow Riparian Forest Southern cottonwood and willow riparian habitat is typically dominated by cottonwood and willow trees and shrubs with understory species such as mugwort, stinging nettle and wild cucumber. The riparian habitat is considered to be an early successional stage as the vegetation community is known to germinate almost exclusively on recently deposited or exposed alluvial soils. In

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-39 Section 3 Environmental Analysis

the absence of disturbance, this habitat type will transition to include oaks and sycamores or, at higher elevations, will include white alder. Within the project area the Southern Cottonwood Willow Riparian Forest is dominated by Black Willows. It occurs throughout the project area and has been mapped as either Cottonwood/Willow/Native Understory or Cottonwood/Willow/Non-Native Understory. Southern California Arroyo Chub/Santa Ana Sucker Perennial Stream Southern California Arroyo Chub/Santa Ana Sucker Stream habitats are defined as perennial streams that contain essential habitat elements for Santa Ana suckers and Southern California arroyo chubs. Both of these species tend to complement each other’s distributions within the Santa Ana River Watershed. Therefore, for purposes of defining habitat they are grouped together. Arroyo chubs prefer low gradient portions of streams with sand and mud substrates and often spawn in warmer water compared to the Santa Ana sucker. Santa Ana suckers are found in higher elevations and higher gradient portions of stream segments. The segment of the Santa Ana River within the Prado Basin does not contain the essential habitat elements to support populations of Santa Ana Suckers or Southern California Arroyo Chubs and therefore these areas would not be considered perennial stream habitat. Special Status Plant Species A review of the California Department of Fish and Wildlife California Diversity Data Base for the Prado Dam, and Corona North USGS Quadrangles was conducted to determine the potential for special status plant species to occur within the project area. A complete listing of special status plant species identified within both quadrangle areas and the potential for the species to occur within the project area is shown in Table 15. A combination of literature searches and field surveys conducted by OCWD Natural Resources Department were used to determine the potential for special status plant species to occur within the project area. The determination on the potential for the species to occur within the project area was based on the following criteria; Present: The species is commonly observed or observed within the project area within the last year. High: The project area supports suitable habitat and the species has been observed within last 5 years and within 5 miles of the project area Moderate: The project area supports suitable habitat and the species has not been observed within last 5 years and not within 5 miles of the project area.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-40 Section 3 Environmental Analysis

Low: The project area lacks suitable habitat for the species and/or the species has not been observed within last 10 years and not within 10 miles of project area.

Table 15: Sensitive Plant List Federal State CNPS MSHCP General Potential Occurrence Habitat Plants Chaparral NL NL 1B.2 NC Coastal Sage Low Potential. The nolina Scrub sediment removal (Nolina channel alignment and cismontane) the sediment storage site do not contain adequate amounts suitable habitat. Last reported 2004 Coal Canyon Ecological reserve Chaparral NL NL 1B.1 NC Coast Bluff Low Potential. The sand Scrub & sediment removal verbena Chaparral with channel alignment and (Abronia sandy soils. the sediment storage villosa var. Flowering site do not contain aurita) period adequate amounts January to suitable habitat. Species September. last reported 1933 in lower Santa Ana Canyon. Coulters NL NL 1B.1 NC Coastal Bluff Low Potential. The saltbrush Scrub, Strand, sediment removal (Atriplex Coastal Sage channel alignment and coulteri) Scrub, valley the sediment storage and foothill site do not support grass lands. adequate amount Flowering suitable habitat. Species period March last reported in 1917 to October. Chino Creek, south of City of Ontario. Intermediate NL NL 1B.2 C Chaparral, Low Potential. The mariposa lily Coastal Sage sediment removal (Calochortus Scrub, Valley channel alignment and weedii var. and Foothill the sediment storage ntermus) Grasslands. site not support Flowering adequate amount period May to suitable habitat. Species July. last reported in 1977 in Santa Ana Canyon. Jokerst’s NL NL 1B.1 NC Coniferous Low Potential. The monardella forests sediment removal channel alignment and the sediment storage site not support adequate amount

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-41 Section 3 Environmental Analysis

suitable habitat. Species last reported in 1952 3 miles south Chino Prison. Robinsons NL NL 1B.2 NC Coastal Sage Low Potential. Small pepper Scrub patch reported in 2010 at grass sediment storage site. (Lepidium Site has been weeded virginicum and replanted with var. riparian plants. Due to robinsonii) disturbed condition of site low potential for species to occur. Santa NL NL 1B.1 NC Coastal Low Potential. The Barbara Marshes sediment removal morning- channel alignment and glory the sediment storage (Calystegia site not support sepium ssp. adequate amount Binghamiae) suitable habitat. Single population reported in Chino in 2001. Smooth NL NL 1B.1 C Chenopod Low Potential. The tarplant scrub, sediment removal (Centromadi meadows and channel alignment and a pungens seeps, riparian sediment storage site do ssp. Laevis) woodlands not support adequate valley and amount of suitable foothill habitat. The Species last grasslands reported 1903 near City with alkaline of Ontario. soils. Flowering period April to September. Slender E E 1B.2 C Sandy places Low Potential. The horned Coastal Sage sediment removal Spineflower Scrub, channel alignment and (Dodecahem Chaparral, storage site do not a cismontane support adequate leptoceras) woodlands, amount habitat. Species stream banks last reported 2005, 1.5 and washes. miles east of Valley Vista Flowering and State Highway 74. period April to June. Many- NL NL 1B.2 C Coastal Sage Low Potential. The stemmed Scrub, sediment removal dudleya chaparral, channel alignment and (Dudleya Valley the sediment storage multicaulis) grasslands. site do not support Flowering adequate amount period April to suitable habitat. Species July. last reported 1983, .8 mile west of Prado Dam

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-42 Section 3 Environmental Analysis

along west facing slope of Santa Ana Canyon. Santa Ana E E 1B.1 C Sandy gravelly Low Potential. The River Soils on River sediment removal woollystar Floodplain. channel alignment and (Eriastrum Flowering the sediment storage densifolium period May to site do not support ssp. September. adequate amount Sanctorum) suitable habitat. Species last reported 1927 near Weir Canyon SR 91 exit. White rabbit NL NL 2.2 C Occurs in Low Potential. The tobacco sandy sediment removal (Pseudogna washes. channel alignment and phalium Flowering the sediment storage leucocephal period July to site do not support um) November. adequate amount suitable habitat. Species last reported 1928 near Historic Rancho Santa Ana Botanical Garden. Coulters NL NL 4.2 C Dry washes,, High Potential. Foothills matilija disturbed sage above sediment re- poppy scrub, entrainment area contain (Romneya chaparral and patches of coastal sage coulteria) often found in habitat. The species was burn areas. observed in 2009 after Flowering recent burn and is within period March known distribution area. to July. Salt Spring NL NL 2.2 NC Chaparral, Low Potential. The checkerbloo Coastal Scrub, sediment removal m lower montane channel alignment and (Sidalalcea conifer forest. the sediment storage neomexican) Flowering site do not support period March adequate amount to June. suitable habitat. Species was reported in 1917 in Chino Creek, south of City of Ontario. San NL NL 1B.2 NC Occurs in Low Potential. The Bernardino freshwater sediment removal aster Wetlands. channel alignment and (Symphyotri Flowering the sediment storage chum period July to site do not support defoliatum) November. adequate amount suitable habitat. Species last reported 1928 3 miles southeast City of Chino. Legend California Native Plant Society Multi-species Habitat (Conservation Plan C (MSHCP Federal CNPS C – covered E- Endangered 1A-Plants presumed extinct in NC – not covered T-Threatened California SSC- Special Species of Concern 1B- Plants rare, threatened, or C-Candidate for Listing endangered in California and NL-Not Listed elsewhere State Listing (California 2-Plants rare, threatened, or

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-43 Section 3 Environmental Analysis

Endangered Species Act, CDFG endangered in California but more FP-Fully Protected common elsewhere E-Endangered 3-Plants about which we need more T-Threatened review S-Sensitive 4-Plants of limited distribution SSC-Special Species of Concern CNPS Threat Rank WL-Watch List .1 Seriously Endangered NL-Not Listed .2 Fairly Endangered .3 Not Very Endangered

Special Status Plant Species with Moderate or Higher to Potential to Occur • Coulter’s Matilija Poppy The site nearest to the project area where Coulter’s Matilija Poppy was observed was in Chino Hills. The area is outside the construction activity impact area. Therefore, no direct or indirect impacts to Coulter’s Matilija Poppy will occur. MSHCP Narrow Endemic Plants According to the MSHCP, the project area is located within the Narrow Endemic Plant Survey Area for the following plant species. The MSHCP requires focused plant surveys be prepared to determine the presence of these species, if the project area supports suitable habitat. • Brand’s phacelia (Phacelia stellaris), • San Diego ambrosia (Ambrosia pumila), • San Miguel savory (Satureja chandleri). After review of the general habitat requirements for the plant species and the habitat conditions at the project area it was determined that there was low potential for the plant species to occur and no focused surveys are required. Therefore, no direct or indirect impacts to Brand’s phacelia, San Diego ambrosia and San Miguel savory will occur. Wildlife The following descriptions of general wildlife populations occurring in Prado Basin and environs are based on several biological studies that have been conducted within the Prado Basin over the last several years. These studies include general biological assessments prepared in association with the Corps SAR Mainstem Project, Western Riverside County Multiple Species Habitat Conservation Plan and annual bird surveys conducted by OCWD and Santa Ana Watershed Association. Avian Species Prado Basin contains a vast expanse of riparian habitat and associated bird populations. The Prado Basin area is extremely important to migratory bird species. In the spring, there is an influx of migratory passerines. In winter, there

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-44 Section 3 Environmental Analysis

are great numbers of wintering waterfowl and raptors. Over 175 different bird species have been observed within the Prado Basin. These species are closely associated with riparian and open-water habitats. Bird species known to occur in emergent willows and freshwater marsh areas, include; Red-winged blackbirds (Agelaius phoeniceus), marsh wrens (Cistothorus palustris), pied-billed grebes (Podilymbus podiceps), American avocet (Recurvirostra Americana), black-necked stilt (Himantopus mexicanus), killdeer (Charadrius vociferous), common yellowthroats (Geothlypis trichas), tricolored blackbirds (Agelaius tricolor), American bitterns (Botaurus lentiginosus), Virginia rails (Rallus limicola), common moorhens (Gallinula chloropus), acorn woodpecker (Melanerpes formicivorus), Nuttall’s woodpecker (Picoides nuttallii), Pacific-slope flycatcher (Empidonax difficilis), ash-throated flycatcher (Myiarchus cinerascens), oak titmouse (Parus inornatus), wrentit (Chamaea fasciata), orange-crowned warbler (Vermivora celata), lesser goldfinch (Carduelis psaltria), California quail (Callipepla californica), western wood-pewee (Contopus sordidulus), belted kingfishers (Ceryle alcyon) and northern rough-winged swallows (Stelgidopteryx serripennis). Bird species known to occur along the edge of the Prado Basin, within taller stands of willow trees and along the river where the canopy is thick, include; Least Bells vireo (Vireo Bellii pusillus), southwestern willow flycatcher (Empidonax traillii extimus), Yellow warblers (Dendroica petechia), yellow- breasted chats (Icteria virens), black phoebes (Sayornis nigricans), green herons (Butorides viresens), lazuli buntings (Passerina amoena), blue grosbeaks (Guiraca caerulea), great blue heron (Ardea herodias), double-crested cormorant (Phalacrocorax auritus), black-crowned night-heron (Nycticorax nycticorax), and tree swallows (Tachycineta bicolor). Species of ducks that are known to occur in the Prado Basin include; American coots (Fulica americana), ruddy ducks (Oxyura jamaicensis), mallards (Anas platyrhynchos), cinnamon teal (Anas cyanoptera), northern shovelers (Anas clypeata), northern pintail (Anas acuta), green-winged teal (Anas crecca), American widgeon (Anas Americana), and ring-necked duck (Aythya collaris). Along the edge of the reservoir, above the riparian habitat with low shrub lands, the following species are known to occur; the western meadowlark (Sturnella neglecta), horned lark (Eremophila alpestris), loggerhead shrikes (Lanius ludovicianus), California towhee (Pipilo crissalis), lesser goldfinch (Carduelis psaltria), bushtit, (Psaltriparus minimus) California thrasher (Toxostoma redivivum), spotted towhee (Pipilo erythrophthalmus), rufous-crowned sparrow (Aimophila ruficeps), Bewick’s wren (Thryomanes bewickii), California quail

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-45 Section 3 Environmental Analysis

(Callipepla californica), wrentit (Chamaea fasciata), lazuli bunting (Passerina amoena). Bird species known to occur in the Prado Basin woodlands include; the house wren (Troglodytes aedon), American goldfinch (Carduelis tristis), black-headed grosbeak (Pheucticus melanocephalus), brown-headed cowbird (Molothrus ater), downy woodpecker (Picoides pubescens), spotted towhee (Pipilo maculatus), mourning dove (Zenaida macroura), Bullock’s oriole (Icterus bullockii), American crow (Corvus brachyrhynchos), Bewick’s wren (Thryomanes bewickii), bushtit (Psaltriparus minimus), song sparrow (Melospiza melodia), western kingbird (Tyrannus verticalis), Cassin’s kingbird (Tyrannus vociferans), hooded oriole (Icterus cucullatus), Anna’s hummingbird (Calypte anna), house finch (Carpodacus mexicanus), European starling (Sturnus vulgaris), blue grosbeak (Passerina caerulea), ash-throated flycatcher (Myiarchus cinerascens), common yellowthroat (Geothlypis trichas), northern mockingbird (Mimus polyglottos), northern flicker (Colaptes auratus), yellow-rumped warblers (Dendroica coronata), White-crowned sparrow (Zonotrichia leucophrys), American pipets (Anthus rubescens), savannah sparrows (Passerculus sandwichensis), Say’s phoebes (Sayornis saya), western bluebirds (Sialia mexicana), and mountain bluebirds (Sialia currucoides). Raptors and birds of prey known to occur within the Prado Basin include; white- tailed kites (Elanus leucurus), red-shouldered hawks, (Buteo lineatus), red-tailed hawks (Buteo jamaicensis), , Cooper’s hawk (Accipiter cooperii), golden eagle (Aguila chrysaetos), turkey vulture (Cathartes aura), osprey (Pandion haliaetus) northern harrier (Circus cyaneus), sharp-shinned hawk (Accipiter striatus), ferruginous hawk (Buteo regalis), bald eagle (Haliaeetus leucocephalus), American kestrel (Falco sparverius), common barn owl (Tyto alba), western screech-owl (Otus kennicottii), great horned owl (Bubo virginianus), burrowing owl (Athene cunicularia ) and long-eared owl (Asio otus). Aquatic Species Historically, the Santa Ana River supported seven species of native freshwater fishes, a freshwater shrimp and a freshwater clam. Presently, only three native fishes, the Santa Ana sucker (Catostomus santaanae), Santa Ana speckled dace (Rhinichthys osculus) and the Arroyo chub (Gila orcutti) are known to occur in the Santa Ana River. The decline of the native fish population is attributed to the presence of predatory exotic fish, reduced and fragmented habitat and the presence of flood control structures and improvements that prevent downstream and upstream movement. Today, fish within the Santa Ana River largely consist of non-native fish species. Common species include carp (Cyprinus carpio), fathead minnow (Pimaphales), green sunfish (Lepomis cyanellus), largemouth

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-46 Section 3 Environmental Analysis

bass (Micropterus salmoides), yellow bullhead (Ameriurus natalis), channel catfish (Ictalurus ounctatus), tilapia (Oreochromis sp.), bluegill (lepomis macrochirus), threadfin shad (Dorosoma petenense), and the mosquito fish (Gambusia affinis). Amphibian Species Ten species of amphibians are known to occur in the Prado Basin. The most common native amphibians are the Pacific tree frogs (Pseudacris regilla) and western toad (Anaxyrus boreas). The most common non-native amphibian are the bullfrog (Bufo catesbeiana) and the African clawed frog (Xenopus laevis). Other amphibian species that may have occurred historically or are no longer present within the Prado Basin includes; ensatina (Ensatina eschescholtzii), black-bellied salamander (Batrachoseps nigriventris), Pacific slender salamander (Batracoseps pacifus), and western spade toad (Spea hammondii). The California red-legged frog (Rana aurora) was historically thought to occur within the Prado Basin, but has not been reported for many years. The last sighting of a red-legged frog was along the south shore of the Prado Basin in 1984. It is believed that the species has been extirpated, in large part due to competition with, and predation by bullfrogs. Reptile Species About 20 species of reptiles are known to occur in the Prado Basin and environs. The western fence lizard (Sceloporus occidentalis) and the side-blotched lizard (Uta stansburiana) are the two most commonly encountered reptile species. Other reptiles found in the study area include: coast horned lizard (Phrynosoma blainvillii), orange throated whiptail (Aspidoscelis hyperythra), silvery legless lizard (Anniella pulchra), western skink, (Piestiodon skiltonianus), southern alligator lizard (Elgaria multicannatus), western whiptail (Aspidoscelis tigris), racer (Coluber constrictor), coachwhip snake (Masticophis glagellum), California whip snake (Masticophis lateralis), gopher snake (Pituophis melanoleucus), common king snake (Lampropeltis getulus), night snake (Hypsiglena torquata), and Southern Pacific rattlesnake (Crotalus virdis). Three turtle species: the red- eared slider (Pseudodemys scripte), the southwestern pond turtle (Actinemys marmorata pallida), and the sprung soft shell (trionyx spuiforus) are known to occur in the Prado Basin. Mammal Species Large mammals known to occur within the Prado Basin and environs include fox (Urocyon cinereoargenteus), coyote (Canis latrans), bobcat (Lynx rufus), mountain lion (Puma concolor), and deer (Odocoileus hemionus). Small mammals known to occur within the Prado Basin include: broad-footed moles

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-47 Section 3 Environmental Analysis

(Scapanus latimanus), jackrabbits (lepus californicus bennettii), cottontail rabbit (Sylvilagus audubonii), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), California ground squirrel (Spermophilus beecheyi), Pacific kangaroo rat (Dipodomys agilis), California pocket mice (Chaetodipus californicus), white- footed mice (Peromyscus spp.), harvest mice (Reithrodontomys megalotis), voles (Microtus californicus), deer mice (peromysus maniculatus), house mice (mus musculus), and pocket gopher (Thomomys bottae).

Special Status Wildlife Species A review of the California Department of Fish and Wildlife California Diversity Data Base for the Prado Dam, and Corona North USGS Quadrangles was conducted to determine the potential for special status wildlife species to occur within the project area. A complete listing of sensitive wildlife species identified within both quadrangle areas and the potential for the species to occur within the project area is shown in Table 16. A combination of site visits conducted in the project area, annual surveys conducted by Santa Ana Watershed Association and local knowledge of the project area was used to determine the potential occurrence of sensitive wildlife species. The determination on the potential for the species to occur within the project area was based on the following criteria.

Present: The species commonly observed or trace signs of the species were observed within the project area within the last year. High: The project area supports suitable habitat and the species has been observed within the last 5 years and within 5 miles of the project area. Moderate: The project area supports suitable habitat but the species has not been observed within the last 5 years and not within 5 miles of the project area. Low: The project area lacks suitable habitat and/or species has not been observed within last 10 years and within 10 miles of the project area.

Table 16: List of Special Status Wildlife Species Federal State MSHCP General Habitat Potential Occurrence Reptiles Southwestern NL SSC C Perennial Ponds, High Potential. Rarely, but pond turtle Lakes, Rivers, Streams, observed in Prado Basin. (Actinemys Creeks, Marshes, and The sediment removal marmorata Irrigation Ditches channel alignment supports pallida) suitable habitat. Orange- NL SSC C Low level Coastal Sage Moderate Potential The throated Scrub, Chaparral, Grass sediment storage site whiptail land, Oak Woodland. contains marginal suitable

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-48 Section 3 Environmental Analysis

Federal State MSHCP General Habitat Potential Occurrence (Aspidosceli Prefers washes and habitat. hyperythra) sandy areas with patches of brush and rocks. Red Diamond NL SSC C Chaparral, Woodland Low Potential. The Rattlesnake and grassland and sediment removal channel (Crotalus desert areas that have and sediment storage site ruber) dense brush and large lack suitable habitat. rocks or boulders. Species last reported in 2001, 1 mile north of Santa Ana River at Horse Shoe Bend in Chino Hills Coast horned NL SSC C Most common in Moderate Potential. The lizard lowlands along sandy sediment storage site (Phrynosoma washes with scattered contains marginal suitable blainvillii) low brushes, requires habitat. open areas for sunning, bushes for cover and abundant supply of ants and other food sources. California red- NL SSC C Forest, mixed Moderate High Potential. sided garter woodlands, grassland, The sediment removal snake marshes and streams. . channel alignment supports (Thamnophis suitable habitat, and the sirtalis species is known to reside in infernalis) Prado Basin. Birds Tricolored NL SSC C Wetlands, Agricultural Moderate High Potential. blackbird Fields The sediment removal (Agelaius channel alignment supports tricolor) suitable habitat. Grasshopper NL SSC C Dense grasslands on Moderate Potential. The sparrow rolling hills, in valleys sediment removal channel (Ammodramus and on hillsides, prefer alignment and sediment savannarum) native grasslands with storage site contain marginal scattered shrubs. suitable amount of habitat. Long-eared NL SSC C Riparian bottomlands Moderate Potential. The owl (Asio otus) within tall willow and sediment removal channel cottonwood trees, live alignment supports suitable oak trees near streams, habitat. needs adjacent open land productive of food sources and the presence of old nests. Burrowing owl NL SSC C Open, dry perennial or Low Potential. The (Athene annual grassland and sediment removal channel cunicularia) scrublands alignment and sediment characterized by low storage site do not support growing vegetation, adequate amount of suitable subterranean nester. foraging/roosting opportunities. Species last reported 2006 .1 mile north of Chino Airport Coastal cactus NL SSC C Coastal Sage Scrub in Low Potential. The wren southern California sediment removal channel (Campylorhync closely associated with alignment and sediment hus areas containing storage site do not support brunneicapillus patches of cholla or adequate amount of suitable ) prickly pear cacti. habitat. Species last reported in Chino Hills 4

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-49 Section 3 Environmental Analysis

Federal State MSHCP General Habitat Potential Occurrence miles west of Prado Dam Yellow Warbler NL SSC C Riparian vegetation Present. (Dendroica associations, prefers The sediment removal Brewsteri) willows, cottonwood, channel alignment supports sycamores for nesting suitable habitat and species and foraging. is commonly reported to occur in Prado Basin. Least Bell’s E E C Summer resident of Present. vireo southern California in The sediment removal (Vireo bellii low riparian habitats in channel alignment supports pusillus) vicinity of water or dry suitable habitat and species river bottoms, nests is annually reported in the placed along margins of Prado Basin. bushes or on twigs landing on pathways, usually willow, mesquite or mulefat. Coastal T SSC C Permanent resident of Low Potential. The California coastal sage scrub, low sediment removal channel gnatcatcher scrub, in arid washes, alignment and sediment (Polioptila on mesas and slopes. storage site lack suitable californica) habitat. Species last reported 2000 in Norco Hills. Western yellow C E C Riparian Woodlands Low Potential. Species billed cuckoo with Thick stands of typically require a minimum (Coccyzus Cottonwoods and of 25 acres of area and americanus Willows forage predominantly in occidentalis) cottonwood tree stands. Surveys conducted by OCWD and SAWA over the last eight years have not reported any sightings of cuckoos within Prado Basin. Based on the lack of occurrence of the species in recent years, it is anticipated that the species could be extirpated from the area (Santa Ana River Interceptor Line Protection/Relocation EIS/EIR, U.S. Army Corps Engineers 2009). Based on the lack of occurrence of the species, the species is presumed to be absent from the project area. Cooper’s hawk NL WL C Woodlands, nest sites Present. (Accipiter mainly in riparian The sediment removal cooperii) growths of deciduous channel alignment and trees. areas near green waste site contain suitable habitat. Species is commonly reported to occur in Prado Basin. White-tailed NL FP C Typically nests at lower Present. The sediment kite elevations in riparian removal channel alignment (Elanus trees, including oaks, and area near green waste leucurus) willows and site support suitable habitat. cottonwoods, forages Species is commonly over open areas. reported to occur in Prado

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-50 Section 3 Environmental Analysis

Federal State MSHCP General Habitat Potential Occurrence Basin. Southwestern E E C Breeds in willow riparian Moderate Potential. The willow forest and shrub ands sediment removal channel flycatcher alignment supports suitable (Empidonax habitat. Most recent traillii extimus) reporting was in 2007 in the vicinity of sediment storage site Yellow NL SSC C Summer resident, Present. breasted chat inhibits riparian thicket The sediment removal (Icteria virens) of willow and other channel alignment support brushy thickets near suitable habitat. Species is water courses, nests in commonly reported to occur low dense riparian in Prado Basin. vegetation. Double-crested NL WL C Inhabits lakes, rivers, Present. cormorant reservoirs, estuaries or Observed The sediment (Phalacrocorax ocean for foraging, removal channel alignment auritus) nests in tall trees or supports suitable habitat and rugged slopes near species is commonly aquatic environments. reported in Prado Basin. Great blue NL SSC C Inhabits shallow Present. heron estuaries, fresh and The sediment removal (Ardea saline emergent channel alignment supports herodias) wetland areas. suitable habitat and species has commonly been reported in Prado Basin. Golden eagle NL FP C Uncommon resident in Moderate Potential. The (Aquila southern California, sediment removal channel chrysaetos) nests primarily in alignment and sediment rugged, isolated storage site do not support mountain areas. adequate amount of suitable habitat. However, species has historically been reported nesting in Chino Hills Sharp-shinned NL WL C Nests in conifer and Moderate Potential. The hawk riparian forests, prefers sediment removal channel (Accipiter north facing slopes near alignment supports suitable striatus) water. habitat American NL NL C Found in emergent Moderate Potential. bittern freshwater marsh The sediment removal (Botaurus habitat and vegetate channel alignment supports Lentiginosus) borders of ponds and suitable habitat. lakes. Swainsons NL T C Breeds in interior Moderate Potential. hawk valleys and high desert The sediment removal (Buteo with scattered large channel alignment and the swainsoni) trees or riparian sediment storage site all woodland corridors contain suitable foraging surrounded by open habitat. fields. Turkey Vulture NL NL C Forages widely over Present. Observed. The (Cathartes many habitats, roosts sediment removal channel aura) communally in open alignment and the area near trees, nests on cliffs, or the green waste site all steep mountains in support suitable foraging shrubby or rocky sites. habitat. Species has commonly been reported in Prado Basin.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-51 Section 3 Environmental Analysis

Federal State MSHCP General Habitat Potential Occurrence Vaux’s swift NL SSC NC Breeds in coniferous Present: Seasonal Migrant, (Chaetura and mixed coniferous sediment removal channel vauxi) forests, requires large alignment supports suitable diameter trees, hollow habitat. Species has been trees form breeding, commonly reported in Prado forages in areas of open Basin. water. Northern NL SSC C Prefers open country, High Potential. harrier grasslands, stepps, The sediment removal (Circus wetland meadows, channel alignment and the cyaneus) agriculture fields, roost area near the green waste and nest on ground in site support suitable habitat shrubby vegetation and species has been often at edge of reported in Prado Basin. marshes. California NL WL C Short-grass prairie, High Potential. The horned lark mountain meadows, sediment storage sites does (Eremophila open coastal plains and support marginal suitable alpestris fallow grain fields. habitat. Species has been action) reported in Prado Basin. Merlin NL WL C Tidal estuaries, open High Potential. (Falco woodlands. Edges of Species known to occur in columbarius) grasslands, requires Prado Basin as winter visitor clumps of trees or and is likely to forage or fly windbreaks for roosting over Prado Basin. in open country. Loggerhead NL SSC C Broken woodland, Moderate Potential. Shrike riparian woodland, The sediment removal (Lanius pinyon-juniper channel alignment support ludovicianus) woodland and washes, suitable habitat and species is known to forage in upland habitats within Prado Basin. Lincoln NL NL C Breeds in montane Moderate Potential. Not sparrow wetlands, meadows, observed in Prado Basin. (Melospiza and riparian scrub. The sediment removal lincolnii) channel alignment support suitable habitat. Downy NL NL C Forests and woodlands, Present. woodpecker especially riparian The sediment removal (Picoides areas, builds nests in channel alignment and area pubescens) dead trees. near green waste site support suitable habitat and species has been commonly reported in Prado Basin. Amphibians Western NL SSC C Vernal Pools, Riparian Moderate Potential. The spadefoot Habitats sediment removal channel (spea alignment contain suitable hammondii) habitat. Northern NL SSC NC Grasslands. Meadows, Low. The sediment removal leopard frog Forest, Woodlansds, channel alignment lacks and (Lithobates) Marshes and Canals sediment storage site lack suitable habitat. Species last reported 1967 3 miles west of City of Corona. Mammals Mexican long- NL SSC NC Well Lighted Caves Low Potential. tongued bat The sediment removal (Choeronycete alignment and the sediment

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-52 Section 3 Environmental Analysis

Federal State MSHCP General Habitat Potential Occurrence ris mexicana) storage site do not have caves. San E NL C Alluvial Scrub, Sandy Low Potential. The Bernardino Loam Substrate sediment removal channel kangaroo rat alignment and the sediment (Dipodomys storage site do not contain merriami adequate amounts of parvusi) suitable habitat. Species last reported 1972 1.2 miles southeast Corona Airport. Western NL SSC NC Roosts in cracks and Low Potential. The mastiff bat small holes, prefers sediment removal channel (Eumops man-made structures alignment and the sediment perotis storage site all do not californicus) contain adequate amounts of suitable habitat. San Diego NL SSC C Open Range, Present. black-tailed Agricultural Lands, Species is commonly jackrabbit Coastal Shrub observed throughout Prado (Lepus Basin vicinity. Caolifornicus) Pocketed free- NL SSC C Crevices in Rocky Cliffs, Low Potential. The tailed bat caves, tunnels mines sediment removal channel (Nyctinomops under roof tiles alignment and the sediment femorosaccus) storage site do not contain adequate amounts of suitable habitat. Coyote NL NL C Opportunistic predatory, Present. (Canis latrans) exists in many habitats. Known to occur throughout the Prado Basin vicinity. Mountain lion NL NL C Large areas where prey Present. (Felis is available. Known to occur in Prado concolor) Basin and Chino Hills State Park. Bobcat NL NL C Opportunistic predator, Present. (Lynx rufus) many habitats. Known to occur in Prado Basin vicinity. Long-tailed NL NL C Generalist predator, Present. weasel mainly on small animals The sediment removal (Mustela channel alignment and frenata) sediment storage site all supports suitable habitat and species has been observed in Prado Basin. Aquatics Santa Ana T SSC C Cool, Clear Streams, Moderate Potential. The sucker Rivers, rocky Bottom in segment of SAR within (Catostomus riparian woodlands project area contains santaanae) marginal essential habitat elements. Southern NL SSC C Freshwater Rivers, Moderate Potential. The California Creeks, and Streams in segment of SAR within arroyo chub riparian woodlands project area contains (Gila orcutti) marginal essential habitat elements. Legend Federal Endangered Species Act E- Endangered T-Threatened SSC- Special Species of Concern C-Candidate for Listing California Endangered Species Act/California Department Fish Game

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-53 Section 3 Environmental Analysis

Federal State MSHCP General Habitat Potential Occurrence

E-Endangered FP-Fully Protected S-Sensitive SSC-Special Species of Concern T-Threatened WL-Watch List Multi species Habitat Conservation Plan (MSHCP) C-Covered NC-Not Covered

Special Status Wildlife Species with Moderate or Higher Potential to Occur within Project Areas Federal/State-Endangered, Threatened, Fully Protected Species • Least Bell’s Vireo (Vireo belli pusillus) • Southwestern Willow Flycatcher (Empidonax traillii extimus) • White-tailed Kite (Elanus leucurus) • Golden Eagle (Aquila chrysaetos) • Swainson’s Hawk (Buteo swainsoni) • Santa Ana Sucker (Catostomus santaanae) Federal/State-Candidate, Species of Special Concern • Southwestern Pond Turtle (Actinemys marmorata) • Orange Throated Whiptail (Aspidoscelis hyperythra) • Coast Horned Lizard (Phrynosoma blainvillii) • California Red-Sided Gartersnake (Thamnophis sirtalis inferbalis) • Tri-colored Blackbird (Agelaius tricolor) • Long-Eared Owl (Asio oyus) • Yellow Warbler (Dendroica petechia brewsteri) • Yellow-Breasted Chat (Icteria virens) • Great Blue Heron (Ardea Herodias) • Vaux’s Swift (Chaetura vauxi) • Northern Harrier (Circus cyaneus) • Loggerhead Shrike (Lanius ludovicianus) • Western Spadefoot (spea hammondii) • San Diego Black-Tailed Jackrabbit (Lepus californicus bennettii) • Southern California Arroyo Chub (Gila orcutti) • Grasshopper Sparrow (Ammodramus savannarum) State Watch List Species • Cooper’s Hawk (Accipiter cooperii) • Double-Crested Cormorant (Phalacrocorax auritus) • Sharp-shinned Hawk (Accipiter striatus) • California Horned Lark (Eremophila alpestris alpestris actia) • Merlin (Falco columbarius) MSHCP Covered Species • Turkey Vulture (Cathartes aura)

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-54 Section 3 Environmental Analysis

• Lincoln’s Sparrow (Melospiza lincolnii) • Downy Woodpecker (Picoides pubescens) • Coyote (Canis latrans) • Mountain Lion (Felis concolor) • Bobcat (Lynx rufus) • Long-tailed Weasel (Mustela frenata) • American Bittern (Botaurus lentiginosus) Critical Habitat Least Bell’s Vireo Critical Habitat In 1994 USFWS designated approximately 48,000 acres as critical habitat for the least Bell’s vireo. The designation encompasses portions of six counties in California including Riverside County and San Bernardino County. The Primary Constituent Elements for the least Bell’s vireo include riparian woodland vegetation that generally contains both canopy and shrub layers, and includes some associated upland habitats. As shown in Figure 8, the sediment removal channel is located on lands designated as critical habitat for the least Bell’s vireo. Southwestern Willow Flycatcher Critical Habitat In 1997 USFWS designated critical habitat for the Southwestern Willow Flycatcher for portions of Riverside and San Bernardino Counties. The Primary Constitute Elements of for the Southwestern Willow Flycatcher are thickets of riparian shrubs and small trees with adjacent surface water. The surface water must be available from May to September during breeding season. As shown on Figure 8 portions of the sediment removal channel are located on lands that have been designated Critical Habitat for the Southwestern Willow Flycatcher. Coastal California Gnatcatcher Critical Habitat In 2007 USFWS re-designated 197,303 acres of habitat in portions of San Diego County, Orange County, Riverside County, San Bernardino County, Los Angeles County and Ventura County as critical habitat for Coastal California Gnatcatcher. The Primary Constituent Elements for the Coastal gnatcatcher are: (1) dynamic and successional sage scrub habitats such as Venturan coastal sage scrub, Diegan coastal sage scrub, Riversidean sage scrub, maritime succulent scrub, Riversidean alluvial fan scrub, southern coastal bluff scrub, and coastal sage chaparral scrub and (2) non-sage scrub habitats such as chaparral, grassland, riparian areas, in proximity to sage scrub habitats that provide space for dispersal, foraging and nesting. As shown on Figure 8 none of the project area is located on lands that have been designated Critical Habitat for the California Gnatcatcher.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-55 Sediment Removal Channel

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Sediment Storage Site E / Green Waste Site Sediment Re-entrainment Area AÆ

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Least Bell's Vireo Critical Habitat Santa Ana Sucker Critical Habitat Prado Basin SMDP 0 1,000 2,000 California Gnat Catcher Critical Habitat Southwestern Willow Flycatcher Critical Habitat Feet Critical Habitat Aerial Imagery Eagle Aerial Spring 2012 Figure 8 Section 3 Environmental Analysis

Santa Ana Sucker Critical Habitat Critical habitat for the Santa Ana sucker was designated by USFWS in 2004. The Primarily Constituent Elements that have been recognized as essential critical habitat for the Santa Ana sucker include; a functioning hydrological system that experiences peaks and ebbs in the water column reflecting seasonal variation in precipitation throughout the year; a mosaic of loose sand, gravel, cobble and boulder substrates in a series of riffles, runs, pools and shallow sandy margins, water depths greater than 1.2 inches, non-turbid water or only seasonally turbid water, water temperatures less than 86 degree and stream habitat that includes algae, aquatic emergent vegetation, macro invertebrates and riparian vegetation. The Critical Habitat for the Santa Ana sucker extends along the Santa Ana River from above the Seven Oaks Dam in the San Bernardino Mountains to the Prado Basin near River Road excluding most of Prado Basin and downstream from Prado Dam to Imperial Highway in Orange County. As shown on Figure 8 the segment of the SAR where the sediment re-entrainment area is located is designated critical habitat area for the Santa Ana sucker. Wildlife Movement Corridors Corridors and linkages that facilitate regional wildlife movement are generally located near water ways, ridgelines, riparian corridors, flood control channels, contiguous habitat and upland habitat areas. Different types of wildlife movement corridors provide specific types of functions pending on the landscape of the area and habitat conditions. • Movement corridors are physical connections that allow wildlife to move between patches of suitable habitat. • Dispersal corridors are relatively narrow, linear features embedded in a dissimilar matrix that links two or more areas of suitable habitat that would otherwise be fragmented and isolated from one another by rugged terrain, changes in vegetation or human-altered environments. • Habitat linkages are broader connections between two or more habitat areas. • Travel routes are usually landscape feature, such as ridgelines, drainages, canyons or riparian corridors within larger natural habitat areas that are used frequently by animals to facilitate movement and provide access to water, food, cover, den sites or other necessary resources. • Wildlife crossings are small, narrow areas of limited extent that allow wildlife to pass an obstacle or barrier. Crossings typically are manmade

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-57 Section 3 Environmental Analysis

and include culverts, underpasses, drainage pipes, bridges and tunnels to prove access past roads, highways, pipelines or other physical obstacles. The Santa Ana River is considered a wildlife corridor allowing for the movement of wildlife to open space areas such as the Santa Ana Mountains and Chino Hills. Additionally, riparian corridors, and tributary streams within the Prado Basin also function as wildlife movement corridors between landscape features and habitat patches. Federal and State Jurisdictional Aquatic Resources Water of the United States A water body is considered Waters of the U.S. if it is: (1) a traditional navigable water (TNW); (2) a wetlands adjacent to a TNW; (3) non-navigable tributary of a TNW that have perennial or seasonal flow of water; or (4) wetlands that are adjacent to non-navigable tributaries of TNW that have perennial or seasonal flow of water. According to the Federal Clean Water Act, any activity that involves the discharge of dredged or fill material into Waters of the U.S. is subject to approval of 404 Permit from the Corps. Waters of the State of California According to the State Water Code, Waters of the State are defined as any surface water, groundwater or wetlands within the boundary of the State. According to Section 1602 of the California Fish and Game Code any activity that diverts or obstructs the natural flow or change or use of any material activity that diverts or obstructs the natural flow or change or use of any material from the bed, channel, or bank of any river, stream or lake, or deposit fill, debris, waste or other material into any river, stream, or lake, is subject to approval of Streambed Alternation Agreement from the CDFW. CDFW jurisdiction extends up to the top of the slope and adjacent wetland vegetation along a surface water body. Wetland Waters of the United States and State of California Wetland Waters are a subset of jurisdictional Waters of the U.S. and the State. Generally, wetlands are lands where saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface. Presently, there is no single definition of wetlands recognized by the state and the federal government. However, the state and federal definitions do share common terms and concepts. For purposes of this classification, wetlands must have one or more of the following three attributes: (1) at least periodically the land supports hydrophytes; (2) the substrate is predominantly undrained hydric soil; and (3) the substrate is non-soil and is saturated with water or covered by shallow water at some time

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-58 Section 3 Environmental Analysis during the growing season of each year. Wetlands generally include swamps, freshwater, brackish water and saltwater marshes, bogs, vernal pools, periodically inundated salt flats, intertidal mudflats, wet meadows, wet pastures, springs and seeps, portions of lakes, ponds, rivers and streams and all areas which are periodically or permanently covered by shallow water, or dominated by hydrophytic vegetation, or in which the soils are predominantly hydric in nature. Project Area Aquatic Resources The Santa Ana River is considered non-navigable tributary to navigable water that has at least seasonal flow. Therefore, the Santa Ana River is considered Waters of the U.S./State. The proposed sediment storage site is located in upland area and does not contain Waters of the U.S. and State. The storage sites do contain some riparian vegetation. However, the riparian vegetation is isolated and is not classified as Wetland Waters of the U.S. or State. The amount of jurisdictional area within the sediment removal channel and sediment storage sites is shown in Table 17.

Table 17: Sediment Removal Channel U.S./State Jurisdictional Area Site Non-Vegetation Wetlands Waters US/State Waters of US/State Sediment Removal Channel 3.58 34.46 Sediment Storage Site 0 0

3.3.3 Thresholds of Significance • Will the Project have a direct adverse effect on a population of a threatened, endangered or candidate species or the loss or disturbance of important habitat for a listed or candidate species? • Will the Project have a significant adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, and regulations or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service? • Will the Project have a significant adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? • Will the project significantly impede the movement or migration of fish or wildlife? • Will the Project conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance?

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-59 Section 3 Environmental Analysis

• Will the Project be in conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan?

3.3.4 Project Impacts IMPACT BIO-1: Will the Project have a direct adverse effect on a population of a threatened, endangered or candidate species or the loss or disturbance of important habitat for a listed or candidate species. Sensitive Plant Species An online search of CDFW California Natural Diversity Data Base (CNDDB) and California Native Plant Society Online Search was conducted to identify the potential for special status plant species to occur within the project area. The online search identified 15 special status plant species that could potentially occur in the Prado Dam and Corona North USGS Quadrangle area. After review of the general habitat requirements for the plant species and the existing habitat conditions at the project site it was determined that there was low potential for the special status plant species to occur at the sediment removal channel, sediment storage site, or the sediment re-entrainment area. In 2010 a patch of Robinsons Peppergrass was observed at the sediment storage site. The sediment storage site was a former borrow site for the Corps Santa Ana River Mainstem Project at Prado Dam, so it is uncertain if the plant occurred onsite or seedlings were transported to the site during borrowing activities. Since 2010 the area where the Robinsons Peppergrass was observed has been cleared and restored with mulefat plantings. Because of the disturbed condition of the site and the presence of riparian plants, it is unlikely Robinsons Peppergrass will be present. Additionally, a patch of Coulters Matilija Poppy was observed within a recent burn area within the foothills above the sediment re-entrainment site. The proposed sediment re-entraining activities will be confined to along the south levee of the Prado Dam outlet channel and will not impact the foothills above the re-entrainment area. Implementation of the Project will not result in significant adverse impacts to any sensitive plant species. Special Status Wildlife Species Implementation of the Project could result in direct and indirect impacts to sensitive wildlife species and their habitat as a result of construction and operation activities. Potential direct impacts will include; physical impacts to individual species from construction activities and the removal of essential wildlife habitat. Potential indirect impacts will include; construction noise impacts that affects breeding patterns of nesting birds, temporary degradation of the value of adjacent wildlife habitat areas due to disturbances, colonization of invasive

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-60 Section 3 Environmental Analysis

weeds, fugitive dust impacts, increased human presence and increased vehicle traffic occurring in the project area. Least Bell’s Vireo, Southwestern Willow Flycatcher The least Bell’s vireo (vireo) and Southwestern Willow flycatcher (flycatcher) both occur in riparian habitats along watercourses where dense growth of willow trees, cottonwood trees, mulefat and other dense riparian plants are present. As shown on Figure 9, during the 2013 Santa Ana Watershed Association (SAWA) Survey,14 vireo territories were identified within the vicinity of the sediment removal channel and the sediment storage site. As shown on Figure 10, low numbers of the flycatcher have occurred intermittently within the project area within the last 10 years. The construction of the sediment removal channel will temporarily remove all vegetation within the channel alignment. If active nests are located within vegetation during nesting season there will be the potential that active nests could be destroyed and direct impacts to individuals could occur. The vegetation clearing operations to construct the sediment removal channel will occur outside of the nesting season minimizing the potential for active nests to be present. Prior to commencement of vegetation removal activities the vegetation within sediment removal channel will be surveyed for active nests. If active nests are present vegetation removal activities will not proceed in the area until the nests are no longer active. With the implementation of Mitigation Measure BIO-1 potential adverse direct impacts to active nests and individual nesting birds will be avoided. The construction of the sediment removal channel will temporarily remove riparian habitat and potential nesting areas. The amount of riparian habitat that will be temporarily lost will be minimal compared to the overall amount of suitable habitat that exists throughout the Prado Basin. After the demonstration project is completed the native vegetation within the sediment removal channel will be re- established and OCWD will manage the area to ensure that non-native vegetation does not re-establish. To compensate for the temporary loss of native riparian habitat OCWD will restore native riparian vegetation impacted by the project and manage the area during the duration of the project. With the implementation of Mitigation Measure BIO-3 and BIO-4 potential adverse significant direct impacts associated with temporary loss of riparian habitat will be reduced to a less than significant level.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-61 (! (! (! ! (! (! ( (! (! (! (! (! (! (! (! (! (!(! (! (! (! (! (! (! (! (! (! (! (! (! (! (! (! (! (! (! (! (! (! ! (! (! (! ( (! (! (! (! (! (! (! (! (! (! (! (! (! (! (! ! (! ! ( ( ! (! ( (! (! (! (! (! (! (! (! (! (! (! (! (! (!(! (! Sediment Removal (! (! (! Channel (! (! (! (! (! (! (! (! (! (! (! (! (! ! (! (! (! (! (! ( A« (! Green (! Waste (! (! (! (! Site (! (! (! Sediment Storage Site E

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0 500 1,000 !( 2013 Least Bell's Vireo Construction Activity Impact Area Prado Basin SMDP Feet Least Bell's Vireo Locations Aerial Imagery Eagle Aerial Spring 2012 Figure 9 Sediment Removal Channel

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)" 2003 Southwestern Willow Flycatcher )" 2007 Southwestern Willow Flycatcher 0 500 1,000 Prado Basin SMDP )" 2006 Southwestern Willow Flycatcher Construction Activity Impact Area Feet Southwestern Willow Flycatcher Locations Aerial Imagery Eagle Aerial Spring 2012 Figure 10 Section 3 Environmental Analysis

Dredging operations associated with the Project will begin in late winter and will extend into the nesting season. The dredging operations will be confined to the wetted sediment removal channel. Therefore, direct impacts to nesting birds will be avoided. The dredging operations will begin in the winter and will extend into the nesting season. The noise emitted from the dredging operations could discourage individual species from nesting within the vicinity of the sediment removal channel during nesting season. The USFWS has established a noise impact threshold of 60 dBA to minimize indirect construction noise impacts to nesting birds. A noise level in excess of 60 dBA is thought to impair the normal behavior of nesting birds. The 60 dBA construction noise level generated from the dredging operations will extend approximately 500 feet from the sediment removal channel. The construction of the sediment removal channel will not displace known vireo territories or flycatcher territories. Based on the infrequent occurrence of the flycatcher within or adjacent to the construction activity noise impact area of the sediment storage site over the last ten years, it is anticipated that there will be low potential for the flycatcher to occur at the sediment removal channel or the sediment storage site. The construction activity noise impact area along the sediment removal channel will extend into 14 known vireo territories. Depending on noise tolerances, some individuals could continue to nest within the construction activity noise impact area and others could seek other suitable locations to nest in the Prado Basin. To reduce potential construction noise levels to an acceptable level a construction noise mitigation program will be implemented that will include the use of acoustical panels around the work areas, the use of heavy equipment with noise reducing mufflers and the operation of generators and booster pumps in sound proof enclosures. During dredging operations an onsite biological monitor will survey the construction activity noise impact area to confirm if nesting birds are present. If nesting birds are present the biological monitor will determine if the construction activity will cause them to abandon their nests. If the biological monitor determines that the construction activity will not cause nest abandonment then the construction activities will proceed. If it is determined that the noise generated from dredging will cause nest abandonment and additional noise measures cannot be implemented to prevent nest abandonment, then dredging activity near the nest shall cease in the area until the nest is no longer active. With the implementation of Mitigation Measure BIO-5 and BIO-8 potential construction noise impacts will be reduced to a less than significant level. There is low potential that small numbers of vireos could nest within the construction activity noise impact area during periods when heavy equipment is not operating,

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-64 Section 3 Environmental Analysis

in particular when the dredge is circulating along the sediment removal channel and because of the dense vegetation and limited accessibility in the project area, there is the potential that an active nest might not be identified and the breeding patterns of nesting birds could be disrupted. Even though there is low potential for low numbers of vireos to nest within the construction activity noise impact area during dredging activities, the potential that the construction noise impacts could disrupt breeding patterns of nesting vireos is considered a significant adverse impact. However, because low numbers are only expected to occur, the potential disruption of breeding patterns of a few vireos will not jeopardize the survivability of the species. The sediment storage site will require grading to create suitable work areas for green waste processing and for the storage and handling of sediment removed from the sediment removal channel. The sediment storage site does not contain suitable nesting habitat. Therefore, no direct impacts to nesting birds will occur. However, in the vicinity of the storage site there is suitable nesting habitat. The grading activities at the sediment storage site will occur outside of nesting season. Therefore, adverse construction noise impacts to potential nearby nesting birds will be avoided. The green waste processing activities at the sediment storage site will occur outside of nesting season. Therefore, indirect construction noise impacts to potential nearby nesting birds will be avoided. However, the sediment handling activities at the sediment storage site will occur during nesting season and potential adverse construction noise impacts could discourage birds from nesting within the construction activity noise impact area. The construction noise emitted from the sediment handling activities will be intermittent and sound attenuation measures will be implemented at the work site to reduce noise levels to less than 60 dBA. With the implementation of Mitigation Measure BIO-5 potential adverse construction noise impacts to potential nearby nesting birds will be reduced to a less than significant level. The sediment re-entrainment activities will occur along the levee of the Prado Dam outlet structure. Along the Prado Dam outlet channel there is no suitable nesting habitat. However, downstream of the re-entrainment area there is riparian vegetation which could provide suitable nesting habitat. The re- entrainment activities will be confined to the levee and will not result in significant adverse direct impacts to the riparian vegetation in the river. Additionally, the sediment re-entrainment activities will occur outside of nesting area. Therefore, potential adverse direct impacts and indirect construction noise impacts to nesting birds will be avoided.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-65 Section 3 Environmental Analysis

Least Bell’s Vireo and Southwestern Willow Flycatcher Critical Habitat Implementation of the Project will directly impact 39.31 acres of area that has been designated critical habitat for the vireo, of which 13.25 acres consist of cottonwood/willow, 12.6 acres consist of arundo, 1.25 acres consist of eucalyptus and .80 acre consists of open aquatic water. A total of 13.25 acres of vegetation that is considered primary constituent elements for the vireo will be temporary impacted. Implementation of the Project will directly impact 14.94 acres of area that has been designated critical habitat for the flycatcher, of which 5.57 consists of cottonwood/willow, 6.59 consists of arundo and 2.78 acres consists of open aquatic water. A total of 5.57 acres of vegetation that is considered primary constituent elements for critical habitat for the flycatcher will be temporarily impacted. Any permanent overall reduction in the amount of the critical habitat could have a significant adverse impact on the breeding success of the vireo and flycatcher. The direct impacts to the critical habitat associated with the Project are temporary because no permanent vegetation removals will occur. After the Project is completed the native vegetation will be re-established within the sediment removal channel and OCWD will manage the area to ensure that non- native vegetation does not re-establish. To compensate for the temporary loss of native riparian habitat OCWD will restore native riparian vegetation and manage the area during the duration of the project. With the implementation of Mitigation Measures BIO-3 and BIO-4 there will be no permanent overall reduction in critical habitat and potential significant adverse impacts associated with the temporary loss of critical habitat for the vireo and the flycatcher will be reduced to a less than significant level. Native Fish Historically, populations of Santa Ana sucker (sucker) and Southern California arroyo chub (chub) have been reported in the Santa Ana River both upstream and downstream of Prado Dam The Santa Ana River can be described in three sub-reaches; Prado Dam to Imperial Highway (Santa Ana Canyon Reach), Imperial Highway to Chapman Avenue (Recharge Area Reach) and Chapman Avenue to Pacific Ocean (Lower Reach). Santa Ana Canyon Reach The segment of the Santa Ana River within the Santa Ana Canyon Reach has several distinctive characteristics. At the Prado Dam outlet structure to the Green River Golf Course the river has a relatively flat slope. Within this reach the river flow is perennial and the floodplain is covered with riparian vegetation and the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-66 Section 3 Environmental Analysis

banks are moderately incised and vegetated islands dot the main channel. Near the Green River Golf Course the slope increases and the river becomes more incised. Between the Green River Golf Course and Weir Canyon Road the flood plain becomes much more expansive with several flow splits forming natural islands. Riparian vegetation is mostly concentrated near the river bank. This reach does not contain any other water control structures. Downstream of Weir Canyon Road the river channel has several drop structures and is more confined The bed material along Santa Canyon Reach is much coarser consisting of gravels and cobbles compared to the sandy bed material of the river above Prado Dam. The dominant bed form in this reach is pool-riffle, where high gradient high velocity riffles flow into low gradient low velocity pools. Additionally, there are several stretches of the river bottom that is dominated by gravel and cobble. A reasonable explanation for the more coarse sediment in this reach is the close proximity of the Santa Ana Mountains which provides a source for the material. Additionally, the river bed is armoring due to entrapment of sand behind Prado Dam. This reach contains some of primary constituent elements for the sucker and chub. However, surface flows along this reach can be very fast and turbid making it difficult for suckers or chubs to find food or shelter and the presence of drop structure prevents upstream movement. Additionally, there is high population of exotic fish that poses a significant predation threat. Therefore, this reach is considered to contain marginal quality habitat for the sucker and chub. Recharge Reach The recharge area reach extends from the drop structure immediately downstream of the Imperial Highway Bridge to the drop structure immediately downstream of State Route 22. Several man made hydraulic structures are located throughout the recharge area that confines and controls the water and sediment flow. This area is actively managed by OCWD for groundwater recharge under a long term maintenance agreement issued by California Department of Fish and Wildlife. The river flow is perennial entering the recharge reach, but a combination of water diversion, ponding behind inflatable dams and recharge into the river bed creates an ephemeral reach in the downstream segment near Chapman Avenue. The ephemeral nature of flow decreases regular sediment transport during base flow. Much of the sediment transport occurs during high intensity low duration winter storms and high-flow releases from Prado Dam. The bed material consists predominantly of sand with small amounts of cobbles. The bed material in the recharge reach has coarsened overtime due to the lack

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-67 Section 3 Environmental Analysis

of incoming sediment supply. It is unlikely the bed material within the recharge area could ever consist of gravel and cobbles, as in the Santa Ana Canyon Reach because of the lack of close source material for large sediment. The recharge area lacks primary constituent elements for the sucker and chubs, contains many water control structures and has a high exotic fish population. Therefore, the recharge area reach is considered to have poor quality habitat for the suckers and chubs. Lower Reach The flow is the lower reach is ephemeral. The reach has a mild longitudinal slope and has been converted to a trapezoidal shape. Half of the channel is completely lined with concrete. The first stretch of this reach runs through a golf course is in a somewhat natural shape. The lower channel portion has a natural riverbed and is subjected to tidal fluctuations. Several grade control structures are present throughout the reach. In those segments of the river that have an earthen bottom the bed material is mostly sandy with small amounts of gravel. Due to lack of perennial water and other primary constituent elements this reach of the river is considered to have poor quality habitat for suckers and chubs. Native Fish Surveys Surveys for native fish were conducted upstream of Prado Dam, within the former Prado Dam approach channel and outlet channel, along the Santa Ana River in the Santa Ana Canyon Reach, near the Green River Golf Course and along the reach of the Santa Ana River between Weir Canyon and Imperial Highway. The surveys are presented in Appendix C. Santa Ana River above Prado Dam The Santa Ana Watershed Association conducted native fish surveys in the Santa Ana River from the Rialto Channel confluence down to the River Road Bridge. The survey area coincides with the annual Riverwalk which was initiated in 2006 to evaluate the makeup of the substrate in the river. The Riverwalk survey area is broken up into 13 sections with 122 points. For this survey, 32 points were randomly chosen and included at least one point from each of the 13 Riverwalk sections. The surveys were conducted weekly from May 2013 through August 2013. Point 119 and point 121 were the 2 points surveyed that were closest to River Road Bridge. Upstream Prado Dam Point 119 Point 119 was surveyed on May 30th, 2013 and is located approximately 728 meters upstream of the River Road Bridge. This portion of the river is wide (~40m) and shallow. The substrate was made up of 100% sand and silt. The

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-68 Section 3 Environmental Analysis

banks were vegetated but not undercut. No native fish were captured at this site. Below in Table18 is an inventory of the species collected during the survey.

Table 18: Fish Survey Upstream Prado Dam Point 119 May 30 2013

Species Number of individuals captured Crayfish 1 Mosquito Fish 126

Upstream Prado Dam Point 121 Point 121 was surveyed on May 30th, 2013 and is located approximately 216 meters upstream of the River Road Bridge. This portion of the river was wide (over 50m) and shallow. The substrate was made up of almost 100% sand. The banks were vegetated but not undercut. Two sucker fry were collected at this site. No other native fish were captured. Below in Table 19 is an inventory of the species collected during the survey.

Table 19: Fish Survey Upstream Prado Dam Point 119 May 30 2013

Species Number of individuals captured Bullhead 3 Crayfish 2 Fathead Minnow 3 Largemouth Bass 1 Mosquito Fish 180 Santa Ana Sucker 2

Prado Dam Approach/Outlet Channel On July 1, 2008 the Corps diverted the Santa Ana River flows from the former Prado Dam approach channel to a new channel so that the flows would pass through the dams to new outlet channel. San Marino Associates and ECORP Consulting personnel were engaged to implement fish protection procedures during the diversion. Fish surveys were conducted to determine the presence of native fish. The stream channels in the approach channel and the outlet channel were dewatered to assist in the identification of native fish. As shown in Table 20 within the approach channel fifteen suckers were found and within the outlet channel five suckers were found. No other native fish were identified. Numerous exotic fish were captured including; carp (Cyprinus carpio), black bullhead (Ameiurus melas), fathead minnow (Pimephales promelas), channel catfish (Ictalurus punctatus) and inland silverside (Menidia beryllina). According to San Marino Associates, a comparison of the suckers captured from Prado Dam approach channel and outlet channel with suckers captured in other

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-69 Section 3 Environmental Analysis areas of the Santa Ana River show that the fish were in good condition. According to San Marino Associates the value of habitat conditions were within the range of conditions appropriate for suckers with the exception of the turbidity, which was substantially higher than other places where native fish were found.

Table 20: Fish Survey Prado Dam Approach/Outlet Channel July 1, 2, 2008

Location Species Length (millimeters) Weight (grams) Approach Channel Santa Ana Sucker 45 0.9 Approach Channel Santa Ana Sucker 75 5.2 Approach Channel Santa Ana Sucker 55 1.8 Approach Channel Santa Ana Sucker 70 4 Approach Channel Santa Ana Sucker 50 1.5 Approach Channel Santa Ana Sucker 70 3.7 Approach Channel Santa Ana Sucker 65 3.3 Approach Channel Santa Ana Sucker 65 2.7 Approach Channel Santa Ana Sucker 60 2.7 Approach Channel Santa Ana Sucker 60 2.7 Approach Channel Santa Ana Sucker 60 2.1 Approach Channel Santa Ana Sucker 70 3.9 Approach Channel Santa Ana Sucker 40 0.8 Approach Channel Santa Ana Sucker 63 2.2 Approach Channel Santa Ana Sucker 55 1.3 Outlet Channel Santa Ana Sucker 57 2.2 Outlet Channel Santa Ana Sucker 74 4.8 Outlet Channel Santa Ana Sucker 55 1.3 Outlet Channel Santa Ana Sucker 56 1.5 Outlet Channel Santa Ana Sucker 76 5.7

Santa Ana Canyon Green River Golf Course Reach The Riverside Corona Resource Conservation District conducted surveys for native fish along an approximate .75 mile reach of the Santa Ana River through the Santa Ana Canyon reach of the river near the Green River Golf Course on March 1, 3, 4, 5, 11, 15, 16, 17, 18, 22, 24, 2010, as part of the U.S. Army Corps of Engineers Reach 9 Improvements along the Santa Ana River. Fish surveys were conducted after dewatering most of the river bed to assist in the identification of native fish. A single sucker male approximately 8” in total length was found and a large number of non-native fish were found. Additionally,

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-70 Section 3 Environmental Analysis

Western Pond Turtle was captured. Below in Table 21 is an inventory of fish collected during the survey. Table 21: Fish Survey Santa Ana River Green River Golf Course Reach March 2010 Species Number of Individuals Captured African Clawed Frog 4 Bluegill 39 Bullfrog 2 Bullhead 34 Carp 72 Channel Catfish 164 Crawdad 57 Fathead Minnow 15 Green Sunfish 97 Largemouth Bass 17 Silver-sided Minnow 38 Santa Ana Sucker 1 Western Pond Turtle 1

Santa Ana Canyon Green River Golf Course Reach On April 12, 30, May 1, and 2, 2012 the same reach of the Santa Ana River surveyed by Riverside Corona Resource Conservation District in 2010 was surveyed again for the presence of native fish. Similar to the 2010 survey, exotic fish were the species of dominance in this reach of the river. A combination of silty substrates, deep slack water areas, generally poor water quality and warm summer water temperatures, decreased the quality of the habitat for native fish. According to the survey, although native fish have been present historically, the current habitat conditions indicate that there are marginal chances that populations of native fish are present. Below in Table 22 is an inventory of fish collected during the survey.

Table 22: Native Fish Survey Santa Ana River Green River Golf Course April, March 2012 Species Number of Individuals Captured African Clawed Frog 3 Bluegill 5 Bullfrog 2 Bullhead 11 Carp 134 Channel Catfish 285 Crawdad 408 Fathead Minnow 4

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Green Sunfish 22 Largemouth Bass 28 Silver-sided Minnow 19 Santa Ana Sucker 0 Western Pond Turtle 0

Santa Ana River Weir Canyon to Imperial Highway Reach A fish survey was conducted on November 6th, 2012 along the Santa Ana River between Weir Canyon and Imperial Highway. The survey involved electro shocking and dip nets to collect the fish. In the deeper, faster moving water, a small sein was used as a blocking net on the downstream side to keep affected fish from floating away. The stretch of the river from Weir Canyon to Imperial was chosen as the sampling site because it was wider and slower moving than the upper portions. The vegetation is mostly weedy and low growing which allows the river to spread out over the entire flood plain. There are multiple channels ranging from fast moving channels with a gravel/cobble substrate to slow moving channels with a silty/mucky substrate. Most of the effort was concentrated along the vegetated banks of the swifter moving channels with a gravel/cobble substrate. No native fish were captured or seen during the surveys. As shown in Table 23 a total of 107 non-natives, representing 9 different species, were captured and removed from the system. All non-natives captured in each section were identified and documented. River currents were generally swift in this entire reach but the water was clear and shallow enough to observe and capture the stunned fish. Habitat suitability for native fishes, particularly for suckers was very poor. Given the marginal quality of the aquatic habitat and the abundance and diversity of non-native predators and competitors it is unlikely suckers or chubs would be encountered.

Table 23: Native Fish Survey Santa Ana River Weir Canyon to Imperial Highway April, November 2012 Species Number of Individuals Captured Channel Catfish 5 Common Carp 32 Crayfish 4 Fathead Minnow 21 Green Sunfish 1 Inland Silverside 6 Largemouth Bass 4 Mosquito Fish 23 Yellow Bullhead 11

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Project Impacts Upstream of Prado Dam To construct the sediment removal channel, a new channel will be constructed parallel to the Santa Ana River and an earthen diversion berm will be created to divert a portion of the river flows between both channels. The construction of the sediment removal channel and diversion berm will not occur in the wetted channel of the Santa Ana River. Therefore, no direct impacts to native fish will occur. To ensure native fish do not inadvertently swim into the sediment removal channel during the operation of the Project, a 1/8 inch mesh fish screen will be attached to a temporary gated pipe that will convey Santa Ana River flows into the sediment removal channel. Additionally, 1/8 inch block mesh net will be placed upstream of the project area as an extra layer of protection. The segment of the river between the berm and upstream blocking net will be seined daily during dredging and any native fish found will be relocated to areas where suitable habitat conditions exist and where they will have a higher probability for survival. For these reasons, the likelihood of and risk of direct effects to native fish is small. In the event native fish do occur, the native fish will be relocated to areas that have suitable habitat. During the capture and relocation of native fish potential injury will be unlikely because this activity will be conducted by a qualified biologist approved by CDFW. To minimize adverse impacts to native fish Mitigation Measure BIO-6, BIO-7, BIO-9, BIO-11, BIO-12 and BIO-20 will be implemented. Even though there is low potential for native fish to occur and low potential for native fish to be injured if relocation is required, the potential for native fish to occur and require physical relocation is a significant adverse impact. However, because only low numbers are expected to occur, the adverse impact will not jeopardize the survival of either species. The sediment storage site is located in an upland area. The construction of the sediment storage site, the green waste processing activities and sediment storage and handling activities will not have any adverse impacts on native fish. Downstream of Prado Dam The sediment re-entrainment activities will occur at the terminus of the Prado Dam outlet channel, downstream of the Highway 71 crossing. This segment of the river contains some primary constituent habitat elements for the sucker and chub. However, because of frequent high turbidity and high populations of predatory fish species the habitat is considered marginal. The sediment will be re-entrained outside of spawning season. Therefore, potential impacts to fish spawning will be avoided.

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Recent surveys conducted along the Santa Ana River identified a single male sucker near the Green River Golf Course. Therefore, it is assumed that it is possible that individual fish could swim their way through the outlet channel to downstream areas. If native fish are present in the segment of the river where sediment re-entrainment will occur, it is more than likely that the fish would swim away from where re-entrainment activity is occurring. Additionally, the sediment will be re-entrained during high flows and it is more than likely fish will be seeking refuge in downstream areas where more opportunities exist for refuge. During these periods of high flows the river will experience higher levels of turbidly over the existing high levels of turbidly that currently occurs through this reach of the river. The re-entrained sediment will consist of 1 percent solids and should dilute quickly under high flows. Therefore, the re-entrained sediment is not expected to significantly increase the levels of turbidly at downstream areas where it would unhealthful to native fish. As part of environmental planning for the project boring samples were taken along the sediment removal channel to characterize sediment in the project area that will be re-entrained. As shown in Table 24 chemical analysis of the sediments in the Prado Basin shows no detected organic chemicals, pesticides, PCbs, PAhs, or hydrocarbons. Within the water column there were total dissolved solids, some inorganic nitrogen, and small quantities of metals, which are within the ranges expected for background soils in California.

Table 24: Summary of Soil Environmental Test Results Boring Depth Test Result 12 11-11.5 TPH-GRO ND 12 11-11.5 VOCs ND 12 21-21.5 Organophosphorus Pesticides ND 12 31-31.5 Metals * 3 6-6.5 TPH-DRO/ORO ND 3 11-11.5 PCBs ND 3 21-21.5 VOCs ND 3 25.5-26 TPH-DRO/ORO 3 31-31.5 Total Inorganic Nitrogen 88 mg/kg 16 5-5.56 VOC ND 16 5-5.6 Organophosphorus Pesticides 16 16-16.5 Metals * 16 16-16.5 Chlorinated Herbicides ND 16 21-21.5 Total Dissolved Solids 4500 mg/kg 16 26-26.5 Hexavalent Chromium ND 16 30.5-31 Pesticides ND 28 2.5 Metals ND 28 2.5 TPH-CCID ND 28 12.5 VOCs ND 28 12.5 Organophosphorus Pesticides ND 29 2.5 VOCs ND

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29 2.5 Organophosphorus Pesticides ND 29 12.5 Metals * 29 12.5 TPH-CCID ND * Low levels of some metals (arsenic, barium, chromium, cobalt, copper, lead, nickel, vanadium and zinc were detected above PQL. Detectable concentrations of metals are below EPA Region 9 Regional Screening levels

Since the chemistry of the sediments in the Prado Basin show no detected organic chemicals, pesticides, Polychlorinated biphenyls (PCbs), Polynuclear aromatic hydrocarbons (PAhs), or hydrocarbons, it will be unlikely that sediment extracted from the basin and re-entrained into the river will cause increased concentrations of organic chemicals, pesticides, PCbs, PAhs, or hydrocarbons in the Santa Ana River due to sediment-re-entrainment. Prior to discharging the sediment into the river a water quality monitoring program will be implemented to monitor the sediment material dredged from the sediment removal channel for a wide range of constituents, including; organic chemicals, pesticides, PCbs, PAhs, and hydrocarbons. In the event the sediment exhibits detectable levels of organic substances, pesticides, PCbs, PAhs, or hydrocarbons, that will cause an exceedance of the water quality objectives in the RWQCB Basin Plan, the sediment will not be used for re-entrainment. The sediment re-entrainment will be done in a manner to recreate natural conditions to the extent practicable. This will be done by pulsing the re- entrainment of sediments to reflect a typical storm cycle. Typical storm cycles in California occur over a 24 to 72 hour periods with 24 hours or greater periods between storm systems. Sediment re-entrainment will take place in 72 hour entrainment cycle, assuming adequate flows are available, with 24 hours of no re-entrainment cycle to recreate a natural storm driven sediment suspension cycles as close possible. By pulsing the sediment re-entrainment it allows for dilution of the sediment in the water column which will help minimize turbidity impacts. However, because the sediment will re-entrained during high flows with elevated levels of turbidity, there will be a temporarily exceedance of the Basin RWQCB Bain Plan threshold for turbidity. The Project will monitor for turbidity and where feasible will make adjustments to sediment re-entrainment activities, such reducing amount of solids in the slurry, to minimize turbidity. The Project includes a water quality monitoring plan that will monitor a wide range of constitutes including; metals, total dissolved solids, and indicator bacteria in upstream waters and within the waters where sediment re- entrainment will occur. If significant differences between upstream and downstream samples are observed, sediment re-entrainment rates will be adjusted to ensure they are within acceptable threshold ranges provided in the Regional Water Quality Control Basin Plan.

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To minimize potential construction related adverse water quality impacts during construction and operation of the Project, a series of construction impact minimization measures will be implemented. With the implementation of the Mitigation Measures BIO-13, BIO 14, BIO-15 BIO-16 and BIO-17 potential significant adverse construction related water quality impacts will be reduced to a less than significant level. Changes to Habitat Conditions Upstream of Prado Dam The construction and operation of the sediment removal channel will not substantially change sediment depositional patterns within the Prado Basin reservoir area. However, there will be some increase in bed shear stress and velocity within the reservoir area when the dredging conditions are occurring. An increase in flow velocity and sediment transport capacity at the upstream end of the dredged channel will have the potential to create a head cut or migrating local scour at the upstream end of the project area. The head cutting will help restore a portion of the slope to the river channel and will encourage sediments to migrate into the Prado Basin and expose more existing gravel and cobble deposits along the upper reaches of the river. The exposing of more gravel and cobbles along the river will enhance habitat conditions for native fish. The head cut depth and migration will depend on the incoming flow rates and sediment load, final geometry of the sediment removal channel and channel bed materials encountered during head cut migration. To help measure head cut benefits, a sediment movement monitoring program will be implemented that will monitor head cut activity after the dredging is completed. Down Stream of Prado Dam The objective of the Project is to move sediment around Prado Dam and re- entrain it into the lower Santa Anan River. In order to naturally disperse the sediments downstream, re-entrainment activities will be targeted for high flows (flows greater than 500 cfs) in the lower Santa Ana River. In order to effectively restore natural sediment transport processes to the lower Santa Ana River all sediment types that have been deposited in the Prado Basin will be subject to re- entrainment. Geotechnical borings conducted in the alignment of the sediment removal alignment indicate that most of the sediment will be made up of clay, silt and sand. Some small amounts of pebbles and gravel are expected but will likely be minimal. Figure 11 depicts the size of sediment particles that were sampled from the alignment of sediment removal channel that will be used for re- entrainment. Figure 11 shows that over 50% of the sediment particles are smaller

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-76 Section 3 Environmental Analysis

than 0.1 mm and none of the sediment particles would be larger than 1 mm in size. A sediment transport model was developed to help predict the movement of the re-entrained sediments. Table 25 shows the sediment transport model iterations under different re-entrainment pulse flows, ranging from 250 cfs to up to 5,000 cfs) to determine how many days it would take to re-entrain the targeted 500,000 cubic yards of sediment. Each of these pulse flows was then modeled assuming a “dry”, “median” and “wet” year scenario in the lower Santa Ana River to see how the sediment would move through the system. A shown in Table 25 at the project design flow rate of 500 cfs a total of 43 days of re-entrainment will be needed to re-entrain 500,000 cubic yards of sediment. The sediment re- entrainment will occur over a four period.

Table 25: Durations to Deplete 500,000 yd³ of Sediment for Six Selected Discharges Discharge (cfs) Duration (days) 250 86.8 500 43.4 750 28.9 1,250 17.4 2,000 10.8 5,000 4.3

For study purposes the Santa Ana River has been described as three sub- reaches; Prado Dam to Imperial Highway (Santa Ana Canyon Reach), Imperial Highway to Chapman Avenue (Recharge Area Reach) and Chapman Avenue to Pacific Ocean (Lower Reach). Figure 12 displays each sediment type and the approximate velocity at which each sediment type will settle out in each reach of the Santa Ana River. As shown in Figure 12 at 500 cfs and greater no sand will deposit in the Santa Ana Canyon where more favorable gravel/cobble substrate habitat conditions for the sucker and chub exist. As shown in Figure 12 only pebbles and gravels are likely to deposit in the Santa Ana Canyon Reach and virtually all silts and clays are expected to be carried to the ocean with little or no long term deposition in any of the three reaches. Therefore, with Prado Dam release rates of 500 cfs and greater there will be no significant deposition of sand that will adversely affect the existing substrate of the Santa Ana Canyon Reach where more favorable habitat conditions for native fish exist. Additionally, it is expected that because of its proximity to Santa Ana Mountains, the reach of the Santa Ana River through the Santa Ana Canyon would be continue to receive sediment material from the mountains to help maintain and replenish existing stretches of gravel and cobbles.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-77 Incoming Sediment Load Size Path: K:\Prado\SedimentManagementPlan\MXD\EIR2014\F11_IncomingSedimentLoadSize.mxd Figure 11 E E E

Lower Reach E Recharge Reach E Santa Ana Canyon Reach E

Susceptibility to Sediment Deposition Path: K:\Prado\SedimentManagementPlan\MXD\EIR2014\F12_SusceptibilityDeposit.mxd Figure 12 Section 3 Environmental Analysis

Santa Ana Sucker Critical Habitat The segment of the Santa Ana River below Prado Dam to Imperial Highway has been designated critical habitat for the sucker. The sediment re-entrainment activities will occur within the critical habitat area. However, the Project will not involve any heavy construction activity operating in the segment of the Santa Ana River designated as critical habitat. The sediment re-entrainment activity will occur on the top of the outlet channel and will discharge sediment into the river. The sediment re-entrainment activities will not result in significant adverse water quality impacts. Additionally, sediment transport modeling has indicated that sediment re-entrainment activities will not significantly change the gravel/cobble substrate exhibited in segments of the critical habitat reach of the Santa Ana River. The sediment re-entrainment activities will not reduce the amount or quality of critical habitat. To minimize the potential for construction related water quality impacts a series of construction impact minimization measures will be implemented. With the implementation of the Mitigation Measures BIO-13, BIO 14, BIO-15, BIO-16 and BIO-17 potential construction related adverse water quality impacts will be reduced to an insignificant level. Southwestern Pond Turtle Historically, few numbers of the Southwestern Pond Turtle (pond turtles) have been reported in the Prado Basin. The species as last reported in the Prado Basin in 2010 near OCWD Prado Wetlands. The habitat conditions within the project area are marginal. There is potential that low numbers of the species could be present in the project area where the sediment removal channel will be constructed and operated. If the specie is present, construction operations could result in direct adverse impacts to individuals. Additionally, direct adverse impacts to individuals could also occur from dredging activities, if the species finds it way into the wetted channel. To minimize potential direct adverse impacts OCWD will implement a special status species monitoring program that will focus on onsite biological monitoring prior to construction, during construction and during operation of the Project. Prior to the start of construction of the sediment removal channel a biologist will survey the area for the presence of pond turtles. The survey will be conducted at periods when the species is most active, from February to about November, to increase the potential for identification. If the species is present it will be relocated to locations outside of the work area. Prior to dredging activities the sediment removal channel will be surveyed daily for pond turtles. If the species is present it will be relocated to locations outside of the work area. During the dredging activities sound attenuation barriers will placed along the sediment removal channel to restrict access. Additionally, where needed, blocking nets will be employed along gaps in sound attenuation

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-80 Section 3 Environmental Analysis barriers to further restrict access into the channel. To access the channel to travel across a 30 foot access roads, through the barriers and down the slope of the channel. It is anticipated that if the species occurs they will easily be identified and will kept out of harm’s way. With implementation of Mitigation Measures BIO-6, BIO-7, BIO-9, BIO-11, BIO-18, BiO-19 and BIO-20 potential significant impacts to Southwestern Pond Turtles will be reduced to a less than significant level. Yellow Breasted Chat, Yellow Warbler, Tri-Colored Black Bird, American Bittern, Lincoln’s Sparrow All of the above species are known to occupy freshwater marsh wetland areas, along the edges of ponds and marshes, and in dense riparian thickets near water. Construction of the sediment removal channel will have the potential to temporarily impact potential habitat for all of the above species. The construction of the sediment removal channel will temporarily remove all vegetation within the channel alignment. If active nests are located within vegetation during nesting season there will be the potential that active nests could be destroyed and direct impacts to individuals could occur. The vegetation clearing operations to construct the sediment removal channel will occur outside of the nesting season minimizing the potential for active nests to be present. Prior to commencement of vegetation removal activities the vegetation within the sediment removal channel will be surveyed for occupied nests. If active nests are present, vegetation removal activities will not proceed in the area until the nests are no longer active. With the implementation of Mitigation Measure BIO-1 potential adverse direct impacts to active nests and individual nesting birds will be avoided. Construction of the sediment removal channel will temporarily remove riparian vegetation that is utilized as habitat by all of the above species. The amount of riparian habitat that will be temporarily impacted by the Project will be minimal compared to the overall amount of habitat that will be available within the Prado Basin. Once the demonstration is completed native vegetation will be re- established within the sediment removal channel and OCWD will manage the area to ensure that non-native vegetation does not re-establish. To compensate for the temporary loss of native riparian habitat OCWD will restore native riparian vegetation and manage the area during the duration of the Project. With the incorporation of Mitigation Measures BIO-3 and BIO-4 potential significant adverse direct impacts associated with the temporary loss of riparian habitat will be reduced to a less than significant level.

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Dredging operations for the Project will begin in late winter and extend into nesting season. The dredging operations will be confined to the wetted sediment removal channel. Therefore, direct adverse impacts to nesting birds will be avoided. The dredging operations will generate noise levels that could discourage birds from nesting within the construction activity noise impact area. Depending on noise tolerance, some individual species could continue to nest within the construction activity noise impact area, while other individuals could seek other suitable locations to nest in the Prado Basin. To reduce potential construction noise levels to acceptable levels a construction noise mitigation program will be implemented. With the implementation of Mitigation Measure BIO-5 and BIO-8 potential noise impacts will be minimized. There is potential that some individuals could nest within the construction activity noise impact area when dredging operations are not occurring. During dredging operations an onsite biologist will monitor the project area for the presence of nesting birds. However, because of the dense vegetation and limited accessibility in the project area, there is potential that an active nest may not be identified and could be disrupted by construction noise. The potential for the construction noise impacts to disrupt breeding patterns of nesting birds is considered a significant adverse impact. The sediment storage site will require grading to create suitable work areas for green waste processing and for the storage and handling of sediment removed from the sediment removal channel. The sediment storage site does not contain suitable nesting habitat for the above species. Therefore, no direct impacts to nesting birds will occur. However, in the vicinity of the storage site there is suitable nesting habitat. The grading activities at the sediment storage site will occur outside of the nesting season. Therefore, adverse indirect construction noise impacts to potential nearby nesting birds will be avoided. The green waste processing activities at the sediment storage site will occur outside of the nesting season. Therefore, no adverse indirect construction noise impacts will occur to nesting birds in nearby areas that contain suitable habitat. The sediment handling activities will occur during nesting season and potential adverse indirect construction noise impacts could discourage potential nearby birds from nesting within the construction activity noise impact area. The construction noise emitted from the sediment handling activities will be intermittent and sound attenuation measures will be implemented at the work site to reduce noise levels to less than 60 dBA. With the implementation of Mitigation Measure BIO-5 potential significant adverse indirect construction noise impacts to nesting birds will be reduced to a less than significant level.

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The sediment re-entrainment activities will occur along the levee of the Prado Dam outlet structure. Along the outlet channel there is no suitable nesting habitat. Therefore, potential adverse direct impacts to nesting birds will be avoided. Downstream of the re-entrainment area is riparian vegetation which could provide suitable habitat. The re-entrainment activities will be confined to the levee and will not result in any direct impacts to the riparian vegetation. Additionally, the sediment re-entrainment activities will occur outside of nesting season. Potential adverse direct impacts and adverse indirect construction noise impacts to nesting birds will be avoided. White-Tailed Kite, Coopers Hawk, Long-Eared Owl, Swainsons Hawk, Sharp-Shinned Hawk, Downey Woodpecker, Vaux’s Swift, Double-Crested Cormorant, Great Blue Heron All of the above species occupy and/or nest in trees. The construction of the sediment removal channel will temporarily remove all vegetation and trees within the channel alignment area. The vegetation clearing operations to construct the sediment removal channel will occur outside of the nesting season minimizing the potential for the presence of active nests. Prior to commencement of vegetation removal activities the vegetation within sediment removal channel will be surveyed for occupied nests. If active nests are present vegetation removal activities will not proceed in the area until the nests are no longer active. With the implementation of Mitigation Measure BIO-1 potential adverse direct impacts to active nests and individual nesting birds will be avoided. Additionally, trees that are removed from the area will be inspected to confirm if any nests are present. If nests are encountered they will either be relocated and if not feasible to be relocated a new substitute nest will be created and located outside of the construction activity impact area. With the implementation of BIO-2 potential impact associated loss of nests in trees will be reduced to a less than significant level. Construction of the sediment removal channel will temporarily remove habitat for the above species. However, the amount of habitat that will be temporarily impacted will be minimal compared to the overall habitat that will be available within Prado Basin. Once the Project is completed native vegetation will be re- established within the sediment removal channel and OCWD will manage the area to ensure that non-native vegetation does not re-establish. To compensate for the temporary loss of native riparian habitat OCWD will restore the native riparian vegetation and manage the area during the duration of the project. With the incorporation of Mitigation Measure BIO-3 and BIO-4 potential significant

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-83 Section 3 Environmental Analysis

adverse direct impacts associated with the temporary loss of riparian habitat will be reduced to a less than significant level. Dredging operations associated with the Project will begin in late winter and extend into nesting season. The dredging operations will be confined to the wetted sediment removal channel. Therefore, direct adverse impacts to individuals will be avoided. The dredging operations will generate noise levels that could discourage birds from nesting within the construction activity noise impact area. Depending on noise tolerance, some individual species could continue to nest within the construction activity noise impact area, while other individuals could seek other suitable locations to nest in the Prado Basin. To reduce potential construction noise levels to acceptable levels a construction noise mitigation program will be implemented. With the implementation of Mitigation Measure BIO-5 and BIO-8 potential noise impacts will be minimized. There is potential that some individuals could nest within the construction activity noise impact area when dredging operations are not occurring. During dredging operation an onsite biologist will monitor the project area for the presence of nesting birds. However, because of the dense vegetation and limited accessibility in the project area, there is potential that an active nest may not be identified and could be disrupted by construction noise. The potential for the construction noise impacts to disrupt breeding patterns of nesting birds is considered a significant adverse impact. The sediment storage site will require grading to create suitable work areas for green waste processing and for the storage and handling of sediment removed from the sediment removal channel. The sediment storage site does not contain suitable nesting habitat. However, in the vicinity of the storage site there is some suitable nesting habitat. The grading activities at the sediment storage site will occur outside of nesting season. Therefore, adverse indirect construction noise impacts to potential nearby nesting birds will be avoided. The green waste processing activities at the sediment storage site will occur outside of nesting season. Therefore, adverse indirect construction noise impacts to nesting birds will be avoided. The sediment handling activities will occur during nesting season and potential adverse indirect construction noise impacts could discourage potential nearby birds from nesting within the construction activity noise impact area. The construction noise emitted from the sediment handling activities will be intermittent and sound attenuation measures will be implemented at the work site to reduce noise levels to less than 60 dBA. With the implementation of Mitigation Measure BIO-5 potential significant adverse indirect construction noise impacts will be reduced to a less than significant level.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-84 Section 3 Environmental Analysis

The sediment re-entrainment activities will occur along the levee of the Prado Dam outlet structure. Along the outlet channel there is no suitable nesting habitat. Chino Hills located approximately 300 feet north of the sediment re- entrainment area and does contain suitable habitat. The sediment re-entrainment activities will be confined to the levee and would not impact any offsite habitat areas. Therefore potential adverse direct and indirect impacts to nesting birds will be avoided. Golden Eagle, Turkey Vulture, Northern Harrier, California Horned Lark, Loggerhead Shrike, Merlin, Grasshopper Sparrow All of the above species are known to occupy and/or forage in grassland areas and shrub areas and known to feed on small mammals and insects. The area where the sediment removal channel alignment is located does not support suitable grassland habitat. Therefore, it is very unlikely that any of the above species will be nesting or forging in the area where the sediment removal channel will be located. Therefore, the construction and operation of the sediment removal channel will not result in adverse direct impacts or indirect construction impacts to these species. The sediment storage site contains a mix of coastal sage scrub and non-native grasslands which could provide foraging habitat for the above species. The grading operations at the storage site will result in the temporary loss of foraging area. However, the amount of habitat that will be temporarily impacted will be minimal compared to the overall habitat and potential foraging range that will be available within Prado Basin and the prey that will be temporarily displaced will represent a very small amount of available prey occurring throughout the area and will not result in significant adverse impacts in regards to temporary loss foraging opportunities for these species. To compensate for the temporary loss of coastal sage scrub habitat, OCWD will restore all coastal sage scrub habitat disturbed by the project with in-kind native vegetation. With the implementation of Mitigation Measures BIO-3 and BIO-4 potential significant adverse direct impacts associated with the temporary loss of habitat will be reduced to a less than significant level. In the vicinity of the storage site there is suitable nesting habitat. The grading activities at the sediment storage site will occur outside of nesting season. Therefore, no adverse direct impacts or adverse indirect construction noise impacts to nesting birds will occur. The green waste processing activities at the sediment storage site will occur outside of nesting season. Therefore, adverse direct impacts and adverse indirect construction noise impacts to potential nearby nesting birds will be avoided.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-85 Section 3 Environmental Analysis

The sediment handling activities will occur during nesting season and potential adverse indirect construction noise impacts could discourage potential nearby birds from nesting within the construction activity noise impact area. The construction noise emitted from the sediment handling activities will be intermittent and sound attenuation measures will be implemented at the work site to reduce noise levels to less than 60 dBA. With the implementation of Mitigation Measure BIO-5 potential significant adverse indirect construction noise impacts will be reduced to a less than significant level. The sediment re-entrainment activities will occur along the levee of the Prado Dam outlet structure. Along the outlet channel there is no suitable nesting habitat. Chino Hills located approximately 300 feet north of the sediment re- entrainment area and does contain suitable habitat. The sediment re-entrainment activities will be confined to the levee and would not impact any offsite habitat areas. California Red-Sided Garter Snake, Western Spadefoot Toad The California Red-Sided Garter Snake and the Western Spadefoot Toad both occur in streams, creeks and marshes and have the potential to occur within the area where the sediment removal channel will be constructed. If these species are present, construction operations could result in direct adverse impacts to individuals. Additionally, direct adverse impacts to individuals could also occur from dredging activities, if the species find their way into the wetted channel. To minimize potential direct adverse impacts OCWD will implement a special status species monitoring program that will focus on onsite biological monitoring prior to construction, during construction and during operation of the Project. Prior to the start of construction a biologist will survey the area for the presence of both species. If the species is present it will relocated to locations outside of the work area. Access to the sediment removal channel will be restricted by the presence of sound attenuation barriers and blocking nets around the channel. Additionally, prior to start of dredging each day the sediment removal channel will be surveyed and if present the species will be relocated. With implementation of Mitigation Measures BIO-6, BIO-7, BIO-9 BIO-10, BIO-18, BiO-19 and BIO-20 potential significant adverse direct impacts to individuals will be reduced to a less than significant level. The construction of the sediment removal channel will temporarily remove habitat for both species. However, the amount of habitat that will be temporarily removed will be minimal compared to the overall amount of habitat that will be available in the Prado Basin area. Once the Project is completed open water areas impacted by the Project will be returned to their pre-project condition. The temporary loss of habitat is considered a less than significant impact.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-86 Section 3 Environmental Analysis

The sediment storage site is located in an upland area and does not contain suitable habitat for the above species. The construction and operation of the sediment storage site and the green waste processing area will not result in adverse impacts to the California Red-Sided Garter Snake and the Western Spadefoot. The sediment re-entrainment activities will occur along the levee of the Prado Dam outlet structure. Along the outlet structure there is no suitable nesting or foraging habitat available. The sediment re-entrainment activities will not result in adverse impacts to California Red-Sided Garter Snake and the Western Spadefoot Toad. Coast Horned Lizard, Orange-Throated Whiptail The area where the sediment removal channel will be constructed and operate does not contain suitable habitat for the above species. Therefore, the construction and operation of the sediment removal channel will not result in adverse direct or indirect impacts to these species. The sediment storage site contains a mix of coastal sage scrub and non-native grasslands which could provide suitable habitat for the above species. The site will require grading to create a suitable work area. The grading operations at the site will result in the temporary loss of coastal sage scrub habitat. To compensate for the temporary loss of coastal sage scrub habitat OCWD will restore coastal sage scrub impacted by the project and manage the area during the duration of the project. With the implementation of Mitigation Measures BIO-3 and BIO-4 potential significant adverse direct impacts associated with the temporary loss of coastal sage scrub habitat will be reduced to a less than significant level. Prior to grading activities occurring at the sediment storage site and during the operation of the Project a biologist will monitor the construction activity impact area to determine if any species were present. If needed, construction activity will be halted to allow species to move out of harm’s way or be re-located. Therefore, potential direct impacts to individuals will be avoided. With implementation of Mitigation Measures BIO-6, BIO-7, BIO-9 and BIO-10 potential significant adverse direct impacts to individuals will be reduced to a less than significant level. The sediment re-entrainment activities will occur on the levee of the outlet channel. Along the outlet channel there is not any suitable habitat. Suitable habitat for both species is present in the Chino Hills above the sediment re- entrainment area. The re-entrainment activities will be confined to the outlet channel and will not have any adverse impacts on any habitat in the Chino Hills.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-87 Section 3 Environmental Analysis

San Diego Black Tailed Jack Rabbit, Coyote, Mountain Lion, Bobcat, Long- tailed weasel All of the above species have the potential to occur within the area where sediment removal channel and the sediment storage and green waste processing area will be constructed. During construction most individuals will disperse with the approach of construction equipment. However, in the event some mammals cannot effectively disperse, potential significant adverse direct impacts to individuals could occur. To minimize potential significant adverse direct impacts, biological monitors will be present throughout the construction period to assess the potential for sensitive species to be present within the construction activity impact area. If needed, construction activity will be halted to allow species to move out of harm’s way or be re-located. With implementation of Mitigation Measures, BIO-6, BIO-7, BIO-9, BIO-10, BIO-18, and BIO-19 potential significant adverse direct impacts to individuals will be reduced to a less than significant level. The sediment storage site contains a mix of coastal sage scrub and non-native grasslands which could provide foraging habitat for the above species. The grading activities at the sediment storage site will result in the temporary loss of coastal sage scrub habitat. To compensate for the temporary loss of coastal sage scrub habitat, OCWD will restore coastal sage scrub habitat disturbed by the project with in-kind native vegetation. With the implementation of Mitigation Measures BIO-3 and BIO-4 potential significant adverse direct impacts associated with the temporary loss of habitat will be reduced to a less than significant level. The sediment re-entrainment activities will occur on the levee of the outlet channel. Along the outlet channel there is no any suitable habitat. Suitable habitat for the above species is present in the Chino Hills above the sediment re- entrainment area. The re-entrainment activities would be confined to the outlet channel and will not have any adverse impacts on habitat in the Chino Hills. Level of Impact before Mitigation Significant impact. Mitigation Measures BIO-1: All vegetation removal and clearing activities at the sediment removal channel and sediment storage site and green waste processing activities will be conducted outside of the migratory bird season from March 15 to September 15. Biological monitoring of the sediment removal channel and sediment storage site will begin in February to determine if active nests are present. If active nests are

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-88 Section 3 Environmental Analysis

present vegetation clearing activities near the nests will not occur within 500 feet of an active nest. BIO-2: During vegetation removal activities, trees that are removed from the area will be inspected to determine if any nests are present. If nests are encountered they will either be relocated and if not feasible to be relocated a new substitute nest will be created and located outside of the construction activity impact area. BIO-3: After the sediment demonstration project is completed, OCWD will manage the alignment area of the sediment removal channel for five years to keep all disturbed areas free of exotic vegetation and to re-established native vegetation. A 10-foot edge along the serve road of the sediment removal channel will be maintained. OCWD will plant pole cuttings and remove all non-native vegetation that occurs with the 10-foot edge area BIO-4: To compensate for temporary loss of 8.27 acres of native riparian habitat OCWD will restore native riparian vegetation on a 1:1 ratio and manage the area for duration of the project. To compensate for the temporary loss of 2.3 acres of coastal sage scrub habitat OCWD will restore and manage coastal sage scrub vegetation at a 1:1 ratio. The proposed mitigation will also involve removing 12 acres of arundo from the project area and restoring it with native vegetation. The removal and restoration of 12 acres of arundo with the restoration of 8.27 acres of riparian vegetation and 2.3 acres of coastal sage scrub will provide a total of 22.73 acres of compensatory mitigation and mitigation to temporary impact ratio of 2.15 to 1. BIO-5: To ensure that significant construction noise impacts do not occur to active nests of special status species located within the 500 foot construction activity noise impact area, a construction noise mitigation program will be implemented, and will include the following measures. • During the nesting season portable acoustical panels will be placed along perimeter of the sediment removal channel where the floating dredge and/or heavy equipment is operating to reduce construction levels to less than 60 dBA at the closest active nest of special status species. The acoustical panels will be a minimum of 10 foot by 8 foot with a 2 foot cantilevered top with a STC rating of 25 or greater. • During the nesting season portable acoustic panels will be installed as close as perimeter of the work area of the sediment storage site and sediment re-entrainment work area to reduce construction levels to less than 60dBA at the closest active nest of a special status species. The acoustical panels will be a minimum of 10 foot by 8 foot with a 2 foot cantilevered top with a STC rating of 25 or greater.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-89 Section 3 Environmental Analysis

• All construction equipment will be equipped with noise reduction features, such as mufflers and engine shrouds. • Onsite generators and booster pumps will be enclosed entirely. • During nesting season a noise monitoring program will be implemented to ensure that construction noise levels are less than 60 dBA at the closest active nest of a special status species • During the nesting season weekly surveys will be conducted within 500 feet of active construction areas. The purpose of the survey is to determine presence of active nests of special status species and breeding status of individuals. • A qualified biologist approved by CDFW will monitor constriction activities to determine if the construction activities would result disrupt nesting of special status species that are present within 500 feet of an active work area. If it is determined that the construction activity is disrupting the nesting behavior of a special status species, additional mitigation will be provided. If additional mitigation is not feasible construction in that area will cease and be redirected until the nests of special status species are no longer active or until it is determined that the activity will not disrupt nesting behavior. BIO-6: To avoid impacts to special status wildlife species, prior to any ground disturbing activities, during operation and during demobilization of construction equipment, a qualified biologist approved by CDFW will conduct a pre- construction sweep of the project site for special status wildlife species. During these surveys the biologist will 1) inspect the project site for any special status wildlife species and prepare a list of species observed and record their activity during construction and operation of the project, 2) ensure that habitats within the construction activity impact area are not occupied by special status species and that the quality of that habitat is maintained, 3) in the event of the discovery of a special status species determining if the construction activity would cause adverse impacts and 4) if it is determined that the project activity would have the potential to adversely affect special status species and no other measures are available to avoid adverse impacts the biologist will require the project activity to cease until the species is no longer in harm’s way or is relocated outside of the construction activity impact area. BIO-7: Prior to construction activities, a qualified biologist approved by CDFW will conduct a pre-construction training for all construction crew members. The training will focus on required mitigation measures and conditions of regulatory agency permits and approvals. The training will also include a summary of

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-90 Section 3 Environmental Analysis

special status species and habitats potentially present within and adjacent to the project area. BIO-8: During the operation of the project, a qualified biologist approved by CDFW will monitor the construction activity impact area of the sediment removal channel and sediment storage site for active nests. The focus of monitoring will be to identify the presence or absence of special status species nesting within the construction activity impact area. If nesting birds are present the biological monitor will determine if the construction activity will cause them to abandon their nests. If the biological monitor determines that the construction activity will not cause nest abandonment then the construction activities will proceed. If it is determined that the construction activity is causing nest abandonment and additional noise measures cannot be implemented to prevent nest abandonment, then construction activity shall be re-directed or ceased until the time its is determined by the biologist that the activity would not cause nest abandonment or the nest is no longer active. BIO-9: At the end of each work day a qualified biologist approved by CDFW will inspect the work area to ensure there are no components of the Project that could trap or injure wildlife. BIO-10: Qualified biologist approved by CDFW will be onsite at the sediment storage site to monitor the transfer of sediment from the settling ponds to the storage area to ensure wildlife will not be adversely impacted by construction equipment. BIO-11: Prior to start of sediment removal activities a 1/8 inch fish screen will be secured to a temporary gated pipe that would extend through the diversion berm to divert Santa Ana River flows into the sediment removal channel. A 1/8 inch blocking net will also be installed along the Santa Ana River upstream of the diversion berm. The blocking will be secured with rebar or T-posts that are hammered in at the water’s edge and across the channel. The number of posts used will depend on the width and flow of the channel. If the posts are too far apart, there may be too much pressure on the blocking net and it could tear the net or knock down the posts. The blocking net is placed on the upstream side. The top edge of the blocking net is flipped over each post and held in place with a zip tie or piece of wire. The bottom of the blocking net will be draped down in an “L” shape with the lead line (short part of the “L”) facing upstream. The segment of the river between blocking net and the diversion berm will be surveyed daily for fish. Non-native fish captured will be removed from the site and destroyed. Native fish captured will be relocated to suitable locations outside of the project area.

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BIO-12: To avoid and minimize potential impacts to native fish and critical habitat a native fish impact mitigation program will be implemented and will include the following measures. • Prior to surveys or construction activity, OCWD will submit the name and resumes of the qualified biologist conducting surveys. A qualified biologist in regards to Santa Ana Suckers includes those individuals that hold a section 10(a) (1) (A) Recovery Permit. In regards to Arroyo Chubs a biologist is considered qualified if they have conducted a minimum of 30 hours of field activities with Arroyo Chubs under the supervision of a qualified biologist. • Prior to construction activities within the wetted channel, a qualified biologist will conduct a preliminary survey of the affected water body noting habitat and any fish that are present. If native fish are present seining will be conducted to remove and relocate native fish. • All captured native fish will be kept placed in ice chests filled with Santa Ana River water and aerated. The ice chests will be kept shaded at all times. Any native fish removed from the site will be relocated in suitable habitat upstream of the project area, as determined by a qualified biologist. • If capture and relocation of native fish is necessary, such capture will be achieved through use of one or more of the following methods; fine mesh (0.08 to 0.16 inch), knot-less seine nets, fine mesh (0.16 to 0.24 inch) knot-less hoop nets, modified hoop nets, or similar traps or dip nets of 0.20 inch or finer mesh. The survey methods will be selected so as to minimize potential injury or mortality to native fish. Care will be taken to keep native fish in water as much as possible. Larval fishes will be kept submerged in a dip net until species is identified and released. • Prior to activities that may involve handling of native fish, the qualified biologist will ensure that the hands of all participants are free of sunscreen, lotion or insect repellent. • The qualified biologist will be present during the construction of the earthen berm to split flows between the Santa Ana River and the sediment removal channel. • The qualified biologist will submit a report to USFWS and CDFW identifying the number of any native fish species that were relocated and other measures that were taken to minimize impacts to native fish. The

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-92 Section 3 Environmental Analysis

report will be submitted to USFWS and CDFW no more than 60 days following capture and relocation activities. BIO-13: The construction contractor will be required to implement a water quality monitoring program throughout the construction and operation period of the Project and where needed make adjustments to ensure water quality levels are maintained at acceptable levels. BIO-14: Prior to the start of ground disturbing activities, OCWD will prepare and implement a Storm Water Pollution Prevention Plan (SWPPP). The SWPPP will contain structural and non-structural Best Management Practices to manage storm water runoff, erosion and sedimentation to maintain water quality. BIO-15: Spoil sites will not be located within areas where spoil could be washed into the active stream channel, or where it will cover aquatic or riparian vegetation. BIO-16: No equipment maintenance will be done within or near any stream channel where petroleum products or other pollutants from the equipment may enter these areas under any flow. BIO-17: OCWD construction contractor will prepare a Spill Prevention and Contingency Plan. The Plan shall be implemented prior to and during site disturbance and construction activities. The Plan will include measures to prevent or avoid an incidental leak or spill, including identification of materials necessary for containment and clean-up and contact information. The Plan and necessary containment and clean-up materials shall be kept within the construction area during all construction activities. Workers shall be educated on measures included in the plan at the pre-construction meeting or prior to beginning work on the project. BIO-18: Speed limits of 15 miles per hour or less will be required at all times to avoid potential injury to wildfire in the area. BIO-19: Qualified biologist will monitor access roads to ensure wildlife is not impacted by construction equipment. BIO-20: Prior to the start of construction of the sediment removal channel and prior to dredging each day a qualified biologist, approved by CDFW will survey the sediment removal channel to ensure there are no Southwestern Pond Turtles present. If Southwestern Pond Turtles are present they will be relocated to outside of the work area. Additionally, the biologist shall ensure that sediment removal channel is adequately screened to prevent access.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-93 Section 3 Environmental Analysis

Level of Impact after Mitigation • The Project will have the potential to generate temporary construction noise impacts that could disrupt the breeding patterns of the Federal and State Listed Least Bells Vireo if it occurs within construction activity noise impact area. • The Project will have the potential for native fish to occur within the project area and require physical relocation. • The Project will have the potential to generate temporary construction noise impacts that could disrupt breeding patterns of nesting migratory birds.

IMPACT BIO-2: Will the Project have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, and regulations or by the California Department of Fish and Wildlife or U.S. Fish and Wildlife Service? Implementation of the Project will result in both direct and indirect temporary impacts to sensitive vegetation communities. The direct impacts to vegetation communities will occur from the result of removal of vegetation associated with construction activities. Indirectly construction and operation activities could result in the temporary degradation of the value of adjacent habitat from disturbances and colonization of invasive weeds, generation of fugitive dust, increased human presence, and increased vehicle traffic within the project area. The potential impacts to vegetation communities resulting from the implementation of the Project are shown in Table 26. Table 26: Vegetation Impacts (Acres) Impacted Acreage Cottonwood/Willow-Native Understory 11.45(1) Cottonwood/Willow-Non-Native Understory 10.85(1) Mixed Riparian 3.64 Coastal Sage Scrub 0 Mixed Coastal Sage Scrub /Non-Native grasses/Weeds 4.61 Non-Native Grasslands/Weeds 37.50 Arundo 12.16 Eucalyptus 1.25 Open Water 3.58 Total 85.04 (1) Includes 1.75 acres Impacts for access roads

The implementation of the Project will temporary impact the following sensitive communities; 11.45 acres of cottonwood/willow with native understory, 10.85 acres of cottonwood/willow with non-native understory, 3.64 acre mixed native

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-94 Section 3 Environmental Analysis

riparian vegetation and 4.61 acres mixed coastal sage scrub. The permanent loss of these sensitive communities is considered a significant adverse impact. The impacts to the sensitive communities resulting from the implementation of the Project are considered temporary because no permanent losses to sensitive communities will occur. Once the demonstration project is completed native vegetation will be re-established within the sediment removal channel and OCWD will manage the area to ensure that no non-native vegetation occurs. Additionally, at the sediment storage site OCWD will allow native vegetation to re-establish on areas disturbed by the Project. To compensate for the temporary loss of native riparian vegetation and coastal sage habitat OCWD will restore native riparian vegetation and coastal sage scrub habitat. With the implementation of Mitigation Measures BIO-3 and BIO-4 potential temporary significant adverse direct impacts to sensitive vegetation communities will be reduced to a less than significant level. To help minimize the overall direct impacts to native vegetation associated with construction of the sediment removal channel, OCWD will make adjustments to the channel alignment to avoid higher quality habitat areas. Additionally, construction measures will be implemented to minimize adverse indirect impacts to sensitive vegetation communities that could be caused by construction activity. With the implementation of Mitigation Measures BIO-21, BIO-22, BIO-23, BIO-24, BIO-25 and BIO-26 potential significant adverse indirect construction impacts to sensitive vegetation communities will be reduced to a less than significant level. The sediment removal channel will be situated near the Santa Ana River and an earthen diversion berm will be constructed to divert the flows between the sediment removal channel and the river. The construction of the berm will result in 3.58 acres of temporary impacts to open water habitat along the Santa Ana River. Once the project is completed, the diversion berm will be removed and the area of disturbance will be re-contoured to the pre-project condition. There will be no permanent loss of open water habitat. Level of Impact before Mitigation Potential significant impact. Mitigation Measures Mitigation Measures BIO-3 and BIO-4 are required. BIO-21: Unpaved areas will be watered as needed to control dust on a continual basis. BIO-22: During the detailed design and construction phases of the project, OCWD will continue to minimize impacts to native vegetation and wildlife habitat

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whenever possible. This includes shifting footprints or alignment where necessary and possible. BIO-23: Upon development of final construction plans and prior to site disturbance, OCWD will clearly delineate limits of construction on project plans. All construction, site disturbance and vegetation removal will be located within the delineated construction boundaries. The storage of equipment and materials, temporary stockpiling of soil will be located within designated areas only, and outside of habitat areas. BIO-24: OCWD shall monitor construction activities to assure that vegetation is only removed only from designated areas. Riparian areas not to be disturbed shall be flagged. The perimeter of the work site shall be adequately flagged and fenced to prevent damage to adjacent habitat. BIO-25: During construction, adjacent vegetation will be monitored by OCWD for signs of plant stress. BIO-26: OCWD will have an onsite biologist to review grading plans, monitor all grading, excavation and ground disturbing activities in the streambed associated riparian habitat and monitor all aspects of construction monitoring that pertain to biological resource protection. Level of Impact after Mitigation Less than significant impact. IMPACT BIO-3: Will the Project have a substantial adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? The implementation of the Project will result in 34.46 acres of temporary impacts to Wetland Waters of the US/State and 3.58 acres of temporary impacts to non- wetland Waters of the US/State. The impacts to Wetland Waters of the US/State are considered temporary because no permanent fills will occur. Additionally, the re-entrainment of sediment into the Santa Ana River will not be considered a permanent fill, in that the sediment will be removed from one location in Waters of the US/State and will be placed in a different location in the same Waters of the US/State to allow it to migrate downstream. There will be no net increase in fill material in Waters of the US/State. Once the Project is completed the wetland vegetation will be re-established and OCWD will manage the area to ensure non- native vegetation does not re-establish and open water habitat areas disturbed by the project will be returned to their pre-project condition. Additionally, to compensate for the temporary loss of Wetlands Waters of the US/State, OCWD

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-96 Section 3 Environmental Analysis will restore native riparian wetland habitat and manage the area for the duration of the project. There will be no permanent loss of wetland habitat. The impacts to Wetland Waters of the US/State will require approval of 404 Permit from the Corps, 401 Water Quality Certification from Regional Water Quality Control and Streambed Alteration Agreement from CDFW. As part of the permit application OCWD will prepare a habitat management plan to implement the compensatory mitigation requirements for the Project. With the implementation of Mitigation Measures BIO-3, BIO-4, and BIO-27 temporary significant adverse impacts to Wetland Waters of the US/State will be reduced to a less than significant level. Level of Impact before mitigation Potential significant impact. Mitigation Measures Mitigation Measures BIO-3 and BIO-4. BIO-27: Prior to start of construction activity OCWD will prepare a Habitat Management Plan to implement the project compensatory mitigation requirements and will receive permit approval from the US Army Corps of Engineers, Regional Water Quality Control Board and the California Department of Fish and Wildlife. The HMP will be approved by CDFW prior to the start of construction activity. Level of Impact after Mitigation Less than significant impact. IMPACT BIO-4: Will the Project significantly impede the movement or migration of fish or wildlife. Wildlife Movement The Prado Basin functions as a wildlife movement corridor between the Santa Ana River and the Chino Hills and the Santa Ana Mountains. However, because of dense vegetation that has covered trails, fallen trees and logs and mushy unstable grounds movement through the interior of Prado Basin can be difficult. Existing wildlife movement tends to occur along existing trails and service roads located along the edge of the basin where developed land uses and barriers are located than pose conflicts for wildlife movement. The Project proposes the construction of a sediment removal channel parallel to the Santa Ana River. The construction of the sediment removal channel could temporarily interfere with existing wildlife movements occurring along the river. However, once the channel is constructed wildlife will most likely adapt to the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-97 Section 3 Environmental Analysis presence of channel and will establish movement corridors to avoid the channel. Additionally, the access roads along the channel could function as wildlife corridors when not in operation, which would enhance wildlife movement over the current condition. The construction and operation of the sediment removal channel will occur during daylight hours, which will avoid disturbance to many of the predatory species and other large mammals which typically move in the evening and early morning hours. The sides of the sediment removal channel will be constructed at 2:1 slope to allow wildlife to enter and exit the channel at will to reduce the possibility of stranded and injured wildlife. The sediment storage site is contiguous to open space and functions as a wildlife movement corridor into the interior of the Prado Basin. According to Corps staff both deer and coyotes are known to move through the area. The configuration of the work area at the sediment storage site will be designed so when it is not in operation it would allow for wildlife movement. Such design measures will include reducing the slope and height of stockpiled sediment and providing adequate spacing between sediment stockpiles and settling ponds. Additionally, to minimize construction related impacts to wildlife impacts at the sediment storage site a series of construction impact minimization measures will be implemented. Sediment re-entrainment activities will occur along the south levee of the Prado Dam outlet channel. Chino Hills is located north of the sediment re-entrainment area and provides an open space destination and wildlife corridor for many wildlife species. The sediment re-entrainment activities will be confined to south bank of the outlet channel and will not impede wildlife movement into the Chino Hills. The sediment re-entrainment activities could occur at night which will require onsite lighting during the night time hours. The lighting for the re- entrainment activities will be confined to the work area on the south side of the outlet channel. Sound attenuation noise barriers will be provided around the work area to minimize noise impacts. It is anticipated that wildlife will avoid the area when sediment re-entrainment activities are being conducted. The potential adverse impact on wildlife will be short-term and with the implementation of Mitigation Measures BIO-28, BIO-29 and BIO-30 potential significant adverse impacts associated with wildlife movement will be reduced to a less than significant level. Migratory Birds The riparian forest in the Prado Basin contains an abundance and diversity of bird species. Neotropical migrants depend on deciduous trees and shrubs for foraging during migration and for nesting. The mature trees provide numerous

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-98 Section 3 Environmental Analysis

cavities for cavity dependent wildlife and the taller trees are used by nesting raptors. The emergent vegetation at the water’s edge provides escape cover, shade and a source of food. To avoid direct impacts to nesting birds, the excavation of the sediment removal channel and the grading activities at the sediment storage site will occur outside of nesting season. Within the implementation of Mitigation Measure BIO-1 and BIO-2 potential significant adverse direct impacts to active nests and nesting birds will be avoided. Dredging operations associated with the Project will begin in late winter and extend into the nesting season. The dredging operations will be confined to the wetted sediment removal channel. Therefore, direct impacts to nesting birds will be avoided. The dredging operations will begin in late winter and the noise emitted from the dredging operations could discourage species from nesting within the immediate vicinity of the sediment removal channel when nesting season begins. Depending on noise tolerance, individual species could seek other suitable locations to nest in the Prado Basin. To reduce construction noise levels to an acceptable level a construction noise mitigation program will be implemented. With implementation of Mitigation BIO-4, BIO-6 and BIO-8 potential noise impacts will be minimized. However, there is potential that some migratory birds could nest within the construction activity noise impact area, when construction operations are not occurring and could be disrupted when construction activities re-commences. The potential for construction noise impacts to disrupt the breeding patterns of nesting migratory birds is a significant adverse impact. At the sediment storage site sound attenuation panels will be installed around the work area to reduce adverse indirect construction noise impacts to nesting migratory birds to acceptable levels. The sediment re-entrainment activities will occur outside of nesting season. Potential adverse indirect construction noise impacts to nesting migratory birds will be avoided. Level of Impact before Mitigation Significant Impact. Mitigation Measures Mitigation Measures BIO-1, BIO-2, BIO-4, BIO-6, BIO-8, BIO-28, BIO-29 and BIO-30 are required. BIO-28: Construction lighting at the sediment re-entrainment area will focus on the work site to prevent off site spill-over lighting impacts to wildlife. Construction lighting fixtures will be shielded by providing a side flap on the lights

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BIO-29: A liter control program will be implemented during construction to eliminate the accumulation of trash. Trash shall be removed from trash receptacles at the end of each work day to discourage wildlife movement into work areas. BIO-30: The configuration of the work area at the sediment storage site will be designed so when it is not in operation it would allow for wildlife movement. Such design measures will include reducing the slope and height of stockpiled sediment and providing adequate spacing between sediment stockpiles and settling ponds. Level of Impact after Mitigation The potential for construction noise impacts to disrupt the breeding patterns of nesting migratory birds is a significant adverse impact. IMPACT BIO-5: Will the Project be in conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? Western Riverside County Multiple Species Habitat Management Plan The project area is included within the Western Riverside County Multiple Species Habitat Conservation Plan (MSHCP). The project area is included within Existing Core Area A, which is defined as areas that contain a block of habitat of appropriate size, configuration, and vegetation characteristics to generally support the life history requirements of one or more covered species. Existing Core A is located in the southwest region of the MSHCP Area and is comprised largely of Public/Quasi-Public Lands owned by a variety of entities, but it also contains a small number of privately-owned lands. The core functions as a linkage, connecting Orange County to the west and San Bernardino County to the north. The objective of the MSHCP in this area is to maintain riparian habitat within the existing core and along the existing core edges, the maintenance of existing floodplain processes and the maintenance of water quality along the Santa Ana River. To provide a greater level of management of biological resources, the MSHCP is further divided into Area Plans based on the County of Riverside General Plan. The project area is included within the Temescal Area Plan. The Temescal Area Plan is divided into different subunits based on habitat conditions and conservation focus. The project area is located within the Prado Basin Subunit. The focus of the Prado Basin Subunit is the conservation of wetland habitats, riparian scrub, and cottonwood/willow woodland associated with Prado Basin. The purpose of the Project is to identify a feasible method to remove sediment from the Prado Basin and re-entrain the sediment back into the Santa Ana River.

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The Project will be consistent with the MSHCP Core Area A objectives, in that the Project will remove the sediment from the basin to increase useful life of the dam and to help reverse the trend of declining riparian habitat. The Project will temporary impact 38.10 acres of riparian vegetation. Once the Project is completed the native vegetation will be re-established in areas disturbed by the Project and OCWD would manage the area to ensure that non-native vegetation does not re-establish. To compensate for the temporary loss of native riparian habitat, OCWD will restore disturbed native riparian habitat and manage the area during the duration of the project. With the implementation of Mitigation Measures BIO-3, BIO-4 and BIO-27 potential adverse conflicts with MSHCP Core Area A objectives will be reduced to a less than significant level. County of Orange Santa Ana Canyon Habitat Management Plan The proposed sediment re-entrainment activities will occur upstream of the County of Orange Santa Ana Canyon Habitat Management Plan (HMP). The Santa Ana Canyon Habitat Management Plan was prepared as a requirement of the Final Supplemental Impact Statement for the Phase II General Design Memorandum for the Santa Ana River Mainstem Project. The HMP addresses the floodplain and open wildlife habitat in the Santa Ana Canyon below Prado Dam and provides for planning and management continuity for the canyon habitat from Prado Dam downstream to Weir Canyon. The HMP lists permitted activities within the study area that include; maintenance, repair and operations of flood control works, utilities, trails, bridges, park facilities, habitat restoration, use of recreation trails, hiking, bicycling, construction of remaining regional trail and bikeway segments, wildlife viewing, camping, picnicking and golfing. One objective of the Project is to enhance and restore habitat in the Santa Ana River by preventing further degradation of certain areas of the river sediment transport processes and to prevent further degradation of the Santa Ana River due to sediment starved stream flows. The restoration of the Santa Ana River is consistent with the permitted activities listed in HMP. The proposed sediment re- entrainment activities will occur along the levee of the outlet channel and will not result in any direct adverse impacts to sensitive wildlife or vegetation communities within the HMP study area. Generally, silt and clay sized particles are often undesirable for riparian habitat. The sediment transport modeling prepared for the Project indicates that clay and silt sized particles contained in the sediment re-entrained into the river will be transported through the river and most of it would be released to the ocean. Because the cay and silt particles will be re-entrained during high flows, they would move through the river system quickly and would not result in significant deposits in one location. Additionally, the sediment transport modeling indicates

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-101 Section 3 Environmental Analysis

that the sediment re-entrained into the river will not degrade existing native fish habitat in the Santa Ana Canyon Reach. An analysis of sediment that will be entrained in the river indicates that are no containments in the sediment that will result in adverse health impacts to aquatic life in the river. The implementation of the Project will not result in adverse impacts that will conflict with policies and programs in the HMP that provide for the protection biological resources in the Santa Ana River Level of Impact before Mitigation Potential significant impact. Mitigation Measures Mitigation Measures BIO-2, BIO-3 and BIO-27 are required. Level of Impact after Mitigation Less than significant impact. 3.3.5 Unavoidable Significant Impacts to Listed Sensitive Species The temporary construction noise generated from dredging activities could potentially disrupt breeding patterns of State Listed Endangered Species Least Bells Vireo that could potentially occur within the construction activity noise impact area. While the impact is considered a significant adverse impact, the impact will not jeopardize the overall survivability of the species. If it is determined by CDFW that the temporary impacts to breeding patterns constitute a Take, OCWD will seek authorization by Individual Take Permit issued by California Department of Fish and Wildlife or through an Individual Take Permit issued under the Western Riverside County Multiple Species Habitat Management Plan. Authorization for temporary impacts to Federal Listed Species will be coordinated with USFWS. 3.3.6 Orange County Water District Prior Mitigation Commitments in Prado Basin Presently, OCWD and the Corps are implementing a water conservation program at Prado Dam. Under the water conservation program, the Corps temporarily captures excess water behind Prado Dam and controls the amount of water released from the dam to an amount that allows OCWD to percolate the released water into its downstream groundwater recharge basins. The initial agreement between OCWD and the Corps retained water behind the dam for conservation up to the 494 foot elevation all year. In 1993 the initial water conservation agreement was amended to increase the elevation in the dam where water could

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-102 Section 3 Environmental Analysis be stored to the 494 foot elevation during flood season and to the 505 foot elevation during the non-flood season. The retention of water behind the dam increased the periods of time that Prado Basin will be inundated with water. Biological Opinions issued by USFWS determined that the increased periods of inundation will reduce the environmental values of habitat in the Prado Basin and that the reduced environmental values could have an adverse effect on the habitat of the least Bells vireo and the Southwestern willow flycatcher. To compensate for the reduced environmental values in Prado Basin between the 494 foot and 505 foot elevations, OCWD provided monetary contribution to establish a conservation fund to remove arundo from the Santa Ana River watershed, restored 228 acres riparian habitat, established a vireo and flycatcher monitoring program and implemented a brown-headed cowbird trapping program in the Prado Basin. At this time OCWD has met all mitigation requirements. In 2006 the water conservation agreement was amended to allow water to be stored to the 498 foot elevation during the flood season (October 1 through the end of February) and to the 505 foot during the non-flood season (March 1 to September 30). The increased elevation resulted in additional days of inundation at Prado Basin. To compensate for reduced values in the Prado Basin from the additional days of inundation, OCWD provided monetary contribution and restored an additional 37.2 acres of riparian habitat. At this time OCWD has met all mitigation requirements. Based on OCWD prior mitigation commitments the area below 505 foot elevation has been fully mitigated. The area of impact for the construction of the sediment removal channel with access roads is 39.31 acres. A total of 15.44 acres of the sediment removal channel is below the 505 foot elevation and has been fully mitigated. As shown in Table 27, a total of 22.08 acres of the sediment removal channel is above the 505 foot elevation. Within the 22.08 acre area, 12.16 acres consist of arundo which will be removed and re-established with native vegetation. Excluding the area where the arundo will be removed, the project will temporarily impact 8.27 acres of riparian wetland vegetation that will be subject to compensatory mitigation requirements. Table 27: Vegetation Communities at Different Elevations (Acres) Vegetation Community Below 494 ft 494 ft to 498 ft. 498 ft. to 505 ft. Above 505

Cotton/Willow/Native .94 7.03 3.30 1.94 Understory Cottonwood/Willow/Non- 0 .20 2.57 6.33 Native Understory Aquatic 0 .15 3.40 Arundo 0 0 0 12.16 Eucalyptus .71 .54 0 0 Total Acreage 1.65 7.77 6.02 22.08

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3.3.7 Proposed Mitigation Concept The implementation of the Project will result in temporary impacts to 8.27 acres of riparian wetland vegetation and 2.3 acres of coastal sage scrub vegetation that will be subject to compensatory mitigation requirements. OCWD will prepare a Habitat Management Plan (HMP) to implement the Project’s restoration mitigation requirements. The HMP will include restoration activities to re-establish native vegetation in areas disturbed by the Project and will include a compensatory mitigation program to compensate for temporary impacts to riparian wetland vegetation and coastal sage scrub habitat occurring during the operation of the Project. The establishment 12.16 acres of native vegetation in areas that currently contain arundo along with the restoration of 8.27 acres of riparian wetland vegetation and 2.3 acres of coastal sage scrub will provide a total of 22.73 acres of compensatory mitigation and mitigation to temporary impact ratio of 2.15 to 1. A general approach of the proposed restoration activities is discussed below. The HMP prepared for the Project would further refine the approach and include; plant pallets, planting methods, non-native vegetation removal methods and irrigation methods, performance standards, monitoring program, adaptive management strategies and a maintenance plan. Sediment Removal Channel Re-establish Native Vegetation The vegetation removal activities at the sediment removal channel will removal a total of 12.16 acres of Arundo. During the operation of the Project, a 10 foot native vegetation edge along both sides of the sediment removal channel will be planted and maintained by OCWD. Native vegetation pole cuttings will be planted and the area will be maintained to remove non-native vegetation. After the Project is completed, OCWD will re-establish native vegetation within the sediment removal channel through passive restoration. It is anticipated that it would take approximately two years to re-establish the native vegetation. OCWD will maintain the sediment removal channel and access roads along the channel for five years to ensure that non-native vegetation does not re-establish. OCWD will maintain the area monthly or on an as needed basis. Sediment Storage Site Re-establish Native Vegetation After the Project is completed OCWD will remove all non-native vegetation and will seed coastal sage scrub vegetation in areas of the site that contained coastal sage scrub disturbed by the project. OCWD will maintain the sediment storage site for five years to ensure that non-native vegetation does not re-establish. OCWD will maintain the area monthly or on an as needed basis.

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Riparian Wetland Mitigation Sites The Project will temporary impact 8.27 acres of riparian wetland vegetation that will be subject to compensatory mitigation requirements. Two potential mitigation sites have been proposed to compensate for riparian wetland vegetation associated with the construction and operation of the sediment removal channel. Table 28 identifies the type and amount of existing vegetation at each proposed riparian mitigation site, the amount of potential habitat restoration activities and property ownership. Figure 13 and Figure 14 show potential restoration opportunities at each riparian mitigation site. The final selection of riparian mitigation site that will be used for compensatory mitigation will be coordinated with the resource agencies and will be included in the HMP. Table 28: Riparian Mitigation Sites (Acres) Mitigation Site Total Existing Existing Non- Proposed Ownership Acreage Native Native Restoration Vegetation Vegetation Pheasant Field 113.88 45.02 67.53 8.27 OCWD Property Land Adjacent 177.36 46.20 131.16 8.27 Corps Yorba Slaughter Adobe property

Coastal Sage Scrub Mitigation Sites The implementation of the Project will temporary impact 4.6 acres of mixed coastal sage scrub. This vegetation community consist approximately 50% non- native weeds and 50% coastal sage scrub. OCWD will be required to compensate for half of the biological values of the vegetation community. A total of 2.3 acres of coastal sage scrub habitat will be subject to compensatory mitigation requirements. Two potential mitigation sites have been proposed to compensate for coastal sage scrub impacts. Table 29 identifies the type and amount of existing vegetation at each coastal sage scrub mitigation site, the amount of potential habitat restoration activities and property ownership. Figure 15 and Figure 16 show potential restoration opportunities at each coastal sage scrub mitigation site. The final selection of coastal sage scrub mitigation site that will be used for compensatory mitigation will be coordinated with the resource agencies and will be included in the HMP.

Table 29: Coastal Sage Scrub Mitigation Site (Acres) Mitigation Site Total Existing Existing Non- Proposed Ownership Acreag Native Native Vegetation Restoration e Vegetation Pigeon Hill 6.49 1.59 4.89 2.3 OCWD Demonstration 15.31 0 15.31 2.3 Corps Garden Extension

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-105 Remove non-native grasses and weeds. Restore with 8.27 acres native riparian vegetation. Path: K:\Prado\SedimentManagementPlan\MXD\EIR2014\F13_AdobeVeg.mxd

Arundo Cottonwood Willow & Non-Native Understory Non-Native Grasses & Weeds 0 150 300 Prado SMDP Cottonwood Willow & Native Understory Euculyptus USACE Dike Project Area Feet Yorba Slaughter Adobe Property Mitigation Site Aerial Imagery Eagle Aerial Spring 2012 Figure 13 Remove 8.27 arcres of arundo and restore with native riparian vegetation. Path: K:\Prado\SedimentManagementPlan\MXD\EIR2014\F14_PheasantVeg.mxd

Arundo Cottonwood Willow & Native Understory Mixed Riparian 0 150 300 Prado SMDP Bare Ground & Weeds Cottonwood Willow & Non-Native Understory Palms Feet Pheasant Field Mitigation Site Aerial Imagery Eagle Aerial Spring 2012 Figure 14 Remove 2.3 acres non-native grasses and restore with coastal sage scrub. Path: K:\Prado\SedimentManagementPlan\MXD\EIR2014\F15_GardenVeg.mxd

0 150 300 Prado SMDP Non-Native Grasses & Weeds Feet Demonstration Garden Extension Mitigation Site Aerial Imagery Eagle Aerial Spring 2012 Figure 15 Remove 2.3 acres non-native grasses and restore with coastal sage scrub. Path: K:\Prado\SedimentManagementPlan\MXD\EIR2014\F16_PigeonVeg.mxd

0 150 300 Prado SMDP Mixed Coastal Sage & Non-Native Grasses & Weeds Non-Native Grasses & Weeds Feet Pigeon Hill Property Mitigation Site Aerial Imagery Eagle Aerial Spring 2012 Figure 16 Section 3 Environmental Analysis

3.4 CULTURAL RESOURCES 3.4.1 Regulatory Framework Federal Regulations Federal agencies are required to consider the effects of their actions on historic properties under the National Historic Preservation Act (NHPA) Section (§) 106 process. Federal agencies are responsible for initiating Section 106 review and completing the steps in the process outlined in the regulations. Furthermore, Section 106 requires that any federal or federally assisted undertaking, or any undertaking requiring federal licensing or permitting, consider the effect of the action on historic properties listed in or eligible for the National Register of Historic Places (NR). Resource eligibility for listing on the NR is detailed in 36 CFR Part 63 and criteria for resource evaluation is located in 36 CFR Part 60.4 [a-d]. Properties less than 50 years old may be considered for listing in the NR if they exhibit exemplary cultural characteristics. The NHPA established the NR as the official federal list for cultural resources that are considered important for their historical significance at the local, state, or national level. To be determined eligible for listing in the NR, properties must meet specific criteria for historic significance and possess certain levels of integrity of form, location, and setting. The criteria for listing on the NR are nationally significant in American history, architecture, archaeology, engineering, and culture as present in districts, sites, buildings, structures, and objects that possess integrity of location, design, setting, materials, workmanship, feeling, and association. The criteria that are considered to determine historical significance include. • Is the site associated with events that have made a significant contribution to the broad patterns of our history? • Is the site associated with the lives of persons significant in our past? • Does the site embody the distinctive characteristics of a type, period, or method of construction; represent the work of a master; possess high artistic values, represent a significant and distinguishable entity whose components may lack individual distinction? • Does the site yield, or may be likely to yield, information important in prehistory or history? State Regulations At the CEQA level of analysis, a site or structure may be considered an historical resource if it is significant in the architectural, engineering, scientific, economic, agricultural, educational, social, political, military or cultural annals of California

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(PRC §5020.1[j]), or if it meets the criteria for listing on the NR or the California Register of Historical Resources (CR) (14 CFR §4850). CEQA allows for local historic resource guidelines to serve as the CR criteria, if enacted by local legislation, to act as the equivalent of the State criteria. If the resource has integrity and any one of the criteria noted below are met at the State level of analysis, the resource will be considered significant and a direct impact to the cultural resource will be considered a significant impact on the environment. Typically, researchers in California use a 45-year age threshold following State Historic Preservation Office (SHPO) recommendations. The time lag of five years between the State and federal criteria is explained by the fact that it takes about five years to plan for and redevelop any one property: The criteria that are considered to determine historical significance include. • Is the site associated with events that have made a significant contribution to the broad patterns of California’s history and cultural heritage? • Is the site associated with the lives of persons important in our past? • Does the site embodies distinctive characteristics of a type, period, region, or method of construction, or represent the work of an important creative individual, or possesses high artistic values? • Would the site yield, or may be likely to yield, information important in prehistory or history? 3.4.2 Existing Environmental Setting Cultural resources include prehistoric archaeological sites, historic archaeological sites, historic structures, and artifacts made by people in the past. Prehistoric archaeological sites are places that contain the material remains of activities carried out by the native population of the area (Native Americans) prior to the arrival of Europeans in Southern California. Prehistoric sites are defined as sites that contain three or more artifacts that are in association or where there is a feature such as a foundation or bedrock mortar. A site that contains three or less artifacts is called an isolate. Artifacts found in prehistoric sites include flaked stone tools such as projectile points, knives, scrapers, and drills; ground stone tools such as manos, metates, mortars, and pestles for grinding seeds and nuts; and bone tools. Prehistoric facilities and features include hearths, bedrock mortars, rock shelters, rock art, and burials. Historic archaeological sites are places that contain the material remains of activities carried out by people during the period when written records were produced after the arrival of Europeans. Historic archaeological material usually consists of refuse, such as bottles, cans, and food waste, deposited near

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structure foundations. Archaeological investigation of historic period sites is usually supplemented by historical research using written records. Historic structures include houses, commercial structures, industrial facilities, and other structures and facilities more than 50 years old. Prehistoric Setting Early Man Period Spanning the period from approximately 15000 to 6000 B.C., archaeological assemblages attributed to this horizon are characterized by large projectile points and scrapers. The limited data available suggests that prehistoric populations focused on hunting and gathering, moving about the region in small nomadic groups. Technologies associated with ocean resource gathering would have likely been utilized in coastal areas. Millingstone Period Characterized by the appearance of handstones and milling stones, this horizon tentatively dates to between 6000 and 1000 B.C. Assemblages in the early Millingstone Period reflect an emphasis on plant foods and foraging subsistence systems. For inland locales, it has been assumed that exploitation of grass seeds formed a primary subsistence activity. Artifact assemblages include choppers and scraper planes, but there is a general lack of projectile points in excavated assemblages. The appearance of large projectile points in the late portion of the Millingstone Horizon suggests the development of a more diverse economy. The distribution of milling stone sites reflects the theory that aboriginal groups may have followed a modified central-based wandering settlement pattern. In this semi-sedentary pattern, a base camp would have been occupied for a portion of the year, but small population groups seasonally occupied subsidiary camps in order to exploit resources not generally available near the base camp. Sedentism apparently increased in areas possessing an abundance of resources that were available for longer periods. More arid inland regions would have provided a seasonally and aerially dispersed resource base, restricting sedentary occupation Intermediate Period Dating between 1000 B.C. and 750 A.D., the Intermediate Horizon represents a transitional period. Little is known about the people of this period, especially those of inland southern California. Site assemblages retain many attributes of the Millingstone Horizon. Additionally, Intermediate Horizon sites contain large- stemmed or notched projectile points and portable mortars and pestles. The mortars and pestles suggest that the aboriginal populations may have harvested, processed, and consumed acorns. Due to a general lack of data, neither the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-112 Section 3 Environmental Analysis settlement and subsistence systems nor the cultural evolution of this period is well understood. It has been proposed that sedentism increased with the exploitation of storable food resources, such as acorns. The duration and intensity of occupation of base camps increased during this period, especially in the later part of the horizon. Late Prehistoric Period Extending from 750 A.D. to Spanish Contact in 1769 A.D., the Late Prehistoric Horizon reflects an increased sophistication and diversity in technology. Assemblages characteristically contain projectile points, which imply the use of the bow and arrow. In addition, assemblages include steatite bowls, asphaltum, grave goods, and elaborate shell ornaments. Use of bedrock milling stations was widespread during this horizon. Increased hunting efficiency and widespread exploitation of acorns provided reliable and storable food resources. Ethnohistoric Background The northwestern quarter of Riverside County, and the Corona area, includes lands that have been identified with the Luiseño, Gabrieliño, Serrano and Cahuilla groups. This portion of Riverside County includes the northwestern-most portion of documented Cahuilla territory, mapped as extending just beyond the City of Riverside. The Luiseño traditional use area is mapped as extending from the Pacific Ocean inland to Lake Elsinore and Palomar Mountain in the east, and extending from Agua Hedionda in the south to Aliso Creek in the north. The Gabrieliño tribal territory is mapped as extending north from Aliso Creek to just beyond Topanga Canyon along the Pacific Coast, and inland to the City of San Bernardino. Their territory would have included portions of the Santa Ana River situated in the northwestern-most quarter of the northwestern quarter of the modern County of Riverside. The Serrano traditional use area is then mapped to the northeast and east of Gabrieliño lands, encompassing much of the San Bernardino Mountains from the Cajon Pass in the west, past modern Twenty- nine Palms in the east. The Cahuilla The Cahuilla belong to the Shoshonean linguistic family and have had definitive historical relationships with the Hopi of Arizona, the Gabrieliño, and Digueno of the southern Californian coast and the Luiseño of Riverside County, as well as other desert tribes such as the Kamia, Chemehuevi, Paiute, and Serrano. The Cahuilla population prior to Spanish contact could have been as numerous as 6,000 persons, in an area encompassing more than 2,400 square miles. The Cahuilla villages were determined according to their proximity to a defined water source and access to a food-gathering locale. Village sites were usually located

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-113 Section 3 Environmental Analysis near alluvial fans, streams or at the base of mountains for protection against the winds. The Cahuilla can be discussed according to their primary village locality: Desert Cahuilla, Mountain Cahuilla, and Pass Cahuilla, while other Desert Cahuilla settlements were located around hand dug wells and watering holes. Typically, one clan or family occupied several food-gathering locations and guarded these areas against other Cahuilla clans. Cahuilla homes were generally constructed with forked posts, which supported wood ceiling beams. These structures were then completely covered in thatch, which was slightly mixed with sand or soil. In some cases, the floor was slightly subterranean and each house was positioned so that a level of privacy was attained. The Cahuilla homes were generally hidden in mesquite groves, which effectively obscured them from plain view. The first recorded contact between the native Cahuilla and European culture was in 1776. At this time, the Anza expedition was traveling through Los Coyotes Canyon. The next recorded contact does not occur until 1809 through the San Gabriel Mission, when the missionaries were baptizing the Cahuilla. Based on information from the 1823 and 1826 expeditions of Jose Romero, the Cahuilla could speak Spanish and were running cattle from Palm Springs through the San Gorgonio Pass. Mission Indians throughout most of Southern California and Northern Baja California began demanding that the Missions be turned over to them permanently during 1834 to 1835. When this did not occur, local Indian groups began abandoning and rebelling against the missions. In 1851, the Cahuilla were hostile towards the Europeans and planned an uprising in Hemet with plans to attack and destroy Los Angeles; however, with the help of Cahuilla Chief Juan Antonio the uprising was thwarted. Eventually a state of equilibrium developed in the region and Mexican officials and Rancho owners began utilizing local Indians as allies, soldiers, and guardians. In 1842 a band of Mountain Cahuilla served as an auxiliary force for the Lugo family in the Colton-San Bernardino area. A Desert Cahuilla leader named Cabezon also became a Mexican ally. These Indian forces helped in capturing and killing hostages as well as defending livestock. Cahuilla leaders such as Cabezon functioned as intermediaries between other Cahuilla bands, Europeans, and the Spanish-Mexican people. The Luiseño The northwestern quarter of Riverside County includes the extreme northeastern portion of the territory associated with the Luiseño, a tribe once affiliated with the San Luis Rey Mission at Oceanside, California. Historically, the Luiseño spoke a language that belongs to the Cupan group of the Takic subfamily of the Uto-

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Aztecan language family, a language family that includes the Shoshonean groups of the Great Basin. This northern portion of the Luiseño traditional use area is also affiliated with the term Juaneño. Earlier studies used this tribal designation to separate the native groups associated with the Mission San Juan Capistrano from the groups associated with the Mission San Luis Rey. Later studies indicated that the Juaneño and Luiseño groups spoke closely related languages, both part of the Takic subfamily, and once shared many common cultural traits. The language studies indicated that the Juaneño and Luiseño are ethnologically and linguistically an ethnic nationality. Scholars generally use the term Luiseño when discussing the Takic speaking groups associated with both the Mission San Luis Rey and the Mission San Juan Capistrano. Generally, the Luiseño were characterized by the occupation of sedentary villages in subsistence territories that permitted them to reach the majority of their resources within a day’s walk. Villages were commonly located along valley bottoms, streams, or coastal strands. From October to November, much of the village population moved to temporary camps in the mountains to harvest acorns and hunt game. Inland groups also had fishing and gathering spots on the coast that they visited annually. In comparison with the Gabrieliño and Cahuilla, the Luiseño appear to have had higher population density and a more rigid social structure. The Luiseño patterns may have been relatively stable until mission secularization in 1834. Instability could have resulted from the policy of the Catholic Mission fathers or padres to maintain imported European traditional style settlement and economic patterns. The Gabrieliño The arrival of Spanish explorers and the establishment of missions and outposts during the eighteenth century ended the prehistoric period in California. At this time, traditional Gabrieliño society began to fragment as a result of foreign diseases and the mass removal of local Indian groups to the Mission San Gabriel and Mission San Juan Capistrano. The Gabrieliño spoke a language that belongs to the Cupan group of the Takic subfamily of the Uto-Aztecan language family (a language family that includes the Shoshonean groups of the Great Basin). The total Gabrieliño population in about 1770 AD was roughly 5,000 persons, based on an estimate of 100 small villages, with approximately 50 to 200 people per village. Their range is generally thought to have been located along the Pacific coast from Malibu to San Pedro Bay, south to Aliso Creek, then east to Temescal Canyon, then north to the headwaters of the San Gabriel River. Also included were several islands, including Catalina. This large area encompasses the City of Los Angeles, much of Rancho Cucamonga, Corona, Glendale, and Long Beach.

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By 1800, most traditional Gabrieliños had either been killed, or subjugated by the Spanish. The first modern social analyses of Gabrieliño culture took place in the early part of the twentieth century. By this time, acculturation and disease had devastated this group, and the population studied was a remnant of their pre-contact form. Nonetheless, the early ethnographers viewed the Gabrieliño as a chief-oriented society of semi-sedentary hunter gatherers. Influenced by coastal and interior environmental settings, their material culture was quite elaborate and consisted of well-made wood, bone, stone, and shell items. Included among these was a hunting stick made to bring down numerous types of game. Located in an area of extreme environmental diversity, large villages may have been permanent, such as that found on or near Red Hill in Rancho Cucamonga, with satellite villages utilized seasonally. Their living structures were large, domed, and circular thatched rooms that may have housed multiple families. The society exhibited ranked individuals, possibly chiefs, who possessed a much higher level of economic power than unranked persons. The Serrano The Serrano traditional use area is mapped as encompassing the San Bernardino Mountains from the Cajon Pass in the west to beyond modern Twenty-nine Palms in the east, and from about Victorville in the north to near the San Gorgonio Pass in the south. However, these borders are ill defined, due to a lack of reliable data and to the Serrano sociopolitical organization. The Serrano were organized into autonomous lineages occupying defined territories; however, these groups rarely identified a permanent habitation site. These groups were neither politically aligned, nor were they socially connected outside of each localized lineage. For these reasons, the borders of the arbitrarily grouped Serrano peoples would vary greatly from lineage to lineage, depending upon their respective worldviews. Studies on linguistic characteristics have indicated that the term Serrano had been academically applied to four different groups, including the Serrano, Kitanemuk, Vanyume, and the Tataviam. The Vanyume use area has been mapped to the north of Victorville, extending from the Cajon Pass in the west, to near modern Ludlow between the Cady and Bristol Mountains. The Kitanemuk and Tataviam are found within the general vicinity of the Tehachapi Mountains. The Serrano generally spoke a language that also belongs to the Cupan group of the Takic subfamily of the Uto-Aztecan language family, a language family that includes the Shoshonean groups of the Great Basin. The total Serrano population at contact was roughly 2,000 persons. The range of this group was

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limited and restricted by reliable water sources. The Spanish decimated all indigenous groups adjacent to the San Bernardino Mountains, but some Serrano survived for many years. This was due to the ruggedness of the terrain in the far eastern San Bernardino Mountains and to their dispersed population forms the primary historical sources for this group. Serrano populations studied in the early part of the last century were a remnant of their cultural form prior to contact with the Spanish Missionaries. Nonetheless, the Serrano are viewed as clan and moiety-oriented or local lineage-oriented group tied to traditional territories or use areas. Typically, a “village” consisted of a collection of families centered about a ceremonial house, with individual families inhabiting willow-framed huts with tulle thatching. Considered hunter-gatherers, the Serrano exhibited a sophisticated technology devoted to hunting small animals and gathering roots, tubers, and seeds of various kinds. Today, Serrano descendants are found mostly on the Morongo and San Manuel reservations. The term Morongo is derived from Maringa, which is a shortened form of Maringayam. This term is applied to the easternmost division of the Serrano peoples, and is a generic term that incorporates all the families and lineages in the general area, including the Tumukvayam in Banning Water Canyon and Tamianutcem at Twenty-nine Palms Historic Setting City of Corona and Vicinity Originally named South Riverside, the history of the modern City of Corona can be traced to lands once part of a series of ranchos belonging to prominent Spanish-Mexican families. Prior to development of South Riverside, the entire Corona Plain belonged to a variety of families, including the Serranos, Yorbas, Sepulvedas, Cotas, Bandinis, and the Botillers. In April of 1876, the lands of the original Rancho La Sierra, located between Temescal Wash and the east side of the Santa Ana Mountains, were divided among the many heirs of Don Bernardo Yorba. After this division, the central portion of modern Corona was located in the Rancho La Sierra (Yorba). In 1886, R.B. Taylor bought a large quantity of land once located within the Yorba rancho and beyond, consisting of acreage from Vincente Yorba, Pulaski & Goodwin, the Cota family, the Pat Harrington ranch, the Barney Lee ranch, as well as acreage in Temescal Canyon. Taylor believed that the acquisition of the Temescal Canyon lands would provide enough water resources to sustain a town site, and he began to look for investors in his native state of Iowa. Upon his return to Sioux City, Taylor was able to generate $200,000 from business associates, and he returned to California to initiate his business enterprise. R.B Taylor formed the South Riverside Land and Water Company, and appointed himself as a director, as well as his business partners from Iowa. The consortium decided to name the proposed town site South Riverside, in an

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-117 Section 3 Environmental Analysis

effort to capitalize on the already established Riverside colony, and they purchased 12,000 acres of quality agricultural land. Thereafter, Taylor and his investors focused on the development of agricultural enterprises, the establishment of water rights and the sale of smaller parcels to prospective homesteaders. H.C. Kellogg began surveying the town site in July of 1886, with the known version of the completed survey map available in 1891. The most notable feature of the Kellogg survey map was a circular drive approximately 3 miles in length. Known as Grand Boulevard, this circular road encompassed 407 acres, divided into 193 town-blocks. This area would eventually serve as a buggy route for the earliest inhabitants of South Riverside, where they could find all the amenities a community had to offer, including stores, residences, churches, and schools. However, prior to the establishment of this envisioned downtown sphere, water would need to be made directly available to the area. To accomplish this, some of the early townspeople formed the Temescal Water Company in 1887. The company built a water pipeline that sent water from the wetlands of Temescal Canyon onto the proposed town site. Throughout 1886 and 1887, approximately $275,725 worth of lots had been sold to prospective homesteaders and entrepreneurs, water had been supplied, and the first hotel had been constructed. While the early inhabitants began to plant orange and lemon trees upon arriving, it would be several years before any of the groves would yield enough fruit to be profitable. In the meantime, South Riverside began to entice additional residents with its mineral wealth. The Pacific Clay Company was established to produce pottery, tableware, and sewer pipe from the clay available on nearby lands, and the construction of a factory was announced in 1888. About this same time, the Porphyry Paving Company began to bring in equipment and laborers to make use of the porphyry deposits known to the east of the town. These endeavors stimulated an increase in the population of the town; however, it was the arrival of the Santa Ana and Los Angeles Railroad that greatly influenced the population explosion in the area. By June of 1887, the first train arrived at the town site, and South Riverside became an official stop on the rail line. In 1896, the name of South Riverside was officially changed to Corona. This followed an election to determine whether the town should incorporate and whether the townspeople wanted to change the name of the town site. The results of the election revealed that the name Corona was found to be popular. Meaning “crown” in Spanish, the townspeople thought it aptly described and honored circular Grand Boulevard. This election also determined that the City of Corona would incorporate as the first city in the newly formed County of Riverside.

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Since Corona’s incorporation, the population has steadily grown, and the agricultural and mineral resources of the area have been profitable. By 1912, there were 5,000 acres of established lemon and orange groves in the City, and by 1913, Corona shipped more citrus than any other town in Southern California. In addition, the lands to the northwest of downtown were planted in alfalfa, sugar beets, tomatoes, beans, and walnuts. This area also served as pasturage for dairy farms, beginning in about 1914. The lands to the northwest of Corona were especially suitable for agriculture, as the Santa Ana River offered water and rich soils. However, flooding events associated with the River eventually forced Riverside and adjacent counties to consider the idea of a Dam in the region. This first engineering investigation occurred in 1918, and was commissioned by the Boards of Supervisors for Orange, San Bernardino and Riverside Counties. This study was general in nature, and was followed by an in-depth study commissioned by Orange County in 1925. The 1925 study was completed by J. Lippincott, and suggests that the Rincon or Prado Reservoir be created by a dam. Thereafter, efforts were made to map the parcels and owners in the Prado Basin, but the Lippincott plan was rejected by Orange County voters. After another flood in 1927, Orange County residents sought out additional means for controlling the Santa Ana River, and the Orange County Flood Control District (OCFCD) was established through an act of the California legislature. Work on the Prado Dam commenced in the 1930s under the auspices of the OCFCD, and was completed in 1941 by the USACE, Los Angeles District. The dam is the second largest earthen dam in southern California. The Prado Dam facility was determined to be a cultural resource eligible for inclusion in the NRHP for its historical, engineering and architectural values, and various Historic American Engineering Record (HAER) documents have been generated for the associated features. These documents were created at the request of the USACE to mitigate impacts to the resource related to increases in the dam itself (Greenwood and Associates 1996). Since these documents were created, the dam has been increased by 30 feet and the related tower and outlet channel removed. Due to these changes, the Prado Dam facility no longer retains historic integrity and is thereby no longer considered eligible for inclusion in the NRHP. In 1962, the Riverside Freeway (SR-91) was constructed through Corona. Thereafter, downtown Corona went through urban renewal and made great efforts to update the area with new buildings. In the 1980s, citrus and dairy farming began to be phased out, due to their decreasing profitability and the increasing value of agricultural lands for residential development. Then, with the construction of I-15 on the east side of Corona in the late 1980s, new commercial

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and residential developments began, heralding a citywide revitalization. By 2012 Corona's population had grown to 154, 520 persons and the housing stock to 47, 267 housing units. Previous Cultural Resource Evaluations The project area has been evaluated by the U.S. Army Corps Engineers for the potential presence of cultural resources as part of the preparation of Prado Basin Water Conservation Feasibility Study, prepared in 2005. A number of historic and prehistoric resources were identified below the 505 foot elevation. Most of these resources consist of archival locations for which no surface remains were observed as a result of the high amount sedimentation that has built up in the Prado Basin. Four resources were observed and evaluated and were determined to be eligible for the National Register of Historic Places. These four resources included one prehistoric site CA-RIV-2804 and three historic sites CA-RIV-2802- H, CA-RIV-3694-H (Rincon Town site) and CA-RIV-2778 (Aros Serrano Adobe). As part of the Section 106 compliance for Prado Basin Water Conservation Plan, a Memorandum of Agreement (MOA) was negotiated between the Corps, State Historic Preservation Office and the Advisory Council on Historic Preservation was executed. OCWD also participated as a concurring party to the MOA. The MOA outlined specific mitigation measures to be implemented prior to the commencement water conservation activities at Prado Dam. The following is a listing of recorded cultural resources sites identified within one mile radius of the project area.

Site Number Recorder Name and Date Resource Description

33-12622 Archaeological Research Unit, Prehistoric, isolated find consisting of 1988 mano fragment CA-RIV-5523H Greenwood and Associates, 1995 Historic Age, Site consists of former farmstead from early 20th Century CA-Riv-3740H Archaeological Advisory Group, Former site of O.G. Meredith Ranch 1989 CA-RIV-4728H Greenwood Associates, 1992 Historic Age, Former site of Reynolds Ranch CA-RIV-2802H ECOS management , 1984 Historic Age, Former site of adobe dwelling CA-RIV 2754 Lagenwalter and Brock, 1983 Prehistoric, Artifact scatter composed flakes, debitage and ground stone CA-RIV-2755 Lagenwalter and Brock, 1983 Prehistoric, Lithic scatter composed flakes, debitage and ground stone CA-RIV 5808H Archaeological Advisory Group, Historic Age, Former location of William 1996 Fisher Farm. CA-Riv-5809H Archaeological Advisory Group, Historic Age, possible location of 1996 structure that appeared on USGS 1902, Corona, CA CA-RIV-1039H Greenwood Associates, 1995 Historic Age, Site of former Ashcroft

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family ranch CA-RIV-1044H Greenwood Associates, 1995 Historic Age, Site of former Carrillo farm CA-RIV-1451 Caltrans, 1977 Prehistoric, Sparse scatter of lithics CA-RIV-1436 Caltrans, 1977 Sparse scatter of ground stone tools and flakes CA-RIV 2203H USACE, 1981 Historic Age, Former site of Fear Ranch CA-RIV-4761H Greenwood Associates, 1992 Former site of West Ranch CA-SBR-5573H USACE, 1988 Historic Age, Former site of Britski Ranch CA-SBR-1543 ECOS Management Prehistoric, Scatter of lithics CA-SB-7676H Greenwood Associates, 1993 Historic Age, Former site of Ross Ranch CA-SBR-7136H Greenwood Associates, 1992 Historic Age, Former site of Hartshorn Farm P36-060002 ECOS Management, 1993 Prehistoric, isolated find CA-SBR- Michael Brandman Associates, Historic, ditch 12573H 2007 CA-SBR-7136 Greenwood Associates, 1992 Historic Age, Former site of Hartshorn Farm CA-RIV-4760H Greenwood Associates, 1992 Historic Age, Strong Property CA-RIV-100 SL Peck, 1941 Historic Age, Portion of Moreno Ranch CA-RIV-653/H Statistical Research, 1998 Prehistoric Lithic scatter with ground stone. CA-RIV-2803 ECOS Management, 1984 Prehistoric, Small scatter of lithics CA-RIV-2804 ECOS Management, 1984 Prehistoric, Lithic scatter CA-RIV-5253H Greenwood Associates, 1993 Historic Age, Former site of Chino Gun Club 33-13543 ECOS Management, 1983 Prehistoric, Isolated find composed of a mano 33-13544 ECOS Management, 1983 Prehistoric, Isolated find composed of a metate fragment Archival Topographic Map Review Topographic Map Review 1941 USGS Prado This map showed a historic age road trending northeast from Highway 71. Dam, CALIF. 7.5- Three structures appear to be present in the vicinity of Moreno Ranch (CA- minute RIV-100). Highway 71, State Route 91, the Prado Dam, and the Atchison, Topeka and Santa Fe Railroad are all depicted in their current location, as found on the modern 1967 (revised 1981) Prado Dam, CA 7.5-minute topographic map. 1947 USGS This map showed a historic age road trending northeast from Highway 71. Corona, CALIF. Two structures are present in the vicinity of Moreno Ranch (CA-RIV-100). 15-minute Highway 71, State Route 91, the Prado Dam, and the Atchison, Topeka and Santa Fe Railroad are all depicted in their current location, as found on the modern 1967 (revised 1981) Prado Dam, CA 7.5-minute topographic map. 1949 USGS Prado This map showed that historic age structures and features were not Dam, CALIF. 7.5- located as depicted in 1949. Highway 71, State Route 91, the Prado Dam, minute and the Atchison, Topeka and Santa Fe Railroad are all depicted in their current location, as found on the modern 1967 (revised 1981) Prado Dam, CA 7.5-minute topographic map.

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3.4.3 Threshold of Significance • Will the project cause a substantial adverse change in the significance of a historical resource as defined in Section 15064.5 of the CEQA Guidelines? • Will the project cause a substantial adverse change in the significance of an archaeological resource pursuant to Section 15064.5 of the CEQA Guidelines? • Will the project disturb any human remains, including those interred outside of formal cemeteries? • Will the project directly or indirectly disturb or destroy a unique paleontological resource or site? 3.4.4 Project Impacts IMPACT CR-1: Will the project cause a substantial adverse change in the significance of a historical resource as defined in Section 15064.5 of the CEQA Guidelines? IMPACT CR-2: Will the project cause a substantial adverse change in the significance of an archaeological resource pursuant to Section 15064.5 of the CEQA Guidelines? As part of the Section 106 compliance for the Prado Basin Water Conservation Plan, the area below 505 foot elevation was evaluated and investigated and documented for the presence of cultural resources. Approximately 13 acres of the sediment removal channel will be located below 505 foot elevation. Based on the previous investigation, the Project will not adversely impact any known cultural resource site. A total of 22 acres of the sediment removal channel storage site and the entire sediment storage site is located above the 505 foot elevation. There are no historic or archaeological resources known to occur within this portion of the project area. The area is in disturbed condition from previous construction activities and from several feet of sediment that has accumulated over the years, in some areas in excess of 25 feet. Excavation activities associated with the Project will not exceed a depth of 12 feet and will not impact native soils. Therefore, it is unlikely that unknown buried historic resources or archaeological resources will be encountered. The Project will require Section 106 compliance to demonstrate that the Project activities will not result in significant impacts to cultural resources and will require coordination with State Historic Preservation Office to concur that no significant impacts will occur.

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In the event unknown historic resources and archaeological resources are uncovered during implementation of the Project, the Corps and OCWD will be required to comply with 36 CFR 800.11 and additional measures could be required to protect the uncovered historic resources and archaeological resources. These additional mitigation measures will be developed in consultation with the State Historic Preservation Office and the Advisory Council on Historic Preservation. With the implementation of Mitigation Measure CR-1 and CR-2 potential adverse impacts to unknown cultural resources will be reduced to a less than significant level. Level of impact before mitigation Potential significant impact. Mitigation Measure CR-1 Prior to the start of earthwork activities OCWD will be required to comply Section 106 of the National Historic Preservation Action and receive concurrence from the State Historic Preservation Office that implementation of the Project will not result in significant adverse impacts to cultural resources. CR-2: In the event previously unknown resources are uncovered during implementation of the Project, OCWD will be required to comply with 36 CFR 00.11, Properties Discovered during Implementation of an Undertaking. In such an event, additional mitigation measures could be required. These additional mitigation measures will be developed in consultation with the SHPO and the Advisory Council of Historic Preservation. Level of impact after mitigation Less than significant impact. IMPACT: Will the project disturb any human remains, including those interred outside of formal cemeteries? The project area has been evaluated by the US Army Corps Engineers for the potential presence for the preparation of Prado Basin Water Conservation Feasibility Study, prepared in 2005. Local native tribes were coordinated with to determine if unknown Native American cultural resources were known to occur within the project area. As part of the evaluation for the Prado Basin Water Conservation Plan, the area below the 505 foot elevation was evaluated and investigated for the presence of cultural resources. Therefore, the components of the Project implemented below the 505 foot elevation will not result in new adverse Native American cultural resource impacts. Those components of the project implemented above the 505 foot elevation are located in highly disturbed areas that are covered in several feet of sediment. Based on coordination with

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California Native American Heritage Commission there are no Native American cultural resources known to occur in the area. Because of the disturbed condition of the area the likelihood of encountering Native American cultural resources will be very low. As part of compliance with Section 106 of the National Historic Preservation Act, the Corps will conduct further coordination with local tribes to determine if additional resources are known to occur in the project area.. With the implementation of Mitigation Measure CR-3 potential adverse impacts to Native American burial grounds will be reduced to a less than significant level. Level of Impact before mitigation Potential significant impact. Mitigation Measures CR-3: As part of the Project compliance with Section 106 of the Historic Preservation Act and prior to the start of earthwork activities the Corps and OCWD will conduct coordination with local Native American Tribes to determine if known Native American cultural resources are present within the project area Level of impact after mitigation Less than significant impact. IMPACT CR-4: Will the project directly or indirectly disturb or destroy a unique paleontological resource or site? Paleontological resources are fossilized evidence of past life found in the geologic record. Paleontological resource localities are sites where the fossilized remains of extinct animals and/or plants have been preserved. Despite the huge volume of sedimentary rock deposits preserved worldwide and the enormous number of organisms that lived through time, preservation of plant or animal remains as fossils is a rare occurrence. Because of their rarity, fossils are considered significant records of ancient life. Paleontological sensitivity is the potential for a geologic unit to produce scientifically significant fossils. This potential or sensitivity is determined by rock type, the past of the rock unit producing the fossil materials, and what fossil sites are recorded in the unit. A threefold classification of sensitivity is used by many paleontologists working in southern California. A high sensitivity indicates that paleontological resources are currently observed or are recorded within the study area and/or the unit has a history of producing numerous significant fossil remains. A moderate sensitivity indicates paleontological resources have been recovered from the unit and there is likelihood that fossils would be exposed by earth moving activities. A low potential indicates significant fossil are not likely to be found because of random fossil distribution pattern, the extreme youth of the

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rock unit, and/or method of rock formation such as alternation by heat and pressure. Based on Paleontological Overview of Prado Basin prepared for the Corps, the Prado Basin is immediately underlain by non-marine sedimentary deposits of Quaternary age. The area along the Santa Ana River is floored by unconsolidated stream alluvium of Holocene age (less than 10,000 years B.P.), which because of their geologically young age, are not considered to be fossiliferous and the paleontological sensitivity is considered low. The location of the sediment storage sites and green waste site are underlain by poorly to semi-consolidated, commonly reddish silts, sands, and occasional beds and stringers of fine gravel comprising older alluvial stream terrace deposits of the Santa Ana River drainage system. These deposits are late Pleistocene to early Holocene in age. Deposits of this character and age have produced late ice-age land vertebrate fossils from the nearby eastern Puente Hills and other scattered localities in the greater Los Angeles Basin. However, the sensitivity for these deposits to be present in the areas where the sediment storage site is proposed is low. The sediment removal channel and the sediment storage site are located in areas that have low sensitivity to contain paleontological resources. Additionally, the areas are disturbed from several feet of sedimentation that has accumulated over the years and based on the depth of earth work disturbances associated with the Project it will be very unlikely that paleontological resources will be encountered. No adverse impacts to paleontological resources will occur. Level of impact before mitigation Less than significant impact. Mitigation Measures No mitigation measures are required. Level of impact after mitigation Less than significant impact.

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3.5 GEOLOGY This section describes the environmental setting for geology and soils in the project area, applicable regulatory framework and potential project impacts from geologic and soil constraints. The analysis is based on Geotechnical Report prepared for the Sediment Management Demonstration Project by Golder Associates in November of 2010. The report included field explorations, geotechnical analysis, geotechnical laboratory testing and environmental testing. The Geotechnical Report is presented in Appendix D. 3.5.1 Regulatory Framework Federal Federal Soil Protection Act The purpose of the Federal Soil Protection Act is to protect and/or restore the functions of the soil on a permanent sustainable basis. Protection and restoration activities include prevention of harmful soil changes, rehabilitation of the soil of contaminated sites and rehabilitation of water contaminated by contaminated soils. Additionally, the requirements of the Federal Clean Water Act through the National Pollution Discharge Elimination System provide guidance for protection of geologic and soil resources. State Alquist-Priolo Earthquake Fault Zoning Act In response to the severe structural damages caused by the 1971 San Fernando Earthquake, the State of California enacted the Alquist-Priolo Earthquake Fault Zoning Act. This act regulates development near active faults in order to mitigate the hazards of surface fault-rupture. Under the act, the State Geologist is required to delineate special study zones along known active faults. The act also requires that prior to approval of a project, a geologic study is required to be prepared to define and delineate any hazards from surface rupture. A 50-foot setback from any known trace of an active fault is required. Seismic Hazards Mapping Act The Seismic Hazards Mapping Act, enacted in 1977, was developed to protect the public from the effects of strong ground shaking, liquefaction, landslides or other ground failure and from hazards caused by earthquakes. The act requires the State Geologist to delineate various seismic hazard zones and requires cities, counties and other local permitting agencies to regulate certain development projects within these zones.

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California Building Standard Code Title 24 of the California Code of Regulations, also known as the California Building Standards Code, sets forth minimum requirements for building design and construction. The California Building Standards Code is a compilation of three types of building standards from three different origins. • Building standards that have been adopted by state agencies without change from building standards contained in national model codes. • Building standards that have been adopted and adapted from the national model code standards to meet California conditions. • Building standards authorized by the California legislature that constitute extensive additions not covered by the model codes that have been adopted to address particular California concerns. In the context of earthquake hazards, the California Building Standards Code design standards have a primary objective of assuring public safety and a secondary goal of minimizing property damage and maintaining function during and following a seismic event. 3.5.2 Existing Environmental Setting Geology Prado Basin is adjacent to the eastern flank of the Santa Ana Mountains within the Peninsular Range Geomorphic Province of California. The Peninsular Range Geomorphic Province is a physiological area that extends from the San Gabriel Mountains in the north to Baja California in the south. The province is characterized by surface topography with northwest trending faults and mountain ranges and alluvial filled basins separated by similar faults. The Elsinore Trough is a northwest trending fault controlled depression in Prado Basin. The Elsinore Trough contains thousands of feet of tertiary and quaternary sediments and extends from near the City of Temecula in the southeast to near the City of Chino in the northwest. Prado Basin is primarily underlain by axial channel deposits overlain by very young wash deposits. Prado Dam is situated at the southwest corner of the Upper Santa Ana Valley, a broad inland alluvial plain that is part of the larger South Coastal Basin of southern California. The dam is located at the eastern tip of the Chino Hills near the Santa Ana Canyon. These hills are composed of tertiary sediments of the Puente Formation. These sediments consist of poorly consolidated sandstone with hard siltstone and shale interbeds and scattered lens of conglomerate.

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Groundwater Groundwater with the Prado Basin is controlled by the Santa Ana River and the elevation of the water stored behind Prado Dam. Boring samples conducted along the sediment removal channel encountered groundwater at some locations between 5 and 6 feet below ground surface and at some locations 9 to 20 feet below ground surface. Closer to the dam, the soils are typically underwater during and shortly after the rainy season. The depth to groundwater table is expected to increase during after the rainy season. Faulting and Seismic Activity According to the California Geologic Survey Seismic Hazard Zone Map for the Prado Dam Quadrangle, the Elsinore Fault Zone extends in a north- to south direction at the western end of Prado Basin, near State Highway 71. The location of the Elsinore Fault Zone through the Prado Basin is shown on Figure 17. Prado Basin is located in a seismically active area, as is the majority of southern California and the potential for strong ground motion in the project area is considered likely. According to the California Geologic Survey, a fault is defined as a fracture in the crust of the earth along which rocks on one side have moved relative to those on the other side. Most faults are the result of repeated displacements over a long period of time. An inactive fault is a fault that has not experienced earthquake activity within the last 300 million years. An active fault is one that has experienced earthquake activity in the past 11,000 years. A fault that has moved within the last two to three million years, but has not been proven by direct evidence to have moved within the last 11,000 years, is considered potentially active. The major faults in a 30 mile radius of the project area and the maximum moment magnitude are shown in Table 30.

Table 30: Regional Active Faults Fault/Fault Zones Distance to Site (miles) Maximum Earthquake Magnitude

Elsinore Fault 0.0 6.8 Sierra Madre Fault Zone 15.3 7.1 Sierra Madre Ault Zone 17 6.5 Newport Inglewood Fault 25 7.1 San Andreas Fault 27 7.1 Raymond Fault 29 6.5

Liquefaction Liquefaction is the phenomenon in which loosely deposited soils located below the water table undergo rapid loss of shear strength due to excess pore pressure generation when subjected to strong earthquake induced ground shaking.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-128 Sediment Removal A« Channel

Sediment Storage Site E / Green Waste Site

Sediment Re-entrainment Area AÆ

K:\Prado\SedimentManagementPlan\MXD\EIR2014\F17_GeologicConstraints.mxd

0 750 1,500 Proposed Project Areas Proposed Access Roads Alquist-Priolo Fault Zone Prado Basin SMDP Feet Geological Constraints

Aerial Imagery Eagle Aerial Spring 2012 Figure 17 Section 3 Environmental Analysis

Liquefaction is known generally to occur in saturated or near-saturated cohesion less soils at depths shallower than 50-feet below the ground surface. According to California Geologic Survey Seismic Hazard Zone Map for the Prado Dam Quadrangle, the project area is located within areas where historic occurrence of liquefaction has occurred. Landslide Hazards According California Geologic Survey most of the Prado Basin area is free from landslide hazards. However near Chino Hills there is evidence of ancient to recent landslides. A review of aerial imagery indicates that there is evidence of across bedding rotational or joint plane failures along the bluff faces, particularly in the area immediately west of Highway 71 where the bluff face is significantly higher and steeper that the hills to the west. 3.5.3 Threshold of Significance • Will the Project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving rupture of an unknown earthquake fault, as delineated on the most Alquist-Priolo Earthquake Fault Zoning map? • Will the Project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving strong seismic ground shaking? • Will the Project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving liquefaction? • Will the Project result in substantial soil erosion or the loss of top soil? • Will the Project be located on a geologic unit or soil that is instable, or that would become unstable as a result of the project and could potentially result in onsite or offsite landslide, lateral spreading, subsidence, liquefaction or collapse? • Will the Project be located on expansive soil, as defined in Table 18-1-b of the Uniform Building Code, creating substantial risks to life or property? 3.5.4 Project Impacts IMPACT GEO-1: Will the Project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving rupture of an unknown earthquake fault, as delineated on the most Alquist-Priolo Earthquake Fault Zoning map?

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According to the California Geologic Survey Seismic Hazard Zone Map Prado Dam Quadrangle, the Elsinore Fault Zone extends in a north- to south direction at the western end of Prado Basin, near State Highway 71. The Elsinore Fault is an active fault capable of producing an earthquake of 6.8 on the Richter scale. This magnitude earthquake is potentially large enough to result in ground surface rupture impacts in the Prado Basin. According to the Alguist-Priolo Act if an active fault is present, a structure for human occupancy cannot be placed over the trace of the fault and must be setback 50 feet from the fault zone. The Project does not propose the construction of any habitable or permanent structures. Therefore, there will not be a need for a setback requirement. The Elsinore Fault will not extend through the area where the sediment removal channel, sediment storage site and the sediment re-entrainment area will be located. Therefore, there will be minimal potential from ground rupture impacts at these areas. Level of Impact before Mitigation Less than significant impact. Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than significant impact. IMPACT GEO-2: Will the Project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving strong seismic ground shaking? The project area is located in a seismically active region and could be subject to seismic shaking impacts from several active faults in the region. The Elsinore Fault, the closest active fault to the project area could have the capability of producing an earthquake of 6.8 on the Richter Scale. In the event an earthquake of this magnitude occurs, the project area may experience periodic shaking, possibly of considerable intensity. The seismic shaking risk at the project area is similar to other areas in southern California. The Project does not propose any habitable or permanent structures or involves a high number of onsite workers that will be subject to ground shaking impacts. There is the potential that some components of the Project could sustain damage. However, the physical components of the Project will be designed to meet Essential Facilities Standards of the Uniform Building Code to with stand potential seismic shaking impacts caused by an earthquake within an acceptable level of risk. Additionally, all of the components are temporary and could easily be removed and replaced. The

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implementation of the Project will not substantially increase the risk or exposure of people to significant adverse seismic shaking impacts over the current condition and potential adverse seismic shaking impacts will be less then significant. Level of impact before Mitigation Less than significant impact. Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than significant impact. IMPACT GEO-3: Will the project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving liquefaction? According to California Geologic Survey Seismic Hazard Zone Map for the Prado Dam Quadrangle, the project area is located within an area where historic occurrence of liquefaction has occurred. Components of the Project will be designed to meet Essential Facilities Standards of the Uniform Building Code to with stand potential liquefaction impacts caused by an earthquake within an acceptable level of risk. Additionally, the Project does not propose any habitable or permanent structures or involves a high number of workers that will be subject to liquefaction impacts. The implementation of the Project will not substantially increase the risk or exposure of people to significant liquefaction impacts over the current condition. Potential adverse liquefaction impacts will be less then significant. Level of impact before Mitigation Less than significant impact. Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than significant impact. IMPACT GEO-4: Will the project result in substantial soil erosion or the loss of top soil? The construction of the Project will grade and/or excavate approximately 85 acres of area. The exposed soils could be subject to erosion caused by water

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and wind. Additionally, construction equipment and vehicles could transport sediment to other locations in the basin and to offsite locations. Construction projects which disturb one or more acres of soil are required to obtain coverage under a General Construction Permit by the Regional Water Quality Control Board. The Project will involve more than 1 acre of grading and will be required to obtain coverage under a General Construction Permit. The General Construction Permit requires the filing of a Notice of Intent with the Regional Water Quality Control Board and the preparation of a Storm Water Pollution Prevention Plan (SWPPP). The SWPPP will provide a list of Best Management Practices to minimize potential soil erosion impacts. With the implementation of Mitigation Measure GEO-1 potential erosion impacts will be reduced to a less than significant level. Level of Impact before Mitigation Potential significant impact. Mitigation Measures GEO-1: Prior to the start of construction OCWD shall obtain coverage under the General Construction Permit by the Regional Water Quality Control Board and in compliance with the permit shall file a Notice of Intent with the Regional Water Quality Control Board and prepare and implement Storm Water Pollution Prevention Plan. Level of Impact after Mitigation Less than significant impact. IMPACT GEO-5: Will the project be located on a geologic unit or soil that is instable, or that would become unstable as a result of the project and could potentially result in onsite or offsite landslide, lateral spreading, subsidence, liquefaction or collapse? Liquefaction According to California Geologic Survey Seismic Hazard Zone Map for the Prado Dam Quadrangle, the project area is located within an area where historic occurrence of liquefaction has occurred. The Project does not propose any habitable or permanent structures that will be subject to liquefaction impacts. Components of the project will be designed to meet Essential Facilities Standards of the Uniform Building Code to with stand potential liquefaction impacts caused by an earthquake within an acceptable level of risk. The potential risk for liquefaction impacts resulting in loss, injury or death will be less than significant.

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Seismically induced Settlement Settlement is characterized as a sinking of the ground surface relative to surrounding areas and can generally occur where deep alluvial soil deposits are present in valley and basin areas. Subsidence could potentially result in ground fractures that could cause damage to surface improvements. At the Prado Basin the estimated settlement will be approximately 12 to 30 inches. The Project does not propose any habitable or permanent structures that will be subject to seismically induced settlement impacts. Landslides The Prado Basin is not subject to landslide hazards. However, in the Chino Hills above the sediment re-entrainment area there is evidence of ancient to recent landslides. The sediment re-entrainment activities will not occur near the Chino Hills. Therefore, there will not be a risk for landslide hazard impacts. Level of impact before Mitigation Less than significant impact. Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than significant impact. IMPACT GEO-6: Will the Project be located on expansive soil, as defined in Table 18-1-b of the Uniform Building Code, creating substantial risks to life or property? Expansive soils include clay minerals that are characterized by their ability to undergo significant volume change (shrink or swell) due to variations in moisture content. Sandy soils are generally not expansive. Changes in soil moisture content can result from rainfall, irrigation, pipeline leakage, surface drainage, perched groundwater, drought, or other factors. Volumetric change of expansive soil may cause excessive cracking and heaving of structures with shallow foundations, concrete slabs-on-grade, or pavements supported on these materials. Based on subsurface exploration, the near surface soils at the project area are predominantly comprised of loose silty sands and sands with varying amounts of silt and clay. The sandy soils are typically non-expansive. However, the silty clay soil are typically moderately to highly expansive. The Project does not propose the construction of any foundations or structures that will be subject to expansive soil conditions. Potential risks associated with expansive soils will be less than significant.

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Level of Impact before Mitigation Less than significant impact. Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than significant impact.

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3.6 GREENHOUSE GAS EMISSIONS The following analysis is based on the Air Quality and Greenhouse Gas Analysis Report prepared by First Carbon Solutions in October 2013. The Air Quality and Greenhouse Gas Analysis Report are included in Appendix B. 3.6.1 Regulatory Framework Greenhouse Gas Emissions (GHGs) are comprised of atmospheric gases and clouds within the atmosphere that influence the earth’s temperature by absorbing most of the infrared radiation that rises from the sun-warmed surface and that would otherwise escape into space. This process is commonly known as the “Greenhouse Effect”. GHGs are emitted by natural processes and human activities.

GHGs, include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride

(SF6). Other greenhouse gases include water vapor, ozone, and aerosols. Water vapor is an important component of our climate system and is not regulated. Although there could be health effects resulting from changes in the climate and the consequences that can bring about, inhalation of greenhouse gases at levels currently in the atmosphere will not result in adverse health effects, with the exception of ozone and aerosols (particulate matter). The potential health effects of ozone and particulate matter are discussed in air quality criteria pollutant analyses. At very high indoor concentrations (not at levels existing outside), carbon dioxide, methane, sulfur hexafluoride, and some chlorofluorocarbons can cause suffocation as the gases can displace oxygen. The State of California has approved a number regulations providing for the regulation of GHGs. These include; Pavley Regulations: California AB 1493, enacted on July 22, 2002, required the ARB to develop and adopt regulations that reduce greenhouse gases emitted by passenger vehicles and light duty trucks. Executive Order S-3-05: California announced on June 1, 2005, through Executive Order S-3-05, the following reduction targets for greenhouse gas emissions: • By 2010, reduce greenhouse gas emissions to 2000 levels. • By 2020, reduce greenhouse gas emissions to 1990 levels. • By 2050, reduce greenhouse gas emissions to 80 percent below 1990 levels.

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Low Carbon Fuel Standard - Executive Order S-01-07: California approved Executive Order S-01-07 on January 18, 2007. The order mandates that a statewide goal shall be established to reduce the carbon intensity of California’s transportation fuels by at least 10 percent by 2020. SB 1368: In 2006, the State Legislature adopted Senate Bill (SB) 1368, which was subsequently signed into law by the Governor. SB 1368 directs the California Public Utilities Commission to adopt a performance standard for greenhouse gas emissions for the future power purchases of California utilities. AB 32: The California State Legislature enacted AB 32, the California Global Warming Solutions Act of 2006. AB 32 requires that greenhouse gases emitted in California be reduced to 1990 levels by the year 2020. SB 97 and the CEQA Guidelines Update: Passed in August 2007, SB 97 added Section 21083.05 to the Public Resources Code. The code states “(a) On or before July 1, 2009, the Office of Planning and Research shall prepare, develop, and transmit to the Resources Agency guidelines for the mitigation of greenhouse gas emissions or the effects of greenhouse gas emissions as required by this division, including, but not limited to, effects associated with transportation or energy consumption. A new section, CEQA Guidelines Section 15064.4, was added to assist agencies in determining the significance of greenhouse gas emissions. The new section allows agencies the discretion to determine whether a quantitative or qualitative analysis is best for a particular project. However, little guidance is offered on how to determine whether the project’s estimated greenhouse gas emissions are significant or cumulatively considerable. Also amended were CEQA Guidelines Sections 15126.4 and 15130, which address mitigation measures and cumulative impacts respectively. Greenhouse gas mitigation measures are referenced in general terms, but no specific measures are recommended. The revision to the cumulative impact discussion requirement simply directs agencies to analyze greenhouse gas emissions in an EIR when a project’s incremental contribution of emissions may be cumulatively considerable, however it does not answer the question of when emissions are cumulatively considerable. 3.6.2 Existing Environmental Setting A variety of agencies has developed greenhouse gas emission thresholds and/or has made recommendations for how to identify a threshold. However, the thresholds for projects in the jurisdiction of the SCAQMD remain in flux. The California Air Pollution Control Officers Association explored a variety of threshold approaches, but did not recommend one approach. In 2008 the Air Resources

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Board (ARB) recommended approaches for setting interim significance thresholds, in which a draft industrial project threshold suggests that non- transportation related emissions under 7,000 MTCO2e per year will be less than significant; however, the ARB has not approved those thresholds and has not published anything since 2008. The Bay Area Air Quality Management District and the San Joaquin Valley Air Pollution Control District have both developed greenhouse gas thresholds. However, those thresholds are not applicable to the Project since the Project is under the jurisdiction of the SCAQMD. The SCAQMD is in the process of preparing recommended significance thresholds for greenhouse gases for local lead agency consideration (“SCAQMD draft local agency threshold”); however, the SCAQMD Board has not approved the thresholds. The current draft thresholds consist of the following tiered approach: Tier 1 consists of evaluating whether or not the project qualifies for any applicable exemption under CEQA. Tier 2 consists of determining whether the project is consistent with a greenhouse gas reduction plan. If a project is consistent with a qualifying local greenhouse gas reduction plan, it does not have significant greenhouse gas emissions. Tier 3 consists of screening values, which the lead agency can choose, but must be consistent with all projects within its jurisdiction. A project’s construction emissions are averaged over 30 years and are added to a project’s operational emissions. If a project’s emissions are under one of the following screening thresholds, then the project is less than significant:

All land use types: 3,000 MTCO2e per year

Based on land use type: residential: 3,500 MTCO2e per year; commercial: 1,400 MTCO2e per year; industrial: 10,000 MTCO2e; or mixed use: 3,000 MTCO2e per year Tier 4 has the following options: Option 1: Reduce emissions from business as usual by a certain percentage; this percentage is currently undefined Option 2: Early implementation of applicable AB 32 Scoping Plan measures Option 3: 2020 target for service populations (SP), which includes residents

and employees: 4.8 MTCO2e/SP/year for projects and 6.6 MTCO2e/SP/year for plans;

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Option 3: 2035 target: 3.0 MTCO2e/SP/year for projects and 4.1 MTCO2e/SP/year for plans Tier 5 involves mitigation offsets to achieve target significance threshold. 3.6.3 Threshold of Significance • Will the Project generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment? • Will the Project conflict with any applicable plan, policy or regulation of an agency adopted for the purpose of reducing the emissions of greenhouse gasses? 3.6.4 Project Impacts IMPACT GHG-1: Will the Project generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment? The Project will emit greenhouse gases from upstream emission sources and direct sources (combustion of fuels from worker vehicles and construction equipment). Greenhouse gas emissions from project construction equipment and worker vehicles are shown in Table 31. As shown in Table 31 greenhouse gas emissions generated from the construction and operation of the Project will not exceed the 3,000 MTCO2e per year threshold. Therefore, greenhouse gas emissions generated by the Project will be less than significant.

Table 31: Construction Greenhouse Gas Emissions

Source Emissions Model Output Emissions Total (MTCO2e) Multiplier1 Emissions (MTCO2e) Phase 1 - Preconstruction Monitoring Water Quality 5.79 1.00 5.79 Wildlife 26.30 1.00 26.30 Sediment 5.68 1.00 5.68 Phase 2 - Site Preparation Clearing and 43.89 7.20 316.01 Grubbing Grading 23.77 1.00 23.77 Geotech Boring 8.70 1.00 8.70 Phase 3- Infrastructure Construction Grading 45.23 2.79 126.19 Pipeline 10.28 2.98 30.63

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Re-entrainment 11.91 1.00 11.91 Phase 4 - Sediment Removal Dredge 1,195.69 1.00 1,195.69 Phase 5 Sediment Re-entrainment Sediment Re- 271.04 1.00 271.04 entrainment Phase 6 - Monitoring, Mitigation and Site Restoration Monitoring 13.17 8.11 106.81 Mitigation 298.57 3.95 1,179.35 Site Restoration 17.88 4.94 88.33 Total Project Emissions 3,396.20 Averaged over 30 years 113.21 SCAQMD Threshold 3,000 Substantial Impact No Source of emissions: Appendix A: CalEEMod Output. Source of thresholds: South Coast Air Quality Management District 2011a.

Level of Impact before Mitigation Less than significant impact. Mitigation Measure No mitigation measures are required. Level of Impact after Mitigation Less than significant impact. IMPACT GHG-2: Will the Project conflict with any applicable plan, policy or regulation of an agency adopted for the purpose of reducing the emissions of greenhouse gasses? There is no greenhouse gas reduction plan applicable to the Project. The California State Legislature adopted AB 32 in 2006. AB 32 focuses on reducing greenhouse gases to 1990 levels by the year 2020. Pursuant to the requirements in AB 32, the ARB adopted the Climate Change Scoping Plan (Scoping Plan) in 2008, which outlines actions recommended to obtain that goal. The Scoping Plan calls for an “ambitious but achievable” reduction in California’s greenhouse gas emissions, cutting approximately 30 percent from business-as- usual emission levels projected for 2020, or about 10 percent from today’s levels. On a per-capita basis, that means reducing annual emissions of 14 tons of carbon dioxide for every man, woman and child in California down to about 10

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-140 Section 3 Environmental Analysis tons per person by 2020. The Scoping Plan contains a variety of strategies to reduce the State’s emissions. However, none are applicable to the Project. There is no greenhouse gas reduction plan applicable to the project. Therefore the Project will not be in conflict with an applicable plan, policy or regulation of an agency adopted for the purpose of reducing the emissions of greenhouse gases. Level of Impact before Mitigation Less than significant impact. Mitigation Measure No mitigation measures are required. Level of Impact after Mitigation Less than significant impact.

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3.7 HAZARDS/HAZARDOUS MATERIALS This section provides a discussion of potential hazard material sites in the project area and potential hazards to the project area. The analysis is based on Hazards Site Record Search prepared by the Orange County Water District in June of 2013 and is presented in Appendix E. 3.7.1 Regulatory Framework Federal Regulations Resource Conservation and Recovery Act The U.S. Department of Transportation along with the Federal Highway Administration and Federal Railroad Administration regulate the transportation and handling of hazardous materials through the Federal Hazardous Materials Transportation Act and through the Resource Conservation and Recovery Act RCRA). Through these regulations, Congress directed the Environmental Protection Agency to create regulations to manage hazardous materials from the cradle to grave. Under this mandate the Environmental Protection Agency developed strict requirements for all aspects of hazardous materials management, including the treatment, storage and disposal of hazardous substances. The responsibility for implementation of RCRA was given to California EPA’s Department of Toxic Substances Control (DTSC) in August 1992. The DTSC is also responsible for implementing and enforcing California’s own hazardous waste laws, which are known collectively as the Hazardous Waste Control Law. Although similar to RCRA, the California Hazardous Waste Control Law and its associated regulations define hazardous waste more broadly and so regulate a larger number of chemicals. Hazardous wastes regulated by California but not by EPA are called “non-RCRA hazardous wastes. Emergency Planning and Community Right-To-Know Act Authorized by Title III of the Superfund Amendments and Reauthorization Act (SARA), the Emergency Planning and Community Right-to-Know Act (EPCRA) were enacted by Congress as the national legislation on community safety. This law is designed to help local communities protect public health, safety, and the environment from chemical hazards. To implement EPCRA, Congress requires each state to appoint a State Emergency Response Commission (SERC). The SERCs are required to divide their states into Emergency Planning Districts and to name a Local Emergency Planning Committee (LEPC) for each district. Broad representation by fire fighters, health officials, government and media representatives, community groups, industrial facilities, and emergency

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managers ensures that all necessary elements of the planning process are represented. State Regulations California Code of Regulations Title 22, Division 4.5, Chapter 10, The California Code of Regulations defines a hazardous material as substance that because of physical or chemical properties, quantity, concentration or other characteristics may either 1) cause an increase in mortality or an increase in serious, irreversible, or incapacitating, illness or 2) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported or disposed of, or otherwise managed. California Department of Health Services The California Department of Health Services - Toxic Substances Control Division (DTSC) regulates the generation, handling, storage, disposal, and transportation of hazardous waste, oversees the remediation of contaminated sites, and seeks to reduce the quantity of hazardous waste produced in California. While DTSC primarily focuses upon commercial and industrial operations, DTSC also oversees waste evaluation programs, assists in waste determinations to identify harmful substances and concentrations, and implements programs that focus on removing dangerous substances from homes and preventing their improper and unlawful release into the environment. The California Hazardous Substances Control Law establishes regulations and incentives that ensure that generators of hazardous waste employ technology and management practices for proper handling, treatment, recycling, and destruction of these substances prior to disposal. State Emergency Response Act The State Emergency Response Act requires that local jurisdictions establish a Standardized Emergency Management System (SEMS) Multi-Hazard Functional Plan. Accordingly, the Office of Emergency Services, in coordination with all interested State and local agencies, jointly established a standardized emergency management system for use by all emergency response agencies. Local Regulations Hazardous Material Ordinance Local hazardous waste control ordinances establish detailed procedures for monitoring establishments where hazardous waste is generated, stored, handled, disposed, treated, or recycled, and regulate by the issuance of permits and the activities of establishments where hazardous waste is generated. In addition,

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local municipal ordinances adopt by reference the hazardous waste-related California Health and Safety Code which establishes and provides for a program for the prevention of contamination from improper storage of hazardous substances. Most jurisdictions rely on the California Health and Safety Code as a basis for hazardous waste enforcement and monitoring programs. 3.7.2 Existing Environmental Setting Hazardous Materials A material is considered to be hazardous if it appears on a list of hazardous materials prepared by a Federal, State or local agency, or if it has characteristics defined as hazardous by such as agency. Hazardous wastes are hazardous materials that no longer have practical use, such as substances that have been discarded, discharged, spilled, contaminated or are being stored prior to proper disposal. The Hazard Sites Record Search conducted for the project indicates that there are no active hazardous waste sites within the project area. In 1965 one federal lease and one private lease were granted for oil and gas exploration behind Prado Dam. A total of 13 oil wells were drilled and constructed on these two leases and oil and gas were produced in the field from 1965 through 1993. During this period, the wells were submerged numerous times and several oil spills occurred. After an oil spill in 1993, the wells were shut down and corrective action was issued to prevent another spill. In 1996, the wells were plugged and abandoned and pose no hazard risks to the environment. Hazardous Material Soil Testing Geotechnical Boring samples were taken to characterize the soils in the project area. As shown in Table 32 the results of the analysis of the onsite soils show that the soils had non-detectible levels of total petroleum hydrocarbons, volatile organic compounds, organophosphorus, pesticides, PCBs, chlorinated herbicides and hexavalent chromium. Low concentrations of the same metals were detected. However, these levels were well below the EPA Region 9 levels published in 2009 and are within the regional background range for soils in the area suggesting no health risks. Table 32: Summary of Soil Environmental Test Results Boring Depth Test Result

12 11-11.5 TPH-GRO ND 12 11-11.5 VOCs ND 12 21-21.5 Organophosphorus Pesticides ND 12 31-31.5 Metals * 3 6-6.5 TPH-DRO/ORO ND 3 11-11.5 PCBs ND

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3 21-21.5 VOCs ND 3 25.5-26 TPH-DRO/ORO 3 31-31.5 Total Inorganic Nitrogen 88 mg/kg 16 5-5.56 VOC ND 16 5-5.6 Organophosphorus Pesticides 16 16-16.5 Metals * 16 16-16.5 Chlorinated Herbicides ND 16 21-21.5 Total Dissolved Solids 4500 mg/kg 16 26-26.5 Hexavalent Chromium ND 16 30.5-31 Pesticides ND 28 2.5 Metals ND 28 2.5 TPH-CCID ND 28 12.5 VOCs ND 28 12.5 Organophosphorus Pesticides ND 29 2.5 VOCs ND 29 2.5 Organophosphorus Pesticides ND 29 12.5 Metals * 29 12.5 TPH-CCID ND * Low levels of some metals (arsenic, barium, chromium, cobalt, copper, lead, nickel, vanadium and zinc were detected above PQL. Detectable concentrations of metals are below EPA Region 9 Regional Screening levels

3.7.3 Thresholds of Significance • Will the Project be located on a site which is included on a list of hazardous material sites compiled pursuant to Government Code Section 65962.5 and as a result, would create significant hazard to the public or the environment? • Will the Project impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? • Will the Project expose people or structures to a significant risk of loss, injury or death involving wild land fires? 3.7.4 Project Impacts IMPACT HAZ-1: Will the Project be located on a site which is included on a list of hazardous material sites compiled pursuant to Government Code Section 65962.5 and as a result, would create significant hazard to the public or the environment? The Orange County Water District (OCWD) conducted a search of data bases on April 2013 to investigate potential hazardous materials and hazardous waste sites located within a mile radius of the Project. The following data bases were reviewed to determine the presence of hazardous waste sites. • State Water Resources Control Board GeoTracker • California Department of Toxics Substances Control EnviroStor • California Department of Conservation Oil, Gas & Geothermal- DOGGR Online Mapping System

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-145 Section 3 Environmental Analysis

• Comprehensive Environmental Response, Compensation and liability Information System Within ½ mile of the project area three sites were identified as leaking underground tank cleanup sites. All three sites have been remediated and the Santa Ana Regional Water Quality Control Board has issued a closure letter. Two active hazardous waste sites, Corona Brine Ponds and Thomas Ranch/Corona Palisades Business Park were identified between ½ mile and 1.0 mile radius of the project area. Both sites are currently under the oversight of California Department of Toxic Control and currently being remediated and both are not expected to adversely affect project area or project activities. Three abandoned oil wells are located within close proximity of the sediment re- entrainment area. Each well has been destroyed property and poses no hazardous material risks. Based on the record search there are no known hazardous material sites, pursuant to Government Code Section 65962.5 located on or within the vicinity of the project area that would pose a substantial impact to the environment or the public. Level of Impact before Mitigation Less than Significant. Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than significant. Impact HAZ-2: Will the Project impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? The project area could be subject to events, such as earthquakes, wild land fire or flooding that could require evacuation of workers from the project area. As part of the project OCWD will adhere to and incorporate the Corps Prado Basin Safety and Emergency Evacuation Plans and Procedures into the Project work program and emergency planning programs. The Project does not involve a high amount of onsite employees and does not propose any road closures or construction of any permanent structures that could interfere with emergency evacuation plans for the Prado Basin. All components of the Project are temporary and could easily be removed. During the construction and operation of the Project OCWD will coordinate with the Corps on events that have the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-146 Section 3 Environmental Analysis

potential to require evacuation of the project site. In the event evacuation is required OCWD would follow all prescribed emergency evacuation procedures. The implementation of the Project will not interfere or impair emergency response or emergency evacuation plans for the project area. Level of Impact before Mitigation Less than significant. Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than significant. IMPACT HAZ-3: Will the Project expose people or structures to a significant risk of loss, injury or death involving wild land fires? According to the Riverside County General Plan the Prado Basin and greater area has moderate potential for wild land fire susceptibility. Fire protection services to the project area are currently provided by City of Norco Fire Department, City of Corona Fire Department and Riverside County Fire Department, Chino Valley Independent Fire District and the California Department of Forestry. The Project does not involve the construction of any permanent structures that will require long term fire protection services. Therefore, implementation of the project will not have any impact on long term response times to the project area. The Project does not include any uses or materials that will substantially increase risk for wild land fire impacts. All potential flammable substances will be handled in accordance with local, states and federal laws and regulations regarding the handling and storage of flammable materials. The implementation of the Project will not require any road closures that will increase response times to the project area. During the construction and operation of the Project, OCWD will implement the Corps Prado Basin Safety and Emergency Evacuation Plans and Procedures to minimize potential risks to persons or property from wild land fire hazards. Level of Significance before Mitigation Less than significant. Mitigation Measures No mitigation measures are required. Level of Significance after Mitigation Less than significant.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-147 Section 3 Environmental Analysis

3.8 HYDROLOGY/WATER QUALITY This section describes local surface water and groundwater resources, applicable water quality regulations and evaluates potential impacts on water resources in the project area. The analysis is based HEC-RAS Sediment Transport Model conducted for the project and an Assessment of Water and Sediment Patterns within Prado Basin. Both technical studies are included in Appendix D. 3.8.1 Regulatory Framework Federal Clean Water Act The objectives of the Clean Water Act are to restore and maintain the chemical, physical, and biological integrity of Waters of the United States. The Clean Water Act establishes basic guidelines for regulating discharges of pollutants into the Waters of the United States and requires states to adopt water quality standards to protect health, enhance the quality of water resources and to develop plans and programs to implement the Act. Below is a discussion of sections of the Clean Water Act that are relevant to the Prado Basin Sediment Management Demonstration Project. Section 401 Section 401 of the Clean Water Act requires an applicant for a federal permit that involves a discharge into Waters of the United States to obtain certification that the discharges will not result in adverse water quality impacts. This process is known as the Water Quality Certification. For projects in Orange County, the Santa Ana Regional Water Quality Control Board (RWQCB) issues Section 401 Water Quality Certifications. Section 402 Section 402 of the Clean Water Act established the National Pollution Discharge Elimination System (NPDES) to control water pollution by regulating point sources that discharge pollutants into Waters of the United States. In the State of California, the EPA has authorized the State Water Resources Control Board (SWRCB) the permitting authority to implement the NPDES program. The State Water Resources Control Board issues two baseline general permits, one for industrial discharges and one for construction activities (General Construction Permit). Additionally, NPDES Program includes the long-term regulation of storm water discharge from medium and large cities through the MS4 Permit. The County of Riverside is the primary permit holder of the MS4 permit and the cities in Riverside County are co-permittees.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-148 Section 3 Environmental Analysis

Short-Term Storm Water Management Under the General Construction Permit, storm water discharges from construction sites with a disturbed area of one or more acres are required to either obtain individual NPDES permits for storm water discharges or be covered by the Construction General Permit. Coverage under the Construction General Permit is accomplished by completing and filing a Notice of Intent with the SWRCB. Each applicant under the Construction General Permit must ensure that a Storm Water Pollution Prevention Plan (SWPPP) is prepared prior to grading and is implemented during construction. The primary objective of the SWPPP is to identify, construct, implement, and maintain Best Management Practices (BMPs) to reduce or eliminate pollutants in storm water discharges and authorized non-storm water discharges from the construction site during construction. BMPs include; programs, technologies, processes, practices, and devices that control, prevent, remove, or reduce pollution. Long-Term Storm Water Management On October 22, 2012 the updated Water Quality Management Plan (WQMP), a guidance document for the Santa Ana Region of Riverside County was approved by the State Regional Water Quality Board as part of the approval of the County of Riverside 4th Term Municipal NPDES Permit for Area Wide Urban Storm Water Runoff. Under the 4th Term Municipal NPDES Storm Water Permit, construction projects are defined as Priority Development Projects or Other Development Projects based on the type of project and/or level of development intensity. Based on the classification of the project, a Priority Water Quality Management Plan, Non-Priority Water Quality Management Plan or no Water Quality Management Plan may be required. Priority Projects A Project is considered a Priority Development Project if it meets any one of the following criteria; • New development projects that create 10,000 square feet or more of impervious surface. Automotive repair shops. • Restaurants where the land area of development is 5,000 square feet or more including parking area. • Hillside development greater than 5,000 square feet. • Impervious surface of 2,500 square feet or more located within, directly adjacent to (within 200 feet), or discharging directly into receiving waters within Environmentally Sensitive Areas.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-149 Section 3 Environmental Analysis

• Parking lots 5,000 square feet or more including associated drive aisle, and potentially exposed to urban storm water runoff. • All significant redevelopment projects, where significant redevelopment is defined as the addition or replacement of 5,000 or more square feet of impervious surface on an already developed site. • Retail Gasoline Outlets This category includes Retail Gasoline Outlets that meet the following criteria: 5,000 square feet or more, or (b) a projected Average Daily Traffic (ADT) of 100 or more vehicles per day. A project that meets any one of the criteria for a Priority Development Project is required to prepare Project-Specific WQMP based on the approved County of Riverside WQMP. The Project-Specific WQMP is required to demonstrate that project will be able to infiltrate, harvest, evapotranspire or otherwise treat runoff generated from an 85th percentile storm over a 24 hour period. The WQMP requires that Low Impact Development (LID) site design principles be incorporated into the project to reduce and retain runoff to the maximum extent practicable. Such LID site design principles include; but are not limited to, minimizing impervious areas, and designing impervious areas to drain to pervious areas. Other Development Projects Certain projects that do not meet the Priority Development Project criteria are considered Other Development Projects and require incorporation of appropriate LID principles, source control, and other BMPs which may or may not include Treatment Control BMPs. Watershed Protection Projects Watershed Protection Projects, in the context of storm water management, are constructed to prevent economic, social, and environmental damage to the watershed, including receiving waters, by providing the following: • Water quality protection by the proper management of storm water and floodplains • Flood risk reduction to adjacent land uses, stored matter, and stockpiled material • Elimination of the comingling of storm water and hazardous materials • Erosion Mitigation • Restoration of Rivers and Ecosystems • Groundwater Recharge

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-150 Section 3 Environmental Analysis

• Creation of new open space and wetlands • Programs for water conservation, storm water capture and management • Retrofit projects constructed to improve water quality Watershed Protection Projects provide an important environmental benefit toward protecting beneficial uses of waters by preventing storm water from mobilizing pollutant loads and/or managing pollutant sources into receiving waters from adjacent land uses. Any potential impacts upon the environment from Watershed Protection Projects are mitigated through required compliance with CEQA, the United States Army Corps of Engineers 404 Permits, RWQCB Section 401 Water Quality Certification and California Department of Fish and Game Section 1602 Streambed Alteration Agreements. Additionally, Watershed Protection Projects are not considered development projects as they do not involve any post-construction human use or activity, and have no associated pollutants of concern. Consequently, these projects do not require the preparation of a Project-Specific WQMP. Section 404 Section 404 of the Clean Water Act established a permitting program to regulate the discharge of dredged or filled material into waters of the United States. The permitting program is administered by the Corps of Engineers and is enforced by the Environmental Protection Agency. Section 303 (d) Water Bodies Under Section 303 (d) of the Clean Water Act, the State Regional Water Quality Control Board is required to develop a list of impaired water bodies. Each of the individual Regional Water Quality Control Boards are responsible for establishing priority rankings and developing action plans, referred to as total maximum daily loads (TMDLs) to improve water quality of water bodies included in the 303(d) list. State Porter Cologne Water Quality Control Act The Porter Cologne Water Quality Act of 1967 requires the SWRCB and the nine RWQCBs to adopt water quality criteria for the protection and enhancement of Waters of the State of California, including both surface waters and groundwater. The SWRCB sets statewide policy and together with the RWQCB, implements state and federal water quality laws and regulations. Each of the nine regional boards adopts a Water Quality Control Plan or Basin Plan. The water quality of

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-151 Section 3 Environmental Analysis the Santa Ana River and the Prado Basin are under the jurisdiction of the Santa Ana Region Regional Water Quality Control Board. 3.8.2 Existing Environmental Setting Prado Basin Prado Basin is located within the Santa Ana River Watershed. The watershed is approximately 2,650 square miles and is the drainage area for lands in Riverside County, San Bernardino County and Orange County. There are four major tributaries that drain into the Prado Basin; Santa Ana River, Chino Creek, Cucamonga Creek (which flows into Mill Creek) and Temescal Wash. All of these bodies converge behind Prado Dam. The flood control operations behind Prado Dam along with an extremely shallow groundwater table and a very thin aquifer significantly affect the surface flows and subsurface flows in the Prado Basin. Depending on the how dam operates surface water flows may or may percolate behind the dam. There is little groundwater storage in the Prado Basin. Any groundwater in storage is forced to the surface because the foot of Prado Dam extends to bedrock and subsurface flows cannot pass through the barrier created by the dam and surrounding hills. As a result of a combination of high groundwater, storm flow accumulation held behind the dam, ongoing upstream sewage treatment plant effluent and irrigation runoff, perennial flows occur through Prado Basin during periods when there is no flood control waters being held. The primary purpose and beneficial use of Prado Dam is flood control. The dam controls 2,255 square miles of the watershed’s 2,650 square miles. Prado Dam also provides water conservation beneficial uses. The Corps in cooperation with OCWD releases water from Prado Dam that OCWD diverts into a series of recharge basins located downstream of Prado Basin to replenish the Orange County Groundwater Basin. Through a joint agreement with the Corps, water is stored for groundwater recharge purposes behind Prado Dam up to 498 foot elevation during winter and 505 foot elevation in the spring. The flood control use of the Prada Dam requires that vast portions of the basin be inundated with water for periods of time. These periods of inundation provides ideal conditions for riparian and wetland vegetation and is the primary reason why the Prado Basin is the largest riparian forest in southern California and provides habitat for wide a variety of plant and wildlife species. Santa Ana River The Santa Ana River is the most prominent hydrologic feature within the Santa Ana River Watershed. The Santa Ana River is over 100 miles in length and has over 50 contributing tributaries. The headwaters for the Santa Ana River are in

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-152 Section 3 Environmental Analysis the San Bernardino Mountains and flows in a southwesterly direction where it is joined by Chino Creek, Mills Creek and Temescal Wash near Prado Dam. The segment of the Santa Ana River within the Prado Basin is unimproved with a sandy bottom with extensive riparian vegetation along the banks. During the winter months the river maintains flows throughout Prado Basin. In the summer months when the surface water flow is reduced, the surface water flows of the river can dissipate to sheet flow. In 1989 the Corps began construction of the Santa Ana River Mainstem Project, which involved improvements to the Santa Ana River to ensure 200 year flood protection to Orange, Riverside and San Bernardino Counties. The key components of the project involved construction of Seven Oaks Dam, the raising of Prado Dam and increasing channel capacity in key segments of the Santa Ana River. Ongoing Mainstem Project flood control improvements along the Santa Ana River are presently occurring and are expected to conclude sometime near 2020. Downstream of Prado Dam, the Santa Ana River is divided into three geomorphic reaches. The first reach commences near Prado Dam and ends at Weir Canyon Road. The Corps is currently constructing Reach 9 Phase 2B bank protection downstream of Prado Dam. Except for the Reach 9-Phase 2B work this reach is a natural channel with braided and meandering patterns and a relatively steep longitudinal slope compared to the remainder of the lower Santa Ana River. The second geomorphic unit is the groundwater recharge reach, extending from Weir Canyon Road to the State Route 22 Freeway. This section has a natural bed, but the banks have been significantly modified. The river in this reach is contained within a trapezoidal channel with a bottom width of about 325 feet. Several drop and grade structures were constructed in this reach to help maintain the river slope and prevent degradation. Additionally, temporary sand levees are regularly constructed and maintained by OCWD to enhance infiltration of the river water into the groundwater basin. The final geomorphic reach is located between the downstream end of the recharge reach and the Pacific Ocean. This reach has a mild longitudinal slope and has been converted to a trapezoidal shape. A portion of the channel is concrete lined. The first segment of this reach extends through a golf course. A hardscape channel exists under the golf course fill. Below the golf course to Adams Avenue, the channel is fully lined. Below Adams Avenue the channel has a natural riverbed with concrete lined earthen levees that are subject to tidal fluctuations and prone to sediment deposition depending on flood flows and tidal patterns.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-153 Section 3 Environmental Analysis

Santa Ana River Water Quality On a long-term average basis, OCWD recharges approximately 150,000 acre- feet per year (afy) of Santa Ana River water into the basin. This water consists of approximately 100,000 afy base flow (non-storm flow) and 50,000 afy captured storm flow on an average basis. Year-to-year variance in rainfall and regional hydrology result in corresponding variability of these annual flows; captured storm flow generally ranges from approximately 15,000 – 80,000 acre-ft per year, and features a skewed (non-normal) distribution with many below-average (dry) years interspersed with the occasional well-above average (wet) years. From approximately May through October, much of the Santa Ana River flow is tertiary- treated wastewater from treatment facilities in San Bernardino and Riverside counties. Treatment plants that discharge into the Santa Ana River have extensive source control programs, and utilize primary, secondary, and tertiary treatment. Tertiary treatment requires filtration and disinfection of the water so that the water is safe for body contact recreation. This level of treatment results in essentially virus-free water. Because of the high percentage of treated wastewater from upstream treatment plants in the Santa Ana River during non-storm periods, OCWD initiated the Santa Ana River Water Quality and Health (SARWQH) Study in 1994 to further evaluate the use of the Santa Ana River to recharge the basin. The goals of the SARWQH Study were to characterize the quality of the Santa Ana River water and the quality of the basin it recharges, as well as to provide information on overall groundwater quality. The multi-disciplinary study design included an examination of hydrogeology, microbiology, water chemistry, organics, toxicology, and public health. The results of this extensive study helped confirm that current recharge practices using Santa Ana River water are protective of public health. Findings from the SARWQH Study also provided information necessary for the planning and permitting of other OCWD projects, such as the Groundwater Replenishment System (GWRS) that began operation in January 2008. The SARWQH Study’s data collection period extended from 1994 to 2002, and the final report was published in 2004 (OCWD, 2004). An integral part of the SARWQH Study was the objective, third-party review and guidance provided by the Scientific Advisory Panel (SAP). The SAP was formed as an independent review panel under the auspices of the National Water Research Institute (NWRI) to provide critical assessment of the research components of the SARWQH Study. Scientific Advisory Panel members, each with expertise in specific fields related to water quality and public health, met annually to provide a comprehensive review of the research findings. Subcommittees of the SAP also met during the study to review results in specific

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-154 Section 3 Environmental Analysis areas (water chemistry, hydrogeology, microbial water quality, toxicology, and health effects). An independent Scientific Advisory Panel Report evaluating and commenting on research findings of the SARWQH Study was published by NWRI in August 2004 (NWRI, 2004). Based on the SARWQH Study, NWRI’s SAP concluded that: • The recharge of Santa Ana River water into the basin does not currently threaten water quality or public health. • Water quality in the Santa Ana River will continue to change, and these changes may influence OCWD recharge operations. • Emerging chemical and microbiological constituents of concern will require continued vigilance. • OCWD should continue to monitor the quality of Santa Ana River water and groundwater for chemical and biological constituents of public health concern. • Groundwater in the SARWQH Study area is vulnerable to microbial contamination, as indicated by the occasional presence of phage in some water samples. (It should be noted that subsequent monitoring has not validated this conclusion and as such, the NWRI Independent Advisory Panel for OCWD’s Santa Ana River Monitoring Program subsequently determined that groundwater in the study area is not vulnerable to microbial contamination from OCWD’s recharge activities) • Utilities using recharged groundwater supplies from vulnerable sources must do more than rely on drinking water standards and guidelines to ensure safety. • To minimize any risks that might be associated with the vulnerability of groundwater to fecal contamination, disinfection is recommended for production wells in the study area that are found positive for phage (see related italicized note two bullets up). Each year, OCWD prepares a report regarding water quality in the SAR. The first report was prepared in October 2005 (OCWD, 2005), and covered water quality data collected from July 2002 through June 2005. Subsequent annual reports were prepared in the fall of each of the following years and covered data collected during the immediately preceding July – June OCWD Water Year (WY) (OCWD, 2006; OCWD, 2007; OCWD, 2008; OCWD, 2009; OCWD 2010; OCWD, 2011, OCWD, 2012); for example, the fourth annual report was prepared in October 2008 and covered data collected from July 2007 through June 2008.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-155 Section 3 Environmental Analysis

The purpose of this annual report is to: • Summarize the water quality data collected by OCWD for the Santa Ana River and selected monitoring wells adjacent to OCWD’s recharge facilities. • Provide an annual summary of Santa Ana River conditions and water quality to the NWRI Independent Advisory Panel (IAP) for OCWD’s Santa Ana River Monitoring Program (SARMON), which is a follow-on to the SARWQH NWRI SAP and meets annually (NWRI, 2008; NWRI, 2009; NWRI, 2010b, NWRI, 2011; NWRI, 2012; NWRI, 2013). • Evaluate the data with respect to maximum contaminant levels and other available metrics. • Compare the 2012-13 data to the data collected in the SARWQH Study to evaluate if any significant changes in water quality occurred. • Evaluate the data for potential trends in water quality. The major categories of water quality data presented in the annual report are: • Inorganic water quality data, which includes metals, nutrients, general minerals, and radioactivity constituents; • Organic water quality data, which includes volatile organic compounds, pesticides, and other organic constituents; • Disinfection byproducts and disinfection byproduct precursors; • Microbial water quality data, including bacterial indicator data and phageMost of the inorganic water quality data is based on water quality analyses conducted within OCWD’s laboratory. Constituents that are tested in the OCWD laboratory include the inorganic chemicals with primary and secondary drinking water standards, the anions and cations that comprise most of the salts in the Santa Ana River, total dissolved solids (TDS), and other miscellaneous compounds. Radioactivity constituents are analyzed at a contract laboratory. The major groups of inorganic water quality data are metals, nutrients, other inorganic constituents, and radiological constituents. Water quality results for the Santa Ana River below Prado Dam are grouped into these categories in Table 33 for data collected for years 2011 to 2013, with along with the primary and secondary maximum contaminant levels (MCLs) and California Department Public Health Notification Levels ([NLs], formerly called ‘action levels’). Table 33 also lists the minimum and maximum reportable detection limit (RDL) and relevant statistics related to the data.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-156 Section 3 Environmental Analysis Table 33: Summary of Water Quality Data Santa Ana River Below Prado Dam Reported Value Standards No. of MCL Constituent Name Min Max RDL 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL RDL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances METALS Aluminum (dissolved) 1 1 4 18.3 8 6.1 12.2 ug/L 16 0 16 1,000 200 0 Antimony (dissolved) 0.5 0.5 <0.5 0.9 0.2 <0.5 0.7 ug/L 16 8 8 6 0 Arsenic (dissolved) 1 1 2.1 5 3 2.6 3.6 ug/L 16 0 16 10 0 Barium (dissolved) 1 1 29.2 55.7 43.4 37.6 48.9 ug/L 16 0 16 1,000 0 Beryllium (dissolved) 0.5 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 ug/L 16 16 0 4 0 Cadmium (dissolved) 1 1 <1 <1 <1 <1 <1 ug/L 16 16 0 5 0 Chromium (dissolved) 1 1 <1 <1 <1 <1 <1 ug/L 16 16 0 50 0 Cobalt (dissolved) 1 1 <1 1.1 <1 <1 <1 ug/L 16 15 1 NA Copper (dissolved) 1 1 1.1 4.1 2.4 1.8 3.2 ug/L 16 0 16 1,000 1,300 0 Gadolinium (dissolved) 10 10 39.3 58.6 48 ng/L 3 0 3 NA Hexavalent Chromium (dissolved) 0.2 0.2 <0.2 0.6 <0.2 <0.2 <0.2 ug/L 21 20 1 NA Iron (dissolved) 1 1 6.7 52 10.8 9 24.4 ug/L 16 0 16 300 0 Lead (dissolved) 1 1 <1 <1 <1 <1 <1 ug/L 16 16 0 15 0 Manganese (dissolved) 1 1 11.3 218 70.3 49.8 86.8 ug/L 16 0 16 50 500 12 Mercury (dissolved) 0.1 0.1 <0.1 <0.1 <0.1 <0.1 <0.1 ug/L 16 16 0 2 0 Nickel (dissolved) 1 1 1.4 4.6 3 2.5 3.6 ug/L 16 0 16 100 0 Selenium (dissolved) 1 1 <1 <1 <1 <1 <1 ug/L 16 16 0 50 0 Silver (dissolved) 1 1 <1 <1 <1 <1 <1 ug/L 16 16 0 100 0 Thallium (dissolved) 0.5 0.5 <0.5 <0.5 <0.5 <0.5 <0.5 ug/L 16 16 0 2 0 Vanadium (dissolved) 1 1 4.3 11 5.8 5 7.8 ug/L 16 0 16 50 0 Zinc (dissolved) 1 1 3.6 14.5 6.8 4.8 10.3 ug/L 16 0 16 5,000 0

BIOLOGICALS E. Coli (Membrane Filtration - CFU/100ml) 1 1 4 30000 133.5 59.2 225 0 48 0 48 NA Enterococcus(Membrane Filtration-CFU/100ml) 1 1 <1 43000 174.5 47.5 382.5 0 48 1 47 NA Fecal Coliform (Membrane Filtration-CFU/100ml) 1 1 3 4600 170 41 300 0 39 0 39 NA Total Coliform (Membrane Filtration-CFU/100ml) 1 1 19 520000 2050 625 4450 0 48 0 48 NA

NUTRIENTS Ammonia Nitrogen 0.1 0.1 <0.1 0.2 <0.1 <0.1 0.1 mg/L 47 33 14 NA Nitrate + Nitrite Nitrogen 0.1 0.1 0.89 6.62 4.2 3.1 4.8 mg/L 47 0 47 10 0 Nitrate Nitrogen 0.1 0.1 0.83 6.57 4.2 3 4.7 mg/L 47 0 47 10 0 Nitrite Nitrogen 0.002 0.002 0.028 0.135 0.054 0.038 0.079 mg/L 47 0 47 1 0 Organic Nitrogen 0.1 0.1 <0.1 1.2 0.3 <0.1 0.5 mg/L 47 16 31 NA Phosphate Phosphorus (orthophosphate) 0.01 0.01 0.27 1.29 0.84 0.68 1 mg/L 47 0 47 NA Total Kjeldahl Nitrogen 0.2 0.2 <0.2 1.4 0.3 <0.2 0.7 mg/L 47 20 27 NA Total Nitrogen 0.1 0.2 0.891 6.621 4.4 3.2 5.2 mg/L 47 0 47 NA

OTHER INORGANIC CONSTITUENTS Alkalinity-Phenolphthalein 1 1 <1 1.4 <1 <1 <1 mg/L 47 45 2 NA Bicarbonate (as CaCO3) 1 1 87.2 259 225 171 239 mg/L 47 0 47 NA Bicarbonate (as HCO3) 1.2 1.2 106.3 315.7 274.3 208.4 291.3 mg/L 47 0 47 NA

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Reported Value Standards No. of MCL Constituent Name Min Max 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL RDL RDL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances

Boron (dissolved) 0.1 0.1 <0.1 0.3 0.2 0.2 0.3 mg/L 16 1 15 1 0 Bromide 0.1 0.1 <0.1 0.29 0.2 0.1 0.2 mg/L 47 4 43 NA Calcium 0.1 0.5 33 98.1 88.9 70.2 93.4 mg/L 31 0 31 NA Calcium (dissolved) 0.1 0.5 41.5 97.7 84.2 60.3 92.2 mg/L 16 0 16 NA Carbonate (as CaCO3) 1 1 <1 2.9 <1 <1 <1 mg/L 47 45 2 NA Chloride 0.5 0.5 31.1 167 131 91.6 142 mg/L 47 0 47 500 0 Cyanide 5 5 <5 <5 <5 <5 <5 ug/L 12 12 0 150 0 Electrical Conductivity 1 1 362 1220 1090 818 1160 um/c 47 0 47 1,600 0 Filtered Chemical Oxygen Demand 1 1 6 19 9 8 13 mg/L 7 0 7 NA Fluoride 0.1 0.1 0.25 0.45 0.4 0.3 0.4 mg/L 12 0 12 2 0 Hydroxide (as CaCO3) 1 1 <1 <1 <1 <1 <1 mg/L 47 47 0 NA Magnesium 0.1 0.5 7.5 25.1 20.8 16.9 21.8 mg/L 31 0 31 NA Magnesium (dissolved) 0.1 0.5 9.6 23 20 13.9 21.9 mg/L 16 0 16 NA Perchlorate 2.5 2.5 <2.5 <2.5 <2.5 <2.5 <2.5 ug/L 46 46 0 6 0 pH 1 1 7.4 8.3 8.1 8 8.2 UNIT 47 0 47 NA Potassium 0.1 0.5 5.8 14.9 12 10.8 13.3 mg/L 31 0 31 NA Potassium (dissolved) 0.1 0.5 5.1 14.1 12 8.9 13.4 mg/L 16 0 16 NA Silica 1 1 13.7 25.5 21.2 17.2 22.8 mg/L 12 0 12 NA Sodium 0.1 0.5 29 123 106 82.8 112 mg/L 31 0 31 NA Sodium (dissolved) 0.1 0.5 42.2 118 103.5 70.3 114.8 mg/L 16 0 16 NA Sulfate 0.5 0.5 36.9 147 107 86.6 118 mg/L 47 0 47 500 0 Surfactants 0.02 0.02 <0.02 0.14 0.04 <0.02 0.06 mg/L 16 4 12 1 0 Suspended Solids 1 1 7.6 120 50 21 68 mg/L 15 0 15 NA Total Alkalinity (as CaCO3) 1 1 87.2 259 225 171 239 mg/L 47 0 47 NA Total Dissolved Solids 1 1 226 796 664 512 692 mg/L 47 0 47 1,000 0 Total Hardness (as CaCO3) 1 1 113 344 308 242 326 mg/L 31 0 31 NA Total Hardness (as CaCO3) (dissolved) 1 1 143 338 292 207.5 318.5 mg/L 16 0 16 NA Unfiltered Chemical Oxygen Demand 1 1 8 33 14 9 17 mg/L 7 0 7 NA

RADIOLOGICALS* Gross Alpha Excluding Uranium 1.44 2.43 0.03 1 0.245 0 0.875 pCi/L 10 3 7 15 0 Natural Uranium 0.25 0.51 2.03 4.9 3.44 3.3 4.34 pCi/L 11 0 11 20 0

Total Alpha 1.44 2.43 2.63 6.3 3.635 3.148 4.59 pCi/L 10 0 10 15 0 Total Beta 1.19 3.84 5.25 13. 9.41 6.48 11.7 pCi/L 6 0 6 50 0 Total Radium 226 0.131 0.322 0.071 0.2 0.141 0.074 0.197 pCi/L 6 0 6 5 0 Total Radium 228 0.200 0.807 -0.119 0.6 0.18 0.011 0.551 pCi/L 6 1 5 5 0 Total Strontium-90 0.480 1.06 0.071 0.8 0.29 0.114 0.701 pCi/L 5 0 5 8 0 Total Tritium 358 434 -223 20 24.7 0 144.4 pCi/L 9 4 5 20,000 0

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-158 Section 3 Environmental Analysis

Reported Value Standards No. of MCL Constituent Name Min RDL Max RDL 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances VOLATILE ORGANIC COMPOUNDS 1,1,1,2-Tetrachloroethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA 1,1,1-Trichloroethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 200 0 1,1,2,2-Tetrachloroethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 1 0 1,1,2-Trichloroethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 5 0 1,1-Dichloroethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 5 0 1,1-Dichloroethene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 6 0 1,1-Dichloropropene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA 1,2,3-Trichlorobenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA 1,2,3-Trichloropropane 0.005 0.5 ND ND ND ND ND ug/L 96 96 0 0 0 1,2,4-Trichlorobenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 5 0 1,2,4-Trimethylbenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 330 0 1,2-Dibromo-3-chloropropane 0.01 0.5 ND ND ND ND ND ug/L 95 95 0 0 0 1,2-Dibromoethane 0.005 0.5 ND ND ND ND ND ug/L 96 96 0 0 0 1,2-Dichlorobenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 600 0 1,2-Dichloroethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 1 0 1,2-Dichloropropane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 5 0 1,3,5-Trimethylbenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 330 0 1,3-Dichlorobenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 600 0 1,3-Dichloropropane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA 1,4-Dichlorobenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 5 0 1,4-Dioxane 1 1 ND ND ND ND ND ug/L 44 44 0 1 0 2,2-Dichloropropane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA 2-Chloroethylvinyl ether 0.1 1.0 ND ND ND ND ND ug/L 44 44 0 NA 2-Chlorotoluene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 140 0 2-Hexanone 10 10 ND ND ND ND ND ug/L 47 47 0 NA 4-Chlorotoluene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 140 0 4-Isopropyltoluene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA Acetone 10 10 ND 10.9 ND ND ND ug/L 65 64 1 NA Acrolein 10 10 ND ND ND ND ND ug/L 47 47 0 NA Acrylonitrile 10 10 ND ND ND ND ND ug/L 47 47 0 NA Benzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 1 0 bis (2-chloroethyl) ether 5.0 5.0 ND ND ND ND ND ug/L 47 47 0 NA Bromobenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA Bromochloromethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-159 Section 3 Environmental Analysis

Reported Value Standards No. of MCL Constituent Name Min RDL Max RDL 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances Bromomethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA Carbon Disulfide 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 160 0 Carbon tetrachloride 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 1 0 Chlorobenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 70 0 Chlorodifluoromethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA Chloroethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA Chloromethane 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA Chlorotrifluoroethene 0.5 5.0 ND ND ND ND ND ug/L 47 47 0 NA cis-1,2-Dichloroethene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 6 0 cis-1,3-Dichloropropene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 1 0 Dibromomethane 1 1 ND ND ND ND ND ug/L 47 47 0 NA Dichlorodifluoromethane 1 1 ND ND ND ND ND ug/L 47 47 0 1,000 0 Diisopropyl ether 1.0 1.0 ND ND ND ND ND ug/L 47 47 0 NA Ethyl tert-butyl ether 1.0 1.0 ND ND ND ND ND ug/L 47 47 0 NA Ethylbenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 300 0 Freon 123a 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 NA Hexachlorobutadiene 1 1 ND ND ND ND ND ug/L 47 47 0 NA Isopropylbenzene 1 1 ND ND ND ND ND ug/L 47 47 0 770 0 m,p-Xylene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 1,750 0 Methyl Ethyl Ketone (MEK) 5.0 5.0 ND ND ND ND ND ug/L 47 47 0 NA Methyl Isobutyl Ketone (MIBK) 5.0 5.0 ND ND ND ND ND ug/L 47 47 0 120 0 Methyl tert-butyl ether 0.2 0.2 ND ND ND ND ND ug/L 47 47 0 13 5 0 Methylene Chloride 1 1 ND ND ND ND ND ug/L 47 47 0 5 0 Naphthalene 0.5 0.5 ND ND ND ND ND ug/L 54 54 0 17 0 n-Butylbenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 260 0 Nitrobenzene 5.0 5.0 ND ND ND ND ND ug/L 47 47 0 NA o-Xylene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 1,750 0 Propylbenzene 1 1 ND ND ND ND ND ug/L 47 47 0 260 0 sec-Butylbenzene 1 1 ND ND ND ND ND ug/L 47 47 0 260 0 Styrene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 100 0 Tert-amyl methyl ether 1.0 1.0 ND ND ND ND ND ug/L 47 47 0 NA tert-butyl alcohol 2.0 2.0 ND ND ND ND ND ug/L 47 47 0 12 0 tert-Butylbenzene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 260 0 Tetrachloroethene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 5 0 Toluene 0.5 0.5 ND 0.25 ND ND ND ug/L 47 46 1 150 0

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-160 Section 3 Environmental Analysis

Reported Value Standards No. of MCL Constituent Name Min RDL Max RDL 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances Total 1,3-Dichloropropene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 0.5 0 Total Xylenes (m,p,&o) 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 1750 0 trans-1,2 Dichloroethene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 10 0 trans-1,3-Dichloropropene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 0.5 0 Trichloroethene 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 5 0 Trichlorofluoromethane (Freon 11) 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 150 0 Trichlorotrifluoroethane (Freon 113) 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 1200 0 Vinyl Acetate 10 10 ND ND ND ND ND ug/L 47 47 0 NA Vinyl chloride 0.5 0.5 ND ND ND ND ND ug/L 47 47 0 0.5 0

PHENOLS 2,4-Dinitrotoluene 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA 2,6-Dinitrotoluene 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Pentachlorophenol (PCP) 0.1 5.0 ND ND ND ND ND ug/L 24 24 0 1 0

PCBs PCB-1016 0.5 0.5 ND ND ND ND ND ug/L 5 5 0 0.5 0 PCB-1221 0.5 0.5 ND ND ND ND ND ug/L 5 5 0 0.5 0 PCB-1232 0.5 0.5 ND ND ND ND ND ug/L 5 5 0 0.5 0 PCB-1242 0.5 0.5 ND ND ND ND ND ug/L 5 5 0 0.5 0 PCB-1248 0.5 0.5 ND ND ND ND ND ug/L 5 5 0 0.5 0 PCB-1254 0.5 0.5 ND ND ND ND ND ug/L 5 5 0 0.5 0 PCB-1260 0.5 0.5 ND ND ND ND ND ug/L 5 5 0 0.5 0

SOCs 1-Naphthol 5 5 ND ND ND ND ND ug/L 6 6 0 NA 2,2',3,3',4,4',6-Heptachlorobiphenyl 0 1 ND ND ND ND ND ug/L 13 13 0 NA 2,2',3,3',4,5',6,6'-Octachlorobiphenyl 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA 2,2',3,4,4',5',6-Heptabromodiphenylether 0.1 0.1 ND ND ug/L 2 2 0 NA 2,2',3',4,6-Pentachlorobiphenyl 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA 2,2',4,4',5,5'-Hexabromodiphenyl ether 0.1 0.1 ND ND ug/L 2 2 0 NA 2,2',4,4',5,6'-Hexabromodiphenyl ether 0.1 0.1 ND ND ug/L 2 2 0 NA 2,2',4,4',5,6'-Hexachlorobiphenyl 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA 2,2',4,4',5,-Pentabromodiphenyl ether 0.1 0.1 ND ND ug/L 2 2 0 NA 2,2',4,4',6,-Pentabromodiphenyl ether 0 0 ND ND ug/L 2 2 0 NA

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-161 Section 3 Environmental Analysis

Reported Value Standards No. of MCL Constituent Name Min RDL Max RDL 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances 2,2',4,4'-Tetrabromodiphenyl ether 0 0 ND ND ug/L 2 2 0 NA 2,2',4,4'-Tetrachlorobiphenyl 0 1 ND ND ND ND ND ug/L 13 13 0 NA 2,3-Dichlorobiphenyl 0 1 ND ND ND ND ND ug/L 13 13 0 NA 2,4,4'-Tribromodiphenyl ether 0 0 ND ND ug/L 2 2 0 NA 2,4,5-Trichlorobiphenyl 0 1 ND ND ND ND ND ug/L 13 13 0 NA 2-Chlorobiphenyl 0 1 ND ND ND ND ND ug/L 13 13 0 NA bis (2-ethylhexyl) adipate 2 10 ND ND ND ND ND ug/L 13 13 0 400 0 bis (2-ethylhexyl) phthalate 2 10 ND ND ND ND ND ug/L 13 13 0 4 0 Butylbenzyl phthalate 2 10 ND ND ND ND ND ug/L 13 13 0 NA Diethyl phthalate 2 10 ND ND ND ND ND ug/L 13 13 0 NA Dimethyl phthalate 2 10 ND ND ND ND ND ug/L 13 13 0 NA Di-n-butylphthalate 2 10 ND ND ND ND ND ug/L 13 13 0 NA Di-n-octyl phthalate 2 10 ND ND ND ND ND ug/L 13 13 0 NA

POLYCYCLIC AROMATIC HYDROCARBONS 3-Hydroxycarbofuran 2.0 2.0 ND ND ND ND ND ug/L 6 6 0 NA Acenapthene 0.5 0.5 ND ND ND ND ND ug/L 7 7 0 NA Acenapthylene 0.1 1.0 ND ND ND ND ND ug/L 20 20 0 NA Anthracene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Benzo(a)anthracene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Benzo(a)pyrene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 0.2 0 Benzo(b)fluoranthene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Benzo(g,h,i)perylene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Benzo[k]fluoranthene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Chrysene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Dibenzo(a,h)anthracene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Fluoranthene 0.1 0.1 ND ND ND ND ND ug/L 7 7 0 NA Fluorene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Indeno(1,2,3-cd)pyrene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Phenanthrene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA Pyrene 0.1 0.5 ND ND ND ND ND ug/L 20 20 0 NA

PESTICIDES 4,4'-DDD 0.01 0.5 ND ND ND ND ND ug/L 18 18 0 NA

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-162 Section 3 Environmental Analysis

Reported Value Standards No. of MCL Constituent Name Min RDL Max RDL 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances 4,4'-DDE 0.01 0.5 ND ND ND ND ND ug/L 18 18 0 NA 4,4'-DDT 0.01 0.5 ND ND ND ND ND ug/L 18 18 0 NA Aldicarb 1 1 ND ND ND ND ND ug/L 6 6 0 NA Aldicarb sulfone 2 2 ND ND ND ND ND ug/L 6 6 0 NA Aldicarb sulfoxide 2 2 ND ND ND ND ND ug/L 6 6 0 NA Aldrin 0.03 0.5 ND ND ND ND ND ug/L 18 18 0 0.002 0 Baygon 1 1 ND ND ND ND ND ug/L 6 6 0 NA Captan 0.01 1 ND ND ND ND ND ug/L 18 18 0 NA Carbaryl 2 2 ND ND ND ND ND ug/L 6 6 0 NA Carbofuran 1 1 ND ND ND ND ND ug/L 6 6 0 18 0 Chlordane 0.1 0.1 ND ND ND ND ND ug/L 5 5 0 0.1 0 Chlordane-alpha 0.01 0.5 ND ND ND ND ND ug/L 18 18 0 NA Chlordane-gamma 0.01 0.5 ND ND ND ND ND ug/L 18 18 0 NA Chlorobenzilate 0.05 0.5 ND ND ND ND ND ug/L 18 18 0 NA Chloroneb 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 NA Chloropropham 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Chlorothalonil 0.1 5 ND ND ND ND ND ug/L 18 18 0 NA Chlorpyrifos 0.1 1 ND ND ND ND ND ug/L 18 18 0 NA Diazinon 0.1 0.1 ND ND ND ND ND ug/L 5 5 0 6 0 Dichlorvos 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Dieldrin 0.02 0.5 ND ND ND ND ND ug/L 18 18 0 0.002 0 Diflubenzuron 1 1 ND ND ND ND ND ug/L 5 5 0 NA Dimethoate 0.1 5 ND ND ND ND ND ug/L 18 18 0 NA Endosulfan I 0.05 0.5 ND ND ND ND ND ug/L 18 18 0 NA Endosulfan II 0.01 0.5 ND ND ND ND ND ug/L 18 18 0 NA Endosulfan sulfate 0.05 1 ND ND ND ND ND ug/L 18 18 0 NA Endrin 0.03 0.5 ND ND ND ND ND ug/L 18 18 0 2 0 Endrin Aldehyde 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 NA Endrin Ketone 0.1 0.1 ND ND ND ND ND ug/L 5 5 0 NA Ethion 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 NA Ethoprop 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Etridiazole 0.05 0.5 ND ND ND ND ND ug/L 18 18 0 NA Fenarimol 1 5 ND ND ND ND ND ug/L 13 13 0 NA HCH-alpha(Alpha-BHC) 0.02 0.5 ND ND ND ND ND ug/L 18 18 0 0.015 0 HCH-beta(Beta-BHC) 0.02 0.5 ND ND ND ND ND ug/L 18 18 0 0.025 0

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-163 Section 3 Environmental Analysis

Reported Value Standards No. of MCL Constituent Name Min RDL Max RDL 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances HCH-delta(Delta-BHC) 0.02 0.5 ND ND ND ND ND ug/L 18 18 0 NA HCH-gamma (Lindane) 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 0.2 0 Heptachlor 0.01 0.5 ND ND ND ND ND ug/L 18 18 0 0.01 0 Heptachlor epoxide 0.01 0.5 ND ND ND ND ND ug/L 18 18 0 0.01 0 Hexachlorobenzene 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 1 0 Hexachlorocyclopentadiene 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 50 0 Malathion 6 10 ND ND ND ND ND ug/L 5 5 0 NA Methiocarb 4 4 ND ND ND ND ND ug/L 6 6 0 NA Methomyl 1 1 ND ND ND ND ND ug/L 6 6 0 NA Methoxychlor 0.1 1 ND ND ND ND ND ug/L 18 18 0 30 0 Methyl paraoxon 1 5 ND ND ND ND ND ug/L 13 13 0 NA methyl-Parathion 0.5 0.5 ND ND ND ND ND ug/L 5 5 0 NA Mevinphos 1 5 ND ND ND ND ND ug/L 13 13 0 NA MGK 264 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Oxamyl 2 2 ND ND ND ND ND ug/L 6 6 0 50 0 Permethrin-(total of cis/trans) 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 NA Stirofos 2 10 ND ND ND ND ND ug/L 13 13 0 NA Tebuthiuron 1 10 ND ND ND ND ND ug/L 18 18 0 NA Terbufos Sulfone 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Thidiazuron 1 1 ND ND ND ND ND ug/L 5 5 0 NA Toxaphene Mixture 1 1 ND ND ND ND ND ug/L 5 5 0 3 0 trans-nonachlor 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Tricyclazole 2 10 ND ND ND ND ND ug/L 13 13 0 NA Tridemefon 1 5 ND ND ND ND ND ug/L 13 13 0 NA Trithion 0.01 0.5 ND ND ND ND ND ug/L 18 18 0 NA

HERBICIDES 2,4,5-TP (Silvex) 0.5 0.5 ND ND ND ND ND ug/L 11 11 0 50 0 2,4-Dichlorophenoxyacetic Acid 0.5 0.5 ND ND ND ND ND ug/L 11 11 0 70 0 Acetochlor 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Acifluorfen 0.5 0.5 ND ND ND ND ND ug/L 11 11 0 NA Alachlor 0.05 0.5 ND ND ND ND ND ug/L 23 23 0 2 0 Ametryn 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Atrazine 0.100 0.5 ND ND ND ND ND ug/L 18 18 0 1 0 Bentazon 1 1 ND ND ND ND ND ug/L 11 11 0 18 0

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-164 Section 3 Environmental Analysis

Reported Value Standards No. of MCL Constituent Name Min RDL Max RDL 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances Bromacil 0.1 0.5 ND 8.4 ND ND 1.1 ug/L 18 11 7 NA Butachlor 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 NA Butylate 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Cycloate 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Dacthal Acid Metabolites 0.1 0.3 ND 0.3 0.1 ND 0.2 ug/L 11 4 7 NA Dalapon 1 1 ND ND ND ND ND ug/L 11 11 0 200 0 DCPA-Dacthal 0.05 0.5 ND ND ND ND ND ug/L 18 18 0 NA Dicamba 0.081 0.081 ND ND ND ND ND ug/L 11 11 0 NA Dinoseb 0.5 1.0 ND ND ND ND ND ug/L 11 11 0 7 0 Diphenamid 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Diquat 4 4 ND ND ND ND ND ug/L 6 6 0 20 0 Diuron 1.000 1.0 ND 1.2 ND ND 1.1 ug/L 5 3 2 NA Endothall 45 45 ND ND ND ND ND ug/L 5 5 0 100 0 EPTC 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 NA Fluometuron 1 1 ND ND ND ND ND ug/L 5 5 0 NA Fluoridone 2 10 ND ND ND ND ND ug/L 13 13 0 NA Glyphosate 25 25 ND ND ND ND ND ug/L 7 7 0 700 0 Hexazinone 0.1 0.5 ND 0.1 ND ND ND ug/L 13 12 1 NA Linuron 1.000 1.0 ND ND ND ND ND ug/L 5 5 0 NA Metolachlor 0.1 0.8 ND ND ND ND ND ug/L 18 18 0 NA Metribuzin 0.2 0.2 ND ND ND ND ND ug/L 5 5 0 NA Molinate 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 20 0 Napropamide 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Norflurazon 0.5 5.0 ND ND ND ND ND ug/L 18 18 0 NA Paraquat 4 4 ND ND ND ND ND ug/L 6 6 0 NA Parathion 0.5 0.5 ND ND ND ND ND ug/L 5 5 0 NA Pebulate 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Picloram 0.5 0.5 ND ND ND ND ND ug/L 11 11 0 500 0 Prometon 0.1 0.1 ND ND ND ND ND ug/L 5 5 0 NA Prometryn 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 NA Pronamide 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Propachlor 0.1 0.5 ND ND ND ND ND ug/L 23 23 0 90 0 Propanil 1 1 ND ND ND ND ND ug/L 5 5 0 NA Propazine 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 NA Siduron 1 1 ND ND ND ND ND ug/L 5 5 0 NA

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-165 Section 3 Environmental Analysis

Reported Value Standards No. of MCL Constituent Name Min RDL Max RDL 25th 75th No. of No. of No. of Primary Secondary Notification Min Max Median Units or NL Percentile Percentile Samples NDs Detects MCL MCL Level (NL) Exceedances Simazine 0.100 0.5 ND ND ND ND ND ug/L 18 18 0 4 0 Simetryn 1 5 ND ND ND ND ND ug/L 13 13 0 NA Terbacil 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 NA Terbutryn 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Thiobencarb 0.1 0.5 ND ND ND ND ND ug/L 18 18 0 70 1 0 Trifluralin 0.05 0.5 ND ND ND ND ND ug/L 18 18 0 NA Vernolate 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA

OTHER Caffeine 100 500 ND 700 ND ND ND ng/L 18 16 2 NA Isophorone 0.1 0.5 ND ND ND ND ND ug/L 13 13 0 NA Methylisothiocyanate (MITC) 0.01 0.01 ND 0.01 ND ND ND ug/L 44 43 1 NA

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-166 Section 3 Environmental Analysis

In most years, there have been no exceedances of any primary MCLs nor NLs for samples collected in the Santa Ana River at Imperial Highway or at below Prado Dam. There have been a small number of exceedances of the historic perchlorate Notification Level. Nitrate-nitrogen concentrations in the Santa Ana River at below Prado Dam typically range from about 3 to 6 mg/L. The primary MCL for nitrate-nitrogen is 10 mg/L. Overall, arsenic and nitrate are the only two inorganic constituents which were commonly detected at roughly one-quarter to one-half of their respective primary MCLs. However, there were no exceedances of the MCLs. The Basin Plan contains water quality objectives for the Santa Ana River. The objectives of most interest to OCWD with respect to groundwater recharge with Santa Ana River water are those for Reach 2 and Reach 3 of the Santa Ana River. Reach 2 extends upstream from 17th Street in Santa Ana to Prado Dam, and includes the portion of the Santa Ana River where OCWD recharges water through riverbed and diverts water into offstream basins near Imperial Highway. Reach 3 extends from Prado Dam to Mission Boulevard in Riverside. Reach 2 has a 5-year moving average total dissolved solids (TDS) objective of 650 milligrams per liter (mg/L). Reach 3 has objectives for baseflow only, which is measured in August and September. Baseflow objectives for Reach 3 are established for TDS, total nitrogen, hardness, sodium, chloride, sulfate, chemical oxygen demand (COD), and boron (California Regional Water Quality Control Board, 2004). The Reach 2 5-year moving average TDS objective is 650 mg/L. To evaluate compliance with this objective, water quality data from the sampling station at below Prado Dam were used. This site is approximately 200 yards downstream of Prado Dam. Based on data through December 2012, the 5-year monthly volume-weighted moving average is 517 mg/L (SAWPA, 2013), which is in compliance with the water quality objective. This represents an 8 mg/L decrease from the prior year’s calculation and a 7 mg/L increase from two years prior. Additional information on compliance with the water quality objectives is contained in the report “2012 Annual Report of Santa Ana River Water Quality” prepared by SAWPA (SAWPA, 2013). For calendar year 2012, the water quality data were collected during the months August and September under baseflow conditions by the Regional Board. Over the 30-year period, the Reach 3 water quality objectives have been exceeded for COD ten times, total hardness three times, sodium twice, sulfate twice, TDS once, and total nitrogen seven times. Since 1999, all water quality objectives

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-167 Section 3 Environmental Analysis

have been met except for the exceedance of COD in 2007, sodium in 2010 and 2012, and total hardness in 2012. However, a review of the August 2012 baseflow data collected by the Regional Board indicates that the sodium and total hardness data from one sample may have been overestimated by a factor of approximately 2x, as these results are not consistent with the TDS and other inorganic results from the same sample. These elevated results are largely responsible for the 2012 exceedences of the Reach 3 water quality objectives (hardness and sodium), and thus are currently being reviewed by SAWPA and the RWQCB. OCWD routinely monitors the sampling point for the Santa Ana River at below Prado Dam for indicator bacteria. Table 34 summarizes the geometric mean for indicator bacteria at the below dam site. The water year geometric mean values were calculated for all samples with reported values greater than the detection limit of the assay, 1 CFU/100 mL. As noted in Table 34, annual variability is observed with the geometric mean values. The United States Geological Study published a report in 2004 regarding microbial water quality in stormflow in the Santa Ana River (USGS Scientific Investigations Report 2004-5116, 2004). The site sampled along the Santa Ana River was the Imperial Highway site, approximately 11 miles downstream from Prado Dam. At the Imperial Highway site, indicator bacteria were observed to vary significantly during stormflows. For example, during stormflow, total coliforms ranged up to a maximum of 3,400,000 colonies per 100 mL, fecal coliforms ranged up to a maximum of 310,000 colonies per 100 mL, and E. coli up to a maximum of 84,000 colonies per 100 mL.

Table 34: Summary of Indicator Bacteria Water Quality Data Santa Ana River at below Prado Dam

Geometric Mean (CFU/100 mL) Total Fecal July 1 – June 30 No. of samples E. coli Enterococcus coliform coliform Below Prado Dam 14 1,707 121 94 170 2008-2009

2009-2010 15 410 32 38 34

2010-2011 15 1,126 68 56 57

2011-2012 15 2,741 165 147 227

2012-2013 15 1,510 214 158 160 Source: OCWD data (2013)

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Prado Basin Surface Water Management Zone The Prado Basin Management Zone is generally defined by the 566 foot elevation. It extends from Prado Dam up Chino Creek to where Mill Creek becomes Cucamonga Creek and to the concrete lined portion of Temescal Wash. The Prado Basin Management Zone encompasses the Prado Flood Control Basin and the OCWD Prado Constructed Wetlands. Orange County Groundwater Basin The Orange County Groundwater Basin underlies central and northern Orange County and is bordered by the Santa Ana Mountains to the east, the Pacific Ocean to the west, the Newport-Inglewood Fault to the southwest and Coyote Hills to the north. The basin is contiguous and directly connected with the Central Basin of Los Angeles County to the northwest. The basin reaches depths of over 2,000 feet and is comprised of a complex series of interconnected sand and gravel deposits. The aquifer is divided into three sections, shallow, principal and deep. Most of the water in the basin is extracted from the Principal Aquifer. Since 1933, OCWD has been diverting water from the Santa Ana River for groundwater recharge. The flows of the Santa Ana River consist of storm flows and perennial flow (base flow) that increases in the winter and decreases in the summer. The base flow of the Santa Ana River consists almost entirely of treated wastewater discharged from upstream waste water treatment plants. The base flow of the Santa Ana River is the primary source of water to recharge the Orange County Groundwater Basin. Surface water flows of the Santa Ana River are diverted into a series of recharge basins to replenish the groundwater basin. Virtually all of the base flow of the Santa Ana River is captured by OCWD for groundwater recharge and only a portion of the total storm flow of the Santa Ana River is captured by OCWD for groundwater recharge. The storm water that is not captured by OCWD is lost to the ocean. Santa Ana Region Basin Plan Beneficial Uses The Basin Plan designates beneficial uses for waters in the Santa Ana River Watershed and provides quantitative and narrative criteria for a range of water quality constituents applicable to certain receiving water bodies in order to protect beneficial uses. The beneficial uses established in the Basin Plan are shown in Table 35.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-169 Section 3 Environmental Analysis

Table 35: Beneficial Uses Abbreviation Beneficial Use

GWR Groundwater Recharge waters are used for natural or artificial recharge of groundwater for purposes that may include, but are not limited to, future extraction, maintaining water quality or halting saltwater intrusion into freshwater aquifers.

REC 1 Water Contact Recreation waters are used for recreational activities involving body contact with water where ingestion of water is reasonably possible. These uses may include, but are not limited to swimming, wading, water skiing, skin and scuba diving, surfing, whitewater activities, fishing and use of natural hot springs.

REC 2 Non-Contact Water Recreation waters are used for recreational activities involving proximity to water, but not normally body contact with water where ingestion of water would be reasonably possible. These uses may include, but are not limited to picnicking, sunbathing, hiking, beachcombing, camping, boating, tide pool and marine life study, hunting, sightseeing and aesthetic enjoyment in-conjunction with the above activities.

WARM Warm waters support warm water ecosystems that may include but are not limited to, preservation and enhancement of aquatic habitats, vegetation, fish, and wildlife, including invertebrates.

LWARM Limited Warm Freshwater Habitat waters support warm water ecosystems which are severely limited in diversity and abundance.

COLD Cold Freshwater habitat waters support coldwater ecosystems.

BIOL Preservation of Biological Habitats of Special Significance waters support designated areas of habitats.

WILD Wildlife Habitat waters support wildlife habitats that may include, but are not limited to the preservation and enhancement of vegetation and prey species used by waterfowl and other wildlife.

RARE Rare, Threatened or Endangered Species (RARE) waters support habitats necessary for the survival and successful maintenance of plant or animal species designated under state or federal law as rare, threatened or endangered.

MUN Municipal and Domestic Supply waters are used for community, military, municipal or individual water supply systems. These uses may include, but are not limited to drinking water supply.

AGR Agricultural Supply waters are used for farming, horticulture or ranching. These uses may include, but are not limited to irrigation, stock watering, and support of vegetation for range grazing.

IND Industrial Service Supply waters are used for industrial activities that do not depend primarily on water quality. These uses may include, but are not limited to mining, cooling water supply, hydraulic conveyance, gravel washing, fire protection and oil well depressurization.

PROC Industrial Process Supply waters are used for industrial activities that depend primarily on water quality. These uses may include, but are not limited to, process water supply and all uses of water related to product manufacture or food preparation.

NAV Navigation waters are used for shipping, travel, or other transportation by private, commercial or military vessels.

POW Hydropower Generation waters are used for hydroelectric power generation.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-170 Section 3 Environmental Analysis

Abbreviation Beneficial Use

COMM Commercial and Sport fishing waters are used for commercial or recreational collection of fish or other organisms

EST Uses of water that support estuarine ecosystems including, but not limited to preservation or enhancement of estuarine habitats, vegetation, fish, shell fish or wildlife.

MAR Use of water that support marine ecosystems including, but not limited to, preservation or enhancement of marine habitats, vegetation such as kelp, fish, shell fish or wildlife.

SPWN Use of water that support high quality aquatic habitats suitable for reproduction and early development of fish.

SHELL Use of water that support habitats suitable for the collection of filter-feeding shellfish for human consumption, commercial or sports purposes.

The Basin Plan designates beneficial uses for the Santa Ana River, Prado Basin Management Zone and the Orange County Groundwater Basin. Table 36 identifies the beneficial uses for Reach 2, Reach 3 and the Tidal Prism of the Santa Ana River, Prado Basin Management Zone and the Orange County Groundwater Basin. Table 36: Beneficial Uses Prado Basin Orange County Santa Ana Santa Ana Santa Ana Tidal Prism Management Groundwater River River River Santa Ana River Zone Basin Reach 3 Reach 2 Reach 1 GWR NL NL X X NL NL REC-1 X NL X X X X REC-2 X NL X X X X WARM X NL X X I NL WILD X NL X X I X RARE X NL X X NL X AGR X X X X NL NL COMM NL NL NL NL NL X MAR NL NL NL NL NL X MUN NL X NL NL NL NL IND NL X NL NL NL NL PROC NL X NL NL NL NL X- Present or potential Beneficial Use I-Intermittent Beneficial Use NL—Not Listed

Water Quality Objectives The Santa Ana Region Basin Plan establishes Water Quality Objectives for water bodies within their respective watershed to ensure the protection of Beneficial Uses. Table 37 identifies the water quality objectives for Reach 1, Reach 2, Reach 3 and the Tidal Prism Santa Ana River, Prado Basin Management Zone and the Orange County Groundwater Basin.

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Table 37: Water Quality Objectives (mg/L) Reach TDS HARD Sodium Chloride Nitrogen Sulfate Oxygen Demand Santa Ana NA NA NA NA NA NA NA River reach 1 Santa Ana 650 NL NL NL NL NL NL River Reach 2 Santa Ana 700 350 110 140 10 150 30 River Reach 3 Tidal Prism NL NL NL NL NL NL NL Santa Ana River Prado Basin NL NL NL NL NL NL NL Management Zone Orange County 580 NL NL NL 3.4 NL NL Groundwater Basin NL-Not Listed

Section 303 (d) Water Bodies Under Section 303 (d) of the Clean Water Act, the State Regional Water Quality Control Board is required to develop a list of impaired water bodies. Each of the individual Regional Water Quality Control Boards are responsible for establishing priority rankings and developing action plans, referred to as total maximum daily loads (TMDLs) to improve water quality of water bodies included in the 303(d) list. A listing of 303(d) impaired water bodies in the vicinity of the project area is shown in Table 38. Table 38: Impaired Water Bodies Water Body Impairment Santa Ana River, Reach 3 Copper, lead, indicator bacteria Santa Ana River, Reach 2 Indicator bacteria Temescal Creek, Reach 1 pH

3.8.3 Significance Criteria • Will the project violate any water quality standards or waste discharge requirements? • Will the project substantially deplete groundwater supplies or interfere with groundwater recharge, such that there will be a net deficit in aquifer volume or a lowering of the local groundwater table? • Will the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river,

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in a manner which will result in substantial erosion or siltation on or off site? • Will the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, or substantially increase the rate or amount of surface runoff in a manner which will result in flooding on or offsite? • Will the project create or contribute runoff which will exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff? • Will the project create any substantial new sources of polluted runoff, or otherwise degrade water quality? • Will the project place within a 100 year flood hazard structures which will impede or redirect flood flows? • Will the project expose people or structures to a significant risk of loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam? 3.8.4 Project Impacts IMPACT HWQ-1: Will the project violate any water quality standards or waste discharge requirements? Water Quality-Turbidity The Project will involve the use of dredge to remove sediment from the sediment removal channel. There is the potential that the dredging could increase turbidity and decrease water quality in the Prado Basin. Additionally, the sediment re- entrainment activities could increase turbidity in the Santa Ana River downstream of Prado Dam. The Basin Plan has established the following threshold for turbidity for water bodies in the watershed.

Table 39: Basin Plan Turbidity thresholds Natural Turbidity Maximum Increase 0-50 NTU 20% 50-100 NTU 10 NTU Greater than 100 NTU 10%

The sediment re-entrainment activities will occur under high flow conditions when there is high level of turbidity in the river water, similar to a storm event conditions. It is anticipated that the sediment re-entrainment will not significantly increase the level of turbidity that typically occurs from a storm event. Because

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-173 Section 3 Environmental Analysis sediment re-entrainment will occur under turbid conditions, it is unlikely that the Project will be able to adjust the levels of re-entrainment to meet the Basin Plan standard for turbidity. To minimize turbidity impacts the Project will be implemented in a manner to recreate natural storm flow conditions to the extent practicable. This will be done by pulsing the re-entrainment of sediments to reflect a typical storm cycle. Typical storm cycles in California occur over a 24 to 72 hour periods with 24 hours or greater periods between storm systems. Sediment re-entrainment will take place in 72 hour entrainment cycle, assuming adequate flows are available, with 24 hours of no re-entrainment cycle to recreate a natural storm driven sediment suspension cycles as close possible. By pulsing the sediment re-entrainment it allows for dilution of the sediment in the water column which will help minimize turbidity impacts. The Project will monitor for turbidity and where feasible will make adjustments to sediment re-entrainment activities, such reducing the concentration of solids in the sediment/slurry, to minimize potential turbidity impacts. With the implementation of Mitigation Measure HWQ-1 potential turbidity impacts will be minimized. However, because there could be a potential temporary exceedance of the Basin Plan threshold for turbidity the potential impact is considered a short-term significant adverse impact. Basin Plan Beneficial Uses As part of the environmental planning process for the Project, chemical analysis was conducted of the sediment in the Prado Basin that will be dredged for sediment re-entrainment. The chemical analysis showed no detectable organic chemicals, pesticides, PCbs, PAhs, or hydrocarbons. Within the water column there were some total dissolved solids, some inorganic nitrogen, and small quantities of metals; which are all considered to be within the ranges expected for background soils in California and will not conflict with beneficial uses established for the Santa Ana River, Prado Basin Management Zone or the Orange County Groundwater Basin. To ensure beneficial uses are maintained the Project will implement a water quality monitoring plan that will monitor for inorganic and organic chemicals including pesticides, PCBs, PAHs and hydrocarbons, metals, total dissolved solids, indicator bacteria and dissolved oxygen, both upstream in the Prado Basin reservoir pool and downstream within the waters where sediment re- entrainment would occur. The monitoring program will be implemented before construction of the Project, during operation of the Project and after the Project is completed. If significant differences between upstream and downstream samples are observed during sediment re-entrainment activities, the rate of sediment re- entrainment would be adjusted to ensure they are within acceptable threshold

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ranges that are provided in the Basin Plan. With the implementation of Mitigation Measure HWQ-2 the Project will ensure that Basin Plan beneficial uses are maintained. As indicted previously, during sediment re-entrainment the Project will temporarily exceed the Basin Plan threshold for turbidity. Potential turbidity impacts will be minimized by pulsing the sediment re-entrainment and where feasible adjusting the concentration of solids in the sediment/slurry being re- entrained. Basin Plan Water Quality Objectives The sediment re-entrainment activities will occur in the Santa Ana River, downstream of Prado Dam. Therefore, Santa Ana River Reach 2, Santa Ana River Reach 1 and the Santa Ana River Tidal Prism will have the potential to be affected by the sediment re-entrainment activities. The Basin Plan does not define specific numeric water quality objectives for Reach 1 of the Santa Ana River and the Santa Ana River Tidal Prism. Reach 2 of the Santa Ana River where the re-entrainment activities will occur has a total dissolved solids water quality objective of 650 mg/L and the Orange County Groundwater Basin has a total dissolved solids water quality objective of 580 mg/L. Chemical analysis of the sediments in Prado Basin detected some levels of total dissolved solids. However, the levels were within expected background soils in California and will not be in conflict with water quality objectives established in the Basin Plan. A water quality monitoring program will be implemented that will measure total dissolved solids within the sediment before it is re-entrained. If elevated levels are encountered adjustments will be on concentration of solids in the sediment to reduce total dissolved solids to acceptable levels. With the implementation of Mitigation Measure HWQ-2 the Project will ensure that there will be no conflicts with the water quality objectives established in the Basin Plan. As indicted previously, during sediment re-entrainment the Project will temporarily exceed the Basin Plan threshold for turbidity. Potential turbidity impacts will be minimized by pulsing the sediment re-entrainment and where feasible adjusting the concentration of solids in the sediment slurry being re- entrained. Section 303 (d) Impaired Water Bodies Presently, Reach 2 of the Santa Ana River has been identified as 303 (d) impaired water body for indictor bacteria. The sediment material removed from the basin could be stockpiled for a lengthy period of time and there is some potential that bacterial growth could occur. To ensure sediment with elevated

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-175 Section 3 Environmental Analysis

levels of bacterial are not re-entrained a water quality monitoring program will be implemented that will measure indicator bacteria in the sediment material. Sediment that contains elevated levels of bacteria will be segregated and will not be re-entrained. Therefore, the Project will not introduce increase levels of bacterial along Reach 2 of the Santa Ana River that will be conflict with the Basin Plan. With the implementation of Mitigation Measure HWQ-2 the Project will ensure that elevated levels of bacteria are not introduced into Reach 2 of the Santa Ana River. Level of Impact before Mitigation Unavoidable significant impact Mitigation Measures HWQ-1: To minimize turbidity impacts sediment re-entrainment will be done in a manner to recreate natural storm glow conditions to the extent practicable, by pulsing the re-entrainment over a 24 to 72 hour period with 24 hours of no re- entrainment. The project will implement a water quality monitoring program to monitor turbidity levels to ensure and where feasible to adjust rates of sediment re-entrainment to minimize turbidity impacts. If levels of turbidity are below the Basin Plan threshold the pause period could be reduced and/or concentration of solids in the slurry could be increased providing turbidity levels are below the Basin Plan threshold. HWQ-2: The project will implement a water quality monitoring program that will include procedures to monitor for organic chemicals including pesticides, PCBs, PAHs and hydrocarbons, metals, total dissolved solids, indicator bacteria and dissolved oxygen upstream in the Prado Basin reservoir pool and downstream within the waters where sediment re-entrainment would occur. The monitoring program will be implemented before construction of the Project, during operation of the Project and after the Project is completed. If significant differences between upstream and downstream samples are observed during sediment re- entrainment activities, the rate of sediment re-entrainment would be adjusted to ensure they are within acceptable thresholds of the Regional Water Quality Control Board Basin Plain. The water quality monitoring plan will be coordinated with and approved by the Regional Water Quality Control Board as part of the 401 Water Quality Certification for the Project. Level of Impact Significant adverse impact

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IMPACT HWQ-2: Will the Project substantially deplete groundwater supplies or interfere with groundwater recharge, such that there will be a net deficit in aquifer volume or a lowering of the local groundwater table? The Project will not extract underground water supplies. Therefore, the Project will not contribute to the depletion of existing ground water supplies. Sediments re-entrained in the river will be transported to reaches along the river where groundwater recharge occurs. The sediment will facilitate infiltration of river water into the ground water basin and would have a beneficial impact on ground water supplies. Level of Impact before Mitigation Less than significant. Mitigation Measures No mitigation measures required. Level of Impact after Mitigation Less than significant. IMPACT HWQ-3: Will the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which will result in substantial erosion or siltation on or off site? Upstream of Prado Dam The sediment transport analysis indicates that there will not be any significant change to sediment depositional patterns within the Prado Basin reservoir area. However, there will be some increase in bed shear stress and velocity within the reservoir area when the dredging conditions are occurring. An increase in flow velocity and sediment transport capacity at the upstream end of the dredged channel will have the potential to create a head cut or migrating local scour at the upstream end of the project area. Head cutting will help restore a portion of the slope to the river channel and will encourage sediments to migrate into the project area for future removal. The migration of the sediment into Prado Basin will expose existing deposits of gravel and cobbles along reaches of the Santa Ana River upstream of the project area. The exposed gravel and cobble will help restore essential habitat elements in the river for native fish. Head cut depth and migration will depend on the incoming flow rates and sediment load, final geometry of the sediment removal channel and channel bed materials encountered during head cut migration. To help measure head cut benefits, a

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-177 Section 3 Environmental Analysis sediment movement monitoring program will be implemented that will monitor head cut activity after the dredging is completed. Downstream of Prado Dam Based on standard sediment transport principles, flow releases from Prado Dam that are clear water and void of sediment will have the most erosion potential in the downstream reaches. Since the Project involves adding sediment to the flow releases, there should be no significant erosion or siltation impacts as a result of the Project based on the character of the flow augmented with sediment. However, as a result of sediment deposition water surface elevations for a given discharge could increase, if the river bed elevation is increased from the deposition. To the extent the water flows from a typical discharge reach are higher up the river bank than normal, there is the potential for erosion to areas that are newly inundated and are not able to withstand the increased shear stresses and forces caused by the flowing water. However, the amount of erosion is not anticipated to be significant. To help measure sediment deposition and erosion, a sediment movement monitoring program will be implemented at selected locations. The monitoring program will provide data and insights on sediment deposition and erosion occurring from variations in flow rates. Pending on levels of deposition and erosion measurements from the sediment movement monitoring program, adjustments will be made to sediment re-entrainment activities to minimize deposition and erosion impacts. Level of Impact before Mitigation Less than significant impact. Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than significant impact. IMPACT HWQ-4: Will the Project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, or substantially increase the rate or amount of surface runoff in a manner which will result in flooding on or offsite? Upstream of Prado Dam To evaluate the potential for flood impacts upstream of Prado Dam associated with the implementation of the Project an assessment was conducted that simulated flood elevations, water velocities and sediment movement in Prado Basin under a with and without sediment removing condition. The highest

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-178 Section 3 Environmental Analysis simulated flows used in the assessment were 47,800 cfs inflow into Prado Basin and 5,000 cfs outflow from Prado Dam. Additionally, a maximum dam operating water surface elevation of 510 feet and a typical operating water surface elevation of 498 feet were used as conservative downstream boundaries. The results showed insignificant changes to flood inundation levels. The Project will remove sediment from Prado Basin, which will result in a net increase in reservoir storage capacity. The increased reservoir capacity will not increase flood elevation levels and will not adversely impact the frequency, duration or severity of flooding. Downstream of Prado Dam To investigate the potential for increased flooding downstream of the Prado Dam, a HEC-RAS Sediment Transport Analysis was conducted. The analysis evaluated the design flood flows in the lower Santa Ana River following introduction of sediments into the lower Santa Ana River. The analysis concluded that with the implementation of the Project there will be an increase in sediment deposition in several reaches of the river between Prado Dam and the ocean. Table 40 shows the sediment transport model iterations under different re- entrainment pulse flows, ranging from 250 cfs to up to 5,000 cfs) to determine how many days it would take to re-entrain the targeted 500,000 cubic yards of sediment. Each of these pulse flows was then modeled assuming a “dry”, “median” and “wet” year scenario in the lower Santa Ana River to see how the sediment would move through the system. Based on the Project design flow of 500 cfs a total of 43 days will be required to re-entrain 500,000 cubic yards of sediment. If higher flows occur the number of days could be shorter.

Table 40: Durations to Deplete 500,000 yd³ of Sediment for Six Selected Discharges Discharge (cfs) Duration (days) 250 86.8 500 43.4 750 28.9 1,250 17.4 2,000 10.8 5,000 4.3

Since the sediment re-entrainment period will be relatively short and the remaining discharges released from the dam during the year are devoid of sediment, adequate redistribution of the deposited sediment will occur and sufficient freeboard will remain in the lower Santa Ana River at all reaches with the exception of a segment of the river in the vicinity of the OCWD Five Coves inflatable dam. OCWD routinely maintains and re-grades the bottom of the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-179 Section 3 Environmental Analysis recharge reaches of the river near the Five Coves Dam. If excessive sedimentation occurs in the vicinity of Five Coves Dam or in other areas of the recharge reach, OCWD will be able to redistribute deposited sediment though its routine maintenance activities. Additionally, channel incision has removed approximately 3 feet to 15 feet of sediment in the canyon and recharge reach, some of which will be replaced temporarily replaced by the Project. With the implementation of Mitigation Measure HWQ-3 the re-entrainment of the sediment in the Santa Ana River downstream of Prado Dam will not significantly impact the frequency, duration or severity of flooding along the river. Presently, sediment accumulates near the tidal prism of the Santa River, periodically requiring the Orange County Flood Control District to remove the sediment to maintain flood control capacity along the river. The implementation of the Project will contribute additional amounts of sediment that could accumulate near the tidal prism. As part of the ongoing maintenance for the Project, OCWD will coordinate with Orange County Flood Control District on the fair share responsibility for the removal of sediment from the Santa Ana River near the tidal prism. With the implementation of Mitigation Measure HWQ-4 potential adverse impacts associated with the Project contribution to the buildup of sediment near the tidal prism will be reduced to a less than significant level. Onsite Flood Risks At the sediment storage site location the average elevation is 530 feet and the lowest elevation point on the site is 515 feet. The sediment storage site is located within the inundation area and could be subject to flood impacts. During the construction and operation of the Project OCWD will coordinate with the Corps on weather forecasts and in the event a large enough storm is predicted that could pose flood risks to the site and jeopardize the safety of the area, OCWD will de-mobilize and remove all equipment from the site. With the implementation of Mitigation Measure HWQ-4 potential adverse flood impacts will be reduced to a less than substantial level. The proposed sediment re-entrainment area will be located on the outlet channel levee. In the event a large enough storm is predicted that could jeopardize the safety of the area OCWD will de-mobilize and remove all equipment from the site. With the implementation of Mitigation Measure HWQ-5 potential adverse flood impacts will be reduced to a less than substantial level. Level of Impact before Mitigation Potential significant impact. Mitigation Measures

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HWQ-3: During the operation of the project OCWD will routinely re-grade and redistribute the re-entrained sediment in order to maintain adequate freeboard along the river. HWQ-4: Prior to the start of the Project OCWD will coordinate with the Orange County Flood Control District on fair share responsibility to remove sediment that builds up near the Santa Ana River Tidal Prism. HWQ-5: During the construction and operation of the project OCWD will coordinate with the Corps on weather forecasts for the project area. In the event large enough of storm is predicted that could jeopardize the safety of the area, OCWD will de-mobilize and remove all construction equipment from the project area. Level of Impact after Mitigation Less than significant impact. IMPACT HWQ-5: Will the Project create or contribute runoff which will exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff? Long Term Storm Water Management Implementation of the Project will not introduce any new impervious surfaces into the project area. Existing rates of surface water runoff within the project area will not increase. Additionally, the Project will not exceed the threshold of the County of Riverside 4th Term Municipal NPDES Permit for area wide urban storm runoff and will not require the preparation of a Water Quality Management Plan. Additionally, the Project is considered a Watershed Protection Project in that it involves the restoration of the Santa Ana River and ecosystems in the Prado Basin. According County of Riverside 4th Term Municipal NPDES Permit, Watershed Protection Projects are not considered development projects because they do not involve any post construction activities and would have no associated pollutants of concern. Therefore the implementation of the Project will not result in significant long term storm water management impacts. Short Term Construction Storm Water Management The construction of the Project will require the operation of heavy equipment in Prado Basin and near the Santa Ana River. There is the potential for degraded surface water impacts where construction actively will occur. The Project will require issuance of a General Construction Permit by the Regional Water Quality Control Board which will require preparation of Storm Water Pollution Prevention Plan (SWPPP). The SWPPP will include a series of Best Management Practices to protect storm water runoff. With the implementation of Mitigation Measure

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GEO-1 potential adverse construction related storm water runoff impacts will be reduced to a less than substantial level. Level of Impact before Mitigation Potential significant impact. Mitigation Measures Mitigation Measure GEO-1 is required. Level of Impact after Mitigation Less than significant impact. IMPACT HWQ-6: Will the Project create any substantial new sources of polluted runoff, or otherwise degrade water quality As part of environmental planning for the project boring samples were taken along the sediment removal channel to characterize sediment in the project area, As shown in Table 32 chemical analysis of the sediments in the Prado Basin shows no detected organic chemicals, pesticides, PCbs, PAhs, or hydrocarbons. Within the water column there are total dissolved solids, some inorganic nitrogen, and small quantities of metals; which are within ranges expected for background soils in California. Since the chemistry of the sediments in the Prado Basin and water quality sampling of the Santa Ana River entering basin both show no detected organic chemicals, pesticides, PCbs, PAhs, or hydrocarbons, it will be unlikely that sediment extracted from the basin and re-entrained into the river will have detectable levels of organic chemicals, pesticides, PCbs, PAhs, or hydrocarbons Prior to discharging the sediment into the river a water quality monitoring program will be implemented to monitor the sediment material dredged from the sediment removal channel for organic chemicals, pesticides, PCbs, PAhs, and hydrocarbons. In the event the sediment exhibits detected levels of organic substances, pesticides, PCbs, PAhs, or hydrocarbons, the sediment will not be used for re-entrainment. As indicted previously, during sediment re-entrainment the Project could temporarily exceed the Basin Plan threshold for turbidity. Potential turbidity impacts will be minimized by pulsing the sediment re-entrainment and where feasible adjusting the concentration of solids in the sediment slurry being re- entrained. The sediment and water quality sampling detected some total dissolved solids, some inorganic nitrogen and small quantities of metals. All were within the regional background ranges expected for soils in the area and are not expected to result in significant adverse water quality impacts. Prior re-entrainment, the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-182 Section 3 Environmental Analysis sediment will be analyzed for metals. If the sediment contains metals at solid concentrations greater than upper range of the regional background, the sediment will be segregated and not re-entrained. The Project includes a water quality monitoring plan that will monitor for indictor bacteria and dissolved oxygen in upstream waters and within the waters where sediment re-entrainment will occur. If significant differences between upstream and downstream samples are observed, sediment re-entrainment rates will be adjusted to ensure they are within acceptable threshold ranges provided in the Regional Water Quality Control Basin Plan. Construction operations associated with the Project could result is construction related storm water runoff impacts, which could introduce new sources of pollution into project area water bodies. The Project will be required to prepare a Storm Water Pollution Prevention Plan to minimize storm water runoff impacts. With the implementation of Mitigation Measure HWQ-2 and GEO-1 construction related water quality impacts will be reduced to a les then significant level. The Project is considered a Watershed Protection Project and will not involve any post construction activities that will generate pollutants of concern. The Project will require approval of Section 404 Permit and 401 Water Quality Certification. Both the Section 404 Permit and 401 Water Quality Certification will contain conditions to maintain water quality during the operation of the Project. Level of Impact before Mitigation Potential significant impact. Mitigation Measures Mitigation Measures HWQ-1 and GEO-1 is required. Level of Impact after Mitigation Less than significant impact. IMPACT HWQ-7: Will the Project place within a 100 year flood hazard structures which would impede or redirect flood flows The Project does not include the construction of permanent structures that would be subject to 100 year flood hazards. The HEC-RAS analysis prepared for the Project has determined that the implementation of the project would not increase flooding or impede 100 storm flows along the river. With the implementation of Mitigation Measures HWQ-4 and HWQ-5 the potential flood hazards created by the Project will be reduced to a less than significant level.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-183 Section 3 Environmental Analysis

Level of Impact before Mitigation Potential significant impact. Mitigation Measures Mitigation Measures HWQ-3 and HWQ-4 are required. Level of Impact after Mitigation Less than significant impact. IMPACT HWQ-8: Would the project expose people or structures to a significant risk of loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam The Project has been designed to avoid impacts to Prado Dam. The Project will not increase risks for damage to the dam that might cause flooding. The Project will operate under the regulations provided in the Prado Dan Interim Water Control Manual and will not increase the risk of flooding in the project area. During the construction and operation of the Project OCWD will coordinate with the Corps on weather forecasts and the in the event a large enough storm is predicted that could pose flood risks to the site and jeopardize the safety of the area, OCWD will de-mobilize and remove all equipment from the site. With the implementation of Mitigation Measure HWQ-5 potential adverse flood impacts will be reduced to a less than substantial level. Level of Impact before Mitigation Potential significant impact Mitigation Measures Mitigation Measure HWQ-4 is required Level of Impact after Mitigation Less than significant impact.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-184 Section 3 Environmental Analysis

3.9 LAND USE/RELEVANT PLANNING PROGRAMS This section describes existing land uses within the vicinity of the project area, a discussion of relevant land use planning programs and policies and an evaluation of potential land uses impacts. 3.9.1 Regulatory Framework Riverside County General Plan The project area is situated in unincorporated Riverside County and included within Temescal Canyon Area Plan of the Riverside County General Plan. The Land Use Element designates the project area for Open Space Conservation land uses. The intent of the Open Conservation land use designation is to provide for the protection of open space for natural hazard protection and natural and scenic resource preservation. A focus of the Temescal Canyon Area Plan is the Santa Ana River Corridor and several polices have been established that provide for the protection of natural resources and for the expansion of recreation uses along the Santa Ana River Corridor. Prado Dam Interim Water Control Plan Currently, the operations at Prado Dam are directed by the U.S. Army Corps of Engineers Interim Water Control Manual (During Construction of dam) for Prado Dam and Reservoir and the memorandum of understanding between the Corps and OCWD. The Corps is currently following Plan A of the Interim Water Control Manual and would be implementing Plan A during the construction and operation of the Project. According to the Interim Water Control Manual, three pools are maintained for the operation of the dam; debris pool, buffer pool and flood control pool. Presently, the Corps coordinates releases with OCWD for the debris pool, between elevations 470-490 feet year round. In the flood control pool and during flood releases, the Corps informs OCWD of release plans. The rate of release is based on rainfall, pool elevation, runoff, forecasts, downstream construction and other downstream issues. Within the buffer pool at elevation 490-498 feet during flood season and 498 -505 feet during the non-flood season, different operations can occur depending on the season. If it is expected that the buffer pool space will not be needed for flood control, the buffer pool may be allowed to be filled and the water can be released at an adjusted rate in coordination with the groundwater recharge efforts of OCWD. If the buffer pool is needed for flood control, the water up to 5,000 cfs of water can be released depending on impacts to the downstream construction. During the non-flood season the buffer pool releases are made

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-185 Section 3 Environmental Analysis

according to Memorandum of Understanding with the Corps, U.S. Fish and Wildlife Service and OCWD. U.S. Army Corps of Engineers Prado Dam Recreation Master Plan The existing Prado Dam Recreation Master Plan was prepared in 1976. The intent of the Prado Dam Recreation Master Plan is to guide the orderly and coordinated development of recreation lands in the Prado Dam reservoir area. However, Prado Dam Recreation Master Plan is over 25 years old and no longer adequately implements the Corps policies and goals for the Prado Dam. Presently the Corps is in the process of updating the Prado Dam Recreation Master Plan. Santa Ana River Trail Plan The Santa Ana River Trail is a 75 mile regional riding, biking and hiking trail that is proposed to extend from San Bernardino Mountains to the Pacific Ocean. The majority of the trail is a dual-track trail consisting of a paved Class I Bikeway for bicyclist and pedestrians and a decomposed granite surfaced riding and hiking trail for equestrians, mountain bicyclists and hikers. The trail will enter into the Prado Basin from an existing bridge over the outlet channel and extend along the spillway through the area where the sediment storage site is located. Western Riverside County Multiple Species Habitat Conservation Plan The project area is included in the Western Riverside County Multiple Species Habitat Conservation Plan within Existing Core Area A of the Prado Basin Subunit. The area is comprised largely of Public/Quasi-Public Lands owned by a variety of entities, but it also contains a small number of privately-owned lands. The focus of the Prado Basin Subunit is the conservation of wetland habitats, riparian scrub, and cottonwood/willow woodland associated with Prado Basin. 3.9.2 Existing Environmental Setting The project area is located within the Prado Basin, an existing flood control reservoir. The dominate land use feature in the project area is the Prado Dam and its outlet works. Prado Dam is an earth-fill dam across the Santa Ana River at the Chino Hills. The water surface elevation of the impounded water behind the dam varies depending on the time of year, basin inflow and basin outflow, while taking into account flood control, water conservation and natural resource objectives. Presently, Prado Dam is undergoing modification improvements to increase the outlet works capacity to 30,000 cfs and the height of the spillway to 563 feet. The area surrounding the dam consists mostly of natural open space. The sediment removal channel is proposed in the southeast portion of Prado Basin. The alignment of the sediment removal channel presently consists of

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-186 Section 3 Environmental Analysis dense riparian vegetation. The closest land uses to the sediment removal channel would be the Prado Dam outlet structure located approximately ½ mile to the west and the OCWD Prado Wetlands located approximately ¾ mile to the north. The sediment storage site is located in the southwestern end of Prado Basin between an existing borrow site and the Corona Wastewater Treatment Plant. The site is undeveloped and consists of a mix of native and non-native vegetation. The sediment re-entrainment area is located at terminus of the concrete outlet channel, downstream of Prado Dam. The area surrounding sediment re- entrainment area is undeveloped open space. The closest land uses would be single family residential dwellings located approximately 1/2 mile to west in the City of Corona, and Chino Hills State Park. 3.9.3 Thresholds of Significance • Will the Project physically divide and established community? • Will the Project conflict with any applicable land use plan, policy or regulation of an agency with jurisdiction over the project? • Will the Project conflict with any applicable habitat conservation plan or natural community conservation plan?

3.9.4 Project Impacts IMPACT L-1: Will the Project physically divides and established community? Prado Dam The Project has been designed to minimize impacts to Prado Dam. The sediment removal channel location is situated sufficiently upstream of the outlet works to allow for a vegetation buffer to be provided to trap floating debris as it currently does, thereby minimizing the potential for floating debris to adversely impact the outlet works operations. To minimize safety conflicts during the operation the Project, onsite equipment will be secured to prevent its movement into the dam outlet works. Plans will also be developed for emergency evacuation of equipment and personnel during storm events and when the pool level rises above the level when the Corps needs to discharge at high rates. During the implementation of the Project, the Corps will be operating Prado Dam following the protocol described in the Interim Water Control Plan. The Corps has indicated that the current operational plan allows for coordination of flows.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-187 Section 3 Environmental Analysis

Therefore, the coordination of flows to re-entrain sediment into the Santa Ana River will not be in conflict with the Interim Water Control Plan. To minimize potential seepage impacts, the sediment removal activities will be confined to locations 1,000 feet or more away from the toe of the dam. The construction and operation of the Project will not be in conflict with the operation of Prado Dam and will not result in any adverse impacts that will compromise the structural integrity of the dam. The Project includes a dam operations structures monitoring program that will evaluate seepage before, during and after the Project. The information will be used in the design of a long term sediment management plan within the Prado Basin to help determine the maximum depth to which sediment may be removed behind the dam without compromising dam safety. Santa Ana River Trail The Santa Ana River Trail is planned to enter into the Prado Basin from an existing bridge over the inlet of the outlet channel and will extend along the perimeter of the sediment storage site. As part of the planning process for the Project, OCWD has coordinated with the County of Riverside on the planned alignment of the Santa Ana River Trail and measures have been incorporated into the Project to avoid adverse land use conflicts. With the implementation of Mitigation Measures L-1 potential land use conflicts between the Project and the Santa Ana River Trail will be avoided. OCWD Prado Wetlands OCWD Prado Wetlands are located approximately ¾ mile from the proposed sediment removal channel. The Prado Wetlands has been engineered for treating approximately 100 cubic feet of water per second of the Santa Ana River flow for nitrogen removal. After the water is treated, the treated water is discharged back to the Santa Ana River where it blends with other sources in the Prado Basin. The blended flows pass through Prado Dam and are captured downstream by OCWD and percolated into recharge basins to replenish the Orange County Groundwater Basin. The diversion of Santa Ana River flows into the sediment removal channel will not require a reduction of Santa Ana River flows into the Prado Wetlands and will have no impact on the operation of he wetlands. The wetlands are at a sufficient distance where the construction and operation of the Project will have no adverse impact on them. Level of Impact before Mitigation Potential significant impact. Mitigation Measures

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-188 Section 3 Environmental Analysis

L-1: During final design, construction and operation of the Project OCWD will coordinate with Riverside County Parks and Open Space District and Orange County Parks on the construction and operation of the Project. Level of Impact after Mitigation Less than significant. IMPACT L-2: Will the Project conflict with any applicable land use plan, policy or regulation of an agency with jurisdiction over the project? Riverside County General Plan The Land Use Element designates the project area for Open Space Conservation land uses. The intent of the Open Space Conservation land use designation is to provide for the protection of open space for natural hazard protection, and natural and scenic resource preservation. The purpose of the Project is to identify a feasible method to remove sediment from the Prado Basin and re-entrain it into the Santa Ana River. By removing sediment from Prado Basin the Project will attempt to reverse the current trend of sediment build up and degradation of habitat to achieve the following open space objectives. • Enhance and restore habitat in the Santa Ana River by preventing further degradation of certain areas of the river through sediment transport processes. • Enhance and restore high value habitat in Prado Basin by preventing further accumulation of sediments in Prado Basin. • Prevent further degradation of the Santa Ana River due to sediment starved stream flows. The open space objectives of the Project are consistent with the County of Riverside General Plan Open Space Conservation land use designation planned for the Prado Basin. The implementation of the Project will result in temporary impacts to riparian and coastal sage scrub habitat. The impacts will be temporary and Mitigation Measures BIO-3 and BIO-4 have been incorporated into the Project to compensate for temporary impacts to riparian and coastal sage habitat impacted by the Project. By ensuring no net loss of permanent native habitat in the Prado Basin, the temporary open space impacts associated with the implementation of the Project will not be in conflict with the County of Riverside General Plan.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-189 Section 3 Environmental Analysis

Prado Dam Interim Water Control Manual The Project has been designed to avoid impacts to Prado Dam and outlet works. Additionally, the implementation of the Project will not require changes to dam release rates. Sediment removal and re-entrainment operations will be designed, measured and controlled to accommodate release flows as determined by the Corps under the existing agreements with OCWD. The operation of the Project will not be in conflict with Prado Dam Interim Water Control Manual. City of Corona Lease Agreement Presently, the area where the sediment storage site is located is under a lease agreement with the U.S. Army Corps of Engineers and the City of Corona for future park uses after the Santa Ana River Mainstem Project is completed. The Project will be implemented in the winter of 2014 and will conclude in late 2017, prior to completion of the Mainstem Project. Once the Project is completed the site will be re-contoured and returned to its pre-project condition. Therefore, the temporary use of the sediment storage site will not be in conflict with any City of Corona park plans for the site. With the implementation of Mitigation Measure L- 2, potential land use conflicts with the City of Corona future park plans for the sediment storage site will be reduced to a less than significant level. Level of Impact before Mitigation Potential significant impact. Mitigation Measures Mitigation Measures BIO-3 and BIO-4 are required. L-2: After completion of the Project, OCWD will coordinate with the City of Corona on activities to return the sediment storage site to its pre-project condition. Level of Impact after Mitigation Less than significant. IMPACT L-3: Will the Project conflict with any applicable habitat conservation plan or natural community conservation plan? The purpose of the Project is to identify a feasible method to remove sediment from the Prado Basin and re-entrain the sediment into the Santa Ana River. The Project is consistent with the MSHCP Core Area A Objectives, in that the Project will remove the sediment from the basin to reverse the trend of declining of riparian habitat. The implementation of the Project will result in the temporarily loss of riparian vegetation which will be inconsistent with the objectives for Core Area A. However, the impacts will be temporary and Mitigation Measures BIO-3

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-190 Section 3 Environmental Analysis

and BIO-4 have been incorporated into the project to compensate for temporary impacts to riparian habitat. With the implementation of Mitigation Measures BIO- 3 and BIO-4 potential conflicts with Western Riverside County Multiple Species Habitat Conservation Plan will be avoided. Level of Impact before Mitigation Potential significant impact. Mitigation Measures Mitigation Measures BIO-3 and BIO-4 are required. Level of Impact after Mitigation Less than significant impact.

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3.10 NOISE This section provides an overview of the regulatory framework, the existing noise environment at the project area and surrounding area, and an analysis of potential noise impacts that could result from implementation of the Project. 3.10.1 Regulatory Framework Federal Federal Occupational Safety and Health Administration The adverse impact of noise was officially recognized by the federal government in the Noise Control Act of 1972. The Occupational Safety and Health Administration (OSHA) limit noise exposure of workers to 90 dB Leq or less over eight hours or 105 dB Leq or less over one hour. State State Office of Noise Control Standards The California Office of Noise Control has set the land use compatibility noise standards for different types of land uses and has encouraged local jurisdictions to adopt them. According to the land use compatibility noise standards, for commercial and industrial uses, long-term noise levels up to 65 Community Noise Equivalent Level (CNEL) are normally acceptable; noise levels between 65 and 75 dBA CNEL are “conditionally acceptable,” which means that noise levels are acceptable only when a detailed noise analysis is conducted and needed noise insulation features are included in the design. Long term noise levels between 70 and 80 dBA CNEL are generally unacceptable. For residential development and schools, long term exterior noise levels ranging up to 60 dBA CNEL are classified as “normally acceptable,” based upon the assumption that the homes are built with normal conventional construction. Long term noise levels ranging up to 70 dBA CNEL are conditionally acceptable and noise levels in the 70- to 75-dBA CNEL range are classified as “generally unacceptable, but may proceed if a detailed noise analysis is conducted and needed noise insulation features are included in the design. Local Regulations The local noise regulations that are applicable to the Project include; the Riverside County Noise Ordinance and the City of Corona Noise Ordinance.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-192 Section 3 Environmental Analysis

Riverside County Noise Ordinance The Riverside County Noise establishes countywide standards regulating noise. Table 41 describes the noise standard for various land uses provided in the County’s General Plan Land Use Element.

Table 41: Riverside County Noise Ordinance Standards General Plan Land Use Max Exterior Decibel Max Exterior Decibel Level (dB) Level (dB) 7:00am to 10:00pm 10:00 pm to 7:00 am Residential Estate, Very Low Density 55 45 Residential, Low Density Residential, Medium Density Residential, Medium High Density Residential, High Density Residential, Very High Density Residential, Highest Density Residential Rural Residential, Rural Mountains, Rural 45 45 Desert Retail Commercial, Office Commercial 65 55 Tourist Commercial, Community Center 65 55 Light Industrial, 75 55 Heavy Industrial 75 75 Business Park, Public Facility 65 45 Specific Plan Residential 55 45 Specific Plan Commercial 65 55 Specific Plan Light Industrial 75 55 Specific Plan Heavy Industrial 75 75 Agriculture, Conservation. Conservation 45 45 Habitat, Recreation, Rural, Watershed Mineral Resources 75 45

Exemptions According the Riverside County Noise Ordinance the following activities are exempt from the noise ordinance standards. a. Facilities owned or operated by or for a governmental agency. b. Capital improvement projects of a governmental agency. c. Maintenance or repair of public properties. d. Public safety personnel in the course of executing their official duties. e. Public or private schools and school sponsored activities. f. Agriculture operations on land designated for agriculture uses. g. Wind Energy Conversion Systems. h. Private construction projects located ¼ of a mile or more from an inhabited dwelling. i. Private construction projects located within ¼ mile of an inhabited dwelling, provided that construction does not occur between the hours of 6:00 p.m. and 6:00 a.m. during the months of June through September,

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-193 Section 3 Environmental Analysis

and construction does not occur between the hours of 6:0 p.m. and 7:00 a.m. during the months of October through May. j. Property maintenance, including but not limited to the operation of lawn mowers, leaf blowers provided maintenance occurs between the hours of 7:00 a.m. and 8:00 p.m. k. Motor vehicles, other than off-highway vehicles. l. Heating and air condition equipment. m. Safety, warning and alarm devices. n. The discharge of firearms consistent with all state laws. City of Corona Noise Ordinance The purpose of the City of Corona Noise Ordinance is to regulate noise and vibration in the interest of public health, safety and general welfare. Table 42 describes the noise standard for various land uses in the City.

Table 42: City of Corona Noise Ordinance Standards General Plan Land Use Max Exterior Decibel Level Max Exterior Decibel 7:00am to 10:00pm Level 10:00 pm to 7:00 am Single, Double and Multi Family 55 45 Residential Other Sensitive Land Uses 55 50 Commercial Uses 65 60 Industrial, Manufacturing or 75 70 Agriculture

Exemptions According to the City of Corona Noise Ordinance the following activities are exempt from the noise ordinance standards. 1. Special events pursuant to an approved special use permit. Noise impacts shall be evaluated and conditioned as part of the special use permit. 2. Filming pursuant to a film permit. 3. Activities conducted on public parks, public playgrounds and public or private school grounds, including school athletic and entertainment events that are conducted under the sanction of the school or which a license or permit has been duly issued pursuant to any provisions of city code. 4. Noise sources associated with the maintenance of real property provided the activities take place between the hours of 7:00 a.m. and 8:00 p.m. on any day except Sunday or between the hours of 9:00 a.m. to 8:00 p.m. on Sunday. 5. Any activity to the extent regulation thereof has been preempted by state or federal law.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-194 Section 3 Environmental Analysis

6. Repairs to and replacement of mechanical equipment in residential zones installed by permit prior to May 20, 1993. 7. Approval of noise variance. 3.10.2 Existing Environmental Setting Noise is defined as unwanted sound. Sound becomes unwanted when it creates a nuisance that interferes with normal activities, or when it causes physical harm or otherwise adversely affects human health. The standard unit of measurement of the loudness of sound is the decibel (dB). The zero point on the dB scale is based on the lowest sound level that a healthy, unimpaired human ear can detect. Changes of 3 dB or fewer are only perceptible in laboratory environments. An increase of 10 dB represents a 10-fold increase in acoustic energy, while 20 dB is 100 times more intense, and 30 dB is 1,000 times more intense. Each 10-dB increase in sound level is perceived as approximately a doubling of loudness. Numerous methods have been developed to measure sound over a period of

time, including: Equivalent Sound Level (Leq), Community Noise Equivalent Level (CNEL), Day/Night Average Sound Level (Ldn) and Maximum Noise event (Lmax). Noise level can vary pending on the noise source and duration. Below is description of the units of measure used in this analysis to describe the noise environment.

• Leq: Time variations in noise exposure are typically expressed as a statistical description of the sound pressure level that is exceeded over

some fraction of a given observation period (called Leq). For example, the noise levels exceeded on 10 percent of readings is called L10, the median (50th percentile) reading is called L50, etc. • CNEL: Because community receptors are more sensitive to unwanted noise intrusion during the evening and at night, state law requires that, for planning purposes, an artificial dB increment penalty be added to quiet- time noise levels in a 24-hour noise descriptor called CNEL.

• Ldn: Another commonly used method is the day/night average level or Ldn.

• Ldn is a measure of the 24-hour average noise level at a given location. It was adopted by the U.S. Environmental Protection Agency (EPA) for developing criteria for the evaluation of community noise exposure.

• Lmax: The maximum noise level recorded during a noise event is typically expressed as Lmax.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-195 Section 3 Environmental Analysis

Effects of Noise Physical damage to human hearing begins at prolonged exposure to noise levels higher than 85 dBA. Extended periods of noise exposure above 90 dBA could result in permanent hearing damage. When the noise level reaches 120 dBA, a ticking sensation occurs in the human ear even with short-term exposure. This level of noise is called the threshold of feeling. As the sound reaches 140 dBA, the tickling sensation is replaced by the feeling of pain in the ear. This is called the threshold of pain. A sound level of 190 dBA will rupture the eardrum and permanently the inner ear. Table 43 summarizes typical noise sources, levels, and responses. Table 43: Noise Levels and Human Response

Noise Level Noise Source Response dBA Library 30 Very quiet Refrigerator humming 40 Quiet Quiet office 50 Quiet Normal conversation 60 Intrusive Vacuum cleaner 70 Telephone use difficult Freight train at 50 feet 80 Interferes with conversation Heavy-duty truck at 50 feet 90 Annoying Jet takeoff at 2,000 feet 100 Very annoying; hearing damage at sustained exposure levels Unmuffled motorcycle 110 Maximum vocal effect; physical discomfort Jet takeoff at 200 feet 120 Regular exposure over one minute risks permanent hearing loss Shotgun firing 130 Pain threshold Carrier jet operation 140 Harmfully loud Source: Melville C. Branch and R. Dale Beland, 1970.

Ground Absorption The sound drop-off rate is highly dependent on the conditions of the land between the noise source and receiver. To account for this ground-effect attenuation (absorption), two types of site conditions are commonly used in traffic noise models, soft-site and hard-site conditions. Soft-site conditions account for the sound propagation loss over natural surfaces such as normal earth and ground vegetation. For point sources, a drop-off rate of 7.5 dBA/ for each doubling of distance from the point source is typically observed over soft ground with landscaping, as compared with a 6.0 dBA/for each doubling of distance over

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-196 Section 3 Environmental Analysis

hard ground such as asphalt, concrete, stone and very hard packed earth. Caltrans research has shown that the use of soft-site conditions is more appropriate for the application of the Federal Highway Administration (FHWA) traffic noise prediction model used in this analysis. Noise Barrier Attenuation For a noise barrier to work, it must be high enough and long enough to block the view of the noise source. A noise barrier is most effective when placed close to the noise source or receiver. A noise barrier can achieve a 5 dBA noise level reduction when it is tall enough to break the line-of-sight and greater heights increase the noise reduction. When the noise barrier is a berm instead of a wall, the noise attenuation can be increased by another 3 dBA. Groundborne Vibration The effects of groundborne vibrations typically only cause a nuisance to people, but at extreme vibration levels, damage to buildings may occur. Although groundborne vibration can be felt outdoors, it is typically only an annoyance to people indoors where the associated effects of the shaking of a building can be notable. One method used to quantify vibration amplitude is peak particle velocity (PPV). Because of the typically small amplitudes of vibrations, vibration velocity is often expressed in decibels and is denoted as Lv, and a commonly used abbreviation is VdB, which is based on the reference quantity of one micro-inch per second. Typically, developed areas are continuously affected by vibration velocities of 50VdB or lower. These continuous vibrations are not noticeable to humans whose threshold of perception is around 65 VdB. Construction activity can result in varying degrees of ground vibration, depending on the equipment used on the site. Operation of construction equipment causes ground vibrations that spread through the ground and diminish in strength with distance. Table 44 gives approximate vibration levels for particular construction activities for a wide range of soil conditions.

Table 44: Vibration Source Levels for Construction Equipment

Approximate Vibration Peak Particle Velocity Equipment Level (inches/second) (Lv) at 25 feet 1.518 (upper range) 112 Pile driver (impact) 0.644 (typical) 104 0.734 upper range 105 Pile driver (sonic) 0.170 typical 93 Clam shovel drop (slurry wall) 0.202 94

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-197 Section 3 Environmental Analysis

Approximate Vibration Peak Particle Velocity Equipment Level (inches/second) (Lv) at 25 feet 0.008 in soil 66 Hydromill (slurry wall) 0.017 in rock 75 Vibratory Roller 0.210 94 Hoe Ram 0.089 87 Large bulldozer 0.089 87 Caisson drill 0.089 87 Loaded trucks 0.076 86 Jackhammer 0.035 79 Small bulldozer 0.003 58 Source: Transit Noise, Vibration Impact Assessment, Federal Transit Administration, May 2006

3.10.3 Thresholds of Significance • Will the Project exposure of persons to or generation of noise levels in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? • Will the Project cause a substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project? • Will the Project expose persons to or generation excessive groundborne vibration or groundborne noise levels?

3.10.4 Project Impacts IMPACT N-1: Will the project exposure of persons to or generation of noise levels in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? The Project is a demonstration project that will be implemented over a five year period. Once the Project is completed all construction and operational activity will cease and no Project related noise impacts will occur. There will not be a permanent increase in ambient noise levels in the project area. The Project involves four primary activities that could result in potential temporary noise impacts. These activities are the construction and operation of the sediment removal channel, green waste processing activities, the construction and operation of the sediment storage and handling site and the operation of the sediment re-entrainment. Each of these activities has their own unique mix of construction equipment and associated temporary noise impacts.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-198 Section 3 Environmental Analysis

Construction of Sediment Removal Channel The construction of the sediment removal channel will involve the removal of vegetation from the sediment removal channel alignment and rough grading of the area with heavy construction equipment. The nosiest piece of equipment that will be operating will be a dozer at an estimated noise level of 82 dBA at 50 feet. The noise generated from the construction of the sediment removal channel will be intermittent and will below the OSHA standard of 90 dBA over an eight hour period. Therefore, the construction activities will not be in conflict with the OSHA standard and potential adverse noise impacts will be less than significant. There are no sensitive receptors in the vicinity of the sediment removal channel. The construction of the sediment removal channel will occur during the day and will be exempt under the Riverside County Noise Ordinance and the City of Corona Noise Ordinance. Therefore, noise impacts associated with the construction of the sediment removal channel will not be in conflict with Riverside County Noise Ordinance and the City of Corona Noise Ordinance and potential adverse noise impacts will be less than significant. To minimize noise impacts in the project area Mitigation Measures N-1 and N-2 will be implemented. Green Waste Processing The vegetation removed from the sediment removal channel will be processed at a green waste area. The nosiest piece of equipment that will be operating will be a tub grinder at an estimated noise level of 85 dBA at 50 feet. The noise generated from the green waste processing activities will be intermittent and will be below the OSHA standard of 90 dBA over an eight hour period. Therefore, the construction activities will not be in conflict with the OSHA standard and potential adverse noise impacts will be less than significant. There are no sensitive receptors in the nearby vicinity of the green waste processing area. The green waste processing activities will occur during the day and will be exempt under the Riverside County Noise Ordinance and the City of Corona Noise Ordinance. To minimize noise impacts in the project area Mitigation Measures N- 1 and N-2 will be implemented. Hydraulic Dredging The sediment will be removed from the sediment removal channel and conveyed by pipeline to the sediment storage site with the use of a hydraulic dredge and booster pumps. The nosiest piece of equipment will be the hydraulic dredge at an estimated noise level of 85 dBA at 50 feet. The operation of the hydraulic dredge will be below the OSHA standard of 90 dBA over an eight hour period. Therefore, the proposed sediment removal activities will not be in conflict with the OSHA standard and potential adverse noise impacts will be less than significant.

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The dredging activities will occur during the day and will be exempt under the Riverside County Noise Ordinance and the City of Corona Noise Ordinance. To minimize noise impacts in the project area Mitigation Measures N-1 and N-2 will be implemented. Sediment Storage/Handling The construction of the sediment storage and handling site will involve grading to create suitable work area. The nosiest piece involved with the construction and operation of the site will be a dozer at an estimated noise level 82 dBA at 50 feet. The operation of the dozer will be intermittent and will be below the OSHA standard of 90 dBA over an eight hour period. Therefore, the construction and operation sediment storage and handling site will not be in conflict with the OSHA standard and potential adverse noise impacts will be less than significant. The construction and operation of the sediment storage and handling site will occur during the day and will be exempt under the Riverside County Noise Ordinance and the City of Corona Noise Ordinance. To minimize noise impacts in the project area Mitigation Measures N-1 and N-2 will be implemented. Sediment Re-Entrainment The nosiest piece of equipment that will be involved with sediment re- entrainment will be the use of a crane at an estimated noise level of 81 dBA at 50 feet. The operation of the crane will be intermittent and below the OSHA standard of 90 dBA over an eight hour period. Therefore, the proposed sediment re-entrainment activities will not be in conflict with the OSHA standard and potential adverse noise impacts will be less than significant. The closest sensitive receptors to sediment re-entrainment activities are existing single family homes located approximately 2,600 feet to the west, along Feather River Road and existing single family homes located 1,700 feet to the south, along Manor Way within the City of Corona. The City of Corona Noise Ordinance establishes a maximum day time exterior noise standard of 55 dBA and a maximum exterior nigh time noise standard of 45 dBA. Sediment re-entrainment activities could occur 24 hours per day depending if high rates of surface water flows are available. During the day time hours sediment re-entrainment activities will be exempt under the Riverside County and City of Corona Noise Ordinance. During the night time hours the single family homes along Feather River Road could be exposed to an estimated noise level of up to 48 dBA, and the single family homes along Manor way could be exposed to an estimated noise level of up to 51 dBA. The noise levels generated from sediment re-entrainment activities will exceed the City of Corona Noise Ordinance night time noise standard and potential adverse noise impacts will be significant. To reduce noise levels below

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-200 Section 3 Environmental Analysis

the City of Corona night time noise standard sound attenuation enclosure will be provided around the crane and onsite monitoring will occur to ensure that maximum noise levels standards are not exceeded. With the implementation of Mitigation Measures N-3 and N-4 potential adverse noise impacts will be reduced to a less than significant level. Level of Impact before Mitigation Potential significant impact. Mitigation Measures N-1: The project applicant will ensure that all booster pumps and generators are contained in sound attenuation enclosures. N-2: The project applicant will require construction contractors to use only construction equipment that have noise-reduction features, such as mufflers and engine shrouds. N-3: The project applicant will ensure that during sediment re-entrainment activities a sound attenuation enclosure is provided around the operating crane. N-4: The project applicant will demonstrate that Mitigation Measure N-3 adequately reduces noise levels to meet City of Corona night time noise standards. During operation, noise measurements will be taken. If the noise measurements are above the night time standard additional sound attenuation measures shall be implemented to meet the noise standard. Level of Impact after Mitigation Less than significant. IMPACT N-2: Will the Project cause a substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project? Construction of Sediment Removal Channel Construction of the sediment removal channel will temporary increase ambient noise levels within the project area. There are no sensitive receptors in the vicinity of the sediment removal channel that will temporary be impacted by construction noise impacts generated from the construction of the sediment removal channel. The noise generated from the construction of the sediment removal channel would be intermittent and will occur during the day when they are exempt under the County of Riverside Noise Ordinance and City of Corona Noise Ordinance. With the implementation of Mitigation Measures N-1 and N-2 potential adverse noise impacts will be minimized and will be less than significant.

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Green Waste Processing The green waste processing activities will temporary increase ambient noise levels within the project area. There are no sensitive receptors in the vicinity of the green waste processing area that will be temporary be impacted by construction noise impacts generated from green waste processing activities. The noise generated from the green waste processing activities will be intermittent and will occur during the day when they are exempt under the County of Riverside Noise Ordinance and City of Corona Noise Ordinance. With the implementation of Mitigation Measures N-1 and N-2 potential adverse noise impacts will be minimized and will be less than significant. Hydraulic Dredging The operation of the hydraulic dredge will temporary increase the ambient noise levels within the project area. There are no sensitive receptors in the vicinity of the sediment removal channel that would be temporary be impacted by noise impacts generated from the operation of the hydraulic dredge. The noise generated from the operation of the hydraulic dredge will be intermittent and will occur during the day when they are exempt under the County of Riverside Noise Ordinance and City of Corona Noise Ordinance. With the implementation of Mitigation Measures N-1, and N-2, potential adverse noise impacts will be minimized and will be less than significant. Sediment Storage/Handling The construction and operation of the sediment storage and handling site will temporary increase ambient noise levels within the project area. There are no sensitive receptors in the vicinity of the sediment storage and handling site that would be temporary impacted by noise impacts generated from the sediment storage and handling activities. The activities will occur during the day when they are exempt under the County of Riverside Noise Ordinance and City of Corona Noise Ordinance. With the implementation of Mitigation Measures N-1 and N-2 potential adverse noise impacts will be minimized and will be less than significant. Sediment Re-Entrainment Sediment re-entrainment activities may occur 24 hours per day depending if high rates of surface water flows are available. Existing single family within the vicinity of the project will experience a temporary increase in ambient noise levels. During the day time hours sediment re-entrainment activities will be exempt under the Riverside County and City of Corona Noise Ordinance. During the night hours the single family homes could be exposed to an estimated noise level above the City of Corona Noise Ordinance night time noise standard and

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-202 Section 3 Environmental Analysis potential adverse noise impacts will be significant. To reduce noise levels below the City of Corona Noise Ordinance sound attenuation enclosure will be provided around the crane and onsite monitoring will occur to ensure that maximum noise levels standards are not exceeded. With the implementation of Mitigation Measures N-3 and N-4 potential adverse noise impacts will be reduced to a less than significant level. Level of Impact before Mitigation Less than significant. Mitigation Measures Mitigation Measures N-3 and N-4 are required. Level of Impact after Mitigation Less than significant. IMPACT L-3: Will the project expose persons to or generation of excessive groundborne vibration or groundborne noise levels? The County of Riverside and the City of Corona do not have specific thresholds to determine potentially significant vibration impacts. The Federal Transit Administration’s ground-borne vibration impact thresholds were used to measure if the project activities could result in potentially substantial vibration impacts. A vibration impact is considered significant if it results in construction impact of 0.2 inch per second or an operation impact of .04 inch per second. The Project activities will occur periodically and will be short-term in nature. Therefore, an operational vibration threshold will not apply to the Project. Construction of Sediment Removal Channel The piece of equipment that will have the highest potential for vibration impacts will be dozer with a peak particle velocity of .089. The peak velocity is below the Federal Transit Administrations ground-borne vibration impact threshold of .02 inch per second. Therefore, potential vibration impacts will be less than significant. Green Waste Processing The piece of equipment that will have the highest potential for vibration impacts will be a tub grinder. The tub grinder is not included in Table 33. Potential vibration levels will be similar to those of a large dozer with a peak particle velocity of .089. The peak velocity is below the Federal Transit Administrations ground-borne vibration impact threshold of .02 inch per second. Therefore, potential vibration impacts will be less than significant.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-203 Section 3 Environmental Analysis

Hydraulic Dredging The hydraulic dredge is not included in Table33. Potential vibration levels will be similar to those of a small dozer with a peak particle velocity of .003. The peak velocity is below the Federal Transit Administrations ground-borne vibration impact threshold of .02 inch per second. Therefore, potential vibration impacts will be less than significant. Sediment Storage/Handling The piece of equipment that will have the highest potential for vibration impacts will be large dozer with a peak particle velocity of .089. The peak velocity is below the Federal transit Administrations ground-borne vibration impact threshold of .02 inch per second. Therefore, potential vibration impacts will be less than significant. Sediment Re-Entrainment The piece of equipment that will have the highest potential for vibration impacts will be a crane. Cranes are not included in Table 33. Potential vibration levels will be similar to those of large dozer with a peak particle velocity of .089. The peak velocity is below the Federal Transit Administrations ground-borne vibration impact threshold of .02 inch per second. Therefore, potential vibration impacts will be less than significant. Level of Impact before Mitigation Less than significant. Mitigation Measures No mitigation measures are required. Level of Impact after Mitigation Less than Significant.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-204 Section 3 Environmental Analysis

3.11 TRANSPORTATION This section provides an overview of the regulatory framework, existing project area circulation system and analysis of potential impacts to the circulation system that could result from implementation of the Project. 3.11.1 Regulatory Framework Riverside County General Plan Circulation Element The Circulation Element guides the design of the transportation system in Riverside County. The Circulation Element establishes peak hour traffic level of service standards on County and State Highways. The Circulation Element establishes LOS "C" along all County of Riverside maintained roads and conventional state highways. As an exception, LOS "D" may be allowed in Community Development areas, only at intersections of any combination of Secondary Highways, Major Highways, and Urban Expressways, conventional state highways or freeway ramp intersections. LOS "E" may be allowed in designated community centers to the extent that it would support transit-oriented development and walkable communities. Riverside County Congestion Management The purpose of the 2007 Riverside County Congestion Management Program (CMP) is to develop a coordinated approach to manage and decrease traffic congestion by linking various transportation, land use, and air quality planning programs throughout the County. According to the Riverside County CMP, the adopted minimum level of service (LOS) is LOS E or better, and a deficiency plan is required if the CMP facility LOS is reduced to LOS F. The Riverside County Congestion Management Program facilities located within the Project area is State Route 91. As identified in the CMP, State Route 91 (SR-91) between State Route 71 and Interstate 15 (I-15) had a LOS of “F” in 1991 when the CMP was first established, and therefore, is exempt from CMP requirements. City of Corona Circulation Element Circulation Element provides the necessary framework to guide the growth and development of the City’s transportation related infrastructure, and integrates land use and transportation planning by ensuring that all existing and future developments have adequate circulation. The Circulation Element establishes acceptable Level of Service D or better on arterial streets wherever possible. At some key locations, such as heavily traveled freeway interchanges, LOS E may be adopted as the acceptable standard, on a case-by-case basis. The City of Corona has adopted a truck route system that designates various facilities for through truck movements. On those routes, trucks over three tons

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-205 Section 3 Environmental Analysis may legally travel even if they do not have a trip origin or destination along that route. On all other streets, trucks may only travel on them if the truck has an origin or destination at a land use located along the facility. According to the Circulation Element Serfas Club Drive, Auto Center Drive, Lincoln Avenue and Railroad Street are identified as truck routes. 3.11.2 Existing Environmental Setting Regional Access Regional access to the project area will be provided from State Route 91 (SR 91) and State Route 71 (SR 71). SR 91 is a major east–west freeway that serves several regions of the Greater Los Angeles metropolitan area, Orange County and Riverside County. State Route 71 (SR 71) is a freeway/highway of about 15 miles (24 km) in length. The highway is a limited-access freeway in San Bernardino and Riverside counties. The freeway serves as an important diagonally aligned commuter traffic corridor between the cities in the Pomona Valley and the cities of western Riverside County. It is heavily travelled and is used as an alternative to State Route 57 and Interstate 15. Within the vicinity of the project area there are plans are underway for improvements to SR-91 and SR-71. Local Access Local access to the project area will be provided from a combination of existing access roads. Potential access routes will include Serfas Club Drive to Auto Center Drive, Lincoln Avenue to Railroad Street and on an existing dirt service road located along the shoulder of the Santa Ana River. Serfas Club Drive/Auto Center Drive Access to the project area will be provided from Serfas Club Drive exit off of SR- 91 to Auto Center Drive. From Auto Center Drive access will be provided along a dirt road into the Prado Basin. Presently, the City of Corona is constructing a grade separation project at the Burlington Northern Santa Fe railroad crossing at Auto Center Drive. The construction operations will reduce Auto Center Drive to a single lane in each direction for most of the duration of the construction period. Construction operations are planned to occur from August 2013 to August of 2015. Lincoln Avenue/Railroad Street Access to the project area will be provided from Lincoln Avenue exit off of SR-91 to Railroad Street. From Railroad Street access will be provided along a dirt road into the Prado Basin.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 3-206 Section 3 Environmental Analysis

Santa Ana River Access Road Local access to the project area from the west will be provided along a dirt service road located on the shoulder of the Santa Ana River. Access to the service road will be from access roads in OCWD Prado Wetlands. 3.11.3 Thresholds of Significance • Will the Project increase hazards to a design feature or incompatible uses or equipment? 3.11.4 Project Impacts IMPACT T-1: Will the Project increase hazards to a design feature or incompatible uses or equipment? Potential Offsite Impacts The Project is a short-term demonstration project that will conclude in five years. Therefore, there will not be any long-term traffic trips generated by the Project. The majority of the traffic generated from the Project will be onsite construction related traffic. However, the Project will generate some offsite traffic trips associated with the mobilization and demobilization of construction equipment, off-site hauling of green waste, and some daily worker traffic. Table 45 identifies the daily offsite roundtrip traffic trips generated by each construction phase of the Project. Table 45: Roundtrip Traffic Trips Phase Total Daily Roundtrip Number Time Traffic/Vehicle Type Days Period Pre-Construction 7 Trips/Five Light Trucks 30 days Peak Traffic Period Monitoring Site Preparation 12 Trips/Four Light Trucks 30 days Non-Peak Traffic Period 34 Trips/Five 10-Wheel Trucks Infrastructure 3 Trips/Three 18-wheel Trucks 30 days Non-Peak Traffic Period Construction 2 Trips/Two 10-Wheel Trucks 2 Trips/ One light Truck Sediment Removal 4 Trips/Two Light Trucks 188 Days Peak Traffic Period Sediment Re- 4 Trips/ Two Light Trucks 30 days Peak Traffic Period Entrainment Monitoring, Site 18 Trips/ Six Light Trucks 120 days Peak Traffic Period Restoration As shown above each of the different phases of the Project will generate a minimal amount of roundtrip traffic trips. The majority of the traffic trips generated by the Project will occur during non-peak hour traffic periods. The amount of daily traffic occurring during peak hour periods will be relatively minor and will not cause the closure of any roadway segments or reduce the level of service of any roadway segments or intersections within the project area.

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During the mobilization and demobilization of construction equipment there is the potential that temporary construction traffic congestion could occur at project area roadways and intersections, in particular when construction of the railroad grade separation is occurring along Auto Center Drive. In the event access is not available along Auto Center Drive, then Lincoln Avenue and Railroad Street will become the primary access way into the project area. To minimize potential temporary construction traffic congestion all construction equipment mobilization and demobilization will occur during non-peak hour traffic periods and OCWD will coordinate with the City of Corona on the accessibility of Auto Center Drive, required traffic control measures and truck hauling permits required for the Project. With the implementation of Mitigation Measures T-1 and T-2 potential temporary construction traffic congestion impacts will be reduced to a less than significant level. Potential Onsite Impacts During construction and operation of the Project there will be considerable amount construction equipment traffic occurring within the project area. The construction equipment traffic will be confined to the project area and will not pose hazards to any offsite roadways. To minimize onsite construction equipment traffic conflicts, OCWD will coordinate with the Corps on the preparation of construction traffic control plans that could include; signage, the use of flag man and daily construction route coordination. With the implementation of Mitigation Measure T-3 potential onsite construction traffic conflicts will be reduced to a less than substantial level. Levels of Impact before Mitigation Potential significant impact. Mitigation Measures T-1: Construction equipment mobilization and demobilization activities will not occur during peak traffic periods on public roadways. T-2: Prior to the start of mobilization and demobilization activities OCWD will coordinate with City of Corona on the availability of project access along Auto Center Drive, the need for preparation of traffic control plans and truck hauling permit requirements. T-3: Prior to the start of construction and operation of the project OCWD will coordinate with the Corps on the preparation of traffic control plans that coordinates onsite construction traffic within the project area. Level of Impact after Mitigation Less than significant impact.

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SECTION 4 CUMULATIVE IMPACTS 4.1 CEQA Analysis Requirements A cumulative impact refers to, when two or more individual effects, which considered together, are considerable or which compound or increase other environmental impacts. The CEQA Guidelines require that an EIR discuss the cumulative impacts of a project when a project’s incremental effect is cumulatively considerable, meaning that a projects incremental effects are considerable when viewed in connection with the effects of past, current and probable future projects. According to the CEQA guidelines Section 15130(a) and (b) the purpose of this section is to provide a discussion of significant cumulative impacts which reflects the severity of the impacts and their likelihood of occurrence. The CEQA Guidelines indicate that the discussion of cumulative impacts should include: • Either (1), a list of past, present and probable future projects producing related or cumulative impacts or (B), a summary of projections contained in an adopted general plan or similar document, or in an adopted or certified environmental document which describe or evaluated conditions contributing to a cumulative impact, • A discussion of the geographic scope of the area affected by the cumulative effect, • A summary of expected environmental effects to be produced by these projects, • Reasonable and feasible options for mitigating or avoiding the project’s contribution to any significant cumulative effects.

4.2 Cumulative Analysis Methodology This cumulative analysis is based on an analysis of the Project in combination with potential environmental effects of related projects occurring in the project area and a summary of projections provided in the South Coast Air Quality Management District Air Quality Management Plan. Related projects considered in the analysis include those that have been recently completed, are currently under construction, or are in planning process. The construction schedule for the future projects has been estimated to occur during the timeframe of the Project.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-1 Section 4 Cumulative Impacts

Related Projects Below is a description of related projects, activities and mitigation projects occurring within the Prado Basin and Santa River Floodplain that is considered in the cumulative impact evaluation for the Project. Public Improvement Projects There a several public improvements projects have been implemented or that are in the final planning stages for implementation within the project area. These related projects along with past activities in the Prado Basin have resulted in temporary and permanent impacts to wildlife and habitats in the Prado Basin and the Santa Ana River Floodplain. U.S. Army Corps of Engineers Santa Ana River Mainstem Reach 9 Improvements The Corps is currently implementing major improvements associated with the Santa Ana River Mainstem Project (SARM) along the Santa Ana River downstream to the Pacific Ocean. The improvements along the river near the project area are referred to as the Reach 9 Improvements. The completed improvements within Reach 9 include; Carwash/Strip Mall Embankment, Lower 91 Embankment, Green River Golf Course Channel, and the construction Prado Dam Outlet Channel. Currently the Santa Ana River Mainstem Project is focusing on improvements on the segment of the Santa Ana River between Weir Canyon and the SR 71 Freeway. These projects include the Upper 91 Embankment, fortification of the BNSF Railroad Bridge and the raising of Prado Dam Spillway. Implementation of the project has resulted permanent and temporary impacts to riparian and coastal sage scrub vegetation and perennial stream habitat within the Prado Basin and the Santa Ana River Floodplain. State Route 71/State Route 91 Interchange Improvements The Riverside County Transportation Commission in cooperation with the California Department of Transportation proposes to improve the existing State Route 91/State Route 71 interchange. The proposed improvements include constructing a new direct flyover connector from eastbound State Route 91 to northbound State Route 71 and reconfiguring the eastbound State Router 91 ramp between Green River Road and the State Route 91/State Route 71 interchange. Implementation of the project will result in impacts to areas in Prado basin that contain non-native weeds and grasses and mixed riparian vegetation. State Route 91 Improvements Within the vicinity of the project area State Route 91 would be widen. The

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-2 Section 4 Cumulative Impacts

proposed widening improvements would occur on the north side of the freeway and at the south western end of the project area. Implementation of the project will result in impacts to areas in the Prado Basin that contain non-native weeds and grasses. Relocation of the Santa Ana Receptor Line The Santa Ana Receptor Line (SARI) extends 75 miles from the river's headwater east of the City of San Bernardino to the mouth of the river at the Pacific Ocean between the cities of Newport Beach and Huntington Beach. The SARI line has two pipeline segments that extend through Prado Basin; Reach IVB and Reach IVA. Reach IVB pipeline extends east to west near the toe of Prado Dam and has been re-lined in the current alignment. Reach IVA has been re-lined and relocated west of the current alignment and now ties into the existing pipeline on the north side of the outlet channel, downstream of Prado Dam. The construction activities in Prado Basin or near the outlet channel have been completed. Downstream of the outlet channel the SARI Relocation Project will replace nearly 4 miles of the existing pipeline from the Orange/San Bernardino county line at Green River Golf Club to SAVI Ranch. A proposed 54-inch-diameter pipeline will tie into the existing SARI Line just upstream of the existing metering station at the Green River Golf Club. The new pipeline will then cross the golf course to the south bank of the river where it will be located under the existing bikeway before proceeding downstream through Featherly Park. The new pipeline will connect to the existing SARI Line behind SAVI Ranch. Open-cut excavation and micro- tunneling construction methods will be used to install the new pipeline and facilities. Presently, ongoing construction is occurring downstream of the Green River Golf Course. Implementation of the project has resulted permanent and temporary impacts to riparian and coastal sage scrub vegetation and perennial stream habitat within the Prado Basin and the Santa Ana River Floodplain. Santa Ana River Bike Trail The Santa Ana River Trail is a 75 mile regional riding, biking and hiking trail that extends from San Bernardino Mountains to the Pacific Ocean. The majority of the trail is a dual-track trail consisting of a paved Class I Bikeway for bicyclist and pedestrians and a decomposed granite surfaced riding and hiking trail for equestrians, mountain bicyclists and hikers. The trail will enter into the Prado Basin from an existing bridge over the inlet of the outlet channel and extend through the project area and along the sediment storage site. Implementation of the project could result permanent and temporary impacts to riparian and coastal sage scrub vegetation within the Prado Basin.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-3 Section 4 Cumulative Impacts

Auto Center Drive Grade Separation Project The project involves the construction of a grade separation at the Burlington Northern Santa Fe (BNSF) railroad crossing at Auto Center Drive. The grade separation project will construct a 4-lane over crossing at Auto Center/BNSF Railroad Crossing. Construction is scheduled to begin in August 2013 with completion anticipated by August 2015. During construction Auto Center Drive will be reduced to one travel lane in each direction for most of the duration of the construction period. Activities Existing Water Conservation Activities at Prado Basin Presently, OCWD and the Corps are implementing a water conservation program at Prado Dam. The water conservation program allows water to be stored to the 498 foot elevation during the flood season (October 1 through the end of February) and to the 505 foot during the non-flood season (March 1 to September 30). The retention of water behind the dam increased the periods of time that Prado Basin is inundated with water. Biological Opinions issued by USFWS determined that the increased periods of inundation will reduce the environmental values of habitat in the Prado Basin and that the reduced environmental values could have an adverse effect on the habitat of the least Bells vireo and the Southwestern willow flycatcher. To compensate for the reduced environmental values in Prado Basin between the 494 foot and 505 foot elevations, OCWD provided monetary contribution to establish a conservation fund to remove arundo from the Santa Ana River watershed, restored 265 acres riparian habitat, established a vireo and flycatcher monitoring program and implemented a brown-headed cowbird trapping program in the Prado Basin. Based on OCWD prior mitigation commitments the area below 505 foot elevation has been fully mitigated. The area of impact for the construction of the sediment removal channel with access roads is 39.31 acres. A total of 15.44 acres of the sediment removal channel is below the 505 foot elevation and has been fully mitigated. A total of 22.08 acres of the sediment removal channel is above the 505 foot elevation. Within the 22.08 acre area, 12.16 acres consist of arundo which will be removed and re-established with native vegetation. Excluding the area where arundo will be removed the Project will temporary impact 8.27 acres of riparian vegetation subject to compensatory mitigation requirements. Mitigation Projects The following is a listing mitigation projects included in the County of Orange Santa Ana Canyon Habitat Management Plan (HMP). The HMP has incorporated

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-4 Section 4 Cumulative Impacts

into one plan mitigation projects from several different agencies. The general location of the mitigation projects is shown on Figure 18. County of Orange Arundo Removal Program Since 1996, Orange County Public Works and Orange County Flood Control District have removed invasive weeds primary arundo within the floodplain of the Santa Ana River, as mitigation credit for flood control and road projects that impact Waters of the U.S. and State. Currently, the arundo removal program covers approximately 130 acres of area within floodplain of the Santa Ana River. County of Orange Santa Ana interceptor Line (SARI) The County of Orange is currently relocating the SARI out of the river floodplain and into the south embankment area. There are several small riparian habitat mitigation sites, totaling approximately 1.15 acres that will be installed following completion of the project. The mitigation sites are located between Coal Canyon and SAVI Ranch. US Army Corps of Engineers Santa Ana River Reach 9 Improvements Riparian/Upland Mitigation Sites The Corps has been making and is currently implementing improvements to and installing new flood protection features associated with Santa Ana River Mainstem Project. To mitigate for the Reach 9 Improvements the Corps has identified seven mitigation sites within floodplain. Most of these mitigation projects include upland and riparian vegetation. Three of the mitigation projects; the Car Wash Strip Mall (9.64 acres of mitigation area), Lower 91 Embankment (8.20 acres of mitigation area) and Prado Dam Outlet (5.6 acres of mitigation area) have been completed. The proposed mitigation projects include the Green River Mobile Home Park Project (1.0 acre of mitigation) and for the Green River Estates/Upper 91 Embankment Project (22.9 acres of mitigation). US Army Corps of Engineers Santa Ana River Mainstem Reach 9 Improvements Perennial Stream Restoration Project The Perennial Stream Restoration Project is located immediately upstream of California State Parks property near Coal Canyon, and is generally bounded by the Green River Golf Course to the north and State Route 91 to the south. The restoration involved the conversion of a portion of the adjacent Green River Golf Course and the adjacent streambed to approximately 25 acres of meandering stream within a corridor of emergent vegetation, riparian habitat, mulefat scrub

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-5 A«

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Riparian - City of Anaheim Wetlands Upland - USACE SARP Riparian - USACE SARP Upland - State Parks Upland Santa Ana River Canyon Habitat Management Areas Riparian - County SARI County Invasive Removal Mitigation Areas within Santa Ana Canyon 0 1,500 3,000 Figure 18 Feet Section 4 Cumulative Impacts and upland transitional habitat. The restoration project includes 10 acres of perennial stream. The channels substrate consists of a mixture of sand, gravel, cobbles and boulders and has been designed to provide the diversity of habitat characteristics required for life stages of the Santa Ana Sucker. The Perennial Stream was completed in 2013. City of Anaheim Wetland Mitigation The City of Anaheim created a series of three ponds as mitigation for the construction of an auto center. The construction of the ponds was completed 1986. The mitigation site is located on the north bank of the Santa Ana River between Weir Canyon Road and the Car Wash Strip Mall. 4.3 Cumulative Impact Evaluation Aesthetics The Project and the related projects will not result in any long term aesthetic impacts. Therefore, the Project will not contribute to long term cumulative impacts to aesthetic resources. The Project along with the related projects within the project area will result in temporary short term aesthetic impacts. The Project has incorporated measures to minimize potential aesthetic impacts and it is anticipated that the related projects will also provide mitigation to minimize e construction related aesthetic impacts, which will help to reduce cumulative aesthetic impacts. The temporary aesthetic impacts from the Project and from the related projects will occur at specific areas in the basin for a short period of time and together would not be cumulatively significant. Air Quality To result in a less than a significant adverse impact, the following criteria must be true: • Regional analysis: Emissions of nonattainment pollutants must be below the regional significance thresholds. • Summary of projections: The project must be consistent with current air quality attainment plans including control measures and regulations. • Cumulative health impacts: The project must result in less than significant cumulative health effects from the nonattainment pollutants. Regional Analysis If an area is in nonattainment for a criteria pollutant, then the background concentration of that pollutant has historically exceeded the ambient air quality standard. It follows that if a project exceeds the regional threshold for that

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-7 Section 4 Cumulative Impacts

nonattainment pollutant, then it will result in a cumulatively considerable net increase of that pollutant and result in a significant cumulative impact. The South Coast Air Basin is in nonattainment for PM10, PM2.5, nitrogen dioxide, and ozone. The information shown in Table 12 indicates that the SCAQMD regional emission thresholds will be exceeded for NOX emissions during Phase 2 Clearing and Grubbing, Phase 5 Sediment Re-entrainment, and Phase 6 Mitigation. To reduce adverse air quality impacts to a less than significant level mitigation measures have been incorporated into the project. With the incorporation of Mitigation Measures Air-1 and Air-2, the Project will not be in conflict with the regional analysis. Summary of Projections The geographic scope for cumulative criteria pollution from air quality impacts is the South Coast Air Basin. The South Coast Air Basin is in nonattainment for ozone, particulate matter (PM10 and PM2.5), and nitrogen dioxide, which means that concentrations of those pollutants currently exceed the ambient air quality standards for those pollutants. The SCAQMD is required to prepare and maintain an AQMP and a State Implementation Plan to document the strategies and measures to be undertaken to reach attainment of ambient air quality standards. While the SCAQMD does not have direct authority over land use decisions, it is recognized that changes in land use and circulation planning are necessary to maintain clean air. The SCAQMD evaluated the entire Basin when it developed the AQMP. The following elements are necessary to an adequate discussion of significant cumulative impacts: 1) Either: (A) A list of past, present, and probable future projects producing related or cumulative impacts, including, if necessary, those projects outside the control of the agency, or (B) A summary of projections contained in an adopted general plan or related planning document, or in a prior environmental document which has been adopted or certified, which described or evaluated regional or area wide conditions contributing to the cumulative impact. This analysis of cumulative impacts is based on a summary of projections analysis. The analysis is based on the 2003 and 2007 South Coast Air Quality Management District Air Quality Management Plans (AQMP). The AQMPs describe and evaluate the future projected emissions sources in the South Coast Air Basin and sets forth a strategy to meet both state and federal Clean Air Act planning requirements and federal ambient air quality standards. Therefore, the AQMPs are relevant plans for a cumulative impacts analysis. The 2003 AQMP updates the attainment demonstration for the federal standards for ozone and PM10; replaces the 1997 attainment demonstration for the federal CO standard

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-8 Section 4 Cumulative Impacts

and provides a basis for a maintenance plan for CO for the future; and updates the maintenance plan for the federal nitrogen dioxide standard that the South Coast Air Basin has met since 1992. The 2007 AQMP focuses on ozone and PM2.5. The AQMP also incorporates significant new scientific data, emission inventories, ambient measurements, control strategies, and air quality modeling. A project’s incremental contribution to a cumulative effect is not cumulatively considerable if the project complies with the requirements in a previously approved plan or mitigation program. The Project will comply with the control measures in the 2003 and the 2007 AQMP and all of the SCAQMD applicable rules and regulations. However, because the Project exceeds the SCAQMD significance thresholds, the Project will not be consistent with the most recent AQMP and State Implementation Plan without mitigation. Therefore, the Project presents a significant adverse impact according to this criterion. With the implementation of Mitigation Measure Air -1 potential adverse air quality impacts will be reduced to a less than significant levels and the Project will be consistent with the AQMP. Cumulative Health Impacts The Basin is in nonattainment for ozone, nitrogen dioxide, PM10, and PM2.5, which means that the background levels of those pollutants are at times higher than the ambient air quality standards. The air quality standards were set to protect public health, including the health of sensitive individuals. The regional analysis indicates that without mitigation, the Project will exceed the SCAQMD regional significance thresholds for NOx. To reduce adverse air quality impacts to a less than significant level Mitigation Measures AIR-1 and AIR 2 have been incorporated into the Project. With the incorporation of the mitigation measures, the Project will not be in conflict with the cumulative health impact analysis. Biology Least Bells Vireo The vireo is a Federal and state listed species that is known to occur within the project area. Past activities and related projects in the watershed have resulted in adverse impacts to the species and its habitat which has caused declines in population levels. Since the species listing in 1986, OCWD has implemented a watershed program within the Prado Basin to enhance habitat conditions and vireo populations in the Prado Basin. These activities include; arundo removal, the restoration of native vegetation, implementation of cowbird trapping program and the establishment of a vireo and flycatcher monitoring program. Table 46 below shows the number of vireo territories in the Prado Basin from 1986 to 2013. Since 1986 the number of territories in the Prado Basin has ranged from a

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-9 Section 4 Cumulative Impacts

low of 19 in 1986, to a peak high of 600 in 2005, with an average of 527 territories over the last five years. The increase in vireo territories coincides with restoration and conservation activities that have been conducted in the Prado Basin by OCWD and other agencies and it indicates that population levels are on the rise. The implementation of the Project will not result in any direct impacts that will reduce population levels. However, construction noise from the Project could potentially disrupt breeding patterns of vireos that could occur within the construction activity noise impact area. It is anticipated that those species that have a low tolerance for construction noise will seek alternative locations in the Prado Basin to nest. The increase in vireo territories in the Prado Basin shown in Table 46 indicates that there are suitable amounts of habitat to support large numbers territories for vireos including those temporarily displaced by the Project. The Project’s displacement of a few vireo territories will not contribute considerably to cumulative impacts that will significantly reduce the amount of breeding habitat for available for vireos or result in population reductions that jeopardize the survival of the species.

Table 46: Vireo Territories/Breeding Pairs Prado Basin

700

600

500

400 Territories 300 Pairs 200

100

0

2013 2011 2009 2007 2005 2003 2001 1999 1997 1995 1993 1991 1989 1987

Southwestern Willow Flycatcher Over the last ten years, 7 flycatcher territories have intermittently occurred within the project area, with the most recent sitting occurring in 2007. Based on the pattern of the last ten years, low numbers of flycatchers are expected to occur in the same general area. The implementation of the Project will not result in any direct impacts or indirect construction noise impacts that will displace existing flycatcher territories. Additionally, the project will not result in the permanent loss

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-10 Section 4 Cumulative Impacts of habitat that could affect the ability of species to nest in the Prado Basin. Therefore, the Project activities will not contribute considerably to significant cumulative impacts that will cause reduction in population levels or result in significant impacts to their habitat that could lead to population level reductions. Native Fish Past activities and related projects in the watershed have cumulatively contributed to reduced habitat conditions within the project area, which has led to declines in native fish population in the Santa Ana River. Recent surveys have identified small numbers of native fish, both suckers and chubs, upstream and downstream of Prado Dam. The low numbers can be attributed marginal habitat conditions and high exotic fish populations. Based on previous surveys, if any native fish do occur within the project area, it is anticipated they will be in low numbers. The Project includes measures to avoid impacts to native fish and given the low potential for native fish to occur, the likelihood of and risk from project related direct effects to native fish is low. In the event native fish do appear they will be relocated exclusively to areas where suitable habitat conditions exist. The potential for injury during relocation is unlikely because this activity will be conducted by a CDFW approved biologist. The Project will not degrade existing habitat conditions for native fish. The construction and operation of the project will cause head cutting along the Santa Ana River upstream of the project area. The head cutting will facilitate the movement of sediment into the Prado Basin and will expose existing gravel and cobble substrates along stretches of the Santa Ana River that are now buried, which will enhance existing habitat conditions native fish. The low potential for the Project to impact a low number of native fish will not contribute considerably to significant cumulative impacts that will reduce population levels that will jeopardize the survival of the sucker or chub. The Project activities will help to enhance native fish habitat upstream of the project area which will have a beneficial impact on native fish and could lead to the development of an approach to enhance native fish habitat at larger scale to help sustain and potentially increase native fish populations in the watershed. Southwestern Pond Turtle Past and related projects in the watershed have reduced the amount of wetland habitat for the Southwestern Pond Turtle. The pond turtle appears infrequently in low numbers the Prado Basin. The Project includes measures to avoid direct impacts to the species. Therefore, the Project will not contribute considerably to cumulative impacts that will reduce population levels in the Prado Basin. The Project will not permanently reduce wetland habitat for the pond turtle within the

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-11 Section 4 Cumulative Impacts

project area. The Project will temporary remove some habitat for the species. However, the amount of habitat removed represents a small amount of the overall habitat that is available in the Prado Basin and the temporary loss of habitat associated with the project will not contribute considerably to cumulative impacts that will significantly reduce population levels to jeopardize the survival of the species. Sensitive Vegetation Communities Past activities and related projects occurring in the Santa Ana River and in the Prado Basin have reduced the amount sensitive vegetation communities in the watershed. The implementation of the Project along with the related projects will have the potential to further reduce the amount of sensitive vegetation communities in the Prado Basin. The Project will provide compensatory mitigation for impacts to sensitive vegetation communities and it is anticipated that the related projects will also provide mitigation for impact to sensitive vegetation communities. With the implementation of compensatory mitigation provided for the Project and for the related projects there will be no net loss of sensitive vegetation communities and potential cumulative impact to sensitive vegetation communities will be less than significant. Downstream of Prado Dam there is several existing and planned riparian mitigation sites within the Santa Ana Canyon Reach of the Santa Ana River, including the Corps Perennial Stream Restoration Project. The Project along with the related projects could have the potential to adversely affect these mitigation sites. Additionally, sediment re-entrainment activities from the Project could adversely affect habitat conditions in the Perennial Stream Restoration Project as well as impact the more favorable native fish habitat conditions that exist along the Santa Ana Canyon Reach. Generally silt and clay sized particles are often undesirable for riparian habitat. The sediment transport models conducted for the Project shows that at the Project design flow of 500 cfs and greater, virtually all silts and clays will be expected to be carried to the ocean with little or no long term deposition in any of the three reaches and no sand would be deposited in the Santa Ana Canyon where the Perennial Stream Restoration Project is located. Only pebbles and gravels will be likely to deposit in the Santa Ana Canyon Reach. Therefore the Project will not incrementally contribute to significant cumulative adverse impacts to riparian mitigation projects located downstream of the project area, or incrementally contribute to significant changes to habitat conditions along Perennial Stream Restoration Project.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-12 Section 4 Cumulative Impacts

Waters of the State Past activities and related projects occurring in the Prado Basin and along the Santa Ana River have resulted in both temporary and permanent impacts to Waters of the State. The Project and the related projects occurring in the Prado Basin and along the Santa Ana River could have the potential to result in permanent and temporary impacts to Waters of the State. The Project and the related projects will be required to compensate for impacts to Waters of the State and ensure there is no permanent loss. Implementation of the Project will not result in any permanent impacts to Waters of the State. Therefore, the Project will not incrementally contribute to the cumulative permanent loss of Waters of the State. The Project will result in temporary impacts to Waters of State and will provide compensatory mitigation to ensure there will be no temporary loss of Waters of the State. With compensatory mitigation provided for the Project and for the related projects there will be no significant cumulative impacts to Waters of the State Wildlife Movement Past activities and related projects in the Prado Basin as well as surrounding land use development around the basin have restricted wildlife movement. The Project activities will not involve the construction of any permanent wildlife barriers. Therefore, the Project will not incrementally contribute to the construction of any permanent barriers that will incrementally contribute cumulative impacts to wildlife movement through the Prado Basin. Mitigation measures have been incorporated into the Project to reduce potential temporary wildlife movement impacts to a less than significant. It is anticipated that related projects will also be required to provide similar mitigation to minimize impacts to wildlife movement. With the implementation of mitigation measure potential cumulative wildlife movement impacts will be less than significant. Migratory Birds Past activities and related projects in the Prado Basin as reduced that amount of nesting habitat for migratory birds. Project will not cause any permanent loss of habitat for migratory birds. Therefore, the Project will not incrementally contribute to the permanent loss of habitat for migratory birds. The Project will temporary remove some nesting habitat for migratory birds. However, the amount of habitat removed represents a small amount of the overall of amount of nesting habitat that is available in the Prado Basin. The temporary removal of nesting when considered with others past and related project occurring in the Prado Basin will not contribute considerably to cumulative impacts that will significantly reduce the amount of nesting habitat for migratory birds.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-13 Section 4 Cumulative Impacts

Cultural Resources The project area has been previously investigated for the presence of cultural resources and it has been determine that the potential for cultural resources to be encountered is low. The Project and other related projects occurring in the project area will have to consult with the Corps and State Historic Preservation Office to confirm that the Project and the related projects will not result in adverse impacts to cultural resources. Compliance with Corps and State Historic Preservation Office recommendations will ensure that cumulative impacts cultural resources within Prado Basin do not occur. The Project will not contribute considerably to cumulative impacts to cultural resources. Geology Implementation of the Project will not result in adverse geologic impacts that will expose people and structures to substantial geologic risks. Therefore, the Project will not contribute considerably to cumulative adverse geologic impacts in the project area. The Project and the related projects will have the potential to create construction related erosion impacts. To minimize construction erosion impacts the Project and the related projects will be required to implement measures to minimize construction erosion impacts. With the implementation of erosion control measures potential adverse cumulative erosion impacts will be reduced to a less than significant level. Greenhouse Gas Construction and operation of the Project will not generate substantial adverse greenhouse gas emission impacts. The Project and the related projects will contribute greenhouse emissions in the regional area. However, the contribution will not be considerable to result in significant adverse cumulative greenhouse gas impacts in the regional area. Hazards/Hazardous Material Construction operations associated with the Project and with related projects will involve the handling of incidental amounts of hazardous materials, such fuels, oil and solvents. The Project and the related projects will be required to comply with Federal, State and local laws and regulations regarding the handling of hazardous materials. The compliance with Federal, State and local laws and regulations regarding the handling of hazardous materials will reduce potential adverse cumulative hazard impacts to a less than significant level.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-14 Section 4 Cumulative Impacts

Hydrology/Water Quality Implementation of the Project will not result in adverse flood impacts to people or structures. Therefore, the Project will not contribute considerably to cumulative adverse flood impacts in the project area. Construction activities associated with the Project and the related projects could generate degraded surface water quality impacts. The Project and the related projects will be required to comply with Federal, State and local surface water quality regulations and standards to maintain water quality. Compliance with the water quality regulations and standards will reduce potential adverse cumulative surface water quality impacts to a less than significant level. Sediment re-entrainment activities associated with the project could temporary exceed the Basin Plan threshold for turbidity. The impact would short-term and will not occur more 43 days over a four year period with considerable of periods of time where no re-entrainment will occur. Additionally, a water quality monitoring program will be implemented to monitor and minimize water quality impacts during the pre-construction, operation and post construction phases of the Project. The Project will not contribute considerably to significant cumulative water quality impacts in the Santa Ana River or the Prado Basin. Land Use/Relevant Planning Programs Implementation of the Project will not result in adverse incompatible land use impacts or result in conflicts with relevant planning programs that apply to the project area. Therefore, the Project will not contribute considerably to adverse cumulative land use impacts in the project area. Noise Implementation of the Project will not generate long term noise impacts within the project area. Therefore, the Project will not contribute considerably to long term adverse cumulative noise impacts in the project area. The Project along with the related projects will generate construction-related short term noise impacts. The Project will comply with local noise requirements and will include mitigation measures to minimize noise impacts. The related projects will also be required to comply with local noise ordinance requirements and if needed will include measures to minimize noise impacts. Compliance with local noise ordinance noise standards will reduce potential, adverse cumulative noise impacts to a less than significant level. Transportation/Traffic The Project and the related projects will not generate long term traffic impacts within the project area. Therefore, the Project will not contribute considerably to

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-15 Section 4 Cumulative Impacts long term adverse cumulative traffic impacts in the project area. The Project and the related projects will generate short term traffic impacts associated with mobilization and demobilization of construction equipment. Additionally, construction activity associated with State Route 71/State Route 91 Interchange Improvements, State Route 91 Improvements and Auto Center Drive Grade Separation Project could cause local traffic congestion within the Project Area. However, the Project and the related projects where needed will be required to implement traffic control plans to minimize traffic congestion. The coordination with local government agencies and implementation of traffic control plans will reduce potential adverse cumulative construction traffic impacts to a less than significant level.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 4-16 Section 5 Other CEQA Sections

SECTION 5 OTHER CEQA SECTIONS 5.1 Growth Inducing Impacts Pursuant to Sections 15126(d) and 15126.2(d) of the CEQA Guidelines, this section evaluates if the Project has the potential to foster economic or population growth, or the construction of additional housing, either directly or indirectly, in the surrounding environment. Specifically, the following questions will be evaluated to determine potential growth inducing impacts associated with the implementation of the Project. • Will the Project remove obstacles to growth through the construction or extension of major infrastructure facilities that do not presently exist in the project area, or through changes in existing regulations pertaining to land development? • Will the Project result in the need to expand one or more public services to maintain desired levels of service? • Will the Project encourage or facilitate economic effects that could result in other activities that could significantly affect the environment? • Will approval of the Project involve some precedent setting action that could encourage and facilitate other activities that could significantly affect the environment? Will the Project remove obstacles to growth through the construction or extension of major infrastructure facilities that do not presently exist in the project area, or through changes in existing regulations pertaining to land development? The purpose of the Project is to explore practical methods to remove sediment from the Prado Basin and re-entrain it into the lower Santa Ana River to help maintain storage behind Prado Dam for water conservation and to help restore sediment transport along the Santa Ana River to enhance habitat within the Prado Basin and to replenish sands along the Santa Ana River. The Project is a temporary demonstration project and does not involve the construction of any new infrastructure or the extension of existing infrastructure to facilitate new construction or growth in the project area. Will the Project result in the need to expand one or more public services to maintain desired levels of service? The implementation of the Project will not require the expansion of any public service to maintain desired levels of service. The Project includes mitigation measures that require coordination with local agencies to reduce potential traffic

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 5-1 Section 5 Other CEQA Sections

congestion on local roadways associated with the mobilization and demobilization of construction equipment to a less than significant level. Will the Project encourage or facilitate economic effects that could result in other activities that could significantly affect the environment? The construction and operation of the Project will generate short-term employment opportunities within the project area. Short-term economic benefits could be realized within the project area from workers purchasing goods and services from local businesses. Such benefits will be short-term and will not result in any activities that could facilitate new growth and result in significant impacts to the environment. Will approval of the Project involve some precedent setting action that could encourage and facilitate other activities that could significantly affect the environment? The purpose of the Project is to explore practical methods to remove sediment from the Prado Basin and re-entrain it into the lower Santa Ana River to help maintain storage behind Prado Dam for water conservation and to restore sediment transport along the Santa Ana River to help replenish sands along coastal areas. Implementation of the Project will not set a precedent that will facilitate growth in the project area. 5.2 Significant Irreversible Changes Section 15126 (C) of the CEQA Guidelines requires that an EIR describe any significant irreversible environmental changes that will be caused by the proposed project should it be implemented. Such a change will occur if one of the following scenarios is involved: • The project will involve a large commitment of non-renewable resources. • Irreversible damage resulting from environmental accidents associated with the project. • The proposed consumption of resources is not justified. The construction and operation of the Project will result in an irretrievable commitment of non-renewable resources in the form of energy supplies. The energy supplies will mostly be fuels to operate heavy equipment and the conveyance of sediment slurry to the outlet channel for re-entrainment into the Santa Ana River. Although the construction and operations of the Project will involve a short-term commitment of energy resources, the Project will help to maintain water conservation storage behind Prado Dam and will reduce the need to import water to meet domestic water needs. Because the energy commitments

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 5-2 Section 5 Other CEQA Sections

to import water are much higher than the amount of energy to construct and operate the Project, there will be a net benefit in regards to the commitment of non-renewable resources within the project area. 5.3 Summary of Project Impacts Significant Adverse Impacts Section 15126.2 (b) of the CEQA Guidelines requires that the EIR describe any significant impacts, including those that can be mitigated but not reduced to less than significant levels. • The Project will have the potential to generate temporary construction noise impacts that could disrupt the breeding patterns of the Federal and State Listed Least Bells Vireo if it occurs within construction activity noise impact area. • The Project will have the potential for native fish to occur within the project area and require physical relocation. • The Project will have the potential to generate temporary construction noise impacts that could disrupt breeding patterns of nesting migratory birds. • The Project during sediment re-entrainment activities could temporary exceeds the regional Water Quality Control Board Basin Plan threshold for turbidity. Significant Impacts Reduced to Less than Significant with Mitigation Measures The Project will result in the less than significant impacts with the incorporation of mitigation measures for the following issues: • Aesthetics • Air Quality • Cultural Resources • Geology and Soils • Hazards • Hydrology/Water Quality • Land Use • Noise • Traffic/Transportation

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 5-3 Section 5 Other CEQA Sections

Less than Significant Impact The Project will result in less than significant impacts and will not require mitigation for the following issue: • Greenhouse Gas Emissions

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 5-4 Section 6 Alternatives to the Proposed Project

SECTION 6 ALTERNATIVES TO THE PROPOSED PROJECT 6.1 Purpose and Scope The California Environmental Quality Act (CEQA) requires that an Environmental Impact Report (EIR) include a discussion of reasonable project alternatives that will feasibly attain most of the basic objectives of a project, but will avoid or substantially lessen any significant effects of a project, and evaluate the comparative merits of the alternatives. The discussion of alternatives shall focus on alternatives to the project or location which are capable of avoiding or substantially lessening any significant effects of the project, even if these alternatives will impede to some degree the attainment of the project objectives, or will be more costly. An environmentally superior alternative shall be identified among the alternatives evaluated in the EIR. An alternative will be environmentally superior to the proposed project if it results in fewer or less than significant environmental impacts and will achieve most of the project objectives. The specific alternative of No Project shall be evaluated along with its impact. The No Project analysis shall discuss the existing conditions at the time the notice of preparation is published, and what will be reasonably expected to occur in the foreseeable future if the project was not approved, based on current plans and consistent with available infrastructure and community services. If the environmentally superior alternative is the No Project alternative, the EIR shall also identify an environmentally superior alternative among the other alternatives. The range of alternatives required in an EIR is governed by a rule of reason that requires the EIR to set fourth only those alternatives necessary to permit a reasoned choice. The alternatives shall be limited to ones that will avoid or substantially lessen any of the significant effects of the project. Among the factors that may be taken into account when addressing the feasibility of alternatives are site suitability, economic viability, availability of infrastructure, general plan consistency, other plans or regulatory limitations, jurisdictional boundaries, and whether the proponent can reasonably acquire, control or otherwise have access to the alternative site. For alternative locations, only locations that will avoid or substantially lessen any of the significant effects of the project need be considered for inclusion in the EIR. An EIR need not consider an alternative whose effect cannot be reasonably be ascertained and whose implementation is remote and speculative.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-1 Section 6 Alternatives to the Proposed Project

6.2 Project Objectives The following project objectives have been established for the Project to help public agencies and decision makers in their review of potential impacts associated with the Project and Project Alternatives. • Remove between 250,000 and 500,000 cubic yards of sediment material from Prado Basin to prevent further loss of storage capacity and to enhance water storage conservation capabilities. • Prevent further degradation of the Santa Ana River due to sediment- starved stream flows. • Allow operation of Prado Dam to take place to maximize water diversion and infiltration between Imperial Highway and the 22 Freeway. • Enhance and restore habitat in the Santa Ana River by preventing further degradation of certain areas of the river through sediment transport processes. • Increase recharge rates in the Santa Ana River by reducing the armoring and incising of the river bed. • Reduce coastal erosion processes by providing sediment to the Santa Ana River that will reach the Pacific Ocean. • Enhance and restore high value habitat in Prado basin by preventing further accumulation of sediments in Prado basin. • Minimize impacts to native vegetation within the Prado Basin. • Collect data and monitor project efforts.

6.3 Planning Criteria To identify potential alternatives to remove between 250,000 and 500,000 cubic yards of material from Prado Basin and re-entrain it into the Santa Ana River a series of geotechnical studies, hydraulic and sediment transport studies and biological studies were prepared. Based on these studies, the following planning criteria were established to guide the formulation of the Project and the Project Alternatives. • Locate sediment removal activities to maximize preferential sand settling from reservoir inflows in the cut areas. • Prevent the excessive generation of new debris and trap incoming debris as experienced under current condition.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-2 Section 6 Alternatives to the Proposed Project

• Minimize the taking of high-value habitat and optimize the removal of Arundo or other invasive lower-value habitat. • The required concentration of re-entrained sediments to the Lower Santa Ana River is currently estimated at approximately 1-percent solids. • Sediment re-entrainment should not occur when flows into the Lower Santa Ana River are less than 500 cfs. • Sediment removal equipment cannot operate during storm events due to wind, wave, and dam operation risks. • Sediment re-entrainment activities should take place in a manner that does not require changes to dam operations. Sediment extraction, staging, and re-entrainment operations need to be synchronized with dam operating criteria that maximizes the volume of water that can be diverted and extracted for water supply, allow control of flood flows as necessary, and remove the volume of sediment that would typically enter Prado Basin. 6.4 Alternatives Eliminated From Further Analysis Based on the planning criteria identified from the technical studies, a series of alternatives were developed that each involved mechanically removing sediments from the Santa Ana River, transporting sediments to a storage and processing site and re-entrainment of the sediment into the lower Santa Ana River, during desirable flow conditions. To eliminate alternatives from further analysis, each alternative was evaluated to determine if it will meet CEQA project objectives and the project planning criteria. The following is a discussion of alternatives that were eliminated from further consideration. Removal of Prado Dam The alternative will meet the CEQA planning objectives of preventing further degradation of the Santa Ana River, allowing habitat to recover in the Santa Ana River, providing sediment to replenish the coast, allowing habitat to recover in the Prado Basin and minimizing impacts to native vegetation in Prado Basin. However, the alternative will not meet the CEQA planning objective of the Project of providing and enhancing water supply storage. For this reason the alternative was eliminated from further consideration. Flushing of sediments from the basin by installation of low-level gates and modification of basin geometry The alternative has the potential to collect debris at the inlet and outlet structures which could affect the operation of the dam. For this reason the alternative was

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-3 Section 6 Alternatives to the Proposed Project

eliminated from further consideration. Flushing of sediments from the basin by passing sediment through outlet structure and modification of basin geometry The alternative was eliminated from further consideration for the same above reason. Mechanical removal and trucking of sediments to the beach for beach sand replenishment This alternative will not meet the CEQA planning objectives for enhancing habitat and sediment balance in the Lower Santa Ana River, extending the life of infrastructure in the lower Santa Ana River, and enhancing infiltration capacity of the lower Santa Ana River. For these reasons the alternative was eliminated from further consideration. Mechanical removal and trucking of sediments to disposal or reclamation facilities The alternative will not meet the CEQA planning objectives for enhancing habitat and sediment balance in the lower Santa Ana River, extending the life of infrastructure in the lower Santa Ana River, enhancing infiltration capacity of the lower Santa Ana River, and providing sediments to coastal systems. For these reasons the alternative was eliminated from further consideration. Mechanical removal of sediments and discharging it to the Lower Santa Ana River through a portion of the SARI line running under the dam The alterative will meet all CEQA planning objectives. However, allowing Prado Basin water and sediments to be transported through a pipe beneath the dam poses geotechnical and dam stability risks that require significant further evaluation by the U.S. Army Corps of Engineers before attempting a field demonstration project. For this reason the alternative was eliminated from further consideration. Mechanical removal and discharging of sediments into the Lower Santa Ana River through a new pipe constructed through the dam The alternative will meet all CEQA planning objectives. However, allowing Prado Basin water and sediments to discharge using a pipe through the dam poses geotechnical and dam stability risks requiring significant further evaluation by the U.S. Army Corps of Engineers before attempting in a field demonstration. For this reason the alternative was eliminated from further consideration.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-4 Section 6 Alternatives to the Proposed Project

Use of Chino Creek as Source of Sediment Removal from Prado Basin The use of Chino Creek as source to remove sediment from the Santa Ana River was rejected because it will not be consistent with the CEQA project objectives of being able to remove between 250,000 cubic yards and 500,000 cubic yards of material from the Prado Basin. Additionally, the alternative will not meet the CEQA objective of minimizing impacts to native vegetation in the Prado Basin. Use of a Hybrid of Temescal Wash and Santa Ana River as Source of Sediment Removal from Prado Basin Use of a hybrid of Temescal Wash and Santa Ana River as source to remove sediment from the Santa Ana River was rejected because it will not be consistent with the CEQA project objectives of being able to remove between 250,000 cubic yards and 500,000 cubic yards of material from the Prado Basin. Additionally, the alternative will not meet the CEQA objective of minimizing impacts to native vegetation in the Prado Basin. Use of Areas within Chino Hills State Park to Store Sediment The alternative will meet the CEQA project objectives. However, the alternative will be inconsistent with the Chino Hills State Park General Park Plan and the alternative does not have support from the California Department of Parks and Recreation. For this reason the alternative was eliminated from further consideration. 6.5 Project Alternatives Considered and Evaluated Because the focus of the operation of the Project is to remove sediment from Prado Basin, it is not feasible to evaluate an offsite location alternative. However, an alternative location for the sediment storage and handling area and green waste processing area has been identified. Additionally, an alternative method to remove sediment from the sediment removal channel was identified. The following Project Alternatives have been selected for further analysis: Alternative 1 - No Project Alternative Alternative 2 - Alternative Sediment Storage Area/Green Waste Area Location Alternative 3 - Alternative Sediment Removal Method 6.5.1 Alternative 1-No Project Alternative Under the No Project Alternative, the proposed sediment management demonstration project will not be implemented. No sediment management

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-5 Section 6 Alternatives to the Proposed Project

activities will be conducted to remove sediment from Prado Basin. There will be no change to the existing conditions at the Prado Basin. Aesthetics Under Alternative 1, the Project will not be implemented. Therefore, no construction or operational aesthetic impacts associate with the Project will occur. There will be no change to existing scenic vistas and no change to the existing aesthetic character of the project area. Under Alternative 1, the Project will not be implemented. There will be no night time construction activity and no potential for night time spill-over lighting impacts. There will be no change to the project area condition. Some portions of the project area will continue to experience night time lighting and glare impacts from existing land uses and road ways. Air Quality Under Alternative 1, the Project will not be implemented. There will not be any construction related air quality impacts. The project area will still be classified as State Non-Attainment Area for ozone, nitrogen dioxide, PM10 and PM2.5 and a Federal Non-Attainment Area for ozone, PM 10 and PM 2.5. Biological Resources Under Alternative 1, there will be no changes to the existing condition of the project area. The project area will continue to have low potential for sensitive plant species to ocurr. Under Alternative 1, the proposed sediment removal channel and sediment storage site will not be constructed. Therefore, there will not be a potential for direct and indirect construction related and operational impacts to occur to sensitive vegetation communities, special status species or their habitat. Under Alternative 1, the Project will not be implemented. There will not be any construction activity and no potential impacts to Wetland Waters of the U.S. or State. Cultural Resources Under the Alternative 1, the Project will not be implemented. No construction activity will occur and there will be no potential for construction related impacts to unknown historic resources, archaeological resources or sacred Native American burial sites. Geology Under Alternative, the Project will not be implemented and there will be no

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-6 Section 6 Alternatives to the Proposed Project

potential risks for geologic impacts. There will be no change to the project area condition. The project area will still be subject to ground rupture impacts, seismic shaking impacts and liquefaction impacts. Under Alternative 1, there will not be any excavation or grading activities that will expose uncovered soils to increase the potential for erosion impacts. Greenhouse Gas Under Alternative 1 the Project will not be implemented. There will be no increase greenhouse gas emissions within the project area generated from construction and operation of the Project. Hazards Under Alternative 1, the Project will not be implemented. There will not be any construction equipment operating within the project area. Therefore, there will not be any increased potential for the accidental release of fuels, oil or solvents into the environment. Hydrology/Water Quality Under Alternative 1, the Project will not be implemented. There will be no activities to remove sediment from Prado Basin and re-entrain it into the Santa Ana River. There will be no change to the project area condition. Sediment will continue to build up and remain behind Prado Dam and ongoing armoring and incising of the lower Santa Ana River channel bottom will continue. Under Alternative 1, there will be no change to the project area condition and existing rates of surface water runoff within the project area will remain the same. Additionally, under Alternative 1, there will be no increased construction activity within the Prado Basin. Therefore, there will not be an increased potential for degraded surface water runoff impacts. Under Alternative 1, there will be no sediment removal and no sediment re- entrainment activities within the Santa Ana River. There will be no potential for conflicts with the Basin Plan or increased potential for adverse water quality impacts. Land Use Under Alternative 1, the Project will not be implemented. The current condition at the project area will not change. There will be no potential impacts or conflicts with existing and planned land uses or conflicts with existing relevant planning programs for the project area.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-7 Section 6 Alternatives to the Proposed Project

Noise Under Alternative 1, the Project will not be implemented. There will be no increased construction or operation noise impacts within the project area and no change to existing ambient noise levels. Transportation/Traffic Under Alternative 1, the Project will not be implemented. There will be no mobilization and demobilization of construction equipment and no potential for traffic congestion at surrounding roadways and intersections. Under Alternative 1, there will be no onsite construction traffic and no potential for construction traffic safety hazards to workers in the project area. Comparison of Project Objectives and Environmental Impacts • Under the No Project Alternative none of the Project Objectives will be achieved. • Compared to the Project, potential impacts to the environment will be less. 6.5.2 Alternative 2- Alternative Sediment Storage Site D Under Alternative 2, the sediment removal channel will be excavated along the alignment of the Santa Ana River. The sediment will be removed from the sediment removal channel by a hydraulic dredging method. Similar to the Project, between 250,000 and 500,000 cubic yards of sediment will be dredged and removed from the sediment removal channel. Alternative will involve require same mix of construction equipment required for the Project, except, that under Alternative 2 the green waste processing and sediment storage and handling activities will occur at Sediment Storage Site D. Sediment Storage Site D is approximately two acres smaller than Storage Site E. At sediment storage site D the sediment will be re-mixed into slurry and conveyed by an above ground discharge pipeline to the Prado Dam outlet channel for sediment re-entrainment. Aesthetics Under Alternative 2 scenic views from Chino Hills State Park, State Route 71, State Route 91 and the Santa Ana River Trail will be temporary interrupted with project construction and operation activities. The short-term adverse changes to existing scenic vistas within the project area will not be significant. Compared to the Project, the level of potential impact will be the same. The construction and operation of Alternative 2 will result in short term aesthetic changes to the project are. Compared to the Project, the level of potential impact

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-8 Section 6 Alternatives to the Proposed Project

will be the same. Under Alternative 2, the project area could be impacted by project night time spill-over lighting impacts from sediment re-entrainment activities. Compared to the Project, the level of potential impact will be the same. Air Quality Under Alternative 2, SCAQMD regional emission thresholds will be exceeded for NOX emissions during Phase 2 Clearing and Grubbing, Phase 5 Sediment Re- entrainment, and Phase 6 Site Restoration. With the implementation of mitigation potential adverse air quality impacts will be reduced to a less than significant level. Compared to the Project, there will be less grading activity and a less amount of construction emissions will be generated. Biological Resources Under Alternative 2, the project activities will be similar to the Project, except that the sediment will be stored at Sediment Storage Site D. Similar to the project the potential for sensitive plants to occur within the project area is low. Implementation of Alternative 2 will not result in adverse impacts to any sensitive plant species. Compared to the Project, the level of potential impact will be the same. Under Alternative 2, the construction of the channel would not displace existing known vireo territories. Under Alternative 2 dredging operations will extend into nesting season. There is potential that some birds could nest within the construction activity noise impact area. Similar to the Project, onsite monitoring and a noise mitigation program will be implemented to minimize noise impacts. However, because of dense vegetation some active nests could be unnoticed and be adversely impacted with construction noise impacts causing a disruption to breeding patterns. The potential for construction noise impact to disrupt breeding birds of nesting birds is a significant adverse impact. Compared to the Project, the level of potential impact will be the same. The level of potential impact to critical habitat for the Least Bells Vireo and Southwestern Willow Flycatcher will be the same compared to the Project. Even though there is low potential for native fish to occur within the project area, the construction and operation of the sediment removal channel would have the potential result in adverse impacts to native fish. The potential for native fish to require re-location is a significant impact. Compared to the Project, the level of potential impact will be the same.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-9 Section 6 Alternatives to the Proposed Project

Under Alternative 2, sediment storage and handling and green waste processing activities will occur at Sediment Storage Site D. Compared to the Project, Alternative 2 will result in 11.25 acres of additional impacts to sensitive vegetation communities. Compared to the Project, Alternative 2 will result in the same amount of impacts to Waters of the State. Compared to the Project potential wildlife movement impacts along the Santa Ana River associated with the construction and operation of the sediment removal channel will be the same. Under Alternative 2 there is the potential that construction noise could disrupt the breeding patterns of migratory birds. Compared to the Project, the level of potential impact will be the same. Cultural Resources Under Alternative 2, the majority of the Project will be implemented below the 505 foot elevation and will not result in adverse impacts to cultural resources. Approximately 22 acres of the sediment removal channel storage site and all of the Sediment Storage Site D is located above the 505 foot elevation. Because of the significant amount of sediment and disturbances to the project area above the 505 foot elevation, the potential for the discovery cultural resources will be low. Compared to the Project the level of potential impact to cultural resources will be the same. Geology The Elsinore Fault extends through Sediment Storage Site D. Therefore, there is potential for ground rupture impacts. Compared to the Project there will be higher potential for ground rupture impacts. The project area could be subject to seismic shaking and liquefaction impacts. Similar to the Project, Alternative 2 does not propose any habitable or permanent structures or involves a high number of workers that will be subject to substantial risks from seismic shaking and liquefaction impacts. In the event ground seismic impacts occur there will be minimal property damage. Compared to the Project, the level of potential impact will be the same. Sediment Storage Site D is approximately two acres smaller than Sediment Storage Site E and will require less grading and less potential for erosion impacts, compared to the Project. Similar to the Project, Alternative 2 will also be required to obtain coverage under a General Construction Permit by the Regional Water Quality Control Board, file a Notice of Intent and the prepare a Storm

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-10 Section 6 Alternatives to the Proposed Project

Water Pollution Prevention Plan (SWPPP). With the implementation of Mitigation Measure GEO-1 potential erosion impacts will be reduced to a less than significant level. Greenhouse Gas The greenhouse gas emissions generated from the construction and operation of Alternative 2 will not exceed the 3,000 MTCO2e per year threshold. Therefore, adverse greenhouse gas emissions generated by Alternative 2 will be less than significant. Sediment Storage Site D is approximately two acres smaller than Sediment Storage Site E and will require less grading and less amounts of greenhouse gas emissions will be generated. Hazardous Materials Similar to the Project, Alternative 2 will involve the handling of incidental amounts of hazardous materials.Compared to the Project, the level of impact will be the same. Hydrology/Water Quality The use of Sediment Storage Site D will not increase or decrease the frequency, duration or severity of flooding along the Santa Ana River, compared to the Project. At Sediment Storage Site D the average elevation is 530 feet and the lowest elevation point on the site is 515 feet. The storage site is located within the inundation area and could be subject to flood impacts. Compared to the Project potential flood risks at the storage site and at the sediment re-entrainment area will be about the same. Implementation of Alternative 2 will not introduce any new impervious surfaces into the project area. Existing rates of surface water runoff within the project area will not increase. Sediment Storage Site D is approximately two acres smaller than Sediment Storage Site E and will require less grading and less potential for erosion impacts, compared to the Project. Similar to the Project, Alternative 2 will require issuance of a General Construction Permit by the Regional Water Quality Control Board and preparation of Storm Water Pollution Prevention Plan (SWPPP) to minimize construction erosion impacts. Under Alternative 2, the project will still be considered a Watershed Protection Project. There will be no substantial long term storm water management impacts. Under Alternative 2 sediment re-entrainment activities will temporary exceed the Basin Plan threshold for turbidity and will result in a temporary short term significant adverse impact. Compared to the Project, the potential for adverse surface water quality impacts will be about the same.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-11 Section 6 Alternatives to the Proposed Project

Land Use/Planning Under Alternative 2 the sediment removal channel will be in the same location as the Project and the construction and operation of it will not adversely affect Prado Dam, OCWD Prado Wetlands or the Santa Ana River Trail. Compared to the Project, the level of impact will be the same. Similar to the Project, Alternative 2 will operate consistent with the Prado Dam Interim Water Control Manual and the Project will not result in conflicts with the operation of Prado Dam. Noise Under Alternative 2, the noise levels generated from the sediment removal activities, green waste processing, sediment storage and handling activities and sediment re-entrainment activities will be below the OSHA standard. The sediment removal activities, green waste processing and sediment storage and handling activities will occur during the day and will be exempt under the Riverside County Noise Ordinance and the City of Corona Noise Ordinance. Compared to the Project, the level of potential impact will be the same. Under Alternative 2 sediment re-entrainment activities could occur during the day and night. During the day sediment re-entrainment activities will below the OSHA standard and will be exempt under the Riverside County Noise Ordinance and City of Corona Noise Ordinance. During the night, the sediment re-entrainment activities will below the OSHA standard but will exceed the City of Corona Noise Ordinance night time noise standard. To reduce noise levels to below the City of Corona Noise Ordinance a sound attenuation enclosure will be provided around the crane and onsite monitoring will occur to ensure that maximum noise levels standards are not exceeded. Compared to the Project, the level of potential noise impacts will be the same. Transportation/Traffic Under Alternative 2, the Project will generate approximately the same amount of construction traffic and will utilize same the same circulation system proposed in the Project. Under Alternative 2, there will not be any roadways closures or long term traffic impacts and with implementation of mitigation measures potential temporary adverse traffic congestion impacts will be reduced to a less than significant level. Compared to the Project, potential traffic impacts will be the same. Under Alternative 2, sediment will be removed from the sediment removal channel and piped to Sediment Storage Site D. The use of Sediment Storage Site D will not increase or decrease the potential for onsite construction

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-12 Section 6 Alternatives to the Proposed Project

equipment traffic conflicts. Compared to the Project, potential construction traffic impacts will be the same. Comparison of Project Objectives and Environmental Impacts • Under Alternative 2 all of the Project Objectives will be achieved. • Compared to the Project, Alternative 2 will require less grading and less construction equipment emissions will be generated. • Compared to the Project, Alternative 2 will result in 11.25 acres of additional impacts to sensitive vegetation communities. • Compared to the Project, Alternative 2 will require less grading and less greenhouse gas emissions will be generated. • Compared to the Project, under Alternative 2 there will be greater potential for ground rupture impacts. • Compared to the Project less, Alternative 2 will require less and there will be lesser amounts of uncovered soils and less potential for erosion impacts. 6.5.3 Alternative 3 - Alternative Sediment Removal Method Under Alternative 3 the sediment removal channel will be excavated along the alignment of the Santa Ana River. Between 250,000 and 500,000 cubic yards of sediment will be removed from the channel with heavy construction equipment. The removed sediment will be transported by heavy equipment to Sediment Storage Site D. At sediment storage site D the sediment will be re-mixed into slurry and conveyed by an above ground discharge pipeline to the Prado Dam outlet channel for sediment re-entrainment. Compared to the Project, Alternative 3 will require a larger fleet of construction equipment. Aesthetics Under Alternative 3 scenic views from Chino Hills State Park, State Route 71, State Route 91 and the Santa Ana River Trail will be temporary interrupted by project construction and operation activities. Compared to the Project, under Alternative 3 there will be higher number of construction equipment operating within the project area which could result in a higher potential for scenic vistas to be temporarily interrupted with construction activity and an increase potential for adverse aesthetic impact changes to the project area. Air Quality Under Alternative 3, SCAQMD regional emission thresholds will be exceeded for NOX emissions during Phase 2 Clearing and Grubbing, Phase 4 Sediment Re-

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-13 Section 6 Alternatives to the Proposed Project

entrainment, and Phase 6 Mitigation. With the implementation of mitigation potential adverse air quality impacts will be reduced to a less than significant level. Compared to the Project Alternative 3 will involve a larger fleet of construction equipment and a greater amount of construction equipment emissions will be generated. However the use of heavy equipment in lieu of dredging will result in less NOX emissions. Biological Resources The potential for sensitive plants to occur within the project area is low. Implementation of Alternative 3 will not result in adverse impacts to any sensitive plant species. Compared to the Project, the level of potential impact will be the same. The construction of the sediment channel would not temporary displace existing known vireo territories. Under Alternative 3 dredging operations will extend into nesting season. There is potential that some birds could nest within the construction activity noise impact area. Similar to the Project, onsite monitoring and a noise mitigation program will be implemented to minimize noise impacts. However, because of dense vegetation some active nests could be unnoticed and be adversely impacted with construction noise impacts causing a disruption to breeding patterns. The potential for construction noise impact to disrupt breeding birds of nesting birds is a significant adverse impact. Compared to the project, the level of potential impact will be the same. The level of potential impact to critical habitat for the Least Bells Vireo and Southwestern Willow Flycatcher will be the same compared to the Project. Even though there is low potential for native to occur within the project area, the construction and operation of the sediment removal channel would have the potential result in significant adverse impacts to native fish. Compared to the Project, the level of potential impact will be the same. Under Alterative 3 the excavated material will be hauled by heavy equipment to Sediment Storage Site D. Compared to the Project, there is a higher potential that adjacent habitat and wildlife species to be trampled by vehicle traffic and nesting or territorial birds could be startled by vehicle noise or human presence. Compared to the Project, Alternative 3 will have a higher potential to result in adverse direct impacts to wildlife species. Compared to the Project, Alternative 3 will result in 11.25 acres of additional impacts to sensitive vegetation communities. Because Alternative 3 will involve the use of more heavy equipment to remove and transport sediment there will be

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-14 Section 6 Alternatives to the Proposed Project

a higher potential for adverse indirect impacts to occur to sensitive vegetation communities. Compared to the Project, Alternative 3 will result in the same amount of impacts to Wetland Waters of the U.S./State. Potential wildlife movement impacts along the Santa Ana River associated with the construction and operation of the sediment removal channel will be the same compared to the Project. The implementation of Alternative 3 will have the potential to disrupt breeding patterns of migratory birds. Compared to the Project the level of potential impact will be the same. Cultural Resources Compared to the Project, the use of heavy equipment to remove sediment and transport sediment will not increase or decrease the potential for impacts to cultural resources. Compared to the Project, the level of potential impact to cultural resources will be the same. Geology The Elsinore Fault extends through Sediment Storage Site D. Compared to the Project there will be a higher potential for ground rupture impacts. The project area could be subject to seismic shaking and liquefaction impacts. Alternative 3 does not propose any habitable or permanent structures or involves a high number of workers that will be subject to substantial risks from seismic shaking or liquefaction impacts. The use of heavy equipment to excavate and transport sediment will not substantially increase the risk for injury, death or property damage from ground rupture impacts, seismic shaking or liquefaction impacts over the current condition. Sediment Storage Site D is approximately two acres smaller than Storage Site E and will require less grading and less potential for erosion impacts, compared to the Project. Similar to the Project, Alternative 3 will also be required to obtain coverage under a General Construction Permit by the Regional Water Quality Control Board, file a Notice of Intent and the prepare a Storm Water Pollution Prevention Plan (SWPPP). With the implementation of Mitigation Measure GEO- 1 potential erosion impacts will be reduced to a less than significant level. Alternative 3 involves the removal of sediment with heavy equipment and the hauling of sediment with off-road vehicles which will increase the potential for sediment to be transported to other locations.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-15 Section 6 Alternatives to the Proposed Project

Greenhouse Gas The greenhouse gas emissions generated from the construction and operation of Alternative 3 will not exceed the 3,000 MTCO2e per year threshold. Therefore, adverse greenhouse gas emissions generated by Alternative 3 will be less than significant. Alternative 3 will involve the operation of a higher amount of construction equipment. Compared to the Project, the amount greenhouse gases generated under Alternative 3 will be slightly higher. Hazards Similar to the Project, Alternative 3 will involve the handling of incidental amounts of hazardous materials. Under Alternative 3 sediment material will be removed with heavy construction equipment and will transported by off-road vehicles to Sediment Storage Site D. Alternative 3 will involve a higher amount of heavy construction equipment and could potentially handle and store larger amounts hazardous materials such as fuel and oil, compared to the Project, increasing the risk for accidental spills. Hydrology/Water Quality The use of heavy equipment to remove and transport sediment will not decrease or increase the frequency, duration or severity of flooding along the river compared the Project. Similar to the Project, Alternative 3 will require issuance of a General Construction Permit by the Regional Water Quality Control Board and preparation of Storm Water Pollution Prevention Plan (SWPPP) to minimize construction storm water runoff impacts. Under Alternative 3, the Project will still be considered a Watershed Protection Project. There will be no substantial long term storm water management impacts. Alternative 3 does not include the use of dredging to remove sediment from sediment removal channel. Therefore, there will be less potential for adverse water quality turbidity impacts. However, the sediment re-entrainment activities under Alternative 3 will still exceed the Basin Plan threshold for turbidity and will result in a temporary short term significant adverse impact. Under Alternative 3 underground water supplies will not be depleted. Sediments re-entrained in the river will be transported to reaches along the river where groundwater recharge occurs. Under Alternative 3 the sediment re-entrainment activities will have a beneficial impact on ground water recharge along the Santa Ana River. The use of heavy equipment to remove and transport sediment will not increase or decrease impacts on ground water supplies, compared to the Project.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-16 Section 6 Alternatives to the Proposed Project

Land Use/Planning The use of heavy equipment would not increase or decrease potential land use conflicts with Prado Dam, OCWD Wetlands or the Santa Ana River Trail. Compared to Project, the level of potential impact will be the same. The use heavy equipment to excavate and transport sediment will not increase or decrease potential conflicts with Western Riverside County Multiple Species Habitat Construction Plan. Noise The noise levels generated from the sediment removal activities, green waste processing, sediment storage and handling activities and sediment re- entrainment activities will be below the OSHA standard. The sediment removal activities, green waste processing and sediment storage and handling activities will occur during the day and will be exempt under the Riverside County Noise Ordinance and the City of Corona Noise Ordinance. Under Alternative 3 sediment will be hauled by heavy equipment to Sediment Storage Site D where it will be stored and processed. The noise levels from the hauling will be comparable to noise levels associated with dredging operations. However, under Alternative 3 there would a large amount of construction equipment in operation and increase potential for construction noise impacts. Under Alternative 3 sediment re-entrainment could occur during the day and night. During the day sediment re-entrainment activities will below the OSHA standard and will be exempt under the Riverside County Noise Ordinance and City of Corona Noise Ordinance. During the night sediment re-entrainment activities will be below the OSHA but will exceed the City of Corona Noise Ordinance night time noise standard. To reduce noise levels below the City of Corona Noise Ordinance a sound attenuation enclosure will be provided around the crane and onsite monitoring will occur to ensure that maximum noise levels standards are not exceeded. Transportation/Traffic Under Alternative 3 the project will utilize same the same circulation system proposed in the Project. Similar to the Project, Under Alternative 3 there will not be any roadways closures or long term traffic impacts. Compared to the project, Alternative 3 will require larger fleet of construction equipment. There will be a higher potential for local traffic congestion during mobilization and demobilization of construction equipment.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-17 Section 6 Alternatives to the Proposed Project

Under Alternative 3 sediment will be removed from the sediment removal channel and will be hauled by heavy construction equipment to Sediment Storage Site D. It is estimated that approximately 100 heavy construction haul round trips will occur daily. Because Alternative 3 will involve a higher amount construction equipment traffic compared to the Project, there will be a higher potential for onsite construction equipment traffic conflicts with vehicles and workers. Comparison of Project Objectives and Environmental Impacts • Under Alternative 3 all of the Project Objectives will be achieved. • Under Alternative 3 there will be higher number of construction equipment operating within the project area. Compared to the project there could be a higher potential for scenic vistas to be temporarily interrupted with construction activity and higher potential for adverse aesthetic impact changes to the project area. • Compared to the Project, Alternative 3 will require less grading and less construction equipment emissions will be generated. • Compared to the Project, the use of heavy equipment to remove sediment from the sediment removal channel instead of a floating dredge will result in less NOX emissions. • Compared to the Project, Alternative 3 will result in 11.25 acres of additional impacts to sensitive vegetation communities. • Because Alternative 3 would involve the use of more heavy equipment to remove and transport sediment there would be a higher potential for adverse indirect impacts to occur to sensitive vegetation communities, compared to the Project. • Under Alterative 3 the excavated material would be hauled by heavy equipment to Sediment Storage Site D. Compared to the Project, there is a higher potential that wildlife species could be trampled by vehicle traffic and nesting or territorial birds could be startled by vehicle noise or human presence. • Compared to the Project, Alternative 3 will require less grading and less greenhouse gas emissions will be generated. • Compared to the Project, under Alternative 3 there will be greater potential for ground rupture impacts.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-18 Section 6 Alternatives to the Proposed Project

• Compared to the Project, Alternative 3 will require less grading and there will be lesser amounts of uncovered soils and less potential for erosion impacts. • Alternative 3 does not include the use of dredging to remove sediment from sediment removal channel. Compared to the Project there will be less potential for adverse turbidity impacts. • Compared to the Project, Alternative 3 will involve a higher amount of heavy construction equipment and could potentially handle and store larger amounts hazardous materials such as fuel and oil increasing the risk for accidental spills. • Because Alternative 3 will involve a higher amount construction equipment traffic compared to the Project, there would be a higher potential for offsite and onsite construction equipment traffic conflicts with vehicles and workers. 6.6 Environmentally Superior Alternative CEQA Guidelines Section 15126(e) (2) requires an EIR to identify an environmentally superior alternative. If the No Project is the environmentally superior alternative, the EIR must also identify an environmentally superior alternative from among the other alternatives. A comparison of the environmental impacts resulting from the implementation of the Project and Project Alternatives is shown in Table 47.

Table 47: Summary of Environmental Impacts Environmental Issue Project Alternative 1 Alternative 2 Alternative 3 No Project Aesthetics LSM L E G Air Quality LSM L L L Biological Resources S L G G Cultural Resources LSM L E E Geology/Soils LSM L G G Greenhouse Gas LS L L L Hazardous Materials LSM L E G Hydrology/Water Quality LSM L L L Land Use LSM L E E Noise LSM L E G Transportation LSM L E G S-Significant Impact L- Less Impact Compare to Project LS-Less than Significant Impact E-Equivalent Impact Compared to Project LSM-Less than Significant with Mitigation G-Greater Impact Compared to Project

No Project Alternative Even though Alternative 1 will result in fewest amounts of adverse impacts to the environment, it will not achieve any of the project objectives and therefore, it is

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-19 Section 6 Alternatives to the Proposed Project

not considered to be the environmentally superior alternative. Alternative 2 Under Alternative 2 all of the Project Objectives will be achieved. Compared to the Project, Alternative 2 will involve 2 acres of less grading and the amount of construction equipment emissions and greenhouse gas emissions will be slightly less. Additionally, with less grading there will be less amounts of uncovered soils and less potential for erosion impacts. Compared to the Project, Alternative 2 will result in over 11 acres of additional impacts to native vegetation within the Prado Basin, which will require additional area for compensatory mitigation. While Alternative 2 would generate slightly less construction equipment emissions and greenhouse gas emissions compared to the project, Alternative 2 would result in substantially more impacts to sensitive vegetation communities and therefore is not considered an environmental superior alternative to the Project. Alternative 3 Alternative 3 will involve a larger fleet of construction equipment and compared to the Project and the alternative will result in greater amounts of construction equipment emissions, greenhouse gas emissions and noise impacts. The increased construction equipment will increase the potential for traffic conflicts and aesthetic impacts in the project area. Compared to the Project, Alternative 2 will result in over 11 acres of additional impacts to native vegetation within the Prado Basin, which will require additional area for compensatory mitigation. Additionally, Alternative 3 involves the use of more heavy construction equipment which will have a higher potential for adverse construction related impacts to native vegetation and wildlife. Compared to the Project, Alternative 3 will result in more sever impacts and therefore is not considered an environmental superior alternative to the Project. Recommendation While Alternative 2 and Alternative 3 attempts to minimize impacts to native vegetation, the Project better achieves the project objective of minimizing impacts to native vegetation within the Prado Basin. In terms of potential impacts to the environment and achieving project objectives, the Project is considered the environmentally superior alternative.

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 6-20 Section 7 List of Preparers and Reviewers

SECTION 7 LIST OF PREPARES AND REVIEWERS Orange County Water District Greg Woodside Director Planning and Watershed Management Richard Zembal Director of Natural Resources Daniel Bott Principal Planner Nathan Scheevel Project Engineer Darla Cirillo Administrative Support

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 7-1 Section 8 References

SECTION 8 REFERENCES Aesthetics California Department of Transportation Scenic Highways Program, Web Site Accessed 2013 Air Quality Prado Basin Sediment Management Demonstration Project Air Quality and Greenhouse Gas Technical Report 2013, First Carbon Solutions Biological Resources Baskin, J., 2008 Fish Protection Activities Prado Basin. California Department Fish and Game, 2012 California Natural Diversity Database. California Native Plant Society, 2012. Electronic Inventory of Rare and Endangered Vascular Plants of California. Moyle, P.B., 2002. Inland Fishes of California. University of California Press, Berkeley. Orange County Water District, 2012. Native Fish Survey Lower Santa Ana River Weir Canyon to Imperial Highway Riverside County Resource Conservation District, 2010, Native Fish Relocation for ACOE Reach 9 Channel Diversions. Saiki, M.K., B.A. Martin, G.W. Knowles and P.W. Tennant. 2007. Life History and Ecological Characteristics of the Santa Ana Sucker, Catostomus santaanae. California Fish and Game, 87-101 Santa Ana Watershed Agency, 2012. Least Bells Vireo Survey. Santa Ana Watershed Association, 2013, Distribution of Santa Ana Suckers along the Santa River. Santa Ana Watershed Association, 2013. Least Bells Vireo Survey. Swift, C.C., 2001. The Santa Ana sucker is the Santa Ana River: distribution, relative abundance, spawning areas, and the impact of exotic predators. Thompson, A.R., J.N. Baskin, C.C Swift, T.R. Haglund, and R.J. Nagel. 2010. Influence of habitat dynamics on the distribution and abundance of the federally threatened Santa Ana Sucker, Catostomus santaanae, in the Santa Ana River. United States Department of Agriculture, 2007. Soil Series

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 8-1 Section 8 References

United States Department of Interior, 2013, Information Planning and Conservation Data Base United States Fish and Wildlife Service, 1994, Designation of Critical Habitat for the Least Bells Vireo, Final Rule. United States Fish and Wildlife Service, 2004, Endangered and Threatened Wildlife and Plants, Proposed Rule to Designate Critical Habitat for the Santa Ana Sucker. United States Fish and Wildlife Service, 2010, Initiation of 5-year Reviews of 34 Species in California and Nevada, and Availability of 96 Completed 5-Year Reviews in California and Nevada. United States Fish and Wildlife Service Revised Critical Habitat for the Santa Ana Sucker, Final Rule. United States Fish and Wildlife Service, 2012, Biological Opinion FWS-WRIV- 11B0269-12F0166, Formal Section 7 Consultation Proposed Reconstruction and Long-Term Operations of the Prado Constructed Wetlands, Riverside County, California United States Fish and Wildlife Service, Designation of Critical Habitat for Southwestern Willow Flycatcher. United States Fish and Wildlife Service, 2013, List of Species of Special Concern. United States Geologic Survey 7.5 Quadrangle Maps, 1981. Black Star Canyon, Corona North, Corona South, Prado Dam, Riverside West, Western Riverside County Multiple Species Habitat Conservation Plan, Riverside County, 2007 Cultural Resources Prado Basin Water Conservation Feasibility Study, 2005 US Army Corps of Engineers, 2005 Geology/Soils California Division of Mines and Geology, 2007. Alquist Priolo Earthquake Fault Zibnes Maps. Greenhouse Gas Prado Basin Sediment Management Demonstration Project Air Quality and Greenhouse Gas Technical Report, 2013, First Carbon Solutions Hazardous Materials Hazardous Site Assessment, Orange County Water District, 2012

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 8-2 Section 8 References

Hydrology/Water Quality Prado Dam Interim Water Control Plan, 1994, United States Army Corp of Engineers California Regional Water Quality Control Board Region 8, 1995. Santa Ana River Basin Water Quality Control Plan. Orange County Groundwater Management Plan, 2005, Orange County Water District Prado basin Sediment Management Demonstration Project Engineering Analysis, January 2013 Land Use/Relevant Planning Programs City of Corona General Plan Land Use Element, County of Riverside General Plan Land Use Element, County of Riverside 4th Term Municipal NPDES Permit, 2012 Environmental Assessment, Santa Ana trail Riverside County, Michael Brandman Associates, 2011 Final Supplement Environmental Assessment Santa Ana River Reach 9, Phase 3, US Army Corps of Engineers, 2013 Prado Dam Draft Flood Control Master Plan, United States Army Corps of Engineers Noise City of Corona Noise Ordinance, 2012 County of Riverside Noise Element, 2012 Traffic River Road Bridge Replacement Project Environmental Assessment/Environmental Impact Report, 2005 Riverside County Transportation Department Riverside County Congestion Management Program, 2012, Riverside County Socioeconomic/Environmental Justice California Department of Finance, 2012

Orange County Water District Prado Basin Sediment Management Project Draft Environmental Impact Report 8-3