SECTION 1.0 INTRODUCTION ...... 1 -1 1.1 Purpose of Environmental Review ...... 1-1 1.2 Statutory Authority and Requirements ...... 1 -1 1.3 Technical Information and Studies ...... 1-2 SECTION 2.0 PROJECT DESCRIPTION ...... 2 -1 2.1 Proposed Project...... 2-1 2.2 Background ...... 2 -1 2.3 Well Site Locations ...... 2 -3 2.4 Monitoring Well Construction Activities ...... 2 -5 2.5 Monitoring Well Long Term Operation and Maintenance Activities ...... 2-9 2.6 Bolsa Chica Flood Control Levee Repairs ...... 2-10 2.7 Bolsa Chica Channel Levee Repair Construction Activities ...... 2-12 2.8 Permits and Approvals ...... 2-13 SECTION 3.0 ENVIRONMENTAL CHECKLIST EVALUATIONS ...... 3-1 SECTION 4.0 ENVIRONMENTAL ANALYSIS ...... 4-1 4.1 Aesthetics ...... 4 -1 4.2 Agricultural Resources/Forest Resources ...... 4-3 4.3 Air Quality ...... 4 -5 4.4 Biological Resources ...... 4-21 4.5 Cultural Resources ...... 4-36 4.6 Geology/Soils ...... 4 -42 4.7 Greenhouse Gas Emissions ...... 4-48 4.8 Hazards/Hazardous Materials ...... 4-52 4.9 Hydrology/Water Quality ...... 4-55 4.10 Land Use/Planning ...... 4-67 4.11 Mineral Resources ...... 4-68 4.12 Noise ...... 4 -69 4.13 Population/Housing ...... 4-87 4.14 Public Services ...... 4 -87 4.15 Recreation ...... 4 -88 4.16 Transportation/Traffic ...... 4-88 4.17 Tribal Resources ...... 4 -91 4.18 Utilities/Service Systems ...... 4-93 SECTION 5.0 REFERENCES ...... 5 -1

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Table of Contents

Table Page Table 1 Mobilization Equipment Mix Monitoring Wells Sites BS13 & BS24 ...... 2-7 Table 2 Well Drilling/Construction Equipment Mix Well Site BS13 ...... 2-7 Table 3 Well Drilling/Construction Equipment Mix Well Site BS24 ...... 2-8 Table 4 Well Development Equipment Mix Well Site BS13...... 2-8 Table 5 Well Development Equipment Mix Well Site BS24...... 2-8 Table 8 Construction-Related Regional Criteria Pollutant Emissions Prior to Mitigation .4- 11 Table 9 Mitigated Construction-Related Regional Criteria Pollutant Emissions...... 4-12 Table 10 Construction-Related Local Criteria Pollutant Emissions ...... 4-13 Table 11 Operational Well Sampling and Redevelopment Regional Criteria Pollutant Emissions...... 4-14 Table 12 Operational Well Sampling and Redevelopment Local Criteria Pollutant Emissions...... 4-15 Table 13: Sensitive Species List ...... 4-24 Table 14 Project Related Greenhouse Gas Annual Emissions ...... 4-50 Table 15: Beneficial Uses ...... 4 -58 Table 16: Tidal Prism Bolsa Chica Channel ...... 4-60 Table 17: Huntington Harbor ...... 4-60 Table 18: Anaheim Bay Outer Bay ...... 4-60 Table 19: Anaheim Bay Seal Beach Wildlife Refuge ...... 4-61 Table 20: Bolsa Bay ...... 4 -61 Table 21: Orange County Groundwater Basin ...... 4-61 Table 22: Water Quality Objectives (mg/L) ...... 4-61 Table 23: Noise Levels and Human Response ...... 4-70 Table 24: City of Huntington Beach Municipal Code Exterior Noise Standards...... 4-72 Table 25: City of Huntington Beach Municipal Code Interior Noise Standards ...... 4-73 Table 26: City of Seal Beach Municipal Code Exterior Noise Standards...... 4-74 Table 27: City of Seal Beach Municipal Code Interior Noise Standards ...... 4-74 Table 28 Phase 1 Mobilization Construction Noise Levels for BS13 ...... 4-76 Table 29 Phase 2 BS13 Well Drilling and Construction Noise Levels ...... 4-77 Table 30 Phase 3 BS13 Monitoring Well Development Noise Levels ...... 4-78 Table 31 Bolsa Chica Channel Levee Repair Phase 1 Clearing, Brubbing, Excavation Noise Levels ...... 4 -79 Table 32 Phase 2 Bolsa Chica Channel Levee Repair Backfill/Compaction Noise Levels ...... 4 -80 Table 33 Phase 3 Bolsa Chica Channel Levee Repair Final Grading Noise Impacts .. 4-80 Table 34 Monitoring Well BS13 Sampling Activities Noise Levels ...... 4-82 Table 35 Monitoring Well BS13 Gauging Activities Noise Levels ...... 4-82 Table 36 Monitoring Well BS13 Redevelopment Activities Noise Levels ...... 4-83 Table 37 Construction Equipment Vibration Noise Levels ...... 4-86

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List of Figures Page Figure 1 Project Location …………………………………………………………………..2-2

Figure 2 Monitoring Wells BS 13 Well Site ...... 2-5 Figure 3 Monitoring Well BS24 Well Site………………………………………………….2-7 Figure 4 Bolsa Chica Channel Levee Repair……………………………………………2-12

Figure 5 Vegetation Communities…………………………………………………………4-22 Figure 6 Wetland Locations………………………………………………………………..4-28

Appendices

Appendix A: Air Quality and Greenhouse Gas Analysis Report prepared by Vista Environmental October 2017. Appendix B: Cultural Resource Record Searches conducted by the South Coast Information Center, California Native American Heritage Commission Appendix C. Geotechnical Evaluation Groundwater Monitoring Well BS13 prepared by Ninyo & Moore December 30, 2016 Appendix C1 Geotechnical Evaluation Bolsa Chica Channel Levee Repair Appendix D: Noise Impact Analysis Report prepared by Vista Environmental October 2017.

SECTION 1.0 INTRODUCTION 1.1 Purpose of Environmental Review The California Environmental Quality Act (CEQA) requires that all state and local government agencies consider the environmental consequences of projects over which they have discretionary authority before taking action on those projects. This Initial Study has been prepared to disclose and evaluate short-term construction related impacts and long-term operational impacts associated with the implementation of the Sunset Gap Monitoring Wells BS13, BS24 and Bolsa Chica Channel Levee Repair Project. Pursuant to Section 15367 of the State CEQA guidelines, the Orange County Water District (OCWD) is the Lead Agency and has the principal responsibility of approving and implementing the proposed Sunset Gap Monitoring Wells BS13, BS24 and Bolsa Chica Channel Levee Repair Project. As the Lead Agency, OCWD is required to ensure that the project complies with CEQA and that the appropriate level of CEQA documentation is prepared. Through preparation of an Initial Study as the Lead Agency, OCWD will determine whether to prepare an Environmental Impact Report (EIR), Negative Declaration or Mitigated Negative Declaration (MND) for the project. If the Lead Agency finds that there is no evidence that the project, either has proposed or as modified to include the mitigation measures identified in the Initial Study prior to its public circulation, may cause a significant effect on the environment, the Lead Agency can prepare a Negative Declaration or Mitigated Negative Declaration for the project. Section 15382 of CEQA Guidelines defines a “significant effect on the environment” as a substantial, or potentially substantial adverse change in any of the physical conditions within the area affected by the project including land, air water, mineral, flora, fauna, ambient noise, aesthetic environment and objects of cultural significance. Based on the conclusions of the Initial Study, OCWD has determined that the appropriate level of environmental documentation for the Sunset Gap Monitoring Wells BS13, BS24 and Bolsa Chica Channel Levee Repair Project is a Mitigated Negative Declaration.

1.2 Statutory Authority and Requirements

This Initial Study/Mitigated Negative Declaration has been prepared in accordance with the CEQA, Public Resources Code Section 21000 et seq., State CEQA Guidelines, and the OCWD CEQA Environmental Procedures. The environmental analysis for the proposed project is based on OCWD Environmental Checklist Form. The Checklist Form is consistent with Initial Study requirements provided in Section 15063 of the State CEQA Guidelines.

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1.3 Incorporation by Reference The reports and information studies are incorporated by reference into the Sunset Gap Monitoring Wells BS13, BS24 and Bolsa Chica Channel Levee Repair Project. • Naval Weapons Station Seal Beach Management Plan. • Naval Weapons Station Seal Beach Cultural Resources Management Plan. • South Coastal Information Center, California Native American Heritage Commission Cultural Resources Record Search.

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SECTION 2.0 PROJECT DESCRIPTION 2.1 Proposed Project The proposed project involves the construction and operation of 11 new monitoring wells at two locations (BS13 and BS24) and geotechnical repairs to the north side of the Bolsa Chica Flood Control Channel levee on the Naval Weapons Station Seal Beach within the City of Seal Beach. The location of the proposed 11 monitoring well sites and the locations of the proposed Bolsa Chica Channel levee repairs are shown in Figure 1. 2.2 Background Sunset Gap The Orange County Groundwater Basin is boarded 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. Along the coastal boundary of the groundwater basin there are four relatively flat elevated areas, known has mesas. The mesas were formed by ground surface uplift along the Newport Inglewood Fault Zone. The ancient meandering of the Santa Ana River has carved notches through the up-lifted areas and has left behind sand and gravel filled deposits beneath the lowland areas between the mesas, known has gaps. Along the coastal boundary of the Orange County Groundwater Basin four gaps have been formed; the Talbert Gap, Alamitos Gap, Bolsa Gap and the Sunset Gap. Groundwater in the shallow aquifers within the gaps is susceptible to seawater intrusion. As early as In 1941 seawater intrusion was identified at the Sunset Gap at depths of about 170 feet below sea level and about 1,000 feet inland from the Newport Inglewood Fault Zone. Recent studies have shown at the Sunset Gap depths of approximately 100-150 feet and 200-250 feet are susceptible to seawater intrusion and pose a serious water quality threat to the Orange County Groundwater Basin. To help monitor salt water intrusion at the Sunset Gap, OCWD is proposing the construction of eleven new monitoring wells at the Naval Weapons Station Seal Beach. Naval Weapons Station Seal Beach The Naval Weapons Station Seal Beach (Naval Weapons Station) is located in northern Orange County between Huntington Beach and Long Beach, California approximately 25 miles south of the City of Los Angeles. The Naval Weapons Station is boarded by the City of Seal Beach to the west, southwest, and north, the City of Westminster to the northeast, the City of Huntington Beach to the south/southeast, and unincorporated Orange County land to the south. Regional access to the Naval Weapons Station is provided from Interstate 405 from the Seal Beach Boulevard exit. Local access is provided by Westminster Avenue which bisects the Naval Weapons Station from east to west and from Seal Beach Boulevard

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which forms the Naval Weapons Stations western boundary. Pacific Coast Highway is elevated across the southwestern portion of the Naval Weapons Station by a bridge over Anaheim Channel, which accesses the Huntington Harbor Marina. Bolsa Chica Road forms the eastern boundary of the Naval Weapons Station. The mission of the Naval Weapons Station is to provide shore-based infrastructure support to the Navy's ordnance mission and other fleet support activities. The Naval Weapons Station achieves its mission through mastery of ordnance management, maintenance and technical support complemented by highly skilled people, unique resources, and strategic seaward proximity to the Pacific Fleet. With the exception of the Seal Beach National Wildlife Refuge, much of the Naval Weapons Station has been developed into support facilities including magazines for ordnance storage, office buildings, roads, railroad revetments, parking lots, housing, recreation facilities, and open space. Basic infrastructure includes 220 buildings, 49 miles of railroad track, 68 miles of paved road, and 127 ammunition magazines. More than 2,000 acres are used for agriculture, which is managed through a leasing program. The Naval Weapons Station is situated in a highly urbanized area and surrounded by a variety of different land uses. Adjacent to the Naval Weapons Station to the northwest, across from Seal Beach Boulevard in Seal Beach, is Hellman Ranch, which supports a golf course, residential uses, and oil production. Located at the south side of the Weapons Station, in unincorporated Orange County, is Sunset Aquatic Park, a marina with parking facilities, picnic tables, a boat launch, boat slips, a marine repair yard, and a Harbor Patrol office. Directly adjacent, Huntington Harbor is a marine-oriented residential development. Seal Beach Wildlife Refuge The Seal Beach Wildlife Refuge encompasses 965 acres and is located in the southwest corner of the Naval Weapons Station. The Seal Beach National Wildlife Refuge was established in 1972 to provide for the conservation, protection, and propagation of native species of fish and wildlife, including migratory birds which are threatened with extinction. In 1974 a Seal Beach National Wildlife Refuge Management Plan was prepared that identified that “the principal objective of the refuge is to preserve and manage the habitat necessary for the perpetuation of two endangered species–the light-footed Ridgeway’s rail and the California least tern. It is also the goal of refuge to preserve habitat used by migrant waterfowl, shore birds, and other water birds. 2.3 Well Site Locations Monitoring Well Site BS13 At Monitoring Well Site BS13, six new adjacent monitoring wells would be installed. As shown on Figure 2, the six monitoring wells would be located at the southern end of the

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Naval Weapons Station on the north side of Bolsa Chica Flood Control Channel. well sites are located on USGS Seal Beach Quadrangle Map, Township 5 South, Range 11 West and Section 18. The clustered wells would be approximately 10 feet apart. Each well site would require an approximate 20 foot wide by 300 foot long work area to construct each well and to stage construction equipment. The closest sensitive receptor would be the Seal Beach Wildlife Refuge located 20 feet to the north and residential land uses located approximately 400 feet to the south. Monitoring Well Site BS24 At Monitoring Well Site BS24, five new monitoring wells would be installed adjacent to an existing monitoring well. As shown on Figure 3, the five monitoring wells would be located adjacent to an existing monitoring well on the Naval Weapons Station, approximately 20 feet south of Bolsa Avenue and approximately 1,800 feet east of Kitts Highway. The well site is located within the Seal Beach National Wildlife Refuge. The well site is located on USGS Seal Beach Quadrangle Map, Township 5 South, Range 12 West, and Section 13.The clustered wells would be approximately 10 feet apart. Each well site would require an approximate 20 foot wide by 300 foot long work area to construct each well and to stage construction equipment. The closest sensitive receptor would be approximately .5 mile to the south. 2.4 Monitoring Well Construction Activities The proposed construction activities would occur in four construction phases over a 68 day period. Phase 1 involves underground utility clearance, installation of a temporary 12- foot high sound panels, and mobilization of the drilling equipment. Phase 2 involves drilling and construction of the monitoring wells. Phase 3 involves development of the monitoring wells. Phase 4 involves site clean-up, demobilization of the drilling equipment, and vault installation. Drilling and development tasks would occur concurrently at the sites. The proposed project would commence utilizing two direct mud rotary drill rigs (one at each site) and would continue through construction operations for the proposed project. Starting at week eight, there would be concurrent work with two development rigs (one at each site). The total number of days where two drilling rigs would be working has been estimated to be 31 days. The total number of days where two development rigs would be working concurrently has been estimated to be 15 days. Utility clearance, sound panel installation, mobilization, development, site clean-up, and demobilization operations would occur between the hours of 6:00 a.m. and 5:00 p.m. Monday through Friday (week days only). Well drilling and construction operations would occur on a 24-hour continuous basis Sunday through Friday (7 days per week).

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Phase 1: Mobilization Phase 1 involves mobilization to the project area. Mobilization would include clearing the borehole locations of underground utilities followed by sound panel installation and mobilization of the drilling equipment. The equipment mix for mobilization is shown in Table 1. This phase of work involves minimal equipment and would be done mostly by hand.

Table 1 Mobilization Equipment Mix Monitoring Wells Sites BS13 & BS24 Pieces of Hours of Days of Activity Equipment Horsepower Equipment Operation Operation Utility Clearance Airvac Rig 1 8 6 155

Sound Panel Installation Forklift 1 8 4 75 Construction Trips, 1 trip mobilizing 1 trip demobilizing. All tips assumed 50 miles. Phase 2: Monitor Well Drilling and Construction Phase 2 involves the drilling and construction of the monitoring wells. The equipment mix for well drilling and construction is shown in Table 2 and Table 3. The proposed monitoring wells would be drilled by the direct mud rotary drilling method. The monitoring wells would include 2-inch diameter PVC casing installed in an 8-inch diameter borehole to a maximum anticipated depth of 700 feet below ground surface (bgs). Once the well drilling is completed, the well would be constructed. The actual depth of the boreholes and final depth of the wells and well screened intervals would be determined based on lithology observed during drilling and geophysical logging of the boreholes. Table 2 Well Drilling/Construction Equipment Mix Well Site BS13 Pieces of Hours of Days of Activity Equipment Horsepower Equipment Operation Operation Direct Mud Well Drilling & Rotary Drilling 1 24 35 550 Construction Rig Well Drilling & Mud System 1 24 35 75 Construction Well Drilling & Forklift 1 2 35 75 Construction Well Drilling & Light Tower 2 12 35 20 Construction Well Drilling & Cement Truck 1 3 6 350 Construction Well Drilling & Cement Pumper 1 3 6 90 Construction Well Drilling & Gravel/Seal 1 24 11 125 Construction Pump Construction Trips, 1 trip mobilizing 1 trip demobilizing. All tips assumed 50 miles.

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Table 3 Well Drilling/Construction Equipment Mix Well Site BS24 Pieces of Hours of Days of Activity Equipment Horsepower Equipment Operation Operation Direct Mud Well Drilling & Rotary Drilling 1 24 32 550 Construction Rig Well Drilling & Mud System 1 24 32 75 Construction Well Drilling & Forklift 1 2 32 75 Construction Well Drilling & Light Tower 2 12 32 20 Construction Well Drilling & Cement Truck 1 3 5 350 Construction Well Drilling & Cement Pumper 1 3 5 90 Construction Well Drilling & Gravel/Seal 1 24 9 125 Construction Pump Construction Trips, 1 trip mobilizing 1 trip demobilizing. All tips assumed 50 miles.

Phase 3: Monitor Well Development Phase 3 involves development airlifting and pumping of the monitoring wells. The equipment mix for well development is shown in Table 4 and Table 5.

Table 4 Well Development Equipment Mix Well Site BS13 Pieces of Hours of Days of Activity Equipment Horsepower Equipment Operation Operation Well Development Pump Rig 1 10 15 325 Well Development Air Compressor 1 10 13 200 Electrical Well Development 1 10 2 20 Generator Development Trips: 15, All tips assumed 50 miles.

Table 5 Well Development Equipment Mix Well Site BS24 Pieces of Hours of Days of Activity Equipment Horsepower Equipment Operation Operation Well Development Pump Rig 1 10 15 325 Well Development Air Compressor 1 10 13 200 Electrical Well Development 1 10 2 20 Generator Development Trips: 15, All tips assumed 50 miles.

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Phase 4: Site Cleanup and Traffic-Rated Vault Installation Phase 4 involves site cleanup and installation of the below ground traffic-rated well vault. This phase of work involves minimal equipment and would be done by hand. There is no list of equipment for this phase. 2.5 Monitoring Well Long Term Operation and Maintenance Activities In general, the operation of the monitoring wells would be passive as there would be no permanent equipment installed in the casings or vaults. OCWD staff would collect groundwater samples semi-annually and gauge water levels on a monthly basis. Groundwater sampling and water level gauging would be conducted separately. During groundwater sampling and maintenance activities, the well casings would be purged via airlifting or by submersible pump. Sample discharge water would be containerized in a water trailer and disposed off-site. In total, the wells would be visited by OCWD staff 14 times per year. One truck and two workers would access the wells for gauging and two trucks and two workers would access the wells for groundwater sampling, assuming a round trip length of 24 miles per trip. The life expectancy of monitoring well is approximately 20 years. Every three to five years OCWD would conduct maintenance activities to redevelop the wells. The mix of construction equipment involved with well sampling, gauging, maintenance/redevelopment is shown in Table 6 and Table 7. Typical monitoring well redevelopment would be completed in one day per well. All sampling, gauging, and redevelopment activities would occur during the day.

Table 6 Monitoring Well Sampling/Gauging/Redevelopment Equipment Mix Well Site BS13 Pieces of Days of Equipment Hours per Day Horsepower Equipment Operation Groundwater Sampling Equipment Utility Truck 2 2 1 300 Air Compressor 1 6 1 200 Generator 1 1 1 20 Water Level Gauging Equipment Utility Truck 1 1 1 300 Redevelopment Equipment Pump Rig 1 10 6 325 Utility Truck 1 2 6 300 Air Compressor 1 6 6 200 Generator 1 6 1 20

Sampling & Redevelopment Trips 6, All trips assumed 40 miles.

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Table 7 Monitoring Well Sampling/Gauging/Redevelopment Equipment Mix Well Site BS24 Pieces of Days of Equipment Hours per Day Horsepower Equipment Operation Groundwater Sampling Equipment Utility Truck 2 2 1 300 Air Compressor 1 6 1 200 Generator 1 1 1 20 Water Level Gauging Equipment Utility Truck 1 1 1 300 Redevelopment Equipment Pump Rig 1 10 6 325 Utility Truck 1 2 6 300 Air Compressor 1 6 6 200 Generator 1 6 1 20

Sampling & Redevelopment Trips 6, All trips assumed 40 miles. 2.6 Bolsa Chica Channel Control Levee Repairs In 2015, during drilling activities for monitoring well BS13X along the Bolsa Chica Flood Control Levee, the ground surface around the well subsided approximately one foot. In addition, scattered ground cracking was observed in a radial pattern approximately 30 to 35 feet around the well. The subsidence and cracking extended into the adjacent Naval Weapons Station access road and created a depression around the well approximately one to two feet deep. Once subsidence occurred, borehole drilling was terminated and the borehole was abandoned by placing 39 cubic yards of cement from ground surface to approximately 360 feet below ground surface. The 22-inch diameter steel conductor casing remains in place to a depth of approximately 67 feet. The proposed repair activities for the access road settlement around the abandoned well would consists of over-excavation and re-compaction of existing fill soils with a geogrid mat and placement and compaction of aggregate base along the access road. The area of work is approximately 60 feet by 50 feet. The location where the proposed levee repair activities would occur is shown in Figure 4. Prior to excavating or other earthwork, the proposed area of repair would be cleared of the existing fence, and stripped of aggregate base or gravel, debris, vegetation, and loose, wet, or otherwise unstable soils. In addition, the existing 22-inch diameter conductor casing and grout for the abandoned well would be removed to a depth of approximately 5 feet below the existing ground surface. Materials generated from the clearing operations would be removed from the project site and disposed at a legal

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Land fill site using a work truck. Provided that the existing gravel and aggregate base can be selectively graded so as to not mix with on-site soils, these materials could be reused near the finish grade elevation. The re-use of the existing aggregate base or gravel would be evaluated at the time of construction. The existing fill material and underlying loose natural soils would be removed and re- compacted so as to provide a re-compacted fill mat with a geogrid material. The re- compaction work would generally consist of 1) removing the existing fill material and/or loose natural soils down to a depth of approximately 5 feet below the existing ground surface near the abandoned well, 2) compacting the exposed natural subgrade soils, and 3) re-compaction of the soil to a relative compaction of 90 percent or more as evaluated by the latest edition of ASTM International (ASTM) D 1557. The depth of remedial excavations should not extend below groundwater. The actual depth and limits of removal would be evaluated by the geotechnical consultant during construction. Wet and soft conditions could be encountered at the base of the over-excavation. Stabilization of soft ground conditions could include additional excavation and placement of 1 to 2 feet of crushed aggregate base material or crushed rock wrapped in filter fabric at the bottom of the over-excavation. Fill would be compacted in horizontal lifts to a relative compaction of 90 percent or more as evaluated by the latest edition of ASTM D 1557. Aggregate base beneath access roads should be compacted to a relative compaction of 95 percent or more. 2.7 Bolsa Chica Channel Levee Repair Construction Activities As shown in Table 8, the Bolsa Chica levee repairs would be implemented in three construction phases over a two week period. Table 8 Bolsa Chica Levee Repair Construction Mix Equipment Equipment Hours Total Hours HP Activity Description Quantity Per Day Days (Total) Rating Phase I Clearing and Grubbing Backhoe 1 8 1 8 100 Excavation Backhoe 1 8 2 16 100 Excavation Work Truck 1 8 2 16 300 Phase II Backfill and compaction Backhoe 1 8 3 24 100 Backfill and compaction Compactor 1 8 3 24 250 Backfill and compaction Water Buffalo 1 8 3 24 5 Phase III Final grading Backhoe 1 8 1 8 100 Final grading Work Truck 1 8 1 8 300

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2.8 Permits and Approvals The Initial Study/Mitigated Negative Declaration prepared for the Sunset Gap Monitoring Wells BS13, BS24 and Bolsa Chica Channel Levee Repair Project would be used as the supporting CEQA environmental documentation for the following approvals and permits. • Orange County Water District Project Approval • Naval Weapons Station Seal Beach Project Approval of License Agreement to allow construction and operation of six monitoring wells at the BS13 Well Site and five monitoring wells at the BS24 Well Site. • County of Orange Encroachment Permit to allow construction and operation of six monitoring wells at the Monitoring Well BS13 Well Site on the Bolsa Chica Channel levee, and repairs to Bolsa Chica Channel Levee. • Special Use Permit from Seal Beach National Wildlife Refuge to allow construction and monitoring at the BS24 Well Site.

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SECTION 3.0 ENVIRONMENTAL CHECKLIST EVALUATIONS The following is the OCWD Environmental Checklist Form that was prepared for the BS13, BS24 and Bolsa Chica Channel Levee Repair Project. The Environmental Checklist Form is consistent with Environmental Checklist form provided in Appendix G of the CEQA Guidelines. I. Project Title: Monitoring Wells BS13, BS24 Bolsa Chica Channel Levee Repair Project

II. Lead Agency Name and Address: Orange County Water District 18700 Ward Street Fountain Valley, CA 92708 III. Project Contact: Daniel Bott

IV. Location: Naval Weapons Station Seal Beach

V. Environmental Determination On the basis of this initial evaluation, I find that:

a) The proposed project COULD NOT have a significant effect on the environment and a NEGATIVE DECLARATION will be prepared. b)  Although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because revisions to the project have been made by or agreed to by the applicant. A MITIGATED NEGATIVE DECLARATION will be prepared.

c) The proposed project MAY have a significant effect on the environment and an ENVIRONMENTAL IMPACT REPORT is required.

d) Although the proposed project could have a significant effect on the environment, because all potentially significant effects (a) have been analyzed adequately in an earlier EIR (EIR No. - ) pursuant to applicable standards and (b) have been avoided or mitigated pursuant to that earlier EIR, including revisions or mitigation measures that are imposed upon the project, nothing further is required.

e) Pursuant to Section 15164 of the CEQA Guidelines, an EIR (EIR No. - ) has been prepared earlier and only minor technical changes or additions are necessary to make the previous EIR adequate and these changes do not raise important new issues about the significant effects on the environment. An ADDENDUM to the EIR shall be prepared.

f) Pursuant to Section 15162 of the CEQA Guidelines, an EIR (EIR No. - ) has been prepared earlier; however, subsequent proposed changes in the project and/or new information of substantial importance will cause one or more significant effects no previously discussed. A SUBSEQUENT EIR shall be prepared.

______Signature Date

______Printed Name

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Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact I. Aesthetics – Would the project:

a) Have a substantial adverse effect on a scenic vista? 

b) Damage scenic resources, including  but not limited to, trees, rock outpourings and historic buildings within a state highway? c) Substantially degrade the existing  visual character or quality of the site and its surroundings? d) Create a new source of substantial  light or glare which would adversely affect day or nighttime views in the area?

II. AGRICULTURAL AND FOREST RESOURCES: In determining whether impacts to agricultural resources are significant environmental effects, lead agencies may refer to the California Agricultural Land Evaluation and Site Assessment Model prepared by the California Department of Conservation as an optional model to use in assessing impacts on agricultural farmland. In determining whether impacts to forest resources, including timberland, are significant environmental effects, lead agencies may refer to information compiled by the California Department of Forestry and Fire Protection regarding the state’s inventory of forest land, including the Forest and Range Assessment Project and the Forest Legacy Assessment project; and forest carbon measurement methodology provided in Forest Protocols adopted by the California Air Resources Board. Would the project:

a) Convert Prime Farmland, Unique  Farmland or Farmland of Statewide Importance (Farmland) to non- agricultural use? (The Farmland Mapping and Monitoring Program in the California Resources Agency, Department of Conservation, maintains detailed maps of these and other categories of farmland.)

b) Conflict with existing zoning for  agricultural use or a Williamson Contract? c) Conflict with existing zoning for, or  cause rezoning of, forest land (as defined in Public Resources Code section 12220(g), timberland (as defined by Public Resources Code section 4526), or timberland zoned

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact Timberland Production (as defined by Government Code section 51104(g)) d) Result in the loss of forest land or conversion of forest land to non-  forest use?

e) Involve other changes in the existing  environment which, due to their location or nature, could individually or cumulatively result in loss of Farmland, to non-agricultural use or conversion of forest land to non- forest use? III. Air Quality – Where available, the significance criteria established by the applicable air quality management or pollution control district may be relied upon to make the following determinations. Would the project:

a) Conflict with or obstruct  implementation of applicable Air Quality Attainment Plan?

b) Violate any stationary source air  quality standard or contribute to an existing or projected air quality violation?

c) Result in a cumulatively considerable  net increase of any criteria pollutant for which the project region is non- attainment under an applicable federal or state ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors)?

d) Expose sensitive receptors to  substantial pollutant concentrations?

e) Create objectionable odors affecting  a substantial number of people? IV. Biological Resources – Would the project:

a) Have a substantial adverse impact,  either directly or through habitat modifications, on any species identified as a candidate, sensitive or special status species in local or regional plans, policies or regulations or by the California Department of

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact Fish and Game or U.S. Fish and Wildlife Services?

b) Have a substantial adverse impact  on any riparian habitat or natural community identified in local or regional plans, policies, and regulations or by the California Department of fish and Game or U.S. Fish and Wildlife Service?

c) Adversely impact federally protected  wetlands (including, but not limited to, marsh, vernal pool, coastal, etc.) either individually or in combination with the known or probable impacts of other activities through direct removal, filling hydrological interruption, or other means?

d) Interfere substantially with the  movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites?

e) Conflict with any local policies or  ordinances protecting biological resources, such as tree preservation policy or ordinance? f) Conflict with the provisions of an  adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? V. Cultural Resources – Would the project:

a) Cause a substantial adverse change  in the significance of a historical resource as defined in Section 15064.5?

b) Cause a substantial adverse change  in the significance of a unique archaeological resource pursuant to define Section 15064.5?

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact

c) Directly or indirectly disturb or  destroy a unique paleontological resource or site? d) Disturb any human remains, including those interred outside of  formal cemeteries? VI. Geology and Soils – Would the project: a) Expose people or structures to potential substantial adverse effects, including the risk of loss, injury, or death involving:

1. Rupture of a known  earthquake fault, as delineated on the most recent on the most recent Alquist- Priolo Earthquake Fault Zoning map issued by the State Geologist for the area or based on other substantial evidence of a known fault?

Strong seismic ground  2. shaking?

3. Seismic-related ground  failure, including liquefaction?

4. Landslides? 

b) Would the project result in  substantial soil erosion or the loss of topsoil?

c) Be located on a geologic unit or soil  that is unstable or that would become unstable as a result of the project and potentially result in on-or off-site landslide, lateral spreading, subsidence, liquefaction or collapse?

d) Be located on expansive soil, as  defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial risks to life or property?

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact

e) Have soils incapable of adequately  supporting the use of septic tanks or alternative waste disposal systems where sewers are not available for the disposal of wastewater? VII. GREENHOUSE GAS EMISSIONS — Would the project?

a) Generate greenhouse gas  emissions, either directly or indirectly, that may have a significant impact on the environment?

b) Conflict with an applicable plan,  policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases? VIII. HAZARDOUS AND HAZARDOUS MATERIALS – Would the project:

a) Create a significant hazard to the  public or the environment through the routine transport, use or disposal of hazardous materials?

b) Create a significant hazard to the  public or environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment?

c) Emit hazardous emissions or handle  hazardous or acutely hazardous materials, substance or waste within one-quarter mile of an existing or proposed school?

d) Be located on a site which is located  on a list of hazardous materials sites compiled pursuant to Government Code Section 659662.5 and, as a result, would it create a significant hazard to the public or the environment?

e) For a project located within an  airport land use plan or where such a plan has not been adopted, within two miles where of a public airport

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact or public use airport, would the project result in a safety hazard for people residing or working in the project area?

f) For a project within the vicinity of a  private airstrip, would the project result in a safety hazard for people residing or working in the project area?

g) Impair implementation of or  physically interfere with an adopted emergency response plan or emergency evacuation plan?

h) Expose people or structures to a  significant risk of loss, injury, or death involving wildland fires, including where wildlands are adjacent to urbanized areas or where residences are intermixed with wildlands? VIX. HYDROLOGY AND WATER QUALITY – Would the project:

a) Violate any water quality standards  or waste discharge requirements?

b) Substantially deplete groundwater  supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level (e.g., the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted)?

c) Substantially alter the existing  drainage pattern of the site or area, including through the alteration of the course of stream or river, in a manner which would result in substantial erosion or siltation on- or off-site?

d) Substantially alter the existing  drainage pattern of the site or area,

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact 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 would result in flooding on- or off-site?

e) Create or contribute runoff water which would exceed the capacity of  existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff? f) Otherwise substantially degrade

water quality? 

g) Place housing within a 100-year  flood hazard area as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map?

h) Place within a 100-year flood  hazard area structures which would impede or redirect flood flows?

i) 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?

(j) Inundation by seiche, tsunami, or  mudflow? X. LAND USE AND PLANNING – Would the project: a) Physically divide an established

community? 

b) Conflict with any applicable land  use plan, policy, or regulation of an agency with jurisdiction over the project (including, but not limited to the general plan, specific plan, local coastal program, or zoning ordinance) adopted for the purpose of avoiding or mitigating an environmental effect?

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact

c) Conflict with any applicable habitat  conservation plan or natural community conservation plan? XI. MINERAL RESOURCES – Would the project: a) Result in the loss of availability of a locally-important mineral resource  recovery site delineated on a local

general plan, specific plan, or other land use plan?

b) Result in the loss of availability of a regionally important mineral  resource.

XII. NOISE – Would the project result in: a) 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?

b) A substantial permanent increase  in ambient noise levels in the project vicinity above levels existing without the project?

c) A substantial temporary or periodic  increase in ambient noise levels in the project vicinity above levels existing without project?

d) For a project located within an  airport land use plan or where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels?

e) For a project within the vicinity of a  private airstrip, would the project expose people residing or working in the project area to excessive noise levels?

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact f) Exposure of persons to or  generation of excessive groundborne vibration or groundborne noise levels? XIII. POPULATION AND HOUSING – Would the project:

a) Induce substantial population  growth in an area, either directly (for example, by proposing new homes and business) or indirectly (for example, through extension of roads or other infrastructure)?

b) Displace substantial numbers of  existing housing, necessitating the construction of replacement housing elsewhere?

c) Displace substantial numbers of  people, necessitating the construction of replacement housing elsewhere? XIV. PUBLIC SERVICES

a) Would the project result in  substantial adverse physical impacts associated with the provision of new or physically altered governmental facilities, need for new or physically altered governmental facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service rations, response times or other performance objectives for any of the public service: Fire protection? Police protection? Schools? Parks? Other public facilities? XV. RECREATION

a) Would the project increase the use  of existing neighborhood and regional parks or other recreational

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact facilities such that substantial physical deterioration of the facility would occur or be accelerated?

b) Does the project include  recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment? XVI. TRANSPORTATION/TRAFFIC Would the project: Conflict with an applicable plan, a) ordinance or policy establishing  measures of effectiveness for the performance of the circulation system, taking into account all modes of transportation including mass transit and non-motorized travel and relevant components of the circulation system, including but not limited to intersections, streets, highways and freeways, pedestrian and bicycle paths, and mass transit?

b) Conflict with an applicable congestion management program,  including but limited to level of service standards and travel demand measures, or other standards established by the county congestion management agency for designated roads or highways?

c) Result in a change in air traffic patterns, including either an  increase in traffic levels or a change in location that results in substantial safety risks?

d) Substantially increase hazards to a design feature (e.g. sharp curves  or dangerous intersections) or incompatible uses (e.g. farm equipment)?

e) Result in inadequate emergency  access?

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact

f) Conflict with adopted policies,  plans, or programs regarding public

transit, bicycle, or pedestrian facilities, or otherwise decrease the

performance or safety of such

facilities?

XVII TRIBAL RESOURCES

a) Would the project cause a substantial adverse change in  the significance of a tribal

cultural resource as either a site, feature, place, cultural

landscape, sacred place, or

object with value to a California Native American Tribes and

that is listed or eligible for

listing in the California Register or Historical resource, or in a

local register of historical

resources.

b) Would the project cause a

substantial adverse change in the significance of a tibal  cultural resource as either a site, feature, place, cultural landscape, sacred place, or object with value to a California Native American Tribe and that is a resource determined by the lead agency in its discretion and supported by substantial evidence to be significant and which the lead agency considers the significance of the resource to a California Native American Tribe.

XVII. UTILITIES AND SERVICE SYSTEMS – Would the project:

a) Exceed wastewater treatment requirements of the applicable  Regional Water Quality Control Board?

b) Require or result in the construction of new water or 

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact wastewater treatment facilities or expansion of existing facilities, the construction of which could cause significant environmental effects?

c) Require or result in the construction of new storm water  drainage facilities or expansion of existing facilities, the construction of which could cause significant environmental effects?

d) Are sufficient water supplies available to serve the project from  existing entitlements and resources or are new or expanded entitlements needed?

e) Result in the determination by the wastewater treatment provider  which serves or may serve the project that it has adequate capacity to serve the project’s projected demand in addition to the provider’s existing commitments?

f) Is the project served by a landfill with sufficient permitted capacity to  accommodate the project’s sold waste disposal needs?

g) Comply with federal, state and local statutes and regulations  related to solid waste?

XVIII. MANDATORY FINDINGS OF SIGNIFICANCE –

a) Does the project have the potential to degrade the quality of the  environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self- sustaining levels, threaten to eliminate a plant or animal community, reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California

Less Than Significant Potentially with Less Than V. Issues & Supporting Information Significant Mitigation Significant No Sources Impact Incorporated Impact Impact history or prehistory?

b) Does the project have impacts that are individually limited but  cumulatively considerable? (“Cumulatively considerable” means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects, effects of other current projects and the effects of probable future projects).

c) Does the project have environmental effects which will  cause substantial adverse effects on human beings, either directly or indirectly?

Note: Authority cited: Sections 21083, 21083.05, Public Resources Code. Reference: Section 65088.

SECTION 4.0 ENVIRONMENTAL ANALYSIS The following environmental analysis responds to the environmental issues listed on the OCWD CEQA Checklist Form. The analysis identifies the level of anticipated impact and where needed includes the incorporation of mitigation measures to reduce potentially significant impacts to the environment to a less than significant level. 4.1 Aesthetics

A. Would the project have a substantial adverse effect on a scenic vista? Monitoring Well Sites BS13, BS24 Less than Significant Impact: Monitoring Well Site BS24 would be constructed on a location within the Naval Weapons Station where there are no public scenic vistas. Therefore, there would not be any adverse impacts to existing scenic vistas. Monitoring Well Site BS13 would be located on the service road along the Bolsa Chica Channel. There is presently a public trail along the southern side of the channel that provides open water views and limited views of the Seal Beach National Wildlife Refuge. The proposed monitoring wells would be housed in underground vaults and would not permanently displace or adversely modify existing scenic vistas. During construction of the monitoring wells existing views of the wildlife refuge would temporarily interrupted with construction activities and a sound attenuation wall. The temporary view impacts would occur along a small segment of the channel and would not affect the overall views of the of the wildlife refuge. The view impacts would be no longer than a few months and once construction operations are completed the scenic vistas into the area would be returned to their pre-project condition. Short-term construction related impacts would be less than significant. No mitigation measures are required. Bolsa Chica Channel Levee Repair Less than Significant Impact: The proposed repairs to the Bolsa Chica Channel Levee would not permanently displace or adversely modify existing scenic vistas. During the repair of the levee existing views of the area would be temporary interrupted with construction equipment. However, the impacts would be no longer than a couple of weeks and once construction operations are completed the scenic vistas into the area would be returned to their project condition. Therefore, short-term construction related impacts would be less than significant. No mitigation measures are required.

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B. Would the project damage scenic resources, including but limited to, trees, rock outpourings, and historic buildings within a State Highway? Less than Significant Impact: According to the California Department of Transportation Scenic Highways Program there are not any State Scenic Highways in the immediate vicinity of the project area. The closest State Scenic Highway would be State Highway 1 which is designated as an Eligible Scenic Highway, located approximately ½ mile from the project area. Because of the distance to State Highway 1 and the presence of intervening structures, the construction activities for the monitoring wells and Bolsa Chica Channel Levee repair would not be within the view shed of State Highway 1. Therefore, implementation of the proposed project would not have any impact on scenic resources along a State Scenic Highway. No mitigation measures are required. C. Would the project substantially degrade the existing visual character or quality of the site and its surrounding? No Impact: The monitoring wells would be housed in underground vaults and would not degrade or contribute to the degradation of the existing aesthetic character of the project area. During construction operations for the monitoring wells and the Bolsa Chica Channel Levee repair the existing open space visual character of the project area would be temporarily replaced with construction equipment and construction activity. The impacts would be no longer than a few months and once construction operations are completed the project area would be returned to its pre-project condition. Short-term construction related impacts would be less than significant. No Mitigation Measures are required. D. Would the project create a new source of substantial light or glare which would adversely affect day or nighttime views in the area. Monitoring Well Sites BS13, BS24 Less than Significant Impact with Mitigation: All of the proposed monitoring wells would be housed in an underground vault. Implementation of the proposed project would not permanently introduce new sources of light and glare into the project area. Therefore, no long-term light and glare impacts would occur. Construction operations for the proposed monitoring wells would require 24 hour drilling. To ensure safe working conditions and proper operation of equipment during the nighttime, floodlights would be used. The BS13 Well Site is within the nearby vicinity of sensitive receptors. If the sensitive receptors are within the line of sight of the flood lights during nighttime construction activities some spill over

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lighting impacts could occur. To minimize the potential for spill over light and glare impacts, the floodlights would be shielded and directed to the construction work site. With the implementation of Mitigation Measures A-1 and A-2 potential light and glare impacts would be less than significant. Bolsa Chica Channel Levee Repair The construction activities for the Bolsa Chica Levee would occur during the day. There would not be any long term or short-term construction related light and glare impacts. No Mitigation Measures are required. Mitigation Measures A-1: Construction lighting fixtures at the BS13 and BS24 Well Sites shall be shielded by providing side flap on lights, or providing a temporary drape/wall so that illumination is confined to within the well site boundaries. Onsite construction lighting shall be arranged so that direct rays shall not shine in or produce glares to nearby residential uses. A-2: If the onsite construction lighting creates a lighting or glare problem for residential properties, OCWD shall 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.

4.2 Agricultural Resources/Forest Resources

A. Would the project convert Prime Farmland, Unique Farmland or Farmland of Statewide Importance to non-agriculture uses? No Impact: There is approximately 2,000 acres of agriculture lands on the Naval Weapons Station. The agriculture lands are located on the north side and south side of Westminster Avenue. According to the State of California Farmland Mapping and Monitoring Program, there are some agriculture lands on the north side of Westminster Avenue that are classified as Farmland of Statewide Importance. The agriculture lands south of Westminster Avenue are classified as Grazing Lands. The proposed monitoring well sites and the proposed construction activities to repair the Bolsa Chica Channel Levee would not occur on any agriculture lands within the Naval Weapons Station. Therefore, the proposed project would not convert any farmland to non-agriculture land uses. No mitigation measures are required.

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B. Would the project be in conflict with existing zoning for agriculture use or a Williamson Contract? No Impact: As indicated above the construction and operation of the proposed monitoring wells and proposed repairs to the Bolsa Chica Levee would not result in impacts to existing agriculture lands on the Naval Weapons Station. Therefore, the proposed project would not be in conflict with any existing agriculture zoning or existing agriculture leases or contracts on the property. No mitigation measures are required. C. Would the project be in conflict with existing zoning for, or cause rezoning of forest land or timberland. No Impact. The City of Seal Beach General Plan designates the Naval Weapons Station for military land uses including where the proposed monitoring wells would be located and where the proposed repairs to the Bolsa Chica Channel Levee would occur. Implementation of the proposed project would not cause change of zone of existing forest or timberlands. No mitigation measures are required. D. Would the project result in the loss of forest land or conversion of forest land to non-forest use? No Impact: The location of the proposed monitoring well and the location where the proposed repairs to the Bolsa Chica Channel Levee would occur are not located on forest lands. Therefore, the implementation of the proposed project would not convert forest land to non-forest land. No mitigation measures are required. E. Would the project involve other changes in the existing environment which, due to their location or nature, could result in conversion of Farmland to non-agriculture use or conversion of forest land to non-forest use? No Impact: The location of the proposed monitoring well and the location where the proposed repairs to the Bolsa Chica Channel Levee would occur are not located on forest lands. Therefore, the implementation of the proposed project would not directly or indirectly result in the loss of any forest land or result in the conversion forest lands to non-forest lands. Additionally, the implementation of the proposed project would not convert existing farmlands within the project area to non-agriculture land uses. No mitigation measures are required.

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4.3 Air Quality The following analysis is based on an Air Quality and Greenhouse Gas Analysis Report prepared by Vista Environmental in October 2017. The Air Quality and Greenhouse Gas Analysis Report is presented in its entirety in Appendix A. Setting The project area is located in the City of Seal Beach in Orange County 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 38 Source Receptor Area. Most of the Source Receptor Areas have Basin operating monitoring stations. The Source Receptor Areas are intended to provide a general representation of the local meteorological, terrain, and air quality conditions within the particular geographical area. The project area is within Source Receptor Area 18, which covers the Orange County coast from Newport Beach to the Los Angeles County line. The most recent three year period of data available, shows that during this period the project area has exceeded Ozone, PM10 and Pm2.5 standards. 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.

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State Regulation A State Implementation Plan (SIP) is a document prepared by each state describing air quality conditions and measures that would 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 SCAQMD develops rules and regulations, establishes permitting requirements for stationary sources, inspects emission sources, and enforces such measures through educational programs or fines, when necessary. SCAQMD is directly responsible for reducing emissions from stationary, mobile, and indirect sources. It has responded to this requirement by preparing a sequence of AQMPs. The Final 2016 Air Quality Management Plan (2016 AQMP) was adopted by the SCAQMD Board on March 3, 2016 and was adopted by CARB on March 23, 2017 for inclusion into the California State Implementation Plan (SIP). The 2016 AQMP was prepared in order to meet the following standards: • 8-hour Ozone (75 ppb) by 2032 • Annual PM2.5 (12 μg/m3) by 2021-2025 • 8-hour Ozone (80 ppb) by 2024 (updated from the 2007 and 2012 AQMPs) • 1-hour Ozone (120 ppb) by 2023 (updated from the 2012 AQMP) • 24-hour PM2.5 (35 μg/m3) by 2019 (updated from the 2012 AQMP) In addition to meeting the above standards, the 2016 AQMP also includes revisions to the attainment demonstrations for the 1997 8-hour ozone NAAQS and the 1979 1-hour ozone NAAQS. The prior 2012 AQMP was prepared in order to demonstrate attainment with the 24-hour PM2.5 standard by 2014 through adoption of all feasible measures. The prior 2007 AQMP demonstrated attainment with the 1997 8-hour ozone (80 ppb) standard by 2023, through implementation of future improvements in control techniques and technologies. These “black box” emissions reductions represent 65 percent of the remaining NOx emission reductions by 2023 in order to show attainment with the 1997 8-

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hour ozone NAAQS. Given the magnitude of these needed emissions reductions, additional NOx control measures have been provided in the 2012 AQMP even though the primary purpose was to show compliance with 24-hour PM2.5 emissions standards. The 2016 AQMP provides a new approach that focuses on available, proven and cost effective alternatives to traditional strategies, while seeking to achieve multiple goals in partnership with other entities to promote reductions in GHG emissions and TAC emissions as well as efficiencies in energy use, transportation, and goods movement. The 2016 AQMP recognizes the critical importance of working with other agencies to develop funding and other incentives that encourage the accelerated transition of vehicles, buildings and industrial facilities to cleaner technologies in a manner that benefits not only air quality, but also local businesses and the regional economy. Although SCAQMD is responsible for regional air quality planning efforts, it does not have the authority to directly regulate air quality issues associated with plans and new development projects throughout the Air Basin. Instead, this is controlled through local jurisdictions in accordance to the California Environmental Quality Act (CEQA). In order to assist local jurisdictions with air quality compliance issues the CEQA Air Quality Handbook (SCAQMD CEQA Handbook), prepared by SCAQMD, 1993, with the most current updates found at http://www.aqmd.gov/ceqa/hdbk.html, was developed in accordance with the projections and programs detailed in the AQMPs. The purpose of the SCAQMD CEQA Handbook is to assist Lead Agencies, as well as consultants, project proponents, and other interested parties in evaluating a proposed project’s potential air quality impacts. Specifically, the SCAQMD CEQA Handbook explains the procedures that SCAQMD recommends be followed for the environmental review process required by CEQA. The SCAQMD CEQA Handbook provides direction on how to evaluate potential air quality impacts, how to determine whether these impacts are significant, and how to mitigate these impacts. The SCAQMD intends that by providing this guidance, the air quality impacts of plans and development proposals will be analyzed accurately and consistently throughout the Air Basin, and adverse impacts will be minimized. A. The project be in conflict with or obstruct implementation of the applicable air quality plan or congestion management plan? Less than Significant with Mitigation: The California Environmental Quality Act (CEQA) requires a discussion of any inconsistencies between a proposed project and applicable local government General Plans and regional plans (CEQA

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Guidelines Section 15125). The regional plan that applies to the proposed project includes the SCAQMD AQMP. Therefore, this section discusses any potential inconsistencies of the proposed project with the AQMP. The purpose of this discussion is to set forth the issues regarding consistency with the assumptions and objectives of the AQMP and discuss whether the proposed project would interfere with the region’s ability to comply with Federal and State air quality standards. If the decision-makers determine that the proposed project is inconsistent, the lead agency may consider project modifications or inclusion of mitigation to eliminate the inconsistency. The SCAQMD CEQA Handbook states that "New or amended GP Elements (including land use zoning and density amendments), Specific Plans, and significant projects must be analyzed for consistency with the AQMP." Strict consistency with all aspects of the plan is usually not required. A proposed project should be considered to be consistent with the AQMP if it furthers one or more policies and does not obstruct other policies. The SCAQMD CEQA Handbook identifies two key indicators of consistency: (1) Whether the project will 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. (2) Whether the project will exceed the assumptions in the AQMP or increments based on the year of project buildout and phase. Both of these criteria are evaluated in the following sections. Criterion 1 - Increase in the Frequency or Severity of Violations? Based on the air quality modeling analysis contained in this report, short-term regional construction air emissions may result in significant NOx impacts based on SCAQMD regional thresholds of significance. Mitigation Measure 1 has been provided to reduce the short-term regional construction air emissions to less than significant levels in the event of concurrent well drilling and construction activities at BS13 and BS24 well sites. Mitigation Measure AIR-1 requires that if concurrent well drilling and construction occurs at both Monitoring Well Sites BS13 and BS24 all diesel equipment with a horsepower of 75 or more utilized during the monitor wells drilling and construction phase of construction activities shall meet the Tier 4 emission standards. The analysis also found that short-term local construction air emissions would not exceed the local thresholds of significance as shown in Table 10.The ongoing

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operation of the proposed project would generate air pollutant emissions that are inconsequential on a regional basis and would not result in significant impacts based on SCAQMD thresholds of significance shown in Table 9. The analysis for long-term local air quality impacts showed that local pollutant concentrations would not be projected to exceed the air quality standards. Therefore, no long- term impact would occur and no mitigation would be required. Therefore based on the information provided above, with implementation of Mitigation Measure AIR-1, the proposed project would be consistent with the first criterion. Criterion 2 - Exceed Assumptions in the AQMP? Consistency with the AQMP assumptions is determined by performing an analysis of the proposed project with the assumptions in the AQMP. The emphasis of this criterion is to insure that the analyses conducted for the proposed project are based on the same forecasts as the AQMP. The AQMP is developed through use of the planning forecasts provided in the RTP/SCS and FTIP. The RTP/SCS is a major planning document for the regional transportation and land use network within Southern California. The RTP/SCS is a long-range plan that is required by federal and state requirements placed on SCAG and is updated every four years. The FTIP provides long-range planning for future transportation improvement projects that are constructed with state and/or federal funds within Southern California. Local governments are required to use these plans as the basis of their plans for the purpose of consistency with applicable regional plans under CEQA. For this project, the City of Seal Beach General Plan defines the assumptions that are represented in the AQMP for the proposed BS13 and BS24 well sites and levee repair site. The proposed well sites and levee repair site are located within the Naval Weapons Station, which is designated Military in the General Plan and zoned Military (ML). Since well drilling and levee repairs are allowed use in all land use designations the proposed project would be consistent with the current land use designations and would not require a General Plan Amendment or zone change. As such, the proposed project would not be anticipated to exceed the AQMP assumptions for the project sites and would be consistent with the AQMP for the second criterion. Based on the above, the proposed project would not result in an inconsistency with the SCAQMD AQMP. Therefore, a less than significant impact would occur in relation to implementation of the AQMP.

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Mitigation Measures AIR-1: If concurrent well drilling and construction activities occur at both Monitoring Wells BS13 and BS24, the project applicant shall require that all diesel equipment with a horsepower of 75 or more utilized during the monitor wells drilling and construction phase of construction activities shall meet the Tier 4 emission standards. B. Would the project violate any air quality standard or contribute substantially to an existing or projected air quality violation? Construction Emissions Less than Significant Impact with Mitigation: The proposed project would consist of construction of 11 new monitoring wells and repairs to the Bolsa Chica Flood Control Levee. The construction emissions have been analyzed for both regional and local air quality impacts as well as potential toxic air impacts. Construction-Related Regional Impacts The CalEEMod model was utilized to calculate the construction-related regional emissions from one monitoring well associated with the proposed project. Each monitoring well would be constructed in four phases. Phase 1 involves underground utility clearance, installation of temporary sound panels, and mobilization of the drilling equipment. Phase 2 involves drilling and construction of the monitoring wells. Phase 3 involves development of the monitoring wells. Phase 4 involves site clean-up, demobilization of the drilling equipment, and vault installation, activities which would involve minimal equipment and would be done primarily by hand. Therefore, emissions from Phase 4 have not been quantified. Drilling and development tasks would occur concurrently at the well sites. The proposed project would be constructed utilizing two direct mud rotary drill rigs, with one operating at each of the sites throughout construction activities. It is estimated that the total number of days where two drilling rigs would be working has been estimated to be 31 days. The total number of days where two development rigs would be working concurrently has been estimated to be 15 days. The proposed Bolsa Chica Flood Control Levee repair activities were also analyzed in the CalEEMod model. The levee repair activities would be conducted in three phases. Phase 1 involves the clearing, grubbing, and excavation of the repair site. Phase 2 involves backfill of the repair site and compaction of fill materials. Phase 3 involves the final grading of the repair site. Levee repair

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activities were anticipated to occur before construction of the new monitoring wells. The worst-case summer or winter daily construction-related criteria pollutant emissions from the proposed project for each phase of well construction activities as well as from concurrent operations are shown below in Table 8. Table 6 Construction-Related Regional Criteria Pollutant Emissions Prior to Mitigation Pollutant Emissions (pounds/day) Activity VOC NOx CO SO2 PM10 PM2.5 Levee Repairs Phase 1 1 On-Site 1.13 11.63 7.95 0.02 0.61 0 2 Off-Site 0.04 0.03 0.31 0.00 0.09 0.02 Total 1.17 11.66 8.26 0.02 0.70 0.58 Levee Repairs Phase 2 On-Site 0.63 7.73 4.49 0.01 0.35 0.32 Off-Site 0.04 0.03 0.31 0.00 0.09 0.02 Total 0.67 7.76 4.80 0.01 0.44 0.34 Levee Repairs Phase 3 On-Site 0.85 8.92 5.54 0.01 0.42 0.39 Off-Site 0.03 0.02 0.20 0.00 0.06 0.02 Total 0.88 8.94 5.74 0.01 0.48 0.41 Mobilization at One Well Site On-Site 0.79 8.34 5.57 0.01 0.46 0.43 Off-Site 0.03 0.26 0.25 0.00 0.07 0.02 Total 0.82 8.60 5.82 0.01 0.53 0.45 Monitor Well Drilling and Construction of One

Well On-Site 6.00 58.84 44.52 0.13 2.63 2.56 Off-Site 0.02 0.17 0.16 0.00 0.04 0.01 Total 6.02 59.01 44.68 0.13 2.67 2.57 Monitor Well Development of One Well On-Site 1.41 13.69 6.95 0.03 0.44 0.43 Off-Site 0.04 0.13 0.34 0.00 0.10 0.03 Total 1.45 13.82 7.29 0.03 0.54 0.46 Concurrent Operation of 2 Drill Rigs 12.04 118.02 89.36 0.26 5.34 5.14 SCAQMD Thresholds 75 100 550 150 150 55 Exceeds Thresholds? No Yes No No No No Notes: 1 Onsite emissions from equipment not operated on public roads. 2 Offsite emissions from vehicles operating on public roads. Source: CalEEMod Version 2016.1.3. The data provided in Table 8 shows that NOx would exceed the regional emissions threshold during the anticipated simultaneous operation of two direct

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mud rotary drill rigs, while all other phases and analyzed pollutants would be within the thresholds. This would result in a significant impact. Mitigation Measure AIR-1 is required if concurrent well drilling and construction activities occur at both BS13 and BS24. Mitigation Measure AIR-1 requires that all diesel equipment with a horsepower of 75 or more utilized during the monitor wells drilling and construction phase of construction activities shall meet the Tier 4 emission standards. Table 9 below shows that with application of Mitigation Measure AIR-1, the proposed project’s NOx emission would be reduced to within the regional emissions thresholds. Therefore, with implementation of Mitigation Measure AIR-1, the construction-related regional criteria pollutant emissions would be less than significant for the proposed project. Table 7 Mitigated Construction-Related Regional Criteria Pollutant Emissions Pollutant Emissions (pounds/day) Activity VOC NOx CO SO2 PM10 PM2.5 Levee Repairs Phase 1 1 On-Site 0.67 5.94 9.24 0.02 0.40 0.37 2 Off-Site 0.04 0.03 0.31 0.00 0.09 0.02 Total 0.71 5.97 9.55 0.02 0.49 0.39 Levee Repairs Phase 2 On-Site 0.63 7.73 4.49 0.01 0.35 0.32 Off-Site 0.04 0.03 0.31 0.00 0.09 0.02 Total 0.67 7.76 4.80 0.01 0.44 0.34 Levee Repairs Phase 3 On-Site 0.40 3.23 6.83 0.01 0.21 0.19 Off-Site 0.03 0.02 020 0.00 0.06 0.02 Total 0.43 3.25 7.03 0.01 0.27 0.21 Mobilization at One Well Site On-Site 0.66 7.08 5.53 0.01 0.36 0.33 Off-Site 0.03 0.26 0.25 0.00 0.07 0.02 Total 0.69 7.34 5.78 0.01 0.43 0.35 Monitor Well Drilling and Construction of One

Well On-Site 2.01 9.83 66.78 0.13 0.37 0.67 Off-Site 0.02 0.17 0.06 0.00 0.04 0.01 Total 10.0 2.03 66.94 0.13 0.41 0.68 0 Monitor Well Development of One Well On-Site 1.14 8.37 11.13 0.03 0.29 0.29 Off-Site 0.04 0.13 0.34 0.00 0.10 0.03 Total 1.18 8.50 11.47 0.03 0.39 0.32 Concurrent Operation of 2 Drill Rigs 20.0 4.06 133.88 0.26 0.82 1.36 0

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Pollutant Emissions (pounds/day) Activity VOC NOx CO SO2 PM10 PM2.5 SCAQMD Thresholds 75 100 550 150 150 55 Exceeds Thresholds? No No No No No No Notes: 1 Onsite emissions from equipment not operated on public roads. 2 Offsite emissions from vehicles operating on public roads. Source: CalEEMod Version 2016.1.3. Construction Related Emissions Construction-related air emissions may have the potential to exceed the State and Federal air quality standards in the project vicinity, even though these pollutant emissions may not be significant enough to create a regional impact to the Air Basin. The local air quality emissions from construction were analyzed through utilizing the methodology described in the LST Methodology. The LST Methodology found the primary criteria pollutant emissions of concern are NOx, CO, PM10, and PM2.5. In order to determine if any of these pollutants require a detailed analysis of the local air quality impacts, each phase of construction was screened using the SCAQMD’s Mass Rate LST Look-up Tables. The Look-up Tables were developed by the SCAQMD in order to readily determine if the daily onsite emissions of CO, NOx, PM10, and PM2.5 from the proposed project could result in a significant impact to the local air quality. Table 10 shows the onsite emissions from the CalEEMod model for the different construction phases and the calculated emissions. Table 8 Construction-Related Local Criteria Pollutant Emissions Pollutant Emissions (pounds/day) Phase NOx CO PM10 PM2.5 Levee Phase 1 11.63 7.95 0.61 0.56 Levee Phase 2 7.73 4.49 0.35 0.32 Levee Phase 3 8.92 5.54 0.70 0.58 Monitor Well Mobilization1 8.34 5.57 0.46 0.43 Monitor Well Drilling and Construction 58.84 44.52 2.63 2.56 Monitor Well Development 13.69 6.95 0.44 0.43 SCAQMD Thresholds for 50 meters (164 feet)2 93 738 13 5 Exceeds Threshold? No No No No Notes: 1 Only Monitor Wells at BS13 were analyzed since the Monitor Wells at BS24 are approximately 0.5 mile from the nearest sensitive receptor. 2 The nearest sensitive receptors are multifamily residential homes located as near as 220 feet (67 meters) from the proposed levee repairs. The 50 meter thresholds provided in the Look-Up Tables were utilized in order to provide a conservative analysis. Source: Calculated from SCAQMD’s Mass Rate Look-up Tables for one acre in Air Monitoring Area 18, North Coastal Orange County.

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The data provided Table 10 shows that none of the analyzed criteria pollutants would exceed the local emissions thresholds for any phase of construction. Therefore, a less than significant local air quality impact would occur from construction of the proposed project. Operational Emissions Less than Significant Impact with Mitigation: In general, operation of the monitoring well would be passive as there would be no permanent equipment installed in the wells. OCWD staff will collect groundwater samples semi- annually and record water levels from the monitoring wells on a monthly. Groundwater sampling and water level gauging would be conducted separately. In total, the monitoring wells would be visited by OCWD staff up to 14 times per year. Every three to five years OCWD would conduct maintenance activities to sample and redevelop the well and the sampling and well redevelopment activities would generate the highest daily criteria pollutant emissions. The CalEEMod model has been utilized to calculate the operational regional emissions from the well sampling and well redevelopment activities. Because water level gauging would require minimal equipment and well sampling and well sampling and redevelopment activities provide a worst-case analysis, water level gauging was not analyzed as a separate phase. The worst-case summer or winter daily operational criteria pollutant emissions from the proposed project for the well sampling and redevelopment activities are shown below in Table 11. Table 9 Operational Well Sampling and Redevelopment Regional Criteria Pollutant Emissions Pollutant Emissions (pounds/day) Activity VOC NOx CO SO2 PM10 PM2.5 Well Sampling Equipment Onsite1 0.72 6.81 3.11 0.01 0.23 0.22 Offsite2 0.02 0.01 0.12 0.00 0.04 0.01 Total 0.74 6.82 3.23 0.01 0.27 0.23 Well Redevelopment Equipment Onsite 1.82 17.98 8.01 0.04 0.57 0.56 Offsite 0.09 0.06 0.71 0.00 0.20 0.05 Total 1.91 18.04 8.72 0.04 0.77 0.61 SCQAMD Thresholds 55 55 550 150 150 55 Exceeds Threshold? No No No No No No Notes: 1 Onsite emissions from equipment not operated on public roads. 2 Offsite emissions from vehicles operating on public roads. Source: CalEEMod Version 2016.1.3.

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The data provided in Table 11 shows that the proposed project would not expose people residing or working in the project area to excessive noise levels from aircraft. Table 11 shows that none of the analyzed criteria pollutants would exceed the regional emissions thresholds. Therefore, a less than significant regional air quality impact would occur from operation of the proposed project. Operations-Related Local Air Quality Impacts Operational air emissions may have the potential to exceed the State and Federal air quality standards in the project vicinity, even though these pollutant emissions may not be significant enough to create a regional impact to the Air Basin. The local air quality emissions from well sampling and redevelopment were analyzed through utilizing the methodology described in the LST Methodology. In order to determine if any of these pollutants require a detailed analysis of the local air quality impacts, the operational well sampling and redevelopment activities were screened using the SCAQMD’s Mass Rate LST Look-up Tables. Table 12 shows the onsite emissions from the CalEEMod model for the operational well sampling and redevelopment activities. Table 10 Operational Well Sampling and Redevelopment Local Criteria Pollutant Emissions Pollutant Emissions (pounds/day) Operational Activities NOx CO PM10 PM2.5 Well Sampling 6.81 3.11 0.23 0.22 Well Redevelopment 17.98 8.01 0.57 0.56 1 SCAQMD Thresholds for 50 meters (164 feet) 93 783 4 2 Exceeds Threshold? No No No No Notes: 1 The nearest sensitive receptors are multifamily residential homes located as near as 220 feet (67 meters) from the proposed levee repairs. The 50 meter thresholds provided in the Look-Up Tables were utilized in order to provide a conservative analysis. Source: Calculated from SCAQMD’s Mass Rate Look-up Tables for one acre in Air Monitoring Area 18, North Coastal Orange County. The data provided n Table 12 shows that the on-going operations of the proposed project would not exceed the local NOx, CO, PM10 and PM2.5 thresholds of significance. Therefore, the on-going operations of the proposed project would create a less than significant operations-related impact to local air quality due to onsite emissions and no mitigation would be required. Mitigation Measures Mitigation Measure AIR-1 is required.

C: Would the project result in cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable federal or state ambient air quality standard?

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Less than Significant Impact with Mitigation: The proposed project would not result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable Federal or State ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors). Cumulative projects include local development as well as general growth within the project area. However, as with most development, the greatest source of emissions is from mobile sources, which travel throughout the local area. Therefore, from an air quality standpoint, the cumulative analysis would extend beyond any local projects and when wind patterns are considered would cover an even larger area. Accordingly, the cumulative analysis for the project’s air quality must be generic by nature. The project area is out of attainment for ozone and PM10 and PM2.5 particulate matter. In accordance with CEQA Guidelines Section 15130(b), this analysis of cumulative impacts incorporates a three-tiered approach to assess cumulative air quality impacts. • Consistency with the SCAQMD project specific thresholds for construction and operations; • Project consistency with existing air quality plans; and • Assessment of the cumulative health effects of the pollutants. Consistency with Project Specific Thresholds Construction-Related Impacts The project site is located in the South Coast Air Basin, which is currently designated by the EPA as a non-attainment area for ozone and PM2.5 and designated by CARB as a non-attainment area for ozone, PM10, and PM2.5. The regional ozone, PM10, and PM2.5 emissions associated with the proposed project have been calculated as shown in Table 8. The above analysis found that short-term regional construction air emissions may result in significant NOx (ozone precursor) impacts based on SCAQMD regional thresholds of significance. Mitigation Measure 1 has been provided to reduce the short-term regional construction air emissions to less than significant levels in the event of concurrent well drilling and construction activities at well sites BS13 and BS24. Mitigation Measure AIR-1 requires that all diesel equipment with a horsepower of 75 or more utilized during the monitor wells drilling and construction phase of construction activities shall meet the Tier 4 emission standards.

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Therefore, with implementation of Mitigation Measure AIR-1, a less than significant cumulative impact would occur from construction of the proposed project. Operational-Related Impacts In general, operation of the monitoring wells will be passive as there would be no permanent equipment installed in the wells. OCWD staff would collect groundwater samples and record water levels periodically. Every three to five years OCWD would conduct maintenance activities to sample and redevelop the wells and the sampling and well redevelopment activities would generate the highest daily criteria pollutant emissions. The regional ozone, PM10 and PM2.5 emissions associated with the well sampling and redevelopment activities are shown in Table 12. The analysis found that development of the proposed project would result in less than significant regional emissions of the precursors to ozone, PM10, and PM2.5 during operational well sampling and redevelopment activities for the proposed project. Therefore, a less than significant cumulative impact would occur from operation of the proposed project. Consistency with Air Quality Plans All proposed well sites are located within public right of ways, which are technically not designated in General Plans or Zoning Maps. Since well drilling is an allowed use in all land use designations, the proposed project is consistent with the current land use designations and would not require a General Plan Amendment or zone change. As such, the proposed project is not anticipated to exceed the AQMP assumptions for the project sites and is found to be consistent with the AQMPs for the Air Basin. Cumulative Health Impacts The Air Basin is designated as nonattainment for ozone, 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 (elderly, children, and the sick). Therefore, when the concentrations of those pollutants exceed the standard, it is likely that some sensitive individuals in the population would experience health effects. The regional analysis shown in Table 9 indicates that the proposed project would not exceed the SCAQMD regional significance thresholds for VOC and NOx (ozone precursors), PM10 and PM2.5.

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As such, the proposed project would result in a less than significant cumulative health impact. Mitigation Measures Mitigation Measure AIR-1 is required. D. Would the project expose sensitive receptors to substantial pollutant concentrations? Less than Significant Impact: The proposed project would not expose sensitive receptors to substantial pollutant concentrations. The local concentrations of criteria pollutant emissions produced in the nearby vicinity of the proposed project, which may expose sensitive receptors to substantial concentrations have been calculated for both construction and operations, which are discussed separately below. The discussion below also includes an analysis of the potential impacts from toxic air contaminant emissions. Construction-Related Sensitive Receptor Impacts The closest sensitive receptors to the BS13 well site are multi-family residential homes located approximately 400 feet to the south. The closest sensitive receptors to the BS24 well site are single family residential homes on the Weapons Station that are located approximately 0.5 mile to the west. The closest sensitive receptors to the proposed Bolsa Chica Channel Levee repairs are multi- family residential homes located approximately 220 feet to the south. The analysis shown in Table 9 found that none of the analyzed criteria pollutants would exceed the local emissions thresholds for any phase of construction. The greatest potential for toxic air contaminant emissions would be related to diesel particulate emissions associated with heavy equipment operations during construction of the proposed project. According to SCAQMD methodology, health effects from carcinogenic air toxics are usually described in terms of “individual cancer risk”. “Individual Cancer Risk” is the likelihood that a person exposed to concentrations of toxic air contaminants over a 70-year lifetime will contract cancer, based on the use of standard risk-assessment methodology. Given the relatively limited number of heavy-duty construction equipment and the short-term construction schedule, the proposed project would not result in a long- term (i.e., 70 years) substantial source of toxic air contaminant emissions and corresponding individual cancer risk. Therefore, no significant short-term toxic air contaminant impacts would occur during construction of the proposed project. As such, construction of the proposed project would result in a less than significant exposure of sensitive receptors to substantial pollutant concentrations.

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Operations-Related Sensitive Receptor Impacts In general, operation of the monitoring wells will be passive as there would be no permanent equipment installed in the wells. OCWD staff would collect groundwater samples and record water levels periodically from the wells. Every three to five years OCWD would conduct maintenance activities to sample and redevelop the well and the sampling and well redevelopment activities would generate the highest daily criteria pollutant emissions. The analysis in Table 12 found that none of the analyzed criteria pollutants would exceed the local emissions thresholds for the operational well sampling and redevelopment activities. Also, as detailed above for construction, the greatest potential for toxic air contaminant emissions would only occur during the well sampling and redevelopment activities that are limited to approximately one week every three to five years. Given, the infrequent activity schedule, the proposed project would not result in a long-term (i.e., 70 years) substantial source of toxic air contaminant emissions and corresponding individual cancer risk. Therefore, no significant short-term toxic air contaminant impacts would occur during operation of the proposed project. As such, operation of the proposed project would result in a less than significant exposure of sensitive receptors to substantial pollutant concentrations. Therefore, operation of the proposed project would result in a less than significant exposure of sensitive receptors to substantial pollutant concentrations. E. Would the project create objectionable odors affecting a substantial number of people? Less than Significant Impact: The proposed project would not create objectionable odors affecting a substantial number of people. Potential odor impacts have been analyzed separately for construction and operations below. Individual responses to odors are highly variable and can result in a variety of effects. Generally, the impact of an odor results from a variety of factors such as frequency, duration, offensiveness, location, and sensory perception. The frequency is a measure of how often an individual is exposed to an odor in the ambient environment. The intensity refers to an individual’s or group’s perception of the odor strength or concentration. The duration of an odor refers to the elapsed time over which an odor is experienced. The offensiveness of the odor is the subjective rating of the pleasantness or unpleasantness of an odor. The location accounts for the type of area in which a potentially affected person

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lives, works, or visits; the type of activity in which he or she is engaged; and the sensitivity of the impacted receptor. Sensory perception has four major components: detectability, intensity, character, and hedonic tone. The detection (or threshold) of an odor is based on a panel of responses to the odor. There are two types of thresholds: the odor detection threshold and the recognition threshold. The detection threshold is the lowest concentration of an odor that will elicit a response in a percentage of the people that live and work in the immediate vicinity of the project site and is typically presented as the mean (or 50 percent of the population). The recognition threshold is the minimum concentration that is recognized as having a characteristic odor quality this is typically represented by recognition by 50 percent of the population. The intensity refers to the perceived strength of the odor. The odor character is what the substance smells like. The hedonic tone is a judgment of the pleasantness or unpleasantness of the odor. The hedonic tone varies in subjective experience, frequency, odor character, odor intensity, and duration. Construction-Related Odor Impacts Potential sources that may emit odors during well construction activities include the extraction of drilling mud and from emissions from diesel equipment. The objectionable odors that may be produced during the construction process would be temporary and would not likely be noticeable for extended periods of time beyond the project site’s boundaries. Due to the transitory nature of construction odors, a less than significant odor impact would occur and no mitigation would be required. Potential Operations-Related Odor Impacts In general, operation of the monitoring wells will be passive as there would be no permanent equipment installed in the wells. OCWD staff would periodically collect groundwater samples and record water levels from the wells. Every three to five years OCWD would conduct maintenance activities to sample and redevelop the well. Potential sources that may emit odors during well sampling and redevelopment activities include the extraction of materials from the wells and from emissions from diesel equipment. The objectionable odors that may be produced during the well sampling and redevelopment activities would be temporary and would not likely be noticeable for extended periods of time beyond the project site’s boundaries. Due to the transitory nature of these odors, a less than significant odor impact would occur and no mitigation would be required.

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4.4 Biological Resources Purpose The purpose of this analysis is to evaluate potential impacts to biological resources associated with the construction and operation of monitoring wells at BS13 and BS24 well sites and potential impacts associated with the repairs to the Bolsa Chica Channel Levee. Methodology The biological assessment was prepared by the OCWD Natural Resource Department in October of 2017. To identify sensitive species, the most recent records of the California Department of Fish and Game Natural Diversity Database, California Native Plant Society Online Listing of Rare and Endangered Plants and the Naval Weapons Station Seal Beach Integrated Natural Resources Management Plan were reviewed. Additionally, a combination of aerial photo interpretation and field investigations and geographic information system software were used to identify biological resources on the project site. Naval Weapons Station Seal Beach Integrated Natural Resources Plan In 2011 Naval Weapons Station Seal Beach Integrated Natural Resources Management Plan was approved to manage biological resources at the Seal Beach National Wildlife Refuge. Subsequently, a Comprehensive Plan written specifically for management of natural resources on Seal Beach National Wildlife Refuge was approved by United States Fish and Wildlife Service (USFWS) and the United States Navy in May of 2012. The Integrated Natural Resources Management Plan is an ecosystem-based plan that was developed in cooperation with, and with mutual agreement of, the USFWS, California Department of Fish and Wildlife (CDFW), the U.S. Army Corps of Engineers (USACE), National Oceanic and Atmospheric Administration (NOAA), and the Regional Water Quality Control Board (RWQCB). The Integrated Natural Resources Management Plan provides for conservation, restoration and management of natural resources at Naval Weapons Station Seal Beach. Vegetation Communities The Naval Weapons Station Seal Beach Integrated Natural Resources Plan identifies vegetation communities on the Naval Weapons Station. As shown in Figure 5, Well Site BS24 would be located in an existing improved roadway and Well Site BS13 would be located along existing flood control channel.

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Monitoring Well Site BS13, Bolsa Chica Channel Levee Repair The proposed BS13 monitoring wells and levee repair activities would be conducted on a dirt surface road located along the Bolsa Chica Channel Levee. The levee is void vegetation. South of the levee is open water. To north is an approximate 20-foot dirt perimeter road that is adjacent coastal salt marsh habitat. The coastal salt marsh habitat is comprised of a hydrologic zone comprised of hydrophytic plants dominated by Cordgrass (Spartina foliosa). Monitoring Well Site BS24 The well site is characterized as highly disturbed given its close proximity to Bolsa Avenue, which is a high traffic road. The well site is composed of 100% base fill gravel. There is no sensitive vegetation located on the well site. To the north and south of the well site is coastal salt marsh. The coastal salt marsh vegetation is comprised of a hydrologic zone comprised of hydrophytic plants dominated by Cordgrass (Spartina foliosa). Pickleweed (Arthrocnemum subterminale) is also found in this area, but in smaller groupings. The second habitat zone borders the wetland and acts as an upland component to the well site. This upland area is composed of both Hydrophytic, and Mesophytic species depending on the proximity to the hydric soil influence of the marsh. This area is much more diverse as far as plant species composition. Dominance in the upland is shared by Pickleweed, and Salt Grass. Alkali Heath (Frankenia salina), Jaumea (Jaumean carnosa), and California Sea Lavender (Limonium californicum) also have a distinctive presence. The upland area on the north side of Bolsa Avenue has a weedy component. A band of non-native grasses makes up part of the mosephytic portion of the upland area between the road and the marsh itself. The primary non-native grass documented was Foxtail Barley (Hordeum murinum). Sensitive Species The Naval Weapons Station Seal Beach Integrated Natural Resources Management Plan, the California Department Fish and Game California Natural Diversity Data Base (CNDDB) and California Native Plant Society Online List of Rare and Endangered Plants was reviewed to identify sensitive plant, wildlife and aquatic species that have been reported on the Naval Weapons Station Seal Beach. A complete listing of the sensitive species that have been reported on Naval Weapons Station Seal Beach is presented in Table 13. The location of sensitive plants reported on Naval Weapons Station Seal Beach is shown on Figure 6.

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The two wildlife species that have highest potential to occur within the project area that could be affected by the proposed project activities would be the Light- footed Ridgeway’s rail and the Belding Savannah Sparrow. The Light-footed Ridgeway’s rail is an endangered bird that nests in the wetlands. The hydrologic habitat near both well sites would be consistent with habitat required for nesting by the Light-footed Ridgeway’s rail. It seems likely that during the nesting season the Ridgeway’s rail would be present. The Belding’s Savannah sparrow is an endangered subspecies found only in salt marshes along California Coast. The Belding’s savannah Sparrow is a year round resident at Seal Beach National Wildlife Refuge. The habitat near the well sites would be consistent with its nesting requirements. This species would likely be present during the breeding season and potentially could use the project area for foraging year round. Table 11: Sensitive Species List Federal State CNPS General Habitat Plants Coast wooly-heads NL NL 1B.2 Coastal Dunes (Nemacaulis denudate var. denudate)

Coulters goldfield NL NL 1.B.1 Coastal Salt Marsh (Lasthenia glabrata ssp. Vernal Pools, Coulteri) Foothill Grasslands Davidson saltscale NL NL 1B.2 Coastal Scrub (Atriplex serenana) Coastal Bluff Scrub Estuary seablite NL NL 1B.2 Marsh Swamps (Suaeda esteroa) Gambels water cress E T 1B.1 Marshes, Swamps (Nasturtium gambelii) Lewis eveing primrose NL NL 3 Coastal Strand (Cammisonia lewisii) Mud nama NL NL 2.2 Marshes, Swamps (Nama stenocarpum) Red sand verbena NL NL 4 Coastal Beach (Abronia maritime) Dunes San Bernardino aster NL NL 1B.2 Marshes, Swamps (Symphyotrichum defoliatum) Sanfords arrowhead NL NL 1B.2 Marshes, Swamps (Sagittaria sanfordii) Salt marsh birds beak E E 1B.2 Coastal Dunes (Cordylanthus maritimus ssp. Maritimus) Seaside calandrinia NL NL 4 Coastal Scrub, (Calandrinia maritime)) Sandy Bluffs Southern tarplant NL NL 1B.1 Marshes, Swamps, (Hemizonia parryi var. Vernal pools, australis) Grasslands

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Federal State CNPS General Habitat Ventura Marsh mil-vetch E E 1B.1 Coastal Salt Marsh (Astragalus pycnostachyus var. lanosissimus) Birds Allens hummingbird SSC NL NL Chaparral, Riparian (Selasphorus sasin) Woodlands American White Pelican NL SSC NL Ocean Coasts, Lake (pelecanus erythrorhynchos) Shores Bank swallow NL T Riparian Vegetation (Riparia riparia) Beldings savannah sparrow NL E NL Coastal Salt (passerculus sandwichensis Marshes belding) Black oystercatcher SSC NL NL Rocky Shoreline, (Haematopus bachmani) Mudflats Black skimmer SSC SSC NL Sandy Beaches (Rynchops niger niger) Black storm-petrel NL SSC NL Open Ocean (oceanodroma melania) Black tern SSC SSC NL Marshes, Ponds, (Chelonians niger Mouths of Rivers, surinamensis Lake Shores Black-vented shearwater SSC NL NL Open Ocean (puffinus opisthomelas) Brant NL SSC NL Tidal Estuaries (Branta bericia) Brewers sparrow SSC NL NL Dense Sagebrush (Spizella breweri) Burrowing owl SSC SSC NL Grasslands, Low (Athene cunicularia) Growing Vegetation California Brown Pelican NL FP NL Ocean Shores (pelicanus occidentalis) California least tern E E NL Sandy Beaches (Sterna antillarum browni) Cassins auket SSC SSC NL Open Ocean (Ptchoramphus) Common loon SSC SSC NL Coastal Shoreline (Gavia immer) Costas hummingbird SSC NL NL Coastal Scrub (Calypte costae) Golden eagle NL FP NL Isolated Mountain (Aquila chrysaetos Ranges Canadensis) Large-billed savannah NL SSC NL Coastal Scrub sparrow (Passerculus sandwichensis rostratus) Lawerences goldfinch SSC NL NL Open Woodlands, (Carduelis lawrencei) Weed Fields, near small bodies of water Light footed Ridgeways rail E E NL Salt Marsh (Rallus obsoletus) Loggerhead shrike SSC SSC NL Riparian Woodland

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Federal State CNPS General Habitat (lanius ludovcianus) Long-billed curlew SSC SSC NL Shores, Marshes, (Numenius americanus) Mudflats Marbled godwit SSC NL NL Shores, Marshes, (Limosa fedoa) Mudflats Mountain plover C SSC NL Open Flat (Charadrius montanus) Tablelands, Prairies Northern harrier NL SSC NL Grasslands, (Circus cyaneus hudsonius) Wetland Meadows, Agriculture Fields Peregrine falcon SSC NL NL Ocean Coasts Lake (Falco peregrinus anatum) Shores Pink-footed shearwater SSC NL NL Open Ocean Water (Puffinus creatopus) Redhead NL SSC NL Tidal Waters (Aythya Americana) Red knot SSC NL NL Coastal Inlets, (Calidris canuts) Estuaries, Bays Sage thrasher SSC NL NL Sagebrush Thickets Oreoscoptres montanus) Short-billed dowitcher SSC NL NL Ponds, Marshes, (Limnodromus griseus) Coastal Mudflats Short-eared owl NL SSC NL Marshes, Meadows, (Asioflammeus flammenus) Prairies Swainsons hawk NL T NL Riparian Woodlands (Buteo swainisoni) and Open Fields Tricolored blackbird SSC SSC NL Wetlands, (Agelaius tricolor) Agriculture Fields Vauxs swift NL SSC NL Coniferous and (Chaetura vauxi) Mixed Coniferous Forests Western snowy plover T SSC NL Sandy Beaches (Charadrius alexandrinus) Lake Shorelines Whimbrel SSC NL NL Tidal Flats (Numenius phaeopus hudsonicus) White-tailed kite SSC FP NL Riparian Trees (Elanus leucurus ) Yellow warbler SSC SSC NL Riparian Vegetation (Dendrica petechia) Reptiles Green sea turtle T NL NL Marine (Chelonia mydas) San Diego Horned lizard NL SSC NL Chaparral, Coastal (Phrynosoma coronatum Sage Scrub blainvillii) Silvery legless lizard NL SSC NL Mixed Woodlands, (Anniella pulchra pulchra) grasslands, Marshes Mammals San Diego black-tailed NL SSC NL Open Range, jackrabbit Agriculture Fields (Lepus californicus bennettii) Southern California Saltmarsh NL SSC NL Coastal Marshes

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Federal State CNPS General Habitat Shrew (Sorex Ornatus) South Coast Vole NL SSC NL Tidal Marshes (microtus Californicus) Western mastiff bat NL SSC NL Small Holes and (Eumops perotis) Cracks, Man Made Structures

Wildlife Movement Corridors Wildlife/Corridors and linkages that facilitate regional wildlife movement are generally near water ways, ridgelines, riparian corridors, flood control channels, contiguous habitat and upland habitat. 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 and include culverts, underpasses, drainage pipes, bridges and tunnels to prove access past roads, highways, pipelines or other physical obstacles. The Naval Weapons Station includes large expanses of open space that provides for movement of wildlife between patches of suitable habitat. Additionally, Bolsa Chica Channel which boarders the eastern and southern end of the weapons station provides an open space linkage to the ocean. However, wildlife access is limited by fencing that is provided along the perimeter of the channel.

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Jurisdictional Aquatic Resources The Naval Weapons Station Seal Beach Integrated Resource Management Plan includes a regulatory jurisdictional determination that identifies the different types of wetlands and potential Clean Water Act Section 404 Jurisdiction Areas at Naval Weapons Station that could be subject to regulation under Section 404 of the Clean Water Act. The jurisdictional determination identified a total of 1,373 acres of jurisdictional wetlands, comprised of six distinct wetland types. The location of the different wetland types is shown in Figure 6. Waters/Wetland Determination As shown on Figure 6, proposed Monitoring Well Site BS24 is located an upland location that contains gravel material and appears to be outside of the Clean Water Act Section 404 Jurisdiction Area. Monitoring Well Site BS13 is located on the service road along the top of the Bolsa Chica Channel levee and according to Naval Weapons Station Seal Beach Wetland Delineation Map the site appears to be outside of the Clean Water Act Section 404 Jurisdiction Area. Additionally, the site is along the top of the levee above the ordinary high water mark and outside of Clean Act Section 404 Jurisdiction Area and above the top of slope of the channel and outside of State of California Jurisdiction Area. Project Impacts A. Would the project have a substantial adverse impact, either directly or through habitat modifications, on any species identified as a candidate, sensitive or special status species in local or regional plans, policies or regulations or by the California Department of Fish and Game or U.S. Fish and wildlife Services? Monitoring Well Site BS24 Sensitive Plant Species No Impact: The proposed well construction activities would occur in areas that have been previously disturbed. The Naval Weapons Station Seal Beach Integrated Natural Resources Management Plan identifies that no sensitive plants have been reported on the proposed well site. During field surveys conducted by OCWD biologist in September of 2017 no sensitive plants were observed at the well site. Based on the lack of occurrence of sensitive plant species and the disturbed condition of the well site there would be no potential that sensitive plant species would be present where the well construction

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activities would occur. Therefore, no direct, indirect or cumulative adverse impacts to sensitive plants would occur. Sensitive Wildlife Species Less than Significant with Mitigation: The well site lacks suitable nesting habitat. However, in the nearby coastal salt marsh areas there would be suitable nesting habitat for the Belding’s Savannah sparrow and the Light Footed Ridgeway’s rail. To avoid potential impacts to nesting birds, the well construction activities would occur outside of nesting season. With the implementation of Mitigation Measure BIO-1, potential adverse direct impacts to nesting birds would be avoided. Both Belding’s Savannah sparrow and the Light Footed Ridgeway’s rail maintain year residency and commonly roost at the Seal Beach National Wildlife Refuge. The well site lacks suitable roosting areas for both species. Therefore, there would not be any direct loss of nesting or roosting habitat for both species. The proposed well drilling activities would require 24 hour drilling. To ensure safe working conditions and proper operation of equipment during the nighttime, floodlights would be used. The light and glare emitted from the floodlights could have indirect adverse impacts on wildlife in adjacent open space areas. To minimize potential light and glare impacts, the floodlights would be shielded and directed to the work site. With the implementation of Mitigation Measure A-1 and A-2 potential indirect adverse light and glare impacts would be reduced to a less than significant level. Monitoring Well Site BS13 Sensitive Plant Species No Impact: The proposed well construction activities would occur in areas that have been previously disturbed. The Seal Beach Integrated Natural Resources Management Plan identifies that no sensitive plants have been reported on the proposed well site. During field surveys conducted by OCWD biologist in September of 2017 no sensitive plants were observed at the well site. Based on the lack of occurrence of sensitive plant species and the disturbed condition of the well site there would be no potential that sensitive plant species would be present where the well construction activities would occur. Therefore, no direct, indirect or cumulative adverse impacts to sensitive plants would occur. Sensitive Wildlife Species Less than Significant Impact with Mitigation: The proposed well site is located on a levee that extends along the Bolsa Chica Channel. The levee itself lacks

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suitable habitat to support sensitive species. However, the site is near a salt marsh habitat and there would be high potential that sensitive species such as the Light-footed Clapper Rail and Beldings Savannah Sparrow could potentially nest in the adjacent salt marsh. The construction of the proposed well would not impact the salt marsh therefore no direct impacts to sensitive species would occur. The will drilling and construction activities at BS13 would occur during the nesting season. The proposed well construction activities would involve the use of heavy construction equipment that would increase ambient noise levels within the project area. The noise emitted from the heavy construction equipment could discourage individual species from nesting or roosting within the study area. Noise levels in excess of 60 dBA are known to impair the normal behavior of nesting birds. The closest nesting area to BS13 well site would be approximately 1,000 feet. Based on the level of noise emissions generated from the proposed construction equipment, the 60 dBA noise level would extend 820 feet into the salt marsh. Therefore, no disruptions to nesting and/or roosting birds would occur. The proposed well drilling activities would require 24 hour drilling. To ensure safe working conditions and proper operation of equipment during the nighttime, floodlights would be used. The light and glare emitted from the floodlights could have indirect adverse impacts on wildlife in adjacent open space areas. To minimize potential light and glare impacts, the floodlights would be shielded and directed to the work site. With the implementation of Mitigation Measure A-1 and A-2 potential indirect adverse light and glare impacts would be reduced to a less than significant level. Bolsa Chica Channel Levee Repair Less than Significant Impact with Mitigation: The proposed well site is located on a levee that extends along the Bolsa Chica Channel on one side and salt marsh on the other. The levee itself lacks suitable habitat to support sensitive species. However, the site is near salt marsh habitat and there would be high potential that sensitive species such as the Light-footed Ridgeway’s rail and Beldings Savannah sparrow could potentially nest in the adjacent salt marsh. The construction of the proposed well would not impact the salt marsh therefore no direct impacts to nesting birds would occur. To avoid potential impacts to nesting birds, the well construction activities would occur outside of nesting season. With the implementation of Mitigation Measure BIO-1, potential adverse direct impacts to nesting birds would be avoided.

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Mitigation Measures Mitigation Measures A-1 and A-2 are required. BIO-1: The construction of monitoring wells at BS24 Well Site and the repairs to the Bolsa Chica Channel Levee will occur outside of the nesting season, which occurs from March 1 to September 15 for light footed Ridgway’s rail and February 1 to July 31 for Beldings Savannah Sparrow. B. Would the project have a substantial adverse impact on any riparian habitat or natural community identified in local or regional plans, policies, and regulations or by the California Department of Fish and Game or U.S. Fish and Wildlife Service? Monitoring Well Site BS24 Less than Significant Impact with Mitigation: The proposed well site is highly disturbed and is composed of 100% base fill gravel. The construction and operation of the proposed monitoring well would not result in direct impacts to sensitive vegetation communities. The proposed well construction activities could result in indirect adverse impacts that could degrade the value of adjacent and nearby coastal salt marsh vegetation. Potential adverse indirect impacts could occur from inadvertent trampling of sensitive vegetation from workers and from vehicle traffic and dust generation from construction equipment. To minimize indirect adverse impacts, all coastal salt marsh vegetation that is immediately adjacent to the work area would be flagged and be identified to stay out. Additionally, dust suppression measures would be implemented to minimize dust impacts. With the implementation of Conservation Measures BIO-2, BIO-3, BIO- 4, and BIO-5 potential indirect adverse impacts to sensitive vegetation communities would be reduced to a less than significant level. Monitoring Well Site BS13 and Bolsa Chica Channel Levee Repair Less than Significant Impact: The proposed well site and level repair location are located on a dirt surface road that runs along the Bolsa Chica Channel Levee. As shown in Figure 5, there are no sensitive vegetation communities located on the Bolsa Chica Channel Levee. The construction and operation of the proposed monitoring wells and repairs to the levee would be confined to the work area. Therefore, no impacts would occur to any sensitive habitats or natural communities. No mitigation measures are required. Mitigation Measures BIO-2: Construction personnel will utilize designated access roads or previously disturbed areas to reach the project area or stage vehicles and equipment.

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BIO-3: Unpaved areas would be watered as needed to control dust on a continual basis. BIO-4: The storage of equipment and materials, temporary stockpiling of soil would be located within designated areas outside of habitat areas. BIO-5: Construction activities would be monitored to assure that vegetation is removed only in the designated areas. Sensitive vegetation adjacent to the work site would be flagged. C. Would the project have a substantially adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act through direct removal, filling hydrological interruption, or other means? Monitoring Well Site BS24 Less than Significant with Mitigation: The well site would be located in an area that contains gravel fill base material. According to the Naval Weapons Station Seal Beach Wetland Delineation Map, the Monitoring Well Site is not located within the Clean Water Act 404 Jurisdiction Area. Therefore, no direct impacts to wetland habitat would occur. The proposed well construction activities could result in indirect adverse impacts that could degrade the value of adjacent and nearby coastal salt marsh vegetation. Potential adverse indirect impacts could occur from inadvertent trampling of sensitive vegetation from workers and vehicle traffic and dust generation from construction equipment. To minimize indirect adverse impacts, all coastal salt marsh vegetation that is immediately adjacent to the work area would be flagged and be identified to stay out. Additionally, dust suppression measures would be implemented to minimize dust impacts. With the implementation of Mitigation Measures BIO-2, BIO-3, BIO-4 and BIO-5 potential indirect adverse impacts to wetland habitat would be reduced to a less than significant level. Monitoring Well Site BS13 and Bolsa Chica Channel Levee Repair No Impact: The proposed well sites are located on a dirt surface levee that runs along the Bolsa Chica Channel. The wells and level repairs would be constructed along the top of the levee, which is above Waters U.S. ordinary high water level jurisdictional area and above Waters of the State top of slope jurisdictional area. Additionally, there are no Wetland Waters of the U.S. and State on the levee. Therefore, the construction and operation of the monitoring wells and the proposed Bolsa Chica Channel levee repairs would not have any impacts on Waters of the U.S. or State or Wetland Waters of the U.S. or State. No mitigation measures are required.

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Mitigation Measures Mitigation Measures BIO-1, BIO-2, BIO-3, BIO-4 and BIO-5 are required. D. Would the project interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? Monitoring Well Site BS13, Bolsa Chica Channel Levee Less than Significant Impact with Mitigation: The construction activities at BS13 Well Site and the repairs to the Bolsa Chica Channel Levee would occur on the Bolsa Chica Channel Levee. Bolsa Chica Channel and the levee both provide an open space linkage for some aquatic and wildlife movement to the ocean. The construction operations on the levee would not impede aquatic wildlife movement in the Bolsa Chica Channel. However, the well construction and levee repair construction activities along the levee could temporary discourage wildlife movement along the levee. It is anticipated that any wildlife movement occurring in the area would detour around the construction activity. Because the amount wildlife movement expected on the levee would be minimal and the impact would be temporary, the potential impact to wildlife movement would be less than significant. The proposed well drilling activities would occur at night. To minimize potential adverse impacts to nocturnal wildlife movement that might occur in the area, the site floodlights would be adjusted to where they are only directed to the work area. With the implementation of Mitigation Measure A1 and A-2 potential adverse indirect light and glare impacts on wildlife movement would be less than significant. The BS13 well site and the location where the levee repair would occur is void of vegetation and lacks suitable habitat for nesting migratory birds. However, the site is adjacent to salt water habitat that provides suitable habitat for migratory birds. The construction of the proposed project would not impact the salt marsh. Therefore no direct impacts to nesting birds would occur. The well drilling and construction activities at BS13 Well Site would occur during the nesting season. The proposed well construction activities would involve the use of heavy construction equipment that would increase ambient noise levels within the study area. The closest nesting area to BS13 well site would be approximately 1,000 feet. Based on the level of noise emissions generated from

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the proposed construction equipment and the distance to the closest nesting area, no disruptions to nesting and/or roosting birds are expected. The construction activities to repair the Bolsa Chica Channel levee would occur outside of nesting season. Therefore, potential construction noise impacts to nesting birds would be avoided. Monitoring Well Site BS24 Less than Significant Impact with Mitigation: The proposed project activities would not result in the construction of any permanent structures that would directly impede wildlife movement. To minimize potential adverse noise impacts sound attenuation barriers would be installed around the construction work area. It is anticipated that any wildlife movement occurring in the area would detour around the construction activities. Because the amount wildlife movement expected on the levee would be minimal and the impact would be temporary, the potential impact wildlife movement would be less than significant. The well construction activities would occur outside of the migratory bird nesting season. Therefore, no direct impacts or indirect construction noise impacts to migratory birds would occur. With the implementation of Mitigation Measure BIO- 1 potential impacts to migratory birds would be avoided. The proposed well drilling activities would occur at night. To minimize potential adverse impacts to nocturnal wildlife movement that might occur in the area, the site floodlights would be adjusted to where they are only directed to the work area. With the implementation of Mitigation Measure A1 and A-2 potential adverse indirect light and glare impacts would be reduced to a less than significant level. Mitigation Measures Mitigation Measures BIO-1, A-1 and A-2 are required. E. Would the project conflict with any local policies or ordinances protecting biological resources, such as tree preservation policy or ordinance? No Impact: There are not local policies providing for the protection of biological resources that would be applicable to the proposed project. F. Would 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?

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No Impact: The natural resources on the Naval Weapons Station are under the management of the Navy through the Naval Weapons Station Seal Beach Integrated Natural Resources Plan. As part of the environmental planning for the construction of the new monitoring wells, OCWD has coordinated with Navy on locations that would not be in conflict with management programs and policies provided in the Integrated Natural Resources Plan. Additionally, mitigation measures have been incorporated into the project to avoid adverse impacts to sensitive species.

4.5 Cultural Resources Introduction 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. 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 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. Setting Prehistoric Background The initial human occupation of California dates back about 12,000 years ago during the Pleistocene Period. This period is termed Early Man Horizon or the San Dieguito Tradition. The first inhabitants of the region focused on hunting large mammals, the largest of which became extinct by about 10,000 years ago. Prehistoric sites representing this time typically yield hunter-gather flaked stone tools, such as scrappers, choppers, and large projectile points. The San Dieguito/Early man traditions are followed by the cultures termed Milling Stone

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Horizon or Encinitas Tradition after 5500 B.C. Prehistoric sites representing this period typically yield large numbers of metates and manos as well as unique artifacts of unknown use, called discoidal and cogged stones. By 3000 B.C. coastal populations begin exhibiting greater reliance on marine resources. This period is termed the Intermediate Horizon. Along the coast, deep sea fishing begins and circular fishhooks and perforated stones, possibly associated with larger nets appeared. Inland, a burgeoning acorn processing technology appeared. The Intermediate Horizon was followed by the Late Prehistoric Horizon or Shoshonean Tradition, beginning around 500 A.D. During this period the bow and arrow, soapstone bowls, callus shell beads, steatite effigies and cremations appeared, along with an increasing population, larger and permanent settlements and expanding trade activities. By 1,000 A.D. smoking pipes and Tizon brownware pottery appeared. Ethnographically, the project area is located within the territorial boundaries of the Gabrielino Indians. The Gabrielinos were Shoshonean, Takic language speakers who resided in the general Los Angeles basin and north Orange County. The Gabrielino were intensive hunter-gathers who used both inland and coastal resources. The Gabrielino people lived in either permanent or semi- permanent villages at two types of locations, coastal estuaries or along major inland watercourses. Villages were the focus of family life. Each village was politically independent with a village headman. Coastal Gabrielo were maritime hunters and gathers, exploiting bay and kelp bed fishing, shellfish and sea mammals. Inland groups more intensively collected plants and hunted terrestrial game such as deer, bear and quail. Historic Background European contact with California began in the 1500s, when mariners such as Juan Cabrillo and Francis Drake explored the California coast. However, it was not until the late 1700s that the Spanish established a continuous presence. Most Spanish colonial activity focused on missions established along the coast, such as San Gabriel in 1771, San Juan Capistrano in 1776 and San Luis Rey in 1798. Missions were the center of Spanish influence in the region and affected native patterns of settlement, culture trade, industry and agriculture. Following the Mexican Revolution of 1821, California became part of the Republic of Mexico. Legal secularization in Mexico later resulted in confiscation of mission lands, which were then granted or sold for farming and ranching.

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In the 1840s, tension between Mexico and the United States culminated in the Mexican-American War. By 1848, the war had resulted in the transfer of leadership in California from Mexico to the United States. The shift in leadership dramatically affected the inhabitants and economy of California. However, it was advent of the railroads and the resulting influx of new residents in the late 1800s that the most impact on the character of southern California. Railroads brought additional new residents and, as the population grew and Euro-Americans became the majority, residential communities sprouted up to house the new inhabitants. Euro-Americans brought industrial capitalism in the form of large scale ranching, agriculture, mining and logging. Additionally, the California Gold Rush brought more American emigrants into California. Large subsistence demands emerged from the gold towns. Ranching in California changed from a hide and tallow trade to beef stock-raising. Numerous ranch hands were hired further expanding California’s labor pool. Bolsa Chica Area Historical Setting Early pioneers called the coastal region including the Bolsa Chica by the name shell, because of the thousands of empty shells left along the beaches and bluffs by Native Americans. In 1899, the Bolsa Chica Gun Club was formed by a group of wealthy businessmen from Los Angeles and Pasadena. A two story structure was built on a mesa overlooking the Pacific Ocean. The Gun Club was responsible for the damming off of Bolsa Chica from direct tidal flow with the ocean. In the 1920’s oil rigs, and associated pipelines and service roads characterized the area. Today oil drilling continues at Bolsa Chica, however at much reduced quantity. In 1944 the Naval Weapons Station Seal Beach was established. The base had two key functions; storing and loading ammunition for U.S. naval ships and providing anti-submarine, anti-torpedo nets for stationary bases at sea. Today the Naval Weapons Station Seal Beach mission is the storing, loading and unloading of weapons systems. Additionally, located on the Weapons Station is the 965 acre Seal Beach Wildlife Refuge. Naval Weapons Station Seal Beach Integrated Cultural Resources Management Plan The Integrated Cultural Resources Management Plan (ICRMP) for Naval Weapons Station Seal Beach provides for the management of cultural resources within the Naval Weapons Station, which includes both archaeological and built environment resources. The ICRMP presents information regarding previously identified cultural resources within Naval Weapons Station Seal Beach and

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defines the appropriate procedures for managing and protecting these resources in compliance with federal cultural resource statutes, regulations, Executive Orders, and instructions. In total, 39 archaeological studies have been conducted at Naval Weapons Station Seal Beach, including 11 surveys, eight archaeological evaluations, and two data recovery programs. These studies have resulted in the survey of all but 40 acres (30 acres in the northeast agricultural field and 10 acres in the southeast agricultural field), resulting in the identification of eight archaeological sites. Eight archaeological sites have been recorded within the boundaries of Naval Weapons Station. Of these, two (CA-ORA-298 and CA-ORA-322/1118) have been determined eligible for the National Register of Historic Places (NRHP) under NRHP Criterion D. Three additional sites (CA-ORA-1502, CA-ORA-1503, and CA-ORA-1504) have been recommended eligible under NRHP Criterion D. Built environmental resources at Naval Weapons Station Seal Beach consist of 230 buildings, 243 structures, 90 utility objects, 51 miles of railroad track, 71 miles of paved road, and 92,268 square feet of wharf. No buildings structures, or objects within the Weapons Station have been determined eligible for the National Register of Historic properties. In 1999, 157 World War II-era properties were determined eligible for the NRHP as contributors to the Naval Weapons Station Seal Beach Seal Beach Historic District. However, a statewide study of California’s historic military built environment in 2000 provided new contextual information that led to the determination in 2003 that all 157 properties were not eligible for the NRHP. Another 1999 study resulted in a recommendation of NRHP eligibility for 19 Cold War-era buildings and structures within the RT&E Area for their role in the development, testing, and manufacturing of the Saturn S-II rocket, which helped send American astronauts to the moon in 1969. While the National Aeronautics and Space Administration (NASA) Saturn S-II Historic District has never been formally determined eligible for the NRHP, it has been treated as a potentially eligible district. Project Impacts A. Would the project cause a substantial adverse change in the significance of a historical resource as defined in Section 15064.5 of the CEQA Guidelines? Less than Significant with Mitigation: The proposed monitoring well sites and the location where the Bolsa Chica Channel Levee repair activities would occur

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are located areas that have been disturbed from previous construction activities. Based on review Naval Weapons Station Seal Beach Integrated Cultural Resources Management Plan are no recorded historic structures on the locations where the proposed monitoring wells levee repair activities would occur. Based on previous surveys conducted at the Naval Weapons Station there would be low potential to encounter unknown historic resources during well drilling activities. As a precaution it is recommended that a halt condition be in place in the unlikely event unknown cultural resources are encountered. If indications of cultural resources are encountered, construction activity in the location of the finding would cease and a qualified archeologist would be retained to examine the resources and determine the significance of the finding. With the implementation of Mitigation Measure CR-1 potential significant impacts to cultural resources would be less than significant. Mitigation Measure CR-1: In the event unknown historic and pre-historic resources are encountered during construction operations, all construction operations within the vicinity of the find shall cease until the time a professional archeologist assesses the find to determine its significance. B. Would the project cause a substantial adverse change in the significance of an archaeological resource pursuant to Section 15064.5 of the CEQA Guidelines? Less than Significant with Mitigation: Potential impacts to archeological resources would be similar to level of impact to historic resources. There would be low potential to encounter archaeological resources at the proposed well sites or at the location where the level repair activities would occur. As a precaution it is recommended that a halt condition be in place in the unlikely event unknown cultural resources are encountered. If indications of cultural resources are encountered, construction activity in the location of the finding would cease and a qualified archeologist would be retained to examine the resources and determine the significance of the finding. With the implementation of Mitigation Measure CR-1 potential significant impacts to cultural resources would be less than significant. Mitigation Measure Mitigation Measure CR-1 is required. C. Would the project disturb any human remains, including those interred outside of formal cemeteries?

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Less than Significant impact with Mitigation: No human remains or cemeteries are known to exist within or near the project area. Therefore, it would be highly unlikely that human remains would be encountered when well drilling and levees repair activities are occurring. In the event of the accidental discovery or recognition of any human remains, CEQA Guidelines Section 15064.5; Health and Safety Code Section 7050.5; Public Resources Code Section 5097.94 and Section 5097.98 must be followed. With the implementation of Mitigation Measure CR-2 potential impacts to human remains would be less than significant. Mitigation Measure CR-2: Project-related earth disturbance has the potential to unearth previously undiscovered human remains, resulting in a potentially significant impact. If human remains are encountered during excavation activities, all work will halt and the County Coroner will be notified (California Public Resources Code §5097.98). The Coroner will determine whether the remains are of forensic interest. If the Coroner determines that the remains are prehistoric, s/he will contact the Native American Heritage Commission (NAHC). The NAHC will be responsible for designating the most likely descendant (MLD), who will be responsible for the ultimate disposition of the remains, as required by Section 7050.5 of the California Health and Safety Code. The MLD will make his/her recommendation within 48 hours of being granted access to the site. The MLD’s recommendation will be followed if feasible, and may include scientific removal and non-destructive analysis of the human remains and any items associated with Native American burials (California Health and Safety Code §7050.5). If the landowner rejects the MLD’s recommendations, the landowner will rebury the remains with appropriate dignity on the property in a location that will not be subject to further subsurface disturbance (California Public Resources Code §5097.98). Paleontological Resources Setting 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.

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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 five-fold 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 rock unit, and/or method of rock formation such as alternation by heat and pressure. D. Would the project directly or indirectly disturb or destroy a unique paleontological resource or site? Less than Significant Impact with Mitigation: A record search was conducted by the Natural Museum of History to identify the potential for paleontological resources to be present within the project area. The entire project area has surficial deposits of younger Quaternary Alluvium derived primarily as fluvial deposits from the Bolsa Chica Channel or from marshy deposits on the Naval Weapons Station Seal Beach, which are unlikely to contain fossil remains. Even though it is very unlikely paleontological resources would be encountered during well drilling and levee repair construction activities, a halt construction activity condition is recommended in the unlikely event paleontological resources are encountered. With the implementation of Mitigation Measure C-3 potential impacts to paleontological resources would be less than significant. Mitigation Measures C-3: In the event evidence of subsurface paleontological resources are encountered during construction, all drilling and other construction activity in the area of the find shall cease and a qualified paleontologist shall determine the significance of the find and if recovery actions are required. If it is determined that the find is significant a Paleontological Resource Mitigation Program shall be prepared.

4.6 Geology/Soils

The following analysis is based on geotechnical studies prepared by Ninyo and Moore Geotechnical Consultants in December of 2016 for the construction of the

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BS13 Monitoring Wells and for repairs to the Bolsa Chica Channel Levee. The technical studies are presented in Appendix C.

A1. Would 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? Less than Significant Impact with Mitigation: According to the California Geologic Survey Seismic Hazard Zone Map Seal Beach Quadrangle, the Newport-Inglewood Fault Zone extends through the Seal Beach National Wildlife Refuge. The Newport-Inglewood Fault is an Active Fault. According to 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 set back from the fault, generally 50 feet from the fault zone. The proposed project does not propose the construction of any structures for human occupancy. Therefore, the construction and operation of the proposed project would not increase the risk injury or death to humans. The proposed monitoring wells would be designed to meet the California Department of Water Resources Well Standards to withstand anticipated ground shaking caused by an earthquake within an acceptable level of risk. To minimize seismic constraints, the proposed repair of the Bolsa Chica Channel levee would be conducted in accordance with recommendations provided in a geotechnical evaluation prepared by Ninyo Moore Geotechnical Consultants. With the implementation of Mitigation Measure GEO-1 and GEO-2 potential seismic shaking impacts would be less than significant. Mitigation Measure GEO-1: The proposed monitoring wells will be designed and constructed in compliance with California Department of Water Resources Well Standards Bulletin 74-90 and Bulletin 74-81. GEO-2: The proposed repair of the Bolsa Chica Channel Levee will be constructed done accordance with geotechnical recommendations provided in the Ninyo & Moore Geotechnical Evaluation of Groundwater Monitoring Well BS13 Bolsa Chica Flood Control Levee, Dated December 14, 2016. A2. Would the project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving strong seismic ground shaking? Less than Significant Impact with Mitigation: The project area is located in a seismically active region that could be subject to seismic shaking during

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earthquakes generated from surrounding active faults in the region. An active fault is one that has historically produced earthquakes or shown evidence of movement within the past 11,000 years. The closest active fault to the project area is the Seal Beach Fault segment of the Newport-Inglewood Fault Zone. The fault zone extends from Long Beach through the Naval Weapons Station, City of Huntington Beach and along the coast to the City of Newport Beach. Additionally, the Palos Verdes Fault Zone lies approximately 8.5 miles offshore from the project area. The Newport-Inglewood Fault is capable of producing an earthquake of 7.5 or greater on the Richter Scale. In the event of an earthquake of this magnitude occurs, the proposed monitoring well sites would have the potential for periodic shaking, possibly of considerable intensity. The degree of shaking that could be felt would depend on the distance from the earthquake source and size of earthquake and type of subsurface material on which the site is situated. The risk for seismic shaking impacts within the project area would be similar to other areas in the southern California region and would not be any greater with the implementation of the proposed project. To minimize seismic constraints the proposed monitoring wells would be designed to meet the California Department of Water Resources Well Standards to withstand anticipated ground shaking caused by an earthquake within an acceptable level of risk and the proposed repairs to the Bolsa Chica Channel Levee would be conducted in accordance with recommendations provided in a geotechnical evaluation prepared by Ninyo Moore Geotechnical Consultants. With the implementation of Mitigation Measures GEO-1 and GEO-2 potential seismic shaking impacts would be less than significant. Mitigation Measure Mitigation Measure GEO-1 and GEO-2 is required. A3. Would the project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving liquefaction? Less than Significant Impact with Mitigation: 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. Liquefaction is known generally to occur in saturated or near-saturated cohesionless soils at depths shallower than 50-feet below the ground surface. According to California Geologic Survey Seismic Hazard Zone Map for the Seal Beach Quadrangle, the project area is located within areas where historic occurrence of liquefaction has occurred. To minimize liquefaction constraints the proposed monitoring wells would be

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designed to meet the California Department of Water Resources Well Standards to withstand anticipated ground shaking and associated liquefaction impacts caused by an earthquake within an acceptable level of risk and the proposed repairs to the Bolsa Chica Channel Levee would be conducted in accordance with recommendations provided in a geotechnical evaluation prepared by Ninyo Moore Geotechnical Consultants. With the implementation of Mitigation Measures GEO-1 and GEO-2 potential seismic shaking impacts would be less than significant. Mitigation Measure Mitigation Measure GEO-1 and GEO-2 is required. A4. Would the project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving landslides? No Impact: The California Geologic Survey Seismic Hazard Zone Map Seal Beach Quadrangle indicates that the project area is not within an earthquake- induced Landslide Zone. Therefore, the potential for landslide impacts would be less than significant. No mitigation measures are required. B. Would the project result in substantial soil erosion or the loss of topsoil? Less than Significant Impact with Mitigation: Construction of the proposed project would result in ground surface disruption during the construction of the proposed monitoring wells and from the destruction of the existing monitoring wells. The proposed project would disturb less than one acre of area and would not be required to obtain coverage under a General Construction Permit or prepare a Storm Water Pollution Prevention Plan. To minimize potential erosion impacts Best Management Practices would be implemented during well construction and well destruction activities. With the implementation of Mitigation Measures GEO-3 potential erosion impacts would be less than significant. Mitigation Measures GEO-3: During construction and operation of the project Best Management Practices shall be implemented to minimize the potential for erosion. Erosion Control Best Management Practices shall include as appropriate; installation of silt fencing and fiber rolls, applying erosion control blanket, erosion control seeding light watering of disturbed areas and stockpiles and preserving existing vegetation.

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C. Would the project be located on a geologic unit or soil that is unstable or that would become unstable as a result of the project and potentially result in on or off site landslide, lateral spreading, subsidence, liquefaction or collapse? Liquefaction Less Than Significant Impact with Mitigation: The project area vicinity is underlain by granular soils and a shallow water table, which suggests that liquefaction could pose a seismic hazard. The California Geologic Survey Seismic Hazard Zone Map Seal Beach Quadrangle indicates that the project area lies within a Liquefaction Hazard Zone. To minimize liquefaction constraints the proposed monitoring wells would be designed to meet the California Department of Water Resources Well Standards to withstand anticipated ground shaking and associated liquefaction impacts caused by an earthquake within an acceptable level of risk and the proposed repairs to the Bolsa Chica Channel Levee would be conducted in accordance with recommendations provided in a geotechnical evaluation prepared by Ninyo Moore Geotechnical Consultants. With the implementation of Mitigation Measures GEO-1 and GEO-2 potential seismic shaking impacts would be less than significant. Mitigation Measure Mitigation Measures GEO-1 and GEO-2 is required. Subsidence Monitoring Well Site BS13, Bolsa Chica Channel Levee Less than Significant Impact with Mitigation: The ground settlement that occurred to the Bolsa Chica Channel Levee in 2015 was evaluated by Ninyo and Moore Geotechnical Consultants. During site visits conducted by Ninyo and Moore, no visible evidence of additional settlement, additional ground cracking or other disturbances were observed. According to Ninyo and Moore, the materials were saturated below depths of approximately 8 feet and the groundwater likely reached equilibrium. According to Ninyo and Moore Geotechnical Consultants the potential for significant future ground settlement would be considered low. To ensure that there would be no settlement constraints associated with the construction of BS13, Ninyo & Moore evaluated the subsurface conditions of the site to support a drill rig and associated equipment and to provide recommendations of a setback distance from the drilling equipment to the abandoned well. The remedial repair recommendations for the Bolsa Chica Channel Levee included; over-excavation of the upper 5 feet of soil, construction

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of compacted fill with three layers of geogrid reinforcement, setback and drainage recommendations. With implementation of the geotechnical improvements, the slope stability analysis conducted by Ninyo and Moore concluded that the drilling equipment loads should not impact the levee slope during the installation of Monitoring Well BS13. With the implementation of Mitigation Measures GEO-1, GEO-2 and GEO-4 potential subsidence impacts would be less than significant. Mitigation Measures Mitigation GEO-1 and GEO-2 required. GEO-4: The installation of Monitoring Well BS13 will be done accordance with geotechnical recommendations provided in the Ninyo & Moore Geotechnical Evaluation of Groundwater Monitoring Well BS13 Bolsa Chica Flood Control Levee, Dated December 30, 2016. Monitoring Well Site BS24 No subsidence has been documented in the project area and the proposed project does not involve the extraction of groundwater. Therefore, potential subsidence impacts associated with the proposed project would be less than significant. No mitigation measures are required. D. Would 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? Monitoring Well BS13, Bolsa Chica Channel Levee Repair Less than Significant Impact with Mitigation: The subsurface conditions underlying the location where the construction activities for the BS13 monitoring wells would occur and the location where the repairs to Bolsa Chica Channel Levee would occur both consist of shallow fill soils overlying interbedded alluvial sediments. Geotechnical evaluations conducted on the sites determined that the proposed project would be geotechnical stable with the incorporation of the design recommendations into the construction activities. With the implementation of Mitigation Measures GEO-1, GEO-2 and GEO-4 potential soil constraints would be less than significant. Monitoring Well Site BS24 Less than Significant Impact: According to the Orange County Soil Survey the soil within project area is mostly Bolsa silt loam or Bolsa silty clay loam which is considered to have severe limitations for development. The proposed project

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does not propose the construction of any foundations or structures that will be subject to soil constraints. To ensure the proposed monitoring wells are geotechnical stable they would be designed to meet the California Department of Water Resources Well Standards. With implementation of Mitigation Measure GEO-1 potential soil constraints would be less than significant. Mitigation Measure Mitigation Measure GEO-1, GEO-2 and GEO-4 is required. E. Would the project have soils incapable of adequately supporting the use of septic tanks or alternative waste disposal systems where sewers are not available for the disposal of wastewater? No Impact: The proposed project does not involve construction of septic tanks or other alternative wastewater disposal systems. No mitigation measures are required.

4.7 Greenhouse Gas Emissions The following analysis is based on the Air Quality and Greenhouse Gas Analysis Report prepared by Vista Environmental in October 2017. The Air Quality and Greenhouse Gas Analysis Report is presented in its entirety in Appendix A. Background 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 criteria pollutant analyses. At very high indoor concentrations (not at levels existing outside), carbon dioxide,

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methane, sulfur hexafluoride, and some chlorofluorocarbons can cause suffocation as the gases can displace oxygen. Regulatory Framework 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. 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.

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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.

Project Impacts A. Would the project generate GHG emissions, either directly or indirectly, that may have a significant impact on the environment? Less than Significant Impact: The operation of the proposed project would not generate GHG emissions, either directly or indirectly. However, the construction of the proposed project, water sampling , well redevelopment activities and repair activities to the Bolsa Chica Channel Levee would emit GFG. The CalEEMod model was utilized to calculate the GHG emissions from each phase of well construction activities, well sampling activities, well redevelopment activities and from repair activities to the Bolsa Chica Channel Levee. Table 14 shows the GHG emissions from each phase of construction at one monitoring well site and the total construction GHG emissions from all 11 monitoring well sites. Table 12 Project Related Greenhouse Gas Annual Emissions Greenhouse Gas Emissions (Metric Tons per Year) Category CO2 CH4 N2O CO2e Construction Levee Repair Phase 1 2.35 0.00 0.00 2.37 Levee Repair Phase 2 3.36 0.00 0.00 3.39 Levee Repair Phase 3 0.62 0.00 0.00 0.63 Monitor Well Mobilization for One Well Site 2.50 0.00 0.00 2.52 Monitor Well Drilling and Construction for One Well 203.38 0.04 0.00 204.45 Site Monitor Well Development for One Well Site 22.08 0.00 0.00 22.19 Total Construction Emissions of 11 Well Sites 2,577.22 0.47 0.00 2,590.94

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1 Amortized Construction Emissions (30 years) 85.91 0.02 0.00 86.36 Operations Well Sampling and Water Levels One Well Site (14 8.08 0.00 0.00 8.11 times per year) Well Redevelopment for One Well Site 9.62 0.00 0.00 9.63 2 Amortized Well Redevelopment Emissions (3 years) 3.21 0.00 0.00 3.21 Total Operational Emission for 11 Well Sites 124.13 0.00 0.00 124.52 Total Annual Emissions (Construction & 210.04 0.02 0.00 210.88 Operations) SCAQMD Modified Draft Threshold of Significance3 2,499 Notes: 1 Construction emissions amortized over 30 years as recommended in the SCAQMD GHG Working Group on November 19, 2009. 2 Well Redevelopment amortized over 3 years as that is the worst-case schedule for well redevelopment. 3 SCAQMD’s Bright Line threshold of 3,000 MTCO2e per year was reduced by 16.7 percent to account for AB 197 and SB 32. Source: CalEEMod Version 2016.1.3. The data provided in Table 14 shows that the proposed project would create

210.88 MTCO2e per year. According to the SCAQMD draft threshold of significance, a cumulative global climate change impact would occur if the GHG emissions created from the on-going operations would exceed 2,499,000

MTCO2e per year which has been modified to account for the more stringent GHG emissions reductions required by AB 197 and SB 32. Therefore, a less than significant generation of greenhouse gas emissions would occur from construction and operation of the proposed project. B. Would the project be in conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases? Less than Significant Impact: The proposed project would not conflict with any applicable plan, policy or regulation of an agency adopted for the purpose of reducing GHG emissions. The proposed project would consist of the construction and operation of 11 new monitoring wells in the City of Seal Beach and minor repairs to the Bolsa Chica Flood Channel Levee. In general, operation of the monitoring wells would be passive as there would be no permanent equipment installed in the well. OCWD staff would collect groundwater samples semi-annually and record water levels from the wells on a monthly basis. In total, each monitoring well would be visited by OCWD staff 14 times per year. Every three to five years OCWD would conduct maintenance activities to sample and redevelop the 11 monitoring wells. The City of Seal Beach has not yet adopted a Climate Action Plan, so the applicable plan is the SCAQMD’s GHG Working Group.

The proposed project is anticipated to create an average of 210.88 MTCO2e per year, which would be well below the SCAQMD modified draft threshold of

significance of 2,499,000 MTCO2e per year that has been modified to account for

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the more stringent GHG emissions reductions required by AB 197 and SB 32.

The SCAQMD developed a bright line threshold of 3,000 MTCO2e per year through a Working Group, which also developed detailed methodology for evaluating significance under CEQA. However, the SCAQMD’s Working Group’s thresholds were prepared prior to the issuance of Executive Order B-30-15 on April 29, 2015 that provided a reduction goal of 40 percent below 1990 levels by 2030. This target was codified into statute through passage of AB 197 and SB 32 in September 2016. The Staff Report Proposed Update to the SB 375 Greenhouse Gas Emission Reduction Targets, prepared by CARB June 2017, provides recommendations the MPOs located within the State to meet the new SB 32 targets. For SCAG, which is the MPO that represents Southern California, including the project site, this Report recommends that SCAG increase its year 2035 efficiency target from an 18 percent reduction to a 21 percent reduction in order to account for AB 197 and SB 32. This equates to a 16.7 percent increase in SCAG reduction target for the year 2035. In order to provide a conservative analysis, the Bright Line threshold of 3,000 MTCO2e per year was reduced by 16.7 percent to account for AB 197 and SB 32, which results in a modified Bright

Line threshold of 2,499 MTCO2e per year. Therefore, the proposed project would not conflict with any applicable plan, policy or regulation of an agency adopted for the purpose of reducing the emissions of greenhouse gases.

4.8 Hazards/Hazardous Materials

A. Would the project create a significant hazard to the public or the environment through the routine transport, use or disposal of hazardous materials. Less than Significant Impact with Mitigation: The long-term operation of the proposed project would not involve the routine transportation, disposal or emission of hazardous materials or waste. Construction operations associated with the project would involve the handling of incidental amounts of hazardous materials, such as fuels, oils and solvents. To minimize the inadvertent release of hazardous substances into the environment, the proposed project would be required to comply with local, State and Federal laws and regulations regarding the handling and storage of hazardous materials. Additionally, all heavy construction equipment operating near the Seal Beach National Wildlife Refuge salt water marsh would be required to have a hazardous material spill prevention plan available in the event of the inadvertent release of hazardous substances into the environment. With implementation of Mitigation Measures HAZ-1 and

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HAZ-2 potential adverse impacts associated with the release of hazardous substances into the environment would be less than significant. Mitigation Measure HAZ-1:-During construction activities the project will be required to comply with local, State and Federal laws and regulations regarding the handling and storage of hazardous substances. HAZ-2: Heavy construction equipment operating near the Seal Beach National Wildlife Refuge salt water marsh will prepare and have available a Hazardous Material Spill Prevention Plan. The Hazardous Material Spill Prevention Plan shall will contingency clean-up plans in the event of an accidental release of hazardous substances into the environment. B. Would the project create a significant hazard to the public or environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? Less than Significant Impact with Mitigation: The operation of the proposed project would not involve any activities that would have the potential to release hazardous materials into the environment. During construction, limited quantities of hazardous materials would be required to operate equipment and vehicles. All federal, state and local laws and regulations would be followed regarding the handling of hazardous materials. The compliance with federal, state and local laws and regulations would reduce potential impacts associated with the handling of hazardous materials during construction to a less than significant level. With implementation of Mitigation Measures HAZ-1 and HAZ-2 potential adverse impacts associated with the release of hazardous substances into the environment would be less then significant. During construction diesel particulate matter emissions would be emitted from construction equipment operations. A significant exposure to diesel particulate matter is a known cancer risk. The construction activities for the project would occur over an approximately 30 day period. The assessment of cancer risk is typically based on a 30- to 70-year exposure period. Because the potential exposure to diesel exhaust from the proposed project would be substantially less than the 30- to 70-year exposure period, the incremental cancer risk to exposed persons would be negligible and the impact would be less than significant. Mitigation Measure Mitigation Measure HAZ-1 and HAZ-2 `is required.

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C. Would the project emit hazardous emissions or handle hazardous or acutely hazardous materials, substance or waste within one-quarter mile of an existing or proposed school. No Impact: The long-term operation and construction activities associated with the proposed project would not emit hazardous emissions, or involve the handling of acutely hazardous substances within one-quarter mile of an existing or proposed school. No mitigation measures are required. D. Would 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? No Impact: Based on coordination with Naval Weapons Station there is no known hazardous waste sites located on or within the nearby vicinity of the project area that would pose a significant impact to the environment or the public. No mitigation measures are required. E. For a project located within an airport land use plan or where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project the result in a safety hazard for people residing or working within the project area? No Impact: The Airport Land Use Commission (ALUC) of Orange County assists local agencies to ensure that here are no direct conflicts with land uses, noise or other issues that will impact the functionality and safety of airport and heliport operations. The ALUC requires that local jurisdictions general plans and zoning ordinances are consistent with Airport Environs Land Use Plans (AELUP’s), which contain noise contours, restrictions for types of construction and building heights in navigable air space, as well as requirements impacting the establishment or construction of sensitive uses within close proximity to airports. The closest airport facility to the project area is the Los Alamitos Joint Forces Training Base. The AELUP for the Los Alamitos Joint Forces Training Base indicates that the project area is within the AELUP Height Restriction Zone. The proposed monitoring wells would be housed in underground faults and would not encroach into any navigable air space. Additionally, the existing monitoring wells destruction activities would not be subject airport related safety hazards. No mitigation measures are required. F. For a project within the vicinity of a private airstrip, would the project result in a safety hazard for people residing or working in the project area?

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No Impact: There are not private air strips within the vicinity of the project area that would pose safety hazards to the public. G. Would the project impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? No Impact: The construction and operation of the proposed project would generate minimal traffic and would not involve any activities that would interfere with emergency response plans. No mitigation measures are required. H. Would the project expose people or structures to a significant risk of loss, injury or death involving wildland fires, including where wildlands are adjacent to urbanized areas or where residences are intermixed with wildlands? No Impact: The project site is not adjacent to or intermixed with wildlands. Therefore, there would not be any potential wildland fire impacts associated with the operation and construction of the proposed project. No mitigation measures are required.

4.9 Hydrology/Water Quality Existing Conditions The project area is located at the northwest area of the lower Santa Ana River watershed. The primary surface water bodies within the project area include; Bolsa Chica Channel, Huntington Harbor, Anaheim Bay and Bolsa Bay. The project area also overlies the Orange County Groundwater Basin. Bolsa Chica Channel Bolsa Chica Channel is regional flood control channel operated by the Orange County Flood Control District. The Bolsa Chica Channel drainage area consists of approximately 5,610 acres and drains into Huntington Harbor and Anaheim Bay. The primary tributaries to Bolsa Chica Channel are Westminster Channel and the Barber Channel. The Bolsa Chica Channel is trapezoidal earth lined channel. Within the project area the channel is approximately 150 feet in width. The Bolsa Chica Channel is designated as Zone A, and 100 year flood flows are contained in the channel. Huntington Harbor Huntington Harbor is 680 acre harbor with five manmade peninsulas islands. The harbor and peninsulas islands are located on the former site of the historic Sunset Bay Estuary Wetlands. The area surrounding Huntington Harbor is predominantly residential with small boat marina activity. Bolsa Chica Channel

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drains directly into Huntington Harbor. The harbor receives limited tidal flushing and as elevated levels water quality pollutants. Anaheim Bay Anaheim Bay is situated between the City of Seal Beach and the Surfside Community. Presently, the U.S Navy controls access to Anaheim Bay from the outer bay, which serves as the main entrance to the U.S. Naval Weapons Station Seal Beach. Anaheim Bay maintains a hydrologic connection to Huntington Harbor. The watershed for Anaheim Bay is approximately 50,000 acres. The primary channel draining onto Anaheim Bay is Bolsa Chica Channel which drains through Sunset Aquatic Park and Huntington Harbor before draining into Anaheim Bay. Bolsa Bay Bolsa Bay is located south from Huntington Harbor. Bolsa Bay consists of an Inner Bolsa Bay and an Outer Bolsa Bay. The Outer Bolsa Bay is directly connected to Huntington Harbor, which is the only area fully open to tidal influence. Inner Bolsa Bay has controlled tidal regime through the use of flood gates to Outer Bolsa Bay. The East Garden Grove Wintersburg Flood Control Channel is the primary flood control channel that drains into Bolsa Bay. 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 to 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. The proposed project would be implemented along the Sunset Gap coastal boundary of the Orange County Groundwater Basin. Recent studies have shown at the Sunset Gap that depths of approximately 100-150 feet and 200-250 feet below surface are susceptible to seawater intrusion and pose a serious water quality threat to the Orange County Groundwater Basin. Regulatory Setting 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

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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 proposed project. 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. The following is listing of 303(d) impaired water bodies in the vicinity of the project area. • Anaheim Bay: Listed impairment Dieldrin, Nickel, PCB, Sediment Toxicity • Huntington Harbor: Listed impairment Chlordane, Copper, Lead, Nickel, Pathogens, PCB, Sediment Toxicity 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, referred as MS4 Permit. Porter Cologne California Water Quality Control Act The Porter Cologne Water Quality Act of 1967 requires the State Water Resources Control Board (SWRCB) and the nine Regional Water Quality Control Boards (RWQCB) 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.

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Regional Water Quality Control Board Beneficial Uses The surface waters and groundwater within the vicinity of the project area is under the jurisdiction of the Santa Ana Region Regional Water Quality Control Board and regulated through the Santa Ana Region Basin Plan (Basin Plan). 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 the beneficial uses. Table 15 describes the beneficial uses in the Basin Plan. Table 13: 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

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Abbreviation Beneficial Use 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.

COMM Commercial and Sportfishing 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.

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Presently, the Basin Plan establishes beneficial uses for Huntington Harbor, Anaheim Outer Bay, Anaheim Inner Bay, and Bolsa Bay. The Basin Plan does not establish any beneficial uses for Bolsa Chica Channel. However, the Basin Plan does establish beneficial uses at the tidal prisms of flood control channels discharging to coastal or bay waters, which applies to Bolsa Chica Channel. Table 16-21 identifies beneficial uses for project area surface water bodies and for the Orange County Groundwater Basin.

Table 14: Tidal Prism Bolsa Chica Channel Beneficial Use Condition MUN + REC 1 X REC 2 X COMM X WILD X MAR X + Excepted Use, X Potential/Present Use, I Intermittent Use

Table 15: Huntington Harbor Beneficial Use Condition MUN + NAV X REC 1 X REC 2 X COMM X WILD X RARE X SPWN X MAR + Excepted Use, X Potential/Present Use, I Intermittent Use

Table 16: Anaheim Bay Outer Bay Beneficial Use Condition MUN + NAV X REC 1 X REC 2 X BIOL X WILD X RARE X SPWN X MAR X + Excepted Use, X Potential/Present Use, I Intermittent Use

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Table 17: Anaheim Bay Seal Beach Wildlife Refuge Beneficial Use Condition MUN + REC 1 X REC 2 X BIOL X WILD X RARE X SPWN X MAR X EST X + Excepted Use, X Potential/Present Use, I Intermittent Use

Table 18: Bolsa Bay Beneficial Use Condition MUN + REC 1 X REC 2 X COMM X BIOL X WILD X RARE X SPWN X MAR X SHEL X + Excepted Use, X Potential/Present Use, I Intermittent Use

Table 19: Orange County Groundwater Basin Beneficial Use Condition MUN X AGR X IND X PROC X + Excepted Use, X Potential/Present Use, I Intermittent Use

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 22 identifies the Water Quality Objectives for surface water bodies and the Orange County Groundwater Basin.

Table 20: Water Quality Objectives (mg/L)

Reach TDS HARD Na CI TIN SO4 COD B Tidal Prism Bolsa Chica NL NL NL NL NL NL NL NL Channel/ Huntington Harbor

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Reach TDS HARD Na CI TIN SO4 COD B Huntington Harbor NL NL NL NL NL NL NL NL Anaheim Bay Outer Bay NL NL NL NL NL NL NL NL Anaheim Bay Seal NL NL NL NL NL NL NL NL Beach Wildlife Refuge Bolsa Bay NL NL NL NL NL NL NL NL Orange County 580 NL NL NL NL NL NL NL Groundwater Basin

Project Impacts A. Would the project violate Regional Water Quality Control Board Water Quality standards or waste discharge standards? The following analysis evaluates if the proposed project would violate water quality standards established in the Santa Ana Region Basin Plan. The analysis evaluates the proposed project consistency with beneficial uses, water quality objectives, compliance with 303 (d) Impaired Water Body requirements and NPDES storm water management requirements. Beneficial Uses Surface Waters-Proposed Monitoring Well Sites Less than Significant Impact with Mitigation: The proposed project involves the construction and operation 11 monitoring wells at the Naval Weapons Station. The construction activities for these monitoring wells would have the potential to result in localized erosion, sediment transport and degraded surface water runoff impacts that could discharge into the Naval Weapons Station and City of Seal Beach municipal storm drain system, Bolsa Chica Channel, Anaheim Bay or the National Wildlife Refuge. During construction activities Best Management Practices would be implemented to minimize construction related water quality impacts to maintain water quality. During the construction monitoring wells and repair activities to the Bolsa Chica Channel Levee Best Management Practices would be followed at all times During maintenance activities the monitoring wells would have to be backwashed. The effluent would be placed in a tank any transported offsite. With the implementation of Mitigation Measures HWQ-1 and HWQ-2 potential conflicts with beneficial uses established in the Santa Ana Region Basin Plan would be less than significant. Orange County Groundwater Basin Less Than Significant Impact: The proposed project would help to monitor if groundwater beneficial uses are maintained. The construction and operation of

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the proposed project would not have any adverse impacts that would result in conflicts with beneficial uses established for the Orange County Groundwater Basin. No mitigation measures are required. Water Quality Objectives Surface Waters No impact: The Santa Ana Region Basin Plan does not identify water quality objectives for Bolsa Chica Channel, Huntington Harbor, Anaheim Bay, Bolsa Bay, Seal Beach Wildlife Refuge or the tidal Prism of Bolsa Chica Channel/Huntington Harbor. Therefore, the construction and operation of the proposed monitoring wells and the repair activities to the Bolsa Chica Channel Levee would not result in conflicts with any water quality objectives for these water bodies. No mitigation measures are required. Orange County Groundwater Basin Less Than Significant Impact: The Santa Ana Region Basin Plan establishes water quality objective of 580 MG/L for TDS for the Orange County Groundwater Basin. The construction and operation of the proposed monitoring wells would not introduce elevated levels of TSD into the groundwater basin that would exceed established water quality objectives. Therefore, the proposed project would not be in conflict with water quality objectives established for the Orange County Groundwater Basin. No mitigation measures are required. Section 303 (d) Impaired Water Bodies Less Than Significant Impact with Mitigation: Huntington Harbor has been identified has an impaired water body for Chlordane, Copper, Lead, Nickel, Pathogens, PCB, and Sediment Toxicity. Anaheim Bay has been identified has an impaired water body for Dieldrin, Nickel, PCB, and Sediment Toxicity. The long term operation of the proposed monitoring wells would not discharge any pollutants into any impaired water body. During maintenance operations, effluent backwater would be placed in tanks and transported offsite. During construction of the proposed project Best Management Practices would be implemented to maintain water quality at the construction sites. With the implementation of Mitigation Measures HWQ-1 and HWQ-2 potential water quality impacts would be less than significant. NPDES Storm Water Management Requirements Less than Significant Impact with Mitigation: As part of the proposed project, subsurface faults with metal covers would be constructed for the proposed

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monitoring wells. Assuming that all 11 monitoring wells would have metal covers, approximately 800 feet of new impervious surfaces would be introduced into the project area. This amount of impervious surfaces would not meet the criteria for a Priority Project under the County of Orange 4th Term Municipal NPDES MS4 Storm Water Permit and therefore the project would not be required to prepare a Water Quality Management Plan. The proposed project may be considered a Non-Priority Project and could be required to prepare Non-Priority Project Plan. The Non-Priority Project Plan would require identification and implementation Best Management Practices to maintain water quality. Prior to the start of construction OCWD would coordinate with the County of Orange and the Naval Weapons Station on the need to prepare a Non-Priority Project Plan for the proposed project. With the implementation of Mitigation Measure HWQ-3 long- term storm water management impacts would be less than significant. Construction operations associated with the proposed project would disturb less than 1 acre of area and would not be required to obtain coverage under a General Construction Permit. During construction operations Best Management Practices would be implemented to manage storm water runoff to maintain water quality in Bolsa Chica Channel, Huntington Harbor, Anaheim Bay, Bolsa Bay, Seal Beach National Wildlife Refuge and within the tidal Prism of Bolsa Chica Channel/Huntington Harbor. These measures include minimizing water and wind erosion, establishing and implementing construction equipment delivery and storage procedures, vehicle and equipment maintenance procedures, stockpiling site requirements and solid waste management. Additionally, any effluent backwash water associated with maintenance activities for the proposed monitoring wells would be placed in a tank and transported offsite to be disposed of properly. With the implementation of Mitigation Measure HWQ-1, HWQ-2 and HWQ-3 potential short-term storm water management impacts would be less than significant. Mitigation Measures HWQ-1:-During construction and maintenance activities for the project, Best Management Practices shall be implemented. These measures shall include where applicable; minimizing water and wind erosion, establishing and implementing construction equipment delivery and storage procedures, vehicle and equipment maintenance procedures, stockpiling site requirements and solid waste management procedures. HWQ-2: Effluent backwash water associated with the maintenance activities for the proposed monitoring wells will be placed in a tank and transported offsite to be disposed of properly.

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HWQ-3: OCWD shall coordinate with the County of Orange and Naval Weapons Station Seal Beach on the preparation of Non-Project Plan to manage long-term storm water impacts. B. Would the project substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level? No Impact: The purpose of proposed project is monitor potential salt water intrusion into the Orange County Groundwater Basin. The proposed project would help to ensure that high quality groundwater supplies are maintained. No mitigation measures are required. C. Would 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 would result in substantial erosion or siltation on or off site? No Impact: The proposed project involves the drilling and construction of 11 monitoring wells. All construction activities would be confined to the well site locations and would not alter any existing drainage patterns. No mitigation measures are required. D. Would 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 would result in flooding on or offsite? Less Than Significant Impact: The construction of the proposed monitoring wells would introduce approximately 800 square feet of new impervious surfaces into the project area. With this amount of new impervious surfaces existing rates of surface water runoff would not increase substantially to cause flooding or alter existing patterns of drainage. No mitigation measures are required. E. Would the project create or contribute runoff which would exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff? Less than Significant with Mitigation: The construction of the proposed monitoring wells would introduce approximately 800 square feet of new impervious surfaces into the project area. With this amount of new impervious surfaces existing rates of surface water runoff would not create or contribute surface water runoff that would exceed existing or planned drainage systems.

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Best Management Practices would be implemented during construction and operation of the project to maintain water quality. With the implementation of Mitigations Measures HWQ-1, HWQ-2 and HWQ-3 potential water quality impacts would be less than significant. Mitigation Measures Mitigation Measures HWQ-1, HWQ-2 and HWQ-3 are required. F. Would the project otherwise degrade water quality? Less than Significant with Mitigation: Implementation of the proposed project would not be in conflict with established beneficial uses and water quality objectives provided in the Santa Ana River Basin Plan, or contribute pollutants to impaired water bodies. Mitigation measures HWQ-1, HWQ-2 and HWQ-3 have been incorporated into the proposed project to reduce construction related storm water runoff impacts and long term storm water management impacts to a less than significant level. Mitigation Measures Mitigation Measures HWQ-1, HWQ-2 and HWQ-3 are required. G. Would the project place housing within a 100-year floodplain, as mapped on a federal Flood Hazard Boundary or Flood insurance Rate map or other flood hazard delineation map? No Impact: The proposed project does not involve construction of any type of housing structures. Therefore, implementation of the proposed project would not subject any housing to potential flood risks. No mitigation measures are required. H. Would the project place within a 100-year floodplain structures which impedes or redirect flows? No Impact: The proposed project would not be constructed in a 100-year floodplain. Additionally the proposed monitoring wells would be at grade and would not redirect or impede any flows into Bolsa Chica Channel. No mitigation measures are required. I. 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? No Impact: The proposed project involves the construction of below ground monitoring wells and the destruction of existing monitoring wells and would not expose people or structures to flood risks. No mitigation measures are required.

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J. Could the project site be inundated by seiche, tsunami, or mudflow? Less than Significant Impact: According to the City of Seal Beach General Plan the project area is not within a tsunami run up area. However, like most coastal communities along the Newport Inglewood Fault, there is risk of tsunami run up impacts if a large seismic event occurs. Implementation of the proposed project would not increase the risk for tsunami impacts over the current condition. The proposed monitoring wells sites are not within vicinity of any impounded water and would not be subject to potential seiche impacts. The proposed project includes geotechnical improvements to the Bolsa Chica Channel Levee to ensure its stability. No mitigation measures are required.

4.10 Land Use/Planning

A. Would the project physically divide an established community? No Impact: The proposed monitoring wells would be constructed and operated on the Naval Weapons Station. OCWD has coordinated with the Naval Weapon Station Staff on the location of the well sites to ensure that the operation of them would not adversely impact any residential communities or neighborhoods that are located on the Naval Weapons Station. No significant adverse impacts to existing communities would occur. No mitigation measures are required. B. Would the project be in conflict with any applicable land use plan, policy or regulation of an agency with jurisdiction over the project adopted for the purpose of avoiding or mitigating an environmental effect? Less than Significant with Mitigation: The proposed monitoring wells would be constructed and operated on the Naval Weapons Station. OCWD has been in coordination with Naval Weapons Station Seal Beach on the selection of the well sites and has determined that the construction and operation of the monitoring wells would not pose conflicts to the operation of the Naval Weapons Station. Prior to the construction of the monitoring wells OCWD would be required to receive an approved access agreement and Special Use Permit to construct and operate the monitoring wells on the Naval Weapons Station. Additionally, along the levee of Bolsa Chica Channel where Monitoring Well Site BS13 and the proposed repairs to the levee would occur, OCWD would need to obtain and access agreement from Orange County Flood Control District. With the implementation of Mitigation Measure L-1 potential land use planning conflicts would be less than significant.

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Mitigation Measure L-1: Prior to the start of monitoring well construction activities OCWD shall coordinate with Naval Weapons Station Seal Beach and Orange County Flood Control District on required permits and approvals needed for the construction and operation of the proposed project. C. Would the project be in conflict with any applicable habitat conservation plan or natural community conservation plan? No Impact: The natural resources on the Naval Weapons Station Seal Beach are under the management of the Navy through the Naval Weapons Station Seal Beach Integrated Natural Resources Plan. As part of the environmental planning for the construction of the new monitoring wells, OCWD has coordinated with Navy on locations that would not be in conflict with management programs and policies provided in the Integrated Natural Resources Plan. No mitigation measures are required.

4.11 Mineral Resources

A. Would the project result in the loss of availability of a locally important mineral resource recovery site delineated on a local general plan, specific plan or other land use? No Impact: The City of Seal Beach General Plan identifies oil extraction operations occurring on Naval Weapons Station Seal Beach. The locations of the proposed monitoring well sites have been coordinated with Naval Weapons Station Seal Beach and no potential conflicts with oil extraction activities have been identified. Additionally, there are no mineral resources in the location where the Bolsa Chica Channel Levee repairs would occur. No mitigation measures are required. B. Would the project result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state? No Impact: The locations of the proposed monitoring well sites and the location where the Bolsa Chica Channel Levee repairs would occur does not contain regionally important mineral resources. No mitigation measures are required.

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4.12 Noise The following analysis is based on a Noise Impact Analysis Report prepared by Vista Environmental in October 2017. The Noise Impact Analysis is presented in its entirety in Appendix C. Background A decibel (dB) is a unit of measurement that indicates the relative intensity of a sound. 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).

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. The 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.

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Noise Levels Noise level can vary pending on the noise source and duration. Table 23 summarizes typical noise sources, levels, and responses.

Table 21: Noise Levels and Human Response

Noise Source Noise Level dBA Response 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/DD is typically observed over soft ground with landscaping, as compared with a 6.0 dBA/DD drop-off rate over 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

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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 Regulatory Programs Federal Regulations There are a number of federal regulations and programs that provide regulations to minimize noise impacts. For example, the Occupational Safety and Health

Administration (OSHA) agency limits noise exposure of workers to 90 dB Leq or less over 8 continuous hours or 105 dB Leq or less over 1 continuous hour. The Federal Aviation Administration (FAA) regulates noise of aircraft and airports. Surface transportation system noise is regulated by a host of agencies, including the Federal Transit Administration, Federal Urban Mass Transit Administration and the Federal Highway Administration. Additionally, the federal government actively advocates that local jurisdictions use their land use regulatory authority to arrange new development in such a way that “noise sensitive” uses are either prohibited from being sited adjacent to a highway or, alternately that the developments are planned and constructed in such a manner that potential noise impacts are minimized. 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 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. For commercial and industrial uses, long-term noise levels up to 65 dBA 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. Conventional construction with closed windows and a fresh air supply system or air conditioning will normally suffice as “acceptable noise

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insulation” features. Long term noise levels between 70 and 80 dBA CNEL are generally unacceptable. Local Regulations Potential noise impacts associated with implementation of the proposed project could impact sensitive receptors in the City of Huntington Beach and the City of Seal Beach. Below are noise regulations from the City of Huntington Beach and the City of Seal Beach that apply to the project. City of Huntington Beach Municipal Code The City of Huntington Beach Municipal Code establishes the following noise regulations that are relevant to the proposed project. 8.40.040 Designated Noise Zones The properties hereinafter described, whether within or without the City, are hereby assigned to the following noise zones: Noise Zone 1: All residential properties; Noise Zone 2: All professional office and public institutional properties; Noise Zone 3: All commercial properties with the exception of professional office properties; and Noise Zone 4: All industrial properties. 8.40.050 Exterior Noise Standards (a) The following noise standards shown in Table 24, unless otherwise specifically indicated, shall apply to all residential property within a designated zone:

Table 22: City of Huntington Beach Municipal Code Exterior Noise Standards

Noise Zone Noise Level Time Period 55 dB(A) 7 a.m. – 10 p.m. 1 50 dB(A) 10 p.m. – 7 a.m. 2 55 dB(A) Anytime 3 60 dB(A) Anytime 4 70 dB(A) Anytime Source: City of Huntington Beach, 2012. The above standard does not apply to the establishment of multi-family residence private balconies and patios. Multi-family developments with balconies or patios

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that do not meet CNEL standards are required to provide occupancy disclosure notices to all future tenants regarding potential noise impacts. (b) In the event the alleged offensive noise consists of entirely or impact noise, simple tone noise, speech, music, or any combination thereof, each of the above noise levels shall be reduced by five (5) dB(A). 8.40.070 Interior Noise Standards (a) The following noise standards shown in Table 25, unless otherwise specifically indicated, shall apply to all real property within a designated zone:

Table 23: City of Huntington Beach Municipal Code Interior Noise Standards

Noise Zone Noise Level Time Period 55 dB(A) 7 a.m. – 10 p.m. 1 45 dB(A) 10 p.m. – 7 a.m. 2, 3, 4 55 dB(A) Anytime Source: City of Huntington Beach, 2012.

8.40.090 Special Provisions The following activities shall be exempt from the provisions of this chapter: (d) Noise sources associated with construction, repair, remodeling, or grading of any real property; provided a permit has been obtained from the City as provided herein; and provided said activities do not take place between the hours of 8 p.m. and 7 a.m. on weekdays, including Saturday, or at any time on Sunday or a federal holiday. (j) Any activity or equipment to the extent that design regulation thereof has been pre-empted by state or federal laws. 8.40.100 Schools, Hospitals and Churches It shall be unlawful for any person to create any noise which causes the noise level at any school, hospital or church while same is in use, to exceed the noise limits specified for exterior noise standards in this chapter, or which noise level unreasonably interferes with the use of such institutions or which unreasonably disturbs or annoys patients in the hospital, provided conspicuous signs are displayed in three (3) separate locations within one-tenth (1/10) of a mile of the institution indicating the presence of a school, hospital or church. City of Seal Beach Municipal Code The City of Seal Beach Municipal Code establishes the following noise regulations that are relevant to the proposed project.

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7.15.010 Designated Noise Zones. The noise zones of the city are as follows: Noise Zone 1: Residential properties. Noise Zone 2: Commercial properties. Noise Zone 3: Industrial, manufacturing and oil properties. 7.15.015 Exterior Noise Standards A. Unless otherwise specifically indicated, the following exterior noise standards shown in Table 26 shall apply to all property within a designated noise zone.

Table 24: City of Seal Beach Municipal Code Exterior Noise Standards

Noise Zone Noise Level Time Period 55 dB (A) 7:00 a.m. – 10:00 p.m. 1 50 dB (A) 10:00 p.m. – 7:00 a.m. 2 65 dB(A) At any time 3 70 dB(A) At any time

Notes: In the event the alleged offensive noise consists of impact noise, simple tone noise, speech, music, or any combination thereof, each of the above noise levels shall be reduced by 5 dB(A). Source: City of Seal Beach Municipal Code Section 7.15.015.

7.15.020 Interior Noise Standards A. Unless otherwise specifically indicated, the following interior noise standards shown in Table 23 shall apply to all residential property within a designated noise zone:

Table 25: City of Seal Beach Municipal Code Interior Noise Standards

Noise Zone Noise Level Time Period 55 dB (A) 7:00 a.m. – 10:00 p.m. 1 50 dB (A) 10:00 p.m. – 7:00 a.m.

7.15.025 Exemptions The following activities are exempt from the provisions of this chapter: E. Noise sources associated with construction, repair, remodeling, or grading of real property performed in the following periods: between 7:00 a.m. and 8:00 p.m. on weekdays and between 8:00 a.m. and 8:00 p.m. on Saturday;

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F. Noise associated with real property maintenance performed in the following periods: between 7:00 a.m. and 8:00 p.m. on weekdays; between 8:00 a.m. and 8:00 p.m. on Saturday; and between 9:00 a.m. and 8:00 p.m. on Sunday or a holiday. G. Activities for which local noise regulations are preempted by federal or state law. Project Impacts A. Would the project expose 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 following analysis evaluates potential noise impacts associated with the construction and operation of the BS13 and BS 24 monitoring wells and construction noise impacts from proposed repairs to the Bolsa Chica Channel Levee to cause an exposure of persons to or generation of noise levels in excess of established Cities of Huntington Beach and Seal Beach noise standards or applicable standards of other agencies. Noise levels in the project area will be influenced by well construction, levee repair construction activities and from on- going well maintenance activities. Monitoring Well BS24 Less than Significant Impact: The nearest sensitive receptors to the BS24 well site are single-family homes on the Naval Weapons Station that are located as near as 0.5 mile west of the proposed well site. Due to the distance to the nearest sensitive receptors to the BS24 monitoring wells, less than significant noise impacts would occur from both construction and operational activities and no further analysis is provided for the BS24 monitoring wells. Monitoring Well BS13 Less than Significant Impact: The nearest sensitive receptor to the BS13 well site are multi-family homes located in the City of Huntington Beach, that are as near as 400 feet to the south of the BS13 well site. The applicable noise standards for the analysis of the BS13 monitoring wells are the City of Huntington Beach Municipal Code and General Plan. Monitoring Well BS13 construction activities involves four construction phases. Below are the potential noise impacts for each construction phase.

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Phase 1 Mobilization (Utility Clearance and Sound Panel Installation) Phase 1 construction activities would include clearing the borehole location of underground utilities followed by sound panel installation and mobilization of the drilling equipment. Construction activities for Phase 1 would occur between 6:00 a.m. and 5:00 p.m., Monday through Friday. Some construction activities could occur outside of the times when construction noise would be exempt under the City of Huntington Beach Municipal Code and these construction activities would be required to adhere to the City of Huntington beach daytime and nighttime exterior noise standards. Both the daytime and nighttime noise impacts were analyzed. Table 26 Phase 1 Mobilization Construction Noise Levels for BS13 Daytime Construction Noise Nighttime Construction Noise Levels (dBA Leq) Levels (dBA Leq) Noise Daytime Exceed Noise Nighttime Exceed Receiver1 Description Level Standard2 Standard? Level Standard2 Standard? 1 MFH at 3536 Bravata 43 55 No 35 50 No 2 MFH at 3496 Bravata 34 55 No 27 50 No 3 MFH at 3552 Bravata 38 55 No 30 50 No 4 MFH at 3582 Bravata 37 55 No 29 50 No 5 MFH at 3608 Bravata 43 55 No 36 50 No 6 MFH at 3662 Montego 43 55 No 35 50 No Notes: 1 Receiver locations shown in Figure 6. 2 The Daytime (7:00 a.m. to 10:00 p.m.) standard is 55 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. 3 The Nighttime (10:00 p.m. to 7:00 a.m.) standard is 50 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. Source: SoundPlan Version 8.0. Table 28 shows that Phase 1 mobilization construction activities would create noise levels as high as 43 dBA Leq during the daytime and 36 dBA Leq during the nighttime at the nearby homes. None of the Receivers would exceed the daytime noise standard of 55 dBA or the nighttime noise standard of 50 dBA. Noise impacts from Phase 1 construction activities would be less than significant. Phase 2 Monitoring Well Drilling and Construction Phase 2 construction activities would include drilling and construction of the monitoring wells. The borehole drilling activities would be required to operate 24- hours per day 7 days a week until completion of the borehole drilling in order to prevent a cave in of the borehole. Some construction activities could occur outside of the times when construction noise would be exempt under the City of Huntington Beach Municipal Code and these construction activities would be required to adhere to the City of Huntington Beach daytime and nighttime exterior

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noise standards. Both the daytime and nighttime noise impacts were analyzed. The noise levels created during the monitor well drilling and construction is shown in Table 29. The calculated noise levels provided in Table 29 accounts for the sound attenuation from the 12-foot high sound wall. Table 27 Phase 2 BS13 Well Drilling and Construction Noise Levels

Daytime Construction Noise Nighttime Construction Noise Levels (dBA Leq) Levels (dBA Leq) Noise Daytime Exceed Noise Nighttime Exceed Receiver1 Description Level Standard2 Standard? Level Standard2 Standard? 1 MFH at 3536 Bravata 50 55 No 50 50 No 2 MFH at 3496 Bravata 38 55 No 38 50 No 3 MFH at 3552 Bravata 38 55 No 38 50 No 4 MFH at 3582 Bravata 46 55 No 46 50 No 5 MFH at 3608 Bravata 49 55 No 49 50 No 6 MFH at 3662 Montego 50 55 No 50 50 No Notes: 1 Receiver locations shown in Figure 6. 2 The Daytime (7:00 a.m. to 10:00 p.m.) standard is 55 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. 3 The Nighttime (10:00 p.m. to 7:00 a.m.) standard is 50 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. Source: SoundPlan Version 8.0. Table 29 shows that the Phase 2 well drilling and construction activities would create noise levels as high as 50 dBA Leq during the daytime and as high as 50 dBA Leq during the nighttime. Table 29 shows that none of the sensitive receptors would exceed the daytime noise standard of 55 dBA or the nighttime noise standard of 50 dBA. With implementation of the 12 foot sound attenuation wall, noise impacts from Phase 2 well drilling and construction activities would be less than significant. The Phase 2 well drilling and construction would be the phase that would create the highest noise levels from the proposed project. The 65 dBA CNEL noise contour would extend as far as 515 feet to the north and the 60 dBA CNEL noise contour would extend as far as 820 feet to the north. Phase 3 Monitoring Well Development Phase 3 construction activities would include development, airlifting and pumping of the monitoring wells. Construction activities for Phase 3 would occur between 6:00 a.m. and 5:00 p.m., Monday through Friday. Some construction activities could occur outside of the times when construction noise would be exempt under the City of Huntington Beach Municipal Code and these construction activities would be required to adhere to the City of Huntington Beach daytime and nighttime exterior noise standards. Both the daytime and nighttime noise impacts

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were analyzed. The noise levels created during the monitor well development are shown in Table 30. The noise levels provided in Table 30 accounts for the sound attenuation from the 12-foot high sound wall.

Table 28 Phase 3 BS13 Monitoring Well Development Noise Levels Daytime Construction Noise Nighttime Construction Noise Levels (dBA Leq) Levels (dBA Leq) Noise Daytime Exceed Noise Nighttime Exceed Receiver1 Description Level Standard2 Standard? Level Standard2 Standard? 1 MFH at 3536 Bravata 39 55 No 31 50 No 2 MFH at 3496 Bravata 31 55 No 23 50 No 3 MFH at 3552 Bravata 35 55 No 27 50 No 4 MFH at 3582 Bravata 32 55 No 24 50 No 5 MFH at 3608 Bravata 38 55 No 31 50 No 6 MFH at 3662 Montego 38 55 No 30 50 No Notes: 1 Receiver locations shown in Figure 6. 2 The Daytime (7:00 a.m. to 10:00 p.m.) standard is 55 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. 3 The Nighttime (10:00 p.m. to 7:00 a.m.) standard is 50 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. Source: SoundPlan Version 8.0. Table 30 shows that the Phase 3 well development activities would create noise levels as high as 39 dBA Leq during the daytime and as high as 31 dBA Leq during the nighttime. Table 30 shows that none of the sensitive receivers would exceed the daytime noise standard of 55 dBA or the nighttime noise standard of 50 dBA. Noise impacts from Phase 3 well development activities would be less than significant. Phase 4 Site Clean Up and Traffic Rated Vault Installation Phase 4 involves site cleanup and installation of the below ground traffic-rates well vault. This phase of work involves minimal equipment and would be done by hand. As such, noise impacts from Phase 4 site cleanup and traffic-rated vault installation activities would be less than significant. Bolsa Chica Channel Levee Repair Less than Significant Impact: The construction activities for the Bolsa Chica Channel levee repair consist of three construction phases, which have been analyzed separately below. Phase 1: Clearing and Grubbing and Excavation Phase 1 activities would include clearing the existing fence and removal of the aggregate base, debris, vegetation, and loose, wet or otherwise unstable soils. In addition, the existing conductor casing and grout from the abandoned well

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would be removed to a depth of approximately five feet below the existing ground surface. Construction activities for Phase 1 would occur between 6:00 a.m. and 5:00 p.m., Monday through Friday. Some construction activities could occur outside of the times when construction noise would exempt under the City of Huntington Beach Municipal Code and these construction activities would be required to adhere to the City of Huntington Beach daytime and nighttime exterior noise standards. Both the daytime and nighttime noise impacts were analyzed. The noise levels created during the Phase 1 levee repairs are shown in Table 31. Table 29 Bolsa Chica Channel Levee Repair Phase 1 Clearing, Brubbing, Excavation Noise Levels Daytime Construction Noise Levels Nighttime Construction Noise (dBA Leq) Levels (dBA Leq) Noise Daytime Exceed Noise Nighttime Exceed Receiver1 Description Level Standard2 Standard? Level Standard2 Standard? 1 MFH at 3536 Bravata Drive 52 55 No 44 50 No 2 MFH at 3496 Bravata Drive 42 55 No 34 50 No 3 MFH at 3552 Bravata Drive 47 55 No 40 50 No 4 MFH at 3582 Bravata Drive 37 55 No 29 50 No 5 MFH at 3608 Bravata Drive 39 55 No 31 50 No 6 MFH at 3662 Montego Drive 34 55 No 27 50 No Notes: 1 Receiver locations shown in Figure 6. 2 The Daytime (7:00 a.m. to 10:00 p.m.) standard is 55 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. 3 The Nighttime (10:00 p.m. to 7:00 a.m.) standard is 50 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. Source: SoundPlan Version 8.0. Table 31 shows that Phase 1 of the levee repairs would create noise levels as high as 52 dBA Leq during the daytime and 44 dBA Leq during the nighttime at the nearby homes. Table 31 shows that none of the sensitive receivers would exceed the daytime noise standard of 55 dBA or the nighttime noise standard of 50 dBA. Noise impacts from Phase 1 of the levee repairs would be less than significant. Phase 2 Backfill and Compaction Phase 2 activities would include backfill and compaction for the levee repairs. Construction activities for Phase 2 would occur between 6:00 a.m. and 5:00 p.m., Monday through Friday. Some construction activities could occur outside of the times when construction noise would be exempt under the City of Huntington Beach Municipal Code and these construction activities would be required to adhere to the City of Huntington Beach daytime and nighttime exterior noise standards. Both the daytime and nighttime noise impacts were analyzed. The noise levels created during the Phase 2 backfill and compaction repairs are shown in Table 32.

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Table 30 Phase 2 Bolsa Chica Channel Levee Repair Backfill/Compaction Noise Levels Daytime Construction Noise Nighttime Construction Noise Levels (dBA Leq) Levels (dBA Leq) Noise Daytime Exceed Noise Nighttime Exceed Receiver1 Description Level Standard2 Standard? Level Standard2 Standard? 1 MFH at 3536 Bravata Drive 55 55 No 47 50 No 2 MFH at 3496 Bravata Drive 45 55 No 38 50 No 3 MFH at 3552 Bravata Drive 50 55 No 43 50 No 4 MFH at 3582 Bravata Drive 40 55 No 32 50 No 5 MFH at 3608 Bravata Drive 42 55 No 34 50 No 6 MFH at 3662 Montego Drive 37 55 No 30 50 No Notes: 1 Receiver locations shown in Figure 6. 2 The Daytime (7:00 a.m. to 10:00 p.m.) standard is 55 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. 3 The Nighttime (10:00 p.m. to 7:00 a.m.) standard is 50 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. Source: SoundPlan Version 8.0. Table 32 shows that Phase 2 of the levee repairs would create noise levels as high as 55 dBA Leq during the daytime and 47 dBA Leq during the nighttime at the nearby homes. Table 32 shows that none of the sensitive receivers would exceed the daytime noise standard of 55 dBA or the nighttime noise standard of 50 dBA. Noise impacts from Phase 2 of the levee repairs would be less than significant. Phase 3 Final Grading Phase 3 activities would include final grading for the levee repairs. Construction activities for Phase 3 would occur between 6:00 a.m. and 5:00 p.m., Monday through Friday. Some construction activities could occur outside of the times when construction noise would be exempt under the City of Huntington Beach Municipal Code and these construction activities would be required to adhere to the City of Huntington Beach daytime and nighttime exterior noise standards. Both the daytime and nighttime noise impacts were analyzed. The noise levels created during the Phase 3 final grading are shown in Table 33. Table 31 Phase 3 Bolsa Chica Channel Levee Repair Final Grading Noise Impacts Daytime Construction Noise Nighttime Construction Noise Levels (dBA Leq) Levels (dBA Leq) Noise Daytime Exceed Noise Nighttime Exceed Receiver1 Description Level Standard2 Standard? Level Standard2 Standard? 1 MFH at 3536 Bravata Drive 52 55 No 44 50 No 2 MFH at 3496 Bravata Drive 42 55 No 34 50 No 3 MFH at 3552 Bravata Drive 47 55 No 40 50 No 4 MFH at 3582 Bravata Drive 37 55 No 29 50 No

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Daytime Construction Noise Nighttime Construction Noise Levels (dBA Leq) Levels (dBA Leq) Noise Daytime Exceed Noise Nighttime Exceed Receiver1 Description Level Standard2 Standard? Level Standard2 Standard? 5 MFH at 3608 Bravata Drive 39 55 No 31 50 No 6 MFH at 3662 Montego Drive 34 55 No 27 50 No Notes: 1 Receiver locations shown in Figure 6. 2 The Daytime (7:00 a.m. to 10:00 p.m.) standard is 55 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. 3 The Nighttime (10:00 p.m. to 7:00 a.m.) standard is 50 dBA as detailed in Section 8.40.090(d) of the Huntington Beach Municipal Code. Source: SoundPlan Version 8.0. Table 33 shows that Phase 3 of the levee repairs would create noise levels as high as 52 dBA Leq during the daytime and 44 dBA Leq during the nighttime at the nearby homes. Table 33 shows that none of the sensitive receivers would exceed the daytime noise standard of 55 dBA or the nighttime noise standard of 50 dBA. Noise impacts from Phase 3 of the levee repairs would be less than significant. B. Would the project result in a permanent increase in ambient noise levels in the project vicinity above levels existing without the project? The proposed monitoring wells would operate continuously 24 hours a day, seven days per week. The monitoring wells would be housed in an underground vault and no noise is anticipated from the continuous operation of the monitoring wells. OCWD on a quarterly basis would visit each well site and collect water samples to monitor salt water intrusion. One truck and two workers would access each well site. Every three to five years OCWD would conduct maintenance activities to redevelop the wells. A typical monitoring well redevelopment process can be completed in one day. Monitoring Wells Sampling Less than Significant Impact: The operational monitor wells sampling activities will occur between 6:00 a.m. and 5:00 p.m., Monday through Friday. Some activities could occur outside of the times when construction noise would be exempt under the City of Huntington Beach Municipal Code and these construction activities would be required to adhere to the City of Huntington Beach daytime and nighttime exterior noise standards. Both the daytime and nighttime noise impacts were analyzed. The noise levels created during the monitor well sampling activities are shown in Table 34.

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Table 32 Monitoring Well BS13 Sampling Activities Noise Levels

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Table 35 shows that the operational monitor well gauging activities would create noise levels as high as 29 dBA Leq during the daytime and as high as 21 dBA Leq during the nighttime. Table 35 shows that none of the sensitive receivers would exceed the daytime noise standard of 55 dBA or the nighttime noise standard of 50 dBA. Noise impacts from the operational monitoring well gauging activities would be less than significant. Monitoring Wells Redevelopment Less than Significant Impact: The operational monitor wells redevelopment activities would occur between 6:00 a.m. and 5:00 p.m., Monday through Friday. Some activities could occur outside of the times when construction noise would be exempt under the City of Huntington Beach Municipal Code and these construction activities would be required to adhere to the City of Huntington Beach daytime and nighttime exterior noise standards. Both the daytime and nighttime noise impacts were analyzed. The noise levels created during the operational monitor well redevelopment activities are shown in Table 36. Table 34 Monitoring Well BS13 Redevelopment Activities Noise Levels

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C. Would the project result in a substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project? Less than Significant Impact: The proposed project would not create a substantial temporary or periodic increase in ambient noise levels in the project vicinity above noise levels existing without the proposed project. The construction activities for each construction phase of the proposed monitoring wells and levee repairs have been analyzed. The analysis determined that the noise levels created from all phases of construction would be within the City of Huntington Beach’s residential noise standards at the nearby homes. Therefore, a less than significant temporary noise level increase would occur from development of the proposed project. D. For a project located within an airport land use plan or where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels? No Impact: The nearest airport to the proposed project site is Los Alamitos Joint Forces Training Center, which is located as near as 2.8 miles north of Wells BS24. The proposed project consists of the development and operation of monitoring wells and levee repairs, which will typically be a passive operation that would not require anyone onsite and would not introduce new sensitive receptors to the project site. No aircraft noise impacts would occur. E. For a project within the vicinity of a private airstrip, would the project expose people residing or working in the project area to excessive noise levels? No Impact: There are not private air airstrips within the vicinity of the study area. Therefore, people would not be exposed to elevated levels of aircraft noise from a private air strip. Groundborne Vibration Ground-borne vibrations consist of rapidly fluctuating motions within the ground that have an average motion of zero. The effects of ground-borne vibrations typically only cause a nuisance to people, but at extreme vibration levels damage to buildings may occur. Although ground-borne 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. Ground-borne noise is an effect of ground-borne vibration and only exists indoors, since it is produced from noise

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radiated from the motion of the walls and floors of a room and may also consist of the rattling of windows or dishes on shelves. Vibration Descriptors There are several different methods that are used to quantify vibration amplitude such as the maximum instantaneous peak in the vibrations velocity, which is known as the peak particle velocity (PPV) or the root mean square (rms) amplitude of the vibration velocity. Due to the typically small amplitudes of

vibrations, vibration velocity is often expressed in decibels and is denoted as (Lv) and is based on the rms velocity amplitude. A commonly used abbreviation is

“VdB”, which in this text, is when Lv is based on the reference quantity of 1 micro inch per second. Vibration Perception Typically, developed areas are continuously affected by vibration velocities of 50 VdB or lower. These continuous vibrations are not noticeable to humans whose threshold of perception is around 65 VdB. Off-site sources that may produce perceptible vibrations are usually caused by construction equipment, steel- wheeled trains, and traffic on rough roads, while smooth roads rarely produce perceptible ground-borne noise or vibration. Vibration Propagation The propagation of ground-borne vibration is not as simple to model as airborne noise. This is due to the fact that noise in the air travels through a relatively uniform median, while ground-borne vibrations travel through the earth which may contain significant geological differences. There are three main types of vibration propagation; surface, compression, and shear waves. Surface waves, or Rayleigh waves, travel along the ground’s surface. These waves carry most of their energy along an expanding circular wave front, similar to ripples produced by throwing a rock into a pool of water. P-waves, or compression waves, are body waves that carry their energy along an expanding spherical wave front. The particle motion in these waves is longitudinal (i.e., in a “push- pull” fashion). P-waves are analogous to airborne sound waves. S-waves, or shear waves, are also body waves that carry energy along an expanding spherical wave front. However, unlike P-waves, the particle motion is transverse or “side-to-side and perpendicular to the direction of propagation.” As vibration waves propagate from a source, the vibration energy decreases in a logarithmic nature and the vibration levels typically decrease by 6 VdB per doubling of the distance from the vibration source. As stated above, this drop-off

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rate can vary greatly depending on the soil but has been shown to be effective enough for screening purposes, in order to identify potential vibration impacts that may need to be studied through actual field tests. Construction Activity Vibration Levels 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. Buildings in the vicinity of the construction site respond to these vibrations with varying results ranging from no perceptible effects at the low levels to slight damage at the highest levels. Table 37 gives approximate vibration levels for particular construction activities. Table 35 Construction Equipment Vibration Noise Levels

Peak Particle Velocity Approximate Vibration Level Equipment (inches/second) (Lv)at 25 feet Upper range 1.518 112 Pile driver (impact) typical 0.644 104 Upper range 0.734 105 Pile driver (sonic) typical 0.170 93 Clam shovel drop (slurry wall) 0.202 94 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: Federal Transit Administration, May 2006.

F. Would the project expose persons to or generation of excessive groundborne vibration or groundborne noise levels? Less than Significant Impact: The proposed project would not expose persons to or generation of excessive groundborne vibration or groundborne noise levels. Vibration impacts from construction and operational activities associated with the proposed project would be a function of the vibration generated by construction equipment, equipment location, sensitivity of nearby land uses, and the timing and duration of the construction activities. The closest sensitive receptors to the BS24 well sites are single family residential homes on the Naval Weapons Station that are located approximately 0.5 mile to the west. The closest sensitive receptors to the proposed levee repairs are multi-family residential homes located approximately 220 feet to the south.

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Since neither the City’s Municipal Code or the General Plan provide a quantifiable vibration threshold, Caltrans guidance has been utilized, which defines the threshold of perception from transient sources at 0.25 inch per second PPV. Table 37 provides a list of construction equipment that is known sources of vibration. Of the equipment listed in Table 37 above, a vibratory roller is the piece of equipment that would be utilized by the proposed project with the highest vibration level, at 0.21 inch per second PPV at 25 feet. Based on typical propagation rates, the vibration level at the nearest offsite receptor (220 feet) would be 0.02 inch per second PPV. The vibration level at the nearest offsite receptor is below the 0.25 inch per second PPV threshold. Therefore, a less than significant vibration impact would be anticipated from construction and operation of the proposed project.

4.13 Population/Housing

A. Would the project induce substantial population growth in an area, either directly or indirectly? No Impact: The proposed project would not extend new infrastructure into any undeveloped area and would not provide underground water supplies to any undeveloped areas. Implementation of the proposed project would not induce any substantial population growth into the project area. No mitigation measures are required. B. Would the project displace substantial numbers of existing housing, necessitating the construction of replacement housing elsewhere? No Impact: The implementation of the proposed project would not displace any existing housing and therefore would not require the construction of any replacement housing. No mitigation measures are required. C. Would the project displace substantial numbers of people, necessitating the construction of replacement housing elsewhere? No Impact: The implementation of the proposed project would not displace any households and therefore would not require the construction of any replacement housing. No mitigation measures are required.

4.14 Public Services

A. Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered governmental

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facilities, need for new or physically altered governmental facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives for fire protection police protection, schools, parks or other public facilities. No Impact: The implementation of the proposed project would not substantially increase the demand for public services over the current level of demand and would not require the construction of any new governmental facilities. No mitigation measures are required.

4.15 Recreation

A. Would the project increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated? No Impact. The implementation proposed project would not involve any activities that would increase the use of existing neighborhood parks or recreation facilities. No mitigation measures are required. B. Does the project include recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment. No Impact. The proposed project does not propose new recreation facilities or proposes to expand existing recreation facilities. No mitigation measures are required.

4.16 Transportation/Traffic

A. Would the project be in conflict with an applicable plan, ordinance or policy establishing measures of effectiveness for the performance of the circulation system, taking into account all modes of transportation including mass transit and non-motorized travel and relevant components of the circulation system, including but not limited to intersections, streets, highways and freeways, pedestrians and bicycle paths. Less than Significant Impact: Construction operations for the new monitoring wells would involve the mobilization and demobilization of construction equipment which could result in short-term traffic congestion impacts along some roadway segments and intersections within the project area circulation system. The impact would be temporary and would not reduce the level of service of any

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project area roadways or intersections and potential traffic impacts would be less than significant. OCWD on a quarterly basis would visit each well site and collect water samples. Additionally, every three to five years OCWD would conduct maintenance activities to redevelopment the wells. The maintenance activities would only involve a couple pieces of construction equipment and would generate minimal amounts of traffic trips. The amount of traffic trips generated from the operation of the proposed project would not result in any adverse impacts on the project area circulation system. No mitigation measures are required. B. Would the project be in conflict with an applicable congestion management program, including, but not limited to level of service standards and travel demand measures, or other standards and travel demand measures, or other standards established by County congestion management agency for designated roads and highways. Less than Significant Impact: The Orange County Transportation Agency is responsible for the implementation of the County Congestion Management Program (CMP). The CMP is designed to reduce traffic congestion at and to provide a mechanism for coordination land use and transportation decisions. The CMP identifies deficit highway and intersections in the County of Orange Circulation System and identifies planned performance standards. When a project generates more than 100 peak hour traffic trips along a CMP highway or 51 or vehicle trips through a CMP intersection, the project is required to prepare a traffic impact study to evaluate the impacts on the CMP highway and intersection. Access to the project area could require travel along CMP highways and intersections. However, the proposed project would not generate 100 peak hour trips during construction and operation and would also not generate 51 trips through a CMP intersection. Therefore, the proposed project would not require preparation of a traffic impact study and would not be in conflict with County of Orange Congestion Management Program. No mitigation measures are required. C. Would the project result in a change in air traffic patterns, including either an increase in traffic levels or a change in location that results in substantial safety risks? No Impact: Implementation of the proposed project would not increase the level of air traffic within the regional area. The closest airport facility to the project area would be the Los Alamitos Joint Forces Training Base. The AELUP for the Los Alamitos Joint Forces Training Base indicates that the proposed monitoring well

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sites are within the AELUP Height Restriction Zone. The proposed monitoring wells would be housed in underground faults and would not encroach into any navigable air space and would not increase safety risks. No mitigation measures are required. D. Would the project increase hazards to a design feature or incompatible uses or equipment? Less than Significant Impact with Mitigation: The long term operation of the proposed project would generate minimal amount of traffic trips. Monitoring Well construction, destruction and redevelopment activities would require the use of large pieces of construction equipment which could require the use of temporary traffic control measure such as flagman to direct the equipment into the project sites. The need for temporary traffic control would be based on the situation need. With the implementation of Mitigation Measure T-1 potential hazards associated with ingress and egress to the well sites would be less than significant. Mitigation Measure T-1: OCWD shall coordinate with the Naval Weapons Station Seal Beach on the need for temporary traffic control for the accessing of heavy construction equipment to the proposed well sites. E. Would the project result in inadequate emergency access? No Impact: The construction and operation of the proposed project would not require the closure of any streets that would impede emergency access. The project mobilization and demobilization of heavy construction equipment could result in some temporary traffic congestion to access the proposed well sites. The impact would be short-term and emergency access would be maintained at all times. No mitigation measures are required. F. Would the project be in conflict with adopted policies, plans, or programs regarding public transit, bicycle, or pedestrian facilities or otherwise decrease the performance or safety of such facilities? Less Than Significant Impact: The construction and operation of the proposed project would not require the closure of public transportation, bicycle or pedestrian circulation system The project mobilization and demobilization of heavy construction equipment could result in some temporary closure for safety reasons. However, the closure would be limited to the time of the mobilization and demobilization activity which in most cases will about one hour. With the

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implementation of Mitigation Measure T-1 potential conflicts with public transportation systems would be less than significant. Mitigation Measure Mitigation Measure T-1 is required.

4.17 Tribal Resources

A. Would the project cause a substantial adverse change in the significance of a tribal cultural resource as either a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with value to a California Native American Tribe and that is listed or eligible for listing in the California Register or Historical Resources, or in a local register of historical resources. Less than Significant Impact with Mitigation: The analysis of potential impacts to tribal resources included; AB Tribal Consultation with local tribes, coordination with California Native American Commission and, coordination with Naval Weapons Station Seal Beach Integrated Cultural Resources Management Plan. AB 52 Tribal Consultation On September 22, 2017 OCWD contacted three local tribes that have requested to be informed of projects under AB 52: These would include Joyce Perry from Juaneno Band of Mission Indians Acjachemen, Andrew Salas from Gabrieleo Band of Mission Indians-Kizh Nation and Anthony Morales San Gabriel Band of Mission Indians. The tribes were requested to provide additional information in regards to Native American cultural resources within the project area and the potential for them to be encountered during the project construction activities. At this time no additional information has been provided. Native American Sacred Lands Search The location of proposed BS13 monitoring wells and the location where the Bolsa Chica Channel Levee repairs would occur were evaluated in Final Initial Study/Mitigation Negative Declaration SCH 2013061039. As part of the evaluation OCWD requested a Native American Sacred Lands Record Search be conducted by the California Native American Heritage Commission to determine the potential for Native American Sacred Lands to be present within the project area. The Native American Heritage Commission identified that there were no known Native American Sacred Lands within the project area.

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Naval Weapons Station Seal Beach Integrated Cultural Resources Management Plan Based on review Naval Weapons Station Seal Beach Integrated Cultural Resources Management Plan there are no recorded tribal resources on the proposed monitoring well sites or along the Bolsa Chica Channel Levee. Based on previous surveys conducted at the Naval Weapons Station there would be low potential to encounter unknown tribal resources. As a precaution it is recommended that a halt condition be in place in the unlikely event unknown tribal cultural resources are encountered. If indications of tribal cultural resources are encountered, construction activity in the location of the finding would cease and a qualified archeologist would be retained to examine the resources and determine the significance of the finding. With the implementation of Mitigation Measure CR-1 potential significant impacts to cultural resources would be less than significant. Mitigation Measure Mitigation Measure CR-1 is required. B. Would the project cause a substantial adverse change in the significance of a tribal cultural resource as either a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with value to a California Native American Tribe and that is a resource determined by the lead agency in its discretion and supported by substantial evidence to be significant and which the lead agency considers the significance of the resource to a California Native American tribe. Less than Significant Impact with Mitigation: Based on coordination with Naval Weapons Station Seal Beach Integrated Cultural Resources Management Plan and local Native American Tribes, it has been determined that it would unlikely Native American resources would be present within the project area. To avoid impacts to unknown cultural resources mitigation measures have been incorporated into the project that would require construction activity to cease in the unlikelihood unknown cultural resources are encountered. With the implementation of Mitigation Measure CR-1 potential impacts tribal resources would be less than significant. Mitigation Measures Mitigation Measure CR-1 is required.

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4.18 Utilities/Service Systems

A. Would the project exceed wastewater treatment requirements of the applicable Regional Water Quality Control Board? No Impact. The construction and operation of the proposed project would not generate any wastewater flows. Therefore, implementation of the proposed project would not exceed any treatment requirements established by the RWQCB. No mitigation measures are required. B. Would the project require or result in the construction of new water or wastewater treatment facilities or expansion of existing facilities, the construction of which could cause significant environmental effects? Less than Significant Impact with Mitigation: The proposed project involves the construction of 11monitoring wells and the repair of a flood control levee. As identified in the initial study, mitigation measures have been incorporated into the project to reduce potentially significant impacts to the environment to a less than significant level. C. Would the project require or result in the construction of new storm water drainage facilities or expansion of existing facilities, the construction of which could cause significant environmental effects? No Impact: The proposed project would involve the repair of flood channel that was previously from well drilling activities along the levee. Implementation of the proposed project would occur within the existing footprint. No mitigation measures are required. D. Are sufficient water supplies available to serve the project from existing entitlements and resources or new or expanded entitlements needed? No Impact. The proposed project involves the construction of monitoring wells to measure the quality of groundwater and does not involve the distribution of water supplies. Therefore, no additional water supplies are needed. No mitigation measures are required. E. Would the project result in the determination by the wastewater treatment provider which serves or may serve the project that it has adequate capacity to serve the project’s projected demand in addition to the providers existing commitments. No Impact: The proposed project does not include any plans to provide wastewater treatment facilities. Therefore, the implementation of the proposed

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project would not have any impact on the capacity of wastewater treatment providers to the area. No mitigation measures are required. F. Is the project served by a landfill with sufficient permitted capacity to accommodate the project solid waste disposal need? Less than Significant Impact: The operation of the proposed project would not require solid waste disposal. Construction operations for the project would generate minimal amounts of solid waste. To minimize the generation of solid waste the proposed project would implement Best Management Practices that would include solid waste management that would recycle appropriate materials. The amount of solid waste generate from proposed project would have a less than significant impact on the capacity of the Brea Olinda Landfill. No mitigation measures are required. G. Would the project comply with federal, state and local statutes and regulations related to solid waste? Less than Significant Impact: The proposed project will not involve any activities that would be in conflict with federal, state and local statutes and regulations related to solid waste. All waste generated from the construction and operation of the project would be disposed of in accordance with local, state and federal laws. No mitigation measures are required. Mandatory Findings of Significance A. Does the project have the potential to degrade the quality of the environment, substantially reduce the habitat of fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory. Less than Significant with Mitigation: Implementation of the proposed project would not result in significant impacts to sensitive species or sensitive vegetation. To avoid potential impacts to nesting birds mitigation measures have been incorporated into the project which would require that well construction activities be conducted outside of the nesting season or be conducted at a distance where construction noise would not disrupt nesting birds. With the implementation of mitigation measures potential impacts to biological resources would be reduced to a less than significant level. The project would not result in any impacts to any known cultural resources. To minimize potential impacts to unknown cultural resources, a halt condition has been incorporated into the construction

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operations for the project to avoid potential impacts to unknown cultural resources. B. Does the project have impacts that are individually limited but cumulatively considerable? Less than Significant Impact with Mitigation: Implementation of the proposed project would not result in significant cumulative impacts. The proposed project would comply with local and regional planning programs, applicable codes and ordinances, State and Federal laws and regulations and project specific mitigation measures. Compliance with these programs would reduce the project incremental contributions to cumulative impacts to a less than significant level. C. Does the project have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly? Less than Significant Impact with Mitigation: The proposed project would not have any substantial effects on human beings. The proposed project would comply with local and regional planning programs, applicable codes, and ordinances, State and Federal laws and regulations and project specific mitigation measures to insure that long term operation activities and short term construction activities associated with the project would not result in direct or indirect adverse impacts to human beings.

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SECTION 5.0 REFERENCES California Department Fish and Game Natural Diversity Database, Accessed October 2017. California Department of Transportation Scenic Highways Program Web Site Access, October 2017. California Environmental Quality Act. 2017. California Environmental Quality Act, State CEQA Guidelines, 2017. California Farmland Mapping Monitoring Program, Web Site Access, October 2017. California Geologic Survey Seismic Hazard Zone Map Los Alamitos Quadrangle, Accessed October 2017. California Native American Heritage Commission Record Search, February 2013. City Huntington Beach General Plan, Site Access October 2017. City of Huntington Beach Municipal Code, Site Access October 2017. City of Seal Beach Anaheim General Plan Site Access October 2017. City of Seal Beach Municipal Code Site Access October 2017. Alamitos Base Environs Land Use Plan, 2017. Los Angeles County Museum of Natural History Record Search, October 2012. Naval Weapons Station Seal Beach Biological Resources Integrated Management Plan Naval Weapons Station Seal Beach Cultural Resources Integrated Management Plan Orange County Water District Groundwater Management Plan, 2009. Regional Water Quality Control Board, Santa Ana River Basin Plan, January 1995.

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