Environmental Analysis

SECTION 3.0 ENVIRONMENTAL ANALYSIS

This section describes the existing conditions of the project study area and the environmental impacts that would occur with implementation of the proposed project. The analysis of each environmental issue area includes a description of the existing conditions within the project study area; the thresholds of significance; an evaluation of how the specific issue area would be affected by implementation of the proposed project; mitigation measures to reduce significant impacts; and residual impacts after mitigation. Alternatives to the project are discussed in Section 7.0, Project Alternatives.

CEQA requires a lead agency to determine the impacts of a project based on the project’s expected effects when compared to certain thresholds of significance. The significance thresholds used in this document are based upon Appendix G of the CEQA Guidelines.

The study area analyzed in this document focuses on locations where potential environmental impacts are anticipated. Changes in the environment, as a result of the project, would be reflected within the study area. For certain environmental issue areas, the area of potential effect encompasses areas extending beyond the project footprint. Refer to the respective section for additional information.

The entire study area lies within the city of San Diego. Refer to Figure 2-2 for a project vicinity map.

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Tijuana River Valley 3.0-2 December 2008 Wetlands Mitigation Project Environmental Analysis 3.1 AGRICULTURAL RESOURCES

This section evaluates the potential impacts of the proposed project on agricultural resources. Impacts to farmland were analyzed using the Land Evaluation and Site Assessment (LESA) Model, which is used for rating the relative quality of land resources based upon specific measurable features. The LESA model is identified in the CEQA Guidelines as an optional methodology for addressing impacts to farmland and agricultural resources. Additional information regarding the LESA model is provided below in Section 3.1.3.

In addition to CEQA requirements, the Tijuana River Valley Local Coastal Program Land Use Plan requires projects to determine if any prime agricultural lands exist, and that a determination be made that continuation of such agricultural uses is infeasible. The Land Use Plan states that “a feasibility analysis is not required for lands acquired by a public agency and managed by the public agency” (Local Coastal Program 1999). The Water Authority, however, strives to attain consistency with local land use plans. The following discussion addresses environmental impacts to agricultural resources that would otherwise apply to the proposed project.

3.1.1 Existing Conditions

Regional Setting

Climate

The south coastal region of San Diego county is subjected to a mild oceanic influenced weather system. Temperatures are moderate as indicated by an average annual temperature of 63.2 degrees Fahrenheit, and sunshine occurs approximately 70 percent of the time. Most growing season in the south coastal area of San Diego county is year-round due to the temperate climate (county of San Diego 2005).

Water Supply

Surface runoff and groundwater supplies in the south coastal area of San Diego county are insufficient to support the agricultural sector. The additional demand is met with water imported by the Metropolitan Water District of Southern California (MWD). MWD wholesales this water to the Water Authority which in turn serves member agencies, such as the city of San Diego. San Diego county growers pay some of the highest prices in the state of California for water. As a consequence, San Diego farmers are known statewide for their low-use irrigation methods (county of San Diego 2005).

Soils

The two onsite soil types are the saline Chino silt loam on 0 to 2 percent slopes (CkA), and Tujunga sand on 0 to 5 percent slopes (TuB). The project site has been extensively disked for

Tijuana River Valley 3.1- 1 December 2008 Wetlands Mitigation Project Environmental Analysis agricultural purposes on an annual basis since the mid 1950s. Due to this long history of intensive land management for agriculture, these distinct soil types may no longer be distinguishable on the project site. The onsite soils are deep, well-drained, fine-grained sandy loams with slightly saline characteristics. Salt accumulation is known to occur within onsite soils.

Local Setting

Agricultural activity in the Tijuana River Valley can be traced back to the 19th century. Agriculture began to replace ranching in the late 1800s, and production peaked in the early 1900s. Following this peak was a steady decline, and by 1965 only about 30 percent of the valley was in agricultural production, with the floods of the early 1980s further decreasing that figure (Water Authority 2004). Review of historical records and aerial maps indicates that the proposed project site has been used occasionally for agricultural purposes since at least 1953 (Water Authority 2008b). An aerial photograph taken in 1928 identifies the project site as undeveloped land, indicating that agricultural production began sometime between 1928 and 1953.

The Tijuana River Valley currently contains a mixture of agricultural fields, equestrian facilities, rural housing, riparian woodland and disturbed habitats. Sand mining and agriculture, which were significant activities in the past, have declined. Agriculture has been in decline for many years due in part to salt intrusion into the water table that, in turn, reduced the soil productivity in this area (city of San Diego 1999d). Other human-caused disturbances to the natural ecosystem include illegal dumping, off-road vehicle riding and water pollution, primarily from locations upstream in Mexico.

The TRVRP, of which the proposed project is a part, contains approximately 480 acres of prime agricultural land (county of San Diego 2006). Some prime agricultural land has been fallow, specifically in the northern part of the TRVRP. Also, the MSCP considers limited agricultural uses to be a compatible and allowable land use within the Tijuana River Valley Subarea.

Important Farmlands

The California Department of Conservation (CDC) Farmland Mapping and Monitoring Program (FMMP) combines technical soil ratings and current land use information to create an inventory of important farmland (CDC 2007). Agricultural lands occur on the majority of the proposed project site within two fallow fields. The westerly field and the northern half of the easterly field are disked on an annual basis, and have been fallow for approximately ten years. The southern half of the easterly field was most recently planted with row crops in 2007. Furrows for irrigation are not evident on most of the project site, and many areas of the agricultural fields contain large amounts of trash and debris within the upper soil surface. Nearly half of the on-site agricultural land is designated as Prime Farmland by the FMMP (CDC 2007), as shown in

Tijuana River Valley 3.1- 2 December 2008 Wetlands Mitigation Project Environmental Analysis Figure 3.1-1. The remaining on-site agricultural land is designated as Farmland of Local Importance. Prime Farmland is defined by the CDC as “land which has the best combination of physical and chemical characteristics for the production of crops. It has the soil quality, growing season and moisture supply needed to produce sustained high yields of crops when treated and managed, including water management, according to current farming methods.” Farmland of Local Importance is defined by the CDC as “land of importance to the local agricultural economy as determined by each county’s board of supervisors and a local advisory committee.”

Williamson Act Contracts

The California Land Conservation Act, also known as the Williamson Act, has been the state’s premier agricultural land protection program since its enactment in 1965. More than 16 million of the state’s 30 million acres of farm and ranch land are currently protected under the Williamson Act (CDC 2008).

The California Legislature passed the Williamson Act in 1965 to preserve agricultural and open space lands by discouraging premature and unnecessary conversion to urban uses. The Act creates an arrangement whereby private landowners contract with counties and cities to voluntarily restrict their land to agricultural and compatible open-space uses. The vehicle for these agreements is a rolling term 10-year contract. In return, restricted parcels are assessed for property tax purposes at a rate consistent with their actual use, rather then potential market value.

The project site is not covered by special agricultural status such as a Williamson Act contract (county of San Diego 2003).

3.1.2 Thresholds of Significance

Thresholds used to evaluate potential impacts to agricultural resources are derived from Appendix G of the State CEQA Guidelines. Significant impacts related to agricultural resources would occur if the project were to:

• Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use. • Conflict with existing zoning for agricultural use, or a Williamson Act contract. • Involve other changes in the existing environment, which, due to their location or nature, could result in conversion of Farmland to non-agricultural use.

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Would the proposed project convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use?

As mentioned earlier, approximately half of the on-site agricultural land is designated as Prime Farmland by the FMMP, and the remaining on-site agricultural land is designated as Farmland of Local Importance. The proposed project would convert these lands to non-agricultural use, resulting in a potentially significant impact. In order to better understand this impact, a LESA analysis has been performed.

As stated earlier, the California Agricultural LESA Model is used for rating the relative quality of land resources based upon specific measurable features. The LESA method was developed by the CDC, intended to provide CEQA lead agencies with an optional methodology to ensure that significant effects on the environment of agricultural land conversions are quantitatively and consistently considered in the environmental review process (Public Resources Code Section 21095).

The LESA Model is composed of six different factors. Two Land Evaluation factors are based upon measures of soil resource quality. Four Site Assessment factors provide measures of a given project’s size, water resource availability, surrounding agricultural lands, and surrounding protected resource lands. For a given project, each of these factors is separately rated on a 100- point scale. The factors are then weighted relative to one another and combined, resulting in a single numeric score for a given project, with a maximum attainable score of 100 points. It is this total project score that becomes the basis for making a determination of a project’s potential significance, based upon a range of established scoring thresholds. The LESA Model worksheets are found in Appendix C to this EIR.

Using the LESA Model, the Land Evaluation portion of the model equals 37.64 points, and the Site Assessment portion equals 28.25 points, for a total project score of 65.89. According to the LESA manual, a score of 60 to 79 points is considered significant unless either the Land Evaluation portion or the Site Assessment portion subscore is less than 20 points. In this case, both subscores are greater than 20, and thus the score is considered significant under CEQA (CDC 1997). As a result, even though the current agricultural use of the land is considered an interim land use, and the project would be consistent with the Tijuana River Valley Local Coastal Program Land Use Plan land use designation prescribed for the site, the project’s physical impacts resulting from conversion of onsite agricultural resources to non-agricultural use would be significant (Impact AG-1).

Tijuana River Valley 3.1- 4 December 2008 Wetlands Mitigation Project Environmental Analysis Would the proposed project conflict with existing zoning for agricultural use, or a Williamson Act contract?

The project site is currently zoned as Open Space – Floodplain (OF-1-1), which is not an agricultural zoning designation. As previously mentioned, the project site is not covered by a Williamson Act contract.

Agriculture is the current prominent use on the site, and much of the land is designated as Prime Farmland (see Figure 3.1-1). However, per the Multiple Species Conservation Program (MSCP) Subarea Plan, the Multi-Habitat Planning Area (MHPA) Guidelines item A18 identifies the project site as having a long-term goal of restoration to native vegetation where possible, consistent with the county’s Framework Management Plan (city of San Diego 1997).

The proposed project would not conflict with existing zoning for agricultural use, or a Williamson Act contract. In addition, while agriculture is the current prominent use on the site, the area has been identified as having a long-term goal of restoration to native vegetation. The proposed project is consistent with this goal. Impacts would be less than significant.

Would the proposed project involve other changes in the existing environment, which, due to their location or nature, could result in conversion of Farmland to non-agricultural use?

The project would result in the conversion of all onsite farmland to non-agricultural use. No other features of the project would result in foreseeable changes in the existing environment that would result in the conversion of offsite Farmland to non-agricultural uses.

3.1.4 Mitigation Measures

Mitigation Measures for Impact AG-1

As stated in Section 3.1.3, impacts to agricultural resources would be significant. Feasible measures to mitigate for the loss of agricultural resources are difficult to identify as demonstrated by the discussion below of two potential mitigation options that were considered but rejected as being infeasible.

Converting Off-site Non-Agricultural Land to Agricultural Use

It would be difficult, if not impossible, to fully mitigate for the loss of agricultural acreage without bringing non-farmed land into agricultural production. Importantly, based on a review of properties for sale in July 2008, adequate land (60 acres) is not available in the Tijuana River Valley. Therefore, this potential mitigation measure is rejected as infeasible.

Tijuana River Valley 3.1- 5 December 2008 Wetlands Mitigation Project Environmental Analysis Conservation Easement

The possibility of enacting a conservation easement over existing agricultural land was also considered by the Water Authority. However, per the CEQA Guidelines Section 15370, an agricultural conservation easement would not in any way avoid, reduce, rectify, minimize, or compensate for the project impact under review.

A conservation easement would not create new farmland, would not reduce the loss of farmland on the project site, and would not reduce impacts on other sites, since none are threatened by conversion as a result of the proposed project. The Water Authority is not required to provide funds to continue farming land that is already being farmed, and which is not the site of any probable future project. For these reasons, a conservation easement is not a valid or feasible mitigation measure for the significant agricultural impacts resulting from the proposed project.

3.1.5 Residual Impacts After Mitigation

No feasible mitigation measures are available to reduce identified significant impacts to agricultural resources, and residual impacts would be significant and unavoidable.

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SUNSET AV

SATURN BL SATURN Legend

Proposed Project Site

HOLLISTER ST CA Dept. of Conservation Farmland Mapping & Monitoring, 2004 Prime Statewide Importance Unique Local Importance Other Land Urban & Built-up Land

AERIAL SOURCE: DIGITAL GLOBE, MARCH 2007 MONUMENT RD Fe et 01,200

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Tijuana River Valley 3.1- 8 December 2008 Wetlands Mitigation Project Environmental Analysis 3.2 RECREATION

This section evaluates the potential impacts of the proposed project on recreation within the TRVRP. The evaluation is based on field observations, a review of maps of the TRVRP, and the county’s 2006 EIR for the Tijuana River Valley Regional Park Trails and Enhancement Project.

3.2.1 Existing Conditions

The TRVRP is composed of approximately 72 miles of dirt roads and pathways that have been created for recreational use (county of San Diego 2006). The park consists of a formal network of trails available to hikers, equestrians, and mountain bikers. Approximately 22.5 miles of this network of trails are designated for equestrian uses. In addition, the TRVRP provides natural open space for the support of native plant and animal species.

As shown in Figure 3.2-1, the project site is approximately located in the center of the TRVRP and is surrounded by various trail designations. The northern portion of the project site is bordered by a multi-use trail, a multi-use trail with shared CBP use, and an equestrian and pedestrian trail. The eastern portion of the site is bordered by a multi-use trail, and the southern portion is bordered by a multi-use trail with shared CBP use. In addition, there is an equestrian and pedestrian trail with shared CBP use running north to south through the project site, along the Saturn Boulevard right-of-way.

Additionally, as shown in Figure 3.2-2, the project site is located partially within the TRNERR. Trails associated with the TRNERR are located within the project vicinity and connect to TRVRP trails, enabling east to west trail access to the Pacific Ocean.

3.2.2 Thresholds of Significance

Thresholds used to evaluate potential impacts to recreation are derived from Appendix G of the State CEQA Guidelines and modified to more pertinently address the proposed project. Significant impacts related to recreation would occur if the project were to:

• 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, or disrupt recreational activities such that a substantial adverse effect on the recreational value of existing facilities would result. • Include recreational facilities or require the construction or improvements of recreational facilities, which might have an adverse physical effect on the environment.

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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?

The project would reduce the use of portions of the TRVRP in the immediate project vicinity during the construction phase. Access points and trails within the project site would be closed or restricted to maintain visitor safety during the construction phase of the project. However, because the regional park offers multiple access points and trails, the inaccessibility to this part of the TRVRP is not expected to substantially increase the use of other areas within the TRVRP. Furthermore, the maximum period of trail closure or restriction would be approximately nine months, a relatively short duration that would be unlikely to result in physical deterioration to other portions of the regional park or other facilities due to redirected demand for passive or active recreation. Temporary trail closure or restriction would not preclude users from bypassing the construction site using other existing nearby trails for east/west or north/south travel. Impacts would be less than significant.

Upon project completion, the closed or restricted access points and trails would be reopened for public use. Because the project does not propose any residential uses or other uses involving occupancy by people, no impact would occur that may increase the use of the trail network or existing neighborhood parks in the vicinity such that substantial physical deterioration of the facility, or an increase in park facilities would occur or be accelerated. Therefore, these impacts would be less than significant.

Does the project include recreational facilities or require the construction or improvements of recreational facilities, which might have an adverse physical effect on the environment?

Short-term

During the 9-month construction period, the proposed project would result in the temporary closure or access restriction of dirt roads and trails within a portion of the TRVRP. These dirt roads and trails are used for recreation on a daily basis and are established facilities for pedestrian activity, mountain biking, equestrian use, and CBP operations. Access to park trails and roads through construction areas would be prohibited or restricted for the duration of construction. Active construction areas would be fenced and access would be limited to authorized personnel. This would result in the direct disturbance of a portion of the TRVRP, an established regional recreational park. Construction activities at the berm extension site would not affect any existing trails or recreational uses.

The direct impact to these recreational facilities would occur during construction and would be limited to a small portion of the TRVRP’s 1,800 total acres. Access to the TRVRP would be

Tijuana River Valley 3.2-2 December 2008 Wetlands Mitigation Project Environmental Analysis open during construction from many other access points. The Water Authority would notify the TRVEA, CBP, local residents, and other interested parties describing the project components, schedule, impacts to recreational uses, and suggested alternative park areas and trails that may be used during construction. A shown in Figure 3.2-2, trail closures or restrictions in the project vicinity would not significantly disturb east-west travel. Several alternate routes north of the site allow access to the western portion of the Tijuana River Valley via existing TRNERR trails. Direct impacts of the access point and trail closures or restrictions would be adverse but less than significant, due to the availability of other portions of the park for recreation and the limited duration of the project.

Secondary or indirect impacts to recreational uses of the park would result from the intrusion of construction noise and dust and a change in park aesthetics due to the construction activities. These secondary impacts would be adverse, but less than significant due to the availability of other portions of the park and the limited duration of project construction.

Long-term

The proposed trail alignment through the project site is consistent with the county of San Diego’s approved trail system, and trails would be designed and constructed in accordance with the guidelines detailed in the county’s Department of Parks and Recreation approved County Trails Program (county of San Diego 2008).

As shown in Figure 2-6, most of the existing roads and trails would be restored to their existing condition or better following construction. One trail would be relocated as part of the proposed project. The equestrian and pedestrian trail with shared CBP use running north to south through the project site along the Saturn Boulevard right-of-way would be relocated. The new location would be along a newly-constructed berm connecting to the existing river berm and trail at the northwest end of the project site (see Figure 2-6). The new trail would be twice as long as the existing trail, and because it joins with the river berm and trail the connectivity of the existing trail system would be maintained. No significant impacts would occur.

At the berm extension site, no trails are located onsite and impacts to trails or recreational uses would also be less than significant.

3.2.4 Mitigation Measures

Short-term construction related impacts to recreation in the TRVRP would be adverse, but less than significant. No significant long-term impacts would result. Therefore, no mitigation measures are required.

3.2.5 Residual Impacts After Mitigation

No significant impacts would result.

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LEGEND Equestrian & Pedestrian Trail - 7.1 Miles 6’ Wide Multi-Use Trail - 6.8 Miles Multi-Use Trail shared with CBP Use - 6.6 Miles Equestrian & Pedestrian Trail shared with CBP - 0.2 Miles CBP Use (Retained) - 8.1 Miles Proposed Staging Area NOTE: Network also includes 1.1 miles of sidewalk/bike land on Sidewalk & Bike Lane on Dairy Mart Road Dairy Mart Road, 0.5 miles of existing multi-use trail within community garden, and 0.2 miles of existing 15’ trail within ballfields. Tijuana River Valley Regional Park (TRVRP) Tijuana River Valley Wetlands Mitigation Site Z:\Projects\j509302\Figs\EIR\Section 3\EIR509302_Fig3-2_01_trails.mxd By: LT 3/12/2008 LT By: 3\EIR509302_Fig3-2_01_trails.mxd Z:\Projects\j509302\Figs\EIR\Section

Fe et 01,200 Tijuana River Valley Wetlands Mitigation Project - EIR FIGURE Tijuana River Valley Regional Park - Formal Trails Network 3.2-1 Environmental Analysis

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Tijuana River Valley 3.2-6 December 2008 Wetlands Mitigation Project LEGEND Tijuana River Valley Wetlands Mitigation Site

Project Site

Feet Z:\Projects\j509302\Figs\EIR\Section 3\EIR509302_Fig3-2_02_statetrails.mxd 3\EIR509302_Fig3-2_02_statetrails.mxd Z:\Projects\j509302\Figs\EIR\Section 0 1,200

SOURCE: TIJUANAESTUARY.COM, JUNE 2003 Tijuana River Valley Wetlands Mitigation Project - EIR FIGURE TRNERR - Trails Network 3.2-2 Environmental Analysis

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3.3 WATER RESOURCES

This section evaluates the potential impacts of the proposed project on water resources, including the project’s impacts to groundwater, drainage patterns, runoff, sedimentation, and erosion. Information on water quality and the hydrology of the site were identified through a literature review that included the following sources: International Boundary and Water Commission (IBWC), Water Quality Control Plan for the San Diego Basin (RWQCB 2006), Porter-Cologne Water Quality Control Act (SWRCB 2005), and the 2006 Proposed List of Impaired Water Bodies (SWRCB 2007). Groundwater and stream information was obtained from sources including the California Department of Water Resources Bulletin 118, the U.S. Geological Survey (Izbicki 1985), and the Groundwater Management Plan for the Tijuana River Basin (Dudek, various dates). Additionally, the Hydraulic and Sedimentation Study for the Wetland Restoration in the Tijuana River Floodplain (Chang 2007) and a Groundwater Dewatering Analysis Memo (Dudek 2008c) were prepared for the proposed project and can be found in Appendix D of this EIR.

3.3.1 Existing Conditions

Environmental Setting

Regional and Site Topography

The topography of the Tijuana Watershed is varied, ranging from coastal plains in the western portion to the Laguna Mountains, which rise over 6,000 feet AMSL. The Tijuana Watershed is 73 percent contained within Mexico and includes the cities of Tijuana and Tecate. On the U.S. side of the border, the cities of Imperial Beach and San Diego, as well as San Diego county, have portions of their jurisdictions within the watershed.

The proposed project is situated in the floodplain of the Tijuana River, south of the current main channel and immediately west of Smuggler’s Gulch. The general topography of the area consists of the broad floodplain and the relatively steep hillside area between the floodplain and international border. In the site vicinity, ground surface elevations range from approximately 19 to 25 feet AMSL in the agricultural fields, with berms situated at elevations up to 34 feet AMSL.

Surface Water

The site is located within the San Ysidro Hydrologic Subarea (HSA), which is a part of the Tijuana Valley Hydrologic Area (HA), all within the Tijuana Hydrologic Unit (HU), as depicted in the Water Quality Control Plan for the San Diego Basin (RWQCB 2006). The Tijuana hydrologic basin is a binational watershed that covers approximately 1,700 square miles on either side of the California – Baja California border. The current population of the entire watershed is approximately one million people (Project Clean Water 2008).

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The major drainages in the Tijuana Watershed include Cottonwood and Campo creeks in the United States, and the Rio Las Palmas system in Mexico. Annual precipitation varies from less than 11 inches to 25 inches further inland near the Laguna Mountains. On the U.S. side, runoff is captured by the Morena Reservoir, completed in 1910 and Barrett Lake, completed in 1921 on Cottonwood Creek. On the Mexico side, runoff is captured by the Rodriguez Reservoir, completed in 1937 (Southern California Wetlands Recovery Project 2008). The three dams in the watershed control 71 percent of the total drainage area. The combined capacity of the dams is 206,000 acre-feet. The reservoirs were designed for water storage and have limited capacity for flood control purposes. However, the three reservoirs control most flows resulting from small storms in the upstream portions of the drainage basin (Chang 2007). The Rodriguez Dam, which is equipped with floodgates on the spillway, is capable of regulating the flow rate of a major flood.

Virtually all of the surface water drainage of the Tijuana HU is via the Tijuana River. The Tijuana River is an intermittent stream with higher flows generally in the wetter months of January through April. Periodically, winter storms have caused flooding in the Tijuana River Valley. During the dry months, generally May through December, flow in the river is caused by agricultural and urban runoff, dam releases, and groundwater releases to the surface. Small drainage features (Goat Canyon, Smuggler’s Gulch, and Canyon del Sol) and man-made drainages (Silva’s Drain and Stewart’s Drain) exist along the border.

Review of stream flow data indicates that the Tijuana River generally loses flow from the International Border to an area near Hollister Street, thereby recharging groundwater (Dudek 1997). In the wet year of 1983, the Tijuana River was a series of interconnected ponds that were maintained throughout the summer by groundwater inflow (Izbicki 1985).

Both the United States and Mexico have signed treaties in which Mexico has agreed to intercept the flow of the Tijuana River during the dry season for its eventual transport to either one of two wastewater treatment plants. During the rainy season, however, the Tijuana River flow is permitted to continue into the U.S. and to discharge into the Tijuana River estuary, whenever the flows exceed 11.4 million gallons per day (CDM 2003).

Smuggler’s Gulch, an approximately 16-foot wide drainage channel that directs drainage into the Tijuana River from a tributary of the river, is located east of the proposed project site. After flow events, there is usually a substantial amount of trash (approximately 4 to 6 feet in height) that periodically accumulates just south of the Disney crossing, a culverted road crossing of the channel. The city and county, as landowners along Smugglers Gulch, are responsible for debris removal and disposal.

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Surface Water Quality

The surface water quality of the Tijuana River is highly variable. Although discharges from the Tijuana River account for only a small percentage of total gauged runoff to the Southern California coast, it contains the highest concentrations of suspended solids, cadmium (Cd), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) of the eight largest creeks and rivers in Southern California (Southern California Wetland Recovery Project 2008). Surface water quality has been affected by occasional large volumes of untreated wastewater flow into the Tijuana River and canyons crossing the border, posing serious risks to public health and the environment in the U.S. (EPA 2008).

Sewage from Tijuana has been flowing into the Pacific Ocean since the 1940s. The water quality problem has worsened in recent years with the substantial growth of Tijuana’s population, along with intensive industrial development associated with the maquiladora (manufacturing and assembly plants) program in Mexico.

Toxicity sampling conducted by San Diego State University (SDSU) in the Tijuana River at Via San Ysidro, approximately 200 meters past the international border along the north bank of the river, indicated that dry weather samples from the Tijuana River had very low toxicity. However, wet weather samples were more toxic. Pollutants include detergents and surfactants, petroleum hydrocarbons, and pesticides.

Section 303(d) of the federal Clean Water Act requires states to identify waters that do not meet water quality standards after applying certain required technology-based effluent limits. Waters that do not meet the water quality standards are referred to as “impaired” water bodies. The 2006 303(d) List classifies the Tijuana River, Tijuana River Estuary, Pacific Ocean at Tijuana HU, and Pine Valley Creek (Upper) as impaired water bodies. Table 3.3-1 identifies the impaired water bodies and their corresponding pollutants or stressors.

The impaired water body nearest to the project site is the Tijuana River, which is impacted by eutrophication, indicator bacteria, low dissolved oxygen, pesticides, solids, synthetic organics, trace elements and trash. No Total Maximum Daily Loads (TMDLs) have been developed to date (SWRCB 2007).

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Table 3.3-1 303(d) List of Impaired Water

Proposed Estimated Pollutant/ Location Potential Source TMDL Size Stressor Completion Affected Eutrophication Indicator Bacteria Dissolved Oxygen Pesticides Tijuana River Nonpoint/Point Source 2019 6 miles Solids Synthetic Organics Trace Elements Trash Eutrophication Nonpoint/Point Source

Indicator Bacteria Nonpoint/Point Source

Lead Nonpoint/Point Source Dissolved Oxygen Urban Runoff/Storm Sewers Wastewater Unknown Nonpoint Source Tijuana River Unknown Point Source Estuary 2019 1,319 Acres Nickel Nonpoint/Point Source

Pesticides Nonpoint/Point Source

Thallium Nonpoint/Point Source

Trash Nonpoint/Point Source

Turbidity Source Unknown Pacific Ocean Shoreline (Tijuana Indicator Bacteria Nonpoint/Point Source 2010 3 miles HU) Enterococcus Grazing-Related Sources 2010 Concentrated Animal Feeding Operations (permitted, point source) Pine Valley Creek Transient encampments 2.9 miles (Upper) Phosphorus Source Unknown 2019

Turbidity Source Unknown 2019 Source: State Water Resources Control Board Proposed 2006 CWA 303 (d) List of Water Quality Limited Segments

Groundwater

Similar to the surface water hydraulic boundaries, groundwater at the site is located in the Tijuana HA (RWQCB 2006). The Tijuana HA is an alluvial aquifer consisting mostly of unconsolidated clays, silts, sand and cobbles deposited by the Tijuana River. Recharge to the alluvial aquifer originates primarily outside of the hydrologic subarea as flow in the Tijuana

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River. Between autumn 1982 and spring 1983, water levels in the aquifer rose as much as seven feet in response to the wet winter and high stream flows, indicating high recharge to the alluvial aquifer (Izbicki 1985). Based on more recent hydrogeologic investigation, the alluvial aquifer extends to approximately 300 feet below ground surface (bgs) approximately 3,500 feet southwest of the project site (Dudek 1997). Near the Pacific Ocean, alluvium is overlain by a coastal lagoon, estuarine silt and clay of approximately 20 to 30 feet thickness. This thin surface layer extends approximately 2,000 to 4,000 feet inland from the coast (JMM 1993). The alluvial aquifer varies in thickness from greater than 300 feet bgs in the east, to 640 feet in the central portion of the valley, to less than 200 feet bgs on the western portion of the valley. Near the mesas to the north and south, the alluvium thins at the margins of the basin, until it is adjacent to the San Diego Formation.

Groundwater was encountered near the surface (less than 30 inches below ground surface) along the most northern edge and especially on the northwestern portion of the site during soil ripping activities conducted by the Integrated Waste Management Board (IWMB 2000). In the vicinity of the site, groundwater is reported to occur from above ground surface (artesian wells) to 15 feet bgs in the spring of 1983, which was a wet year (Izbicki 1985).

Groundwater Quality

Major ion composition of the water from the alluvial aquifer indicates that it is chemically similar to water from the Tijuana River and is characterized as sodium chloride in nature (Izbicki 1985). Generally, the shallowest portion of the alluvial aquifer contains the highest total dissolved solids (TDS) concentrations, which are typically used as indicators to water quality. The historical TDS content in groundwater ranges from 465 to 3,620 milligrams per liter (mg/L) (Dudek 1997).

Historic sea water intrusion problems have occurred within the valley. In the 1970s, overdrafting occurred due to groundwater withdrawals in Tijuana and a decrease in imported water availability due to drought conditions. As groundwater was extracted during this period, the water levels declined to below mean sea level, which caused a reversal of the westerly flow direction of the groundwater, allowing sea water to migrate eastward into the alluvial aquifer. This trend was mitigated in the late 1970s by decreases in pumping of Tijuana River Valley wells due to the availability of imported water.

In September 2004, the Water Authority collected groundwater samples from six wells at and near the project site. The water samples were analyzed for 19 constituents. Results of the laboratory analysis indicate that six constituents exceed the effluent limitations set forth in the general NPDES permit for groundwater discharges. These constituents include fluoride, iron, manganese, nitrogen (nitrate), dissolved solids, and nitrogen (nitrite).

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Flooding

A 100-year flood event is a flood that has a one percent chance of being equaled or exceeded in any given year. The 100-year flood is the standard used by most federal and state agencies and the National Flood Insurance Program as the standard for floodplain management. According to the Federal Emergency Management Agency (FEMA), the site is located in an area of potential flooding during a 100-year flood event (Figure 3.3-1).

Applicable Regulations, Plans, and Standards

Several local, state, and federal regulations govern discharges associated with construction and post-construction storm water runoff to protect the water quality of receiving waters. The following is a summary of the regulatory framework that has been established to protect water resources.

Federal

Clean Water Act (CWA)

Increasing public awareness and concern for controlling water pollution led to enactment of the Federal Water Pollution Control Act Amendments of 1972. As amended in 1977, this law became commonly known as the Clean Water Act. The Act established basic guidelines for regulating discharges of pollutants into the waters of the United States. The Clean Water Act requires that states adopt water quality standards to protect public health, enhance the quality of water resources, and ensure implementation of the Act.

Other provisions of the CWA related to basin planning include Section 208, which authorizes the preparation of waste treatment management plans, and Section 319, which mandates specific actions for the control of pollution from nonpoint sources. The EPA has delegated responsibility for implementation of portions of the CWA to the State Water Resources Control Board (SWRCB) and the Regional Water Quality Control Boards (RWQCBs), including water quality control planning and control programs, such as the National Pollutant Discharge Elimination System (NPDES) program. The NPDES program is a set of permits designed to implement the CWA that apply to various activities that generate pollutants with potential to impact water quality.

Section 303 of the CWA requires states to adopt water quality standards for all surface waters of the U.S. Section 304(a) requires the EPA to publish water quality criteria that accurately reflect the latest scientific knowledge on the kind and extent of all effects on health and welfare that may be expected from the presence of pollutants in water. Where multiple uses exist, water quality standards must protect the most sensitive use. Water quality standards are typically numeric, although narrative criteria based upon biomonitoring methods may be employed where

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numerical standards cannot be established or where they are needed to supplement numerical standards. Section 303(c)(2)(b) of the CWA requires states to adopt numerical water quality standards for toxic pollutants for which EPA has published water quality criteria and which reasonably could be expected to interfere with designated uses of a water body.

National Pollution Discharge Elimination System (NPDES)

The NPDES permit program, as authorized by Section 402 of the CWA, was established 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 SWRCB permitting authority to implement the NPDES program. In general, the SWRCB issues two baseline general permits, one for industrial discharges and one for construction activities. In 1990, the EPA promulgated rules establishing Phase I of the NPDES storm water program for categories of storm water discharge including “medium” and “large” Municipal Separate Stormwater Sewer Systems (MS4s), which generally serve populations of 100,000 or greater. The Phase II Rule that became final on December 8, 1999, expanded the existing NPDES program to address storm water dischargers from construction sites that disturb land equal to or greater than one acre and “small” MS4s.

The San Diego Regional Board issued the municipal storm water National Pollutant Discharge Elimination System (NPDES) permit (“Municipal Permit”) (Order No. 2001-01, NPDES No. CAS0108758) to the county of San Diego, the city of San Diego, the Port of San Diego, and 17 other cities (called Copermittees or dischargers by owning or operating a MS4) on February 21, 2001. The Municipal Permit requires each Copermittee to adopt its own Local Standard Urban Storm Water Mitigation Plan (SUSMP) and ordinances consistent with the Regional Board- approved Model SUSMP. As part of the Phase II of the Municipal Permit, the SWRCB adopted Order No. 2003-0005-DWR (General Permit No. CAS000004) for small MS4s, which requires these MS4s to develop and implement a Storm Water Management Plan with the goal of reducing the discharge of pollutants to the maximum extent possible. The Regional Board requires the owners or operators of these MS4s in watersheds subject to TMDLs to submit Notices of Intent (NOI) to comply with this Order.

Section 10 of the River and Harbors Act

Section 10 of the Rivers and Harbors Act of 1899 requires authorization from the ACOE for the construction of any structure in or over navigable waters of the United States or obstruction or alteration in a navigable water. Structures or work outside the limits defined for navigable waters of the U.S. requires a Section 10 permit if the structure or work affects the course, location, condition, or capacity of the waterbody. Navigable waters are defined as waters that are subject to the ebb and flow of the tide.

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State

Streambed Alteration Agreement

Sections 1600 et seq of the California Fish and Game Code require an agreement between the California Department of Fish and Game and any entity proposing to substantially divert or obstruct the natural flow or effect changes to the bed, channel, or bank of any river, stream, or lake. The agreement is designed to protect the fish and wildlife values of a river, lake, or stream.

Porter Cologne Water Quality Control Act

The Porter Cologne Water Quality Control Act of 1967, Water Code section 13000 et seq., requires the SWRCB and the nine RWQCBs to adopt water quality criteria to protect State waters. These criteria include the identification of beneficial uses, narrative and numerical water quality standards, and implementation procedures. Beneficial uses are identified as the uses of water necessary for the survival or well being of man, plants, and wildlife. These uses of water serve to promote the tangible and intangible economic, social and environmental goals of mankind. Examples include drinking, swimming, industrial and agricultural water supply and the support of fresh and saline aquatic habitats. Water quality objectives seek to protect the most sensitive of the beneficial uses designated for a specific water body. The criteria for the project area are contained in the water quality control plan for the San Diego Basin.

State Water Resource Control Board

The SWRCB is responsible for issuing storm water permits in accordance with the NPDES program. For projects disturbing one or more acres of land, the applicant must file a NOI for coverage under the General Permit for Storm Water Discharges Associated with Construction Activity (General Permit) and prepare a Storm Water Pollution Prevention Plan (SWPPP) that specifies Best Management Practices (BMPs) to prevent pollutants from contacting storm water and procedures to control erosion and sedimentation.

Regional Water Quality Control Board

The proposed project falls within the jurisdiction of the San Diego RWQCB. Each RWQCB is responsible for water quality control planning within their region, often in the form of a basin plan. The RWQCB is also responsible for implementing the provisions of the General Permit, including reviewing SWPPPs and monitoring reports, conducting compliance inspections, and taking enforcement actions. In addition, the San Diego RWQCB issued a general NPDES permit for groundwater discharges to surface waters within the San Diego Region, except San Diego Bay (Order No. R9-2008-0002; NPDES No. CAG919002). Coverage under the permit requires submittal of an application to the RWQCB at least 60 days prior to discharge.

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Regional and Local

Municipal Storm Water Permit

The county and other cities or jurisdictions in the region were issued an updated NPDES Municipal Storm Water Permit on January 24, 2007 by the San Diego RWQCB (Order No. R9- 2007-0001). The recently issued permit renews Permit No. CAS0108758, which was first issued on July 16, 1990 (Order No. 90-42) and later renewed on February 21, 2001. The permit requires the development and implementation of BMPs in development planning and construction of private and public development projects. Development projects are also required to include BMPs to reduce pollutant discharges from the project site in the permanent design. The county requires a Storm Water Management Plan (SWMP) to describe potential construction and post- construction pollutants and identify BMPs to protect water resources.

3.3.2 Thresholds of Significance

Thresholds used to evaluate potential impacts to water resources are based on applicable criteria in Appendix G of the State CEQA Guidelines. A significant impact to water resources would occur if the proposed project were to:

• Violate any water quality standards or waste discharge requirements. • 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. • 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. • 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 off-site. • Create or contribute runoff water which would exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff. • Otherwise substantially degrade water quality. • 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. • Place within a 100-year flood hazard area structures which would impede or redirect flood flows.

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• 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. • Result in inundation by seiche, tsunami, or mudflow.

3.3.3 Impact Analysis

Would the proposed project result in a violation of any water quality standards or waste discharge requirements?

Short-term

Construction of the proposed project would generate off-site sediment and construction material waste. Sedimentation can typically be caused through erosion of unprotected graded slopes and poor stockpile management. Construction material waste can pollute downstream water bodies, resources and aquatic environments if not treated, handled and disposed of properly. Grading would increase the erosion potential of onsite soils, which could lead to offsite sediment transport. Sediment, nutrients, organic compounds, and potential oxygen demanding substances would be the potential pollutants generally of concern for projects disturbing agricultural land.

Construction projects that disturb one or more acres of soil are required to obtain coverage under the General Permit for Discharges of Storm Water Associated with Construction Activity (SWRCB 1999). Construction activity subject to this permit includes clearing, grading and disturbances to the ground such as stockpiling, or excavation. Standard design features and construction measures incorporated into the project, as identified in Section 2.4.2, include compliance with the Construction General Permit which requires the development and implementation of a SWPPP. The SWPPP would contain a site map which shows the construction site perimeter, temporary roadways, general topography both before and after construction, and drainage patterns across the project. The SWPPP would list BMPs that the project will use to protect storm water runoff and the placement of those BMPs. General BMPs include erosion controls, sediment controls, tracking controls, wind erosion control, non-storm water management, and materials and water management. Additionally, the SWPPP would contain a visual monitoring program and a chemical monitoring program for "non-visible" pollutants to be implemented if there were a failure of BMPs.

In addition to sediment and eroded soils, solvents, fuels, oils, trash, or other noxious materials could be carried downstream from the construction site by storm water runoff. In the absence of implementation of BMPs, impacts to surface and groundwater quality in the project area from accidental spills of hazardous materials occurring during construction would be potentially significant. However, BMPs such as straw wattles, gravel bags, and silt curtains, have been incorporated into the project design, as identified in Section 2.4.2. As a result, impacts would be less than significant.

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Long-term

Activities associated with operation of the project that could impact water quality include runoff from the restored wetlands and residual concentrations of pesticides or other environmental contaminants in the former agricultural lands. The project proposes to restore former agricultural lands in the Tijuana River floodplain to wetlands, which would result in improved water quality conditions. Wetlands assist in filtering and treating urban runoff and contaminants such as hydrocarbons, metals, nutrients and sediment. There are four ways a wetland can do this:

1. Degradation [roots and shoots]: Microbes around the roots or metabolism within plants break down and detoxify contaminants. 2. Accumulation [roots, shoots, and leaves]: Plants accumulate contaminants in their shoots and leaves. 3. Dissipation [leaves]: Plants remove contaminants from the soil and transpire them into the atmosphere. 4. Immobilization [shoots and roots]: Plants bind contaminants to the soil, remove the contaminants’ means of transport (water), accumulate the contaminants in their roots, or cause precipitation of the contaminants within the root zone of the plants.

As a result, long-term water quality impacts would be less than significant.

Groundwater

Minor grading to lower the elevation of the project site is required to create onsite wetlands and desired effective flow characteristics. This grading may increase the quantity of shallow groundwater discharging to the surface (daylighting) on the project site. The potential for this daylighting is very low, would be extremely localized, and would not extend for longer than 24 to 48 hours. As previously indicated, groundwater has been encountered less than 30 inches bgs on the project site. Groundwater samples indicate that six constituents exceed the effluent limitations set forth in the general NPDES permit for groundwater discharges. These constituents include fluoride, iron, manganese, nitrogen (nitrate and nitrite), and dissolved solids. Based on specific effluent limitations, the groundwater from the site would require treatment prior discharge to the Tijuana River.

Dewatering may be required at the berm extension site, as well as at the site of the new berm to be constructed at the western boundary of the project site. Dewatering at these sites may result in potential impacts to surface water quality. The project is located in the floodplain of the Tijuana River and upstream of the Tijuana River Estuary and Pacific Ocean. These waterbodies are identified on the SWRCB’s 2006 Section 303 (d) List of Water Quality Limited Segments. As such, the project could result in a violation of water quality standards due to groundwater discharge, and impacts would be significant (Impact WR-1).

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Would the proposed 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?

During short-term grading and construction activities, grading at the site would lower the elevation of the site and may result in the daylighting of shallow groundwater. However, grading would be short-term and would not result in a net deficit in aquifer volume or a short-term lowering of the local groundwater table, and impacts would be less than significant.

Over the long-term, the project proposes to create approximately 40 acres of wetlands on the project site, thereby increasing the quantity of surface water that recharges groundwater at the site. As such, the project would not deplete groundwater supplies or interfere with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level, and impacts would be less than significant.

Would the proposed 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 on- or off-site?

The proposed project involves construction of wetland restoration adjacent to the Tijuana River. It would entail a permanent change from agricultural use to wetlands, and would intentionally alter drainage patterns. The on-site drainage pattern would be substantially altered as a result of the following:

• Blocking lower flows to the north channel (berm extension); • Removing parts of the existing berm that separates the wetlands site from the river channel; • Minor grading at the wetland site; and • Grading in the main channel to allow flow into the wetland site.

In order to evaluate the potential for substantial erosion or siltation, an erosion and sedimentation study, Hydraulic and Sedimentation Study for the Wetland Restoration in the Tijuana River Floodplain (Chang 2007) was prepared. Results of hydraulic modeling conducted in the study indicate that the proposed project would have less than significant effects on river channel scour. The soil disposal area of the wetland mitigation site (Figure 2-6) is located on the west side of the existing Smuggler’s Gulch berm. In this location, the disposal site is not subjected to flow in the Smuggler’s Gulch channel that is contained by existing berms. Within the project site, the disposal area is located in an area of ineffective flow as determined by hydraulic analysis (Chang 2007). Ineffective flow is typified by areas that inundate but where there is no current or water movement. The ineffective flow areas would not retain water for longer than 24 to 48 hours after a flood event, unless another flood event follows the first. Water would migrate off the project

Tijuana River Valley 3.3-12 December 2008 Wetlands Mitigation Project Environmental Analysis

site or percolate into the soil, and long-term standing water conditions would not result. Land features situated at the edge of ineffective flow areas are not subject to scour or erosion, which require higher velocities of water movement. River flow velocities for the proposed project are closely similar to those for existing conditions (Chang 2007), and as a result the project would have no substantial erosion or siltation impacts.

Would the proposed 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 off- site?

As mentioned above, the proposed project, including the berm extension, would alter the drainage pattern of the Tijuana River. The hydraulic modeling performed for the proposed project site (Chang 2007) indicates that the proposed project would neither raise the flood level nor raise the velocities at bridge crossings during the 100-year flood event. The proposed project is not in the immediate vicinity of these bridges, nor does it affect the hydraulics of river flow at the bridge crossings. Comparison of existing water-surface elevations and proposed conditions indicates only minor differences (Chang 2007). With a portion of the River’s flow through the wetland area, the proposed project would not cause any rise in flood level. Therefore, the project would have no substantial flooding impacts.

It should be noted that the berm extension would reduce flows from entering the northern channel. This channel was established in 1992 by extreme flood events. An attempt was made to divert flows from entering the northern channel through the construction of the pilot channel in 1993. However, primary runoff began to flow towards the channel again in early 2005.

With implementation of the berm extension, flows into the northern channel would be limited to greater than 5-year flood events. Any change that occurs would mimic natural conditions within a secondary channel. The location of the secondary channel within the northern channel is consistent with previous flood control management decisions made by the city, county, and ACOE. Therefore, the project is not expected to result in downstream impacts in the region and if changes do occur, those changes would be an overall restoration of wetlands ecology within the Tijuana River valley and no significant impacts would occur.

Would the proposed project create or contribute runoff water which would exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff?

The potential for increased runoff would exist during construction as vegetation is cleared from construction and staging areas. BMPs, such as straw wattles, gravel bags, and silt curtains, would be implemented to prevent increased runoff from leaving the work areas, as identified in Section

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2.4.2. Given the nature of the proposed wetlands mitigation project, no long-term significant increase in runoff would result, and impacts would be less than significant.

Would the proposed project otherwise substantially degrade water quality?

The proposed project would not otherwise substantially degrade water quality. Activities associated with the previous land use of the project site for agricultural purposes may have degraded water quality, as previously indicated in Section 3.3.3. The project proposes to restore these former agricultural lands to wetlands, which would result in improved water quality conditions.

Would the proposed project 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?

The proposed project does not involve construction of housing. Onsite structures are abandoned and not used for housing, and these structures would be removed as part of the proposed project. Therefore, no impacts associated with the placement of housing within a 100-year-flood hazard area would occur.

Would the proposed project place within a 100-year flood hazard area structures which would impede or redirect flood flows?

The project includes one offsite proposed structure which would impede flood flows. The off-site berm extension would be maintained in the Tijuana River to block flow to the north branch channel, redirecting flows toward the project to sustain wetlands. The berm extension has been designed to redirect 2- and 5-year flood flows, however it would not impede the 100-year flood. No structures would be constructed on the proposed wetland project site that would impede or redirect flood flows, and impacts would be less than significant.

Would the proposed project expose people or structures to a significant risk of loss, injury, or death involving flooding, including flooding as a result of the failure of a levee or dam?

The project site is located in an area of potential flooding during a 100-year flood event (Figure 3.3-1) and is also located within a dam inundation area. Barrett Dam is located approximately 10 miles east of the proposed project, and Morena Dam is located approximately 25 miles east of the site. In addition, Rodriguez Dam is located approximately 13 miles southeast of the project site in Tijuana, Mexico and controls portions of the flow of the Tijuana River (county of San Diego 2007a). Failure of any of these dams would affect downstream areas, including the project site. However, the proposed wetlands mitigation project would not expose people or structures to a significant risk or loss of injury or death involving flooding, and impacts would be less than significant.

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During the peak flood flow, there is the potential for localized areas of scour within the project site. However, these areas would return to native grade through sediment accretion as flood waters slow down and recede. Onsite trails and the trails surrounding the project site would be subject to periods of inundation during peak flood events, but are not anticipated to remain inundated for more than 36 hours after the flood waters have receded (Chang 2007). As such, impacts would be less than significant.

Would the proposed project result in inundation by seiche, tsunami, or mudflow?

A tsunami is a water wave or a series of waves generated by a sudden displacement of the surface of the ocean or other deep body of water through displacements associated with large earthquakes, major submarine slides, or exploding volcanic islands. A seiche is a periodic oscillation or “sloshing” of water in an enclosed basin, such as a reservoir. Seiche-generating disturbances include earthquakes, landslides, wave interactions, and changes of wind or air pressure. Seiches can create a range of water-level changes, from imperceptible to those that damage vessels or threaten lives.

The project site is located approximately two miles east of the Pacific Ocean and at approximately 19 to 25 feet AMSL. Based on the elevation and distance to the Pacific Ocean, the potential for damage resulting from a tsunami is considered to be low. There is the potential for a seiche to occur, given the proximity of the project site to a major active fault zone as well as three large reservoirs. However, the periodic oscillation of water within these reservoirs would need to overtop their respective dams, and even if this were to occur the amount of water released would likely not be significant enough to result in inundation of the project site. Potential impacts from mudflow would not result, since the nearest substantial slopes are located approximately 0.25 miles to the south. Impacts would be less than significant.

3.3.4 Mitigation Measures

Implementation of Mitigation Measure WR-1 would reduce Impact WR-1 to below a level of significance:

WR-1 Prior to conducting construction dewatering, the Water Authority or designee shall obtain groundwater discharge coverage under one of the following compliance options as appropriate: an Individual NPDES Permit; or, the General NPDES Permit for Groundwater Waste Discharges from Construction, Remediation, and Permanent Groundwater Dewatering Extraction Projects to Surface Waters within the San Diego Bay Region Except for San Diego Bay (Order No. R9-2008-0002; NPDES No. CAG919002); or, a Waiver of Waste Discharge Requirements. Compliance with all approval terms and conditions shall be required. If the General NPDES Permit is selected, In accordance with the permit, groundwater samples from the site would be collected. These samples would undergo an analysis of potential contaminants

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including, but not limited to, metals, volatile compounds, nitrogen, and coliform. The entire list of compounds to be analyzed is included in the General NPDES Permit. Groundwater containing constituents that exceed the effluent limitations set forth in the General Permit would require treatment prior to discharge into the Tijuana River.

3.3.5 Residual Impacts after Mitigation

With implementation of the mitigation measures listed above, no significant water quality impacts would result.

Tijuana River Valley 3.3-16 December 2008 Wetlands Mitigation Project Legend

Proposed Project Site 100-Year Floodplain TO CAYO AV 500-Year Floodplain

SUNSET AV

SATURN BL SATURN

HOLLISTER ST

DAIRY MART RD

MONUMENT RD

AERIAL SOURCE: DIGITAL GLOBE, MARCH 2007 Fe et 01,500

Tijuana River Valley Wetlands Mitigation Project - EIR FIGURE 100-Year Floodplain 3.3-1 Environmental Analysis

INTENTIONALLY LEFT BLANK

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3.4 BIOLOGICAL RESOURCES

This section evaluates the potential impacts of the proposed project on sensitive biological resources. The evaluation is based on project-specific biological resources reports (Dudek 2008a, 2008b), which are included as Appendix E to this EIR.

3.4.1 Existing Conditions

Surveys Conducted

Sensitive biological resources present or potentially present on the proposed project site were identified through a literature search using the following sources: the California Natural Diversity Database (CNDDB) (CDFG 2007b), U.S. Fish and Wildlife Service (2007, 1998, 1988), California Department of Fish and Game (2007a, b), California Native Plant Society's (CNPS) Inventory of Rare and Endangered Vascular Plants (CNPS 2007), U.S. Army Corps of Engineers (2006) and the scientific literature. General information regarding wildlife species present in the region was obtained from Unitt (1984) for birds, Bond (1977) for mammals, Stebbins (1985) for reptiles and amphibians, and Emmel and Emmel (1973) for butterflies.

The project site and vicinity was surveyed between April 2006 and October 2007. Also, the berm extension area was surveyed in March 2008. Surveys consisted of vegetation mapping, a jurisdictional wetlands delineation, inventory of wildlife and plant species, focused surveys for the federally-listed endangered least Bell’s vireo and southwestern willow flycatcher, and a focused habitat assessment for the federally-listed endangered pacific pocket mouse. During the general and focused surveys, the potential for special status plant and wildlife species to occur on site was assessed, based on the existing vegetation communities, soils, and overall habitat quality of the site.

Sensitive Biological Resources

Sensitive Vegetation Communities

Project Site

Sensitive vegetation communities are those that are considered rare within the region, support sensitive plant and/or wildlife species, or require mitigation pursuant to the USFWS ACOE, CDFG, RWQCB, California Coastal Commission (CCC), county of San Diego and/or the city of San Diego. Disturbed southern willow scrub and freshwater marsh are on-site wetlands communities that are considered sensitive by all of the above resource agencies. In addition, an unvegetated intermittent/ephemeral stream channel is present and is considered a sensitive resource. There are no sensitive upland communities present on the project site. Figure 3.4-1 depicts the spatial distribution of each of these sensitive vegetation communities located within the project site. Sensitive wetlands are described below in more detail.

Tijuana River Valley 3.4-1 December 2008 Wetlands Mitigation Project Environmental Analysis

Berm Extension Site

At the berm extension site, southern willow scrub, disturbed southern willow scrub, open water, mulefat scrub, and tamarisk scrub are on-site communities that are considered sensitive. Figure 3.4-2 depicts the spatial distribution of each of these sensitive vegetation communities located within the project site.

Wetlands and Waters of the U.S.

Project Site

A delineation of wetlands and non-wetland waters of the U.S. (WOUS) was conducted on the project site in March, September, October 2007 and March 2008. A total of 5.07 acres of jurisdictional waters are present onsite. Wetlands communities present within the project area include disturbed southern willow scrub and freshwater marsh (Figure 3.4-3). In addition, non- wetland jurisdictional waters on site includes open channel and open water. Each of these jurisdictional areas is considered sensitive. Regulatory determinations for each of these resources are described below.

The jurisdiction of the ACOE and RWQCB under the federal Clean Water Act requires that jurisdictional features have a hydrological connection or significant nexus with a Traditionally Navigable Waters (TNW). For the project site, the TNW is the Pacific Ocean. The Tijuana River channel is considered a Relatively Permanent Waters (RPW) because it supports standing water for at least 3 months a year. The river is a RPW that flows directly to the TNW and therefore the river and directly adjacent wetlands are also considered WOUS. The wetlands area mapped as freshwater marsh and open water occur within the impounded detention basin within the eastern portion of the project area, contain a direct connection to waters within the Tijuana River (via an inlet pipe through berm) and contain evidence of all three delineation criteria (hydrology, hydric soils and a predominance of hydrophytic vegetation) and therefore are considered a WOUS. These areas are also under the jurisdiction of CDFG, CCC, county of San Diego and the city of San Diego.

In addition, all of the disturbed southern willow scrub located north of the project site’s northern berm contains indicators for all three wetlands criteria, and is directly adjacent to the river, and is therefore considered jurisdictional. All disturbed southern willow scrub areas are also under the jurisdiction of CDFG, CCC, county of San Diego and the city of San Diego.

The open channel (Smuggler’s Gulch) is a direct tributary to the Tijuana River and is considered a non-wetland WOUS. The channel is also under the jurisdiction of the CDFG, CCC, county of San Diego and the city of San Diego.

Tijuana River Valley 3.4-2 December 2008 Wetlands Mitigation Project Environmental Analysis

Areas directly adjacent to the abandoned irrigation basin and Smuggler’s Gulch mapped as disturbed southern willow scrub contain two of three delineation criteria (a predominance of hydrophytic vegetation in association with a stream channel, but lack hydric soils) so they are under the joint jurisdiction of CDFG, CCC, county of San Diego and the city of San Diego, but are not considered WOUS. Areas mapped as disturbed southern willow scrub outside of the berm along Smuggler’s Gulch or the detention basin contains only one delineation criterion (hydrophytic vegetation). No direct evidence of hydric soils or wetlands hydrology was observed in these areas, and therefore these areas are under the jurisdictions of CCC and city of San Diego only.

Berm Extension Site

A total of 3.32 acres of jurisdictional waters are present in the survey area, including mulefat scrub, open water, southern willow scrub, and disturbed southern willow scrub. All of the waters mapped on site are under the jurisdictions of the ACOE, RWQCB, CCC, CDFG, county of San Diego and the city of San Diego. Mule fat scrub, southern willow scrub, and disturbed southern willow scrub are considered wetlands where as open water is a non-wetland jurisdictional waters.

Sensitive Plant Species

Project Site

Based on the project location, mapped vegetation and soils, eight special-status plant species were considered to have a low potential to occur within the project area. These species include the spreading navarretia, Salt marsh bird’s-beak, mud nama, Palmer’s frankenia, San Diego marsh elder, Coulter’s goldfields, Estuary seablite, and decumbent goldenbush. All other species were not expected to occur on site due to a lack of suitable habitat, or are not present based on survey results.

Berm Extension Site

Plant species composition and diversity is similar to that of the nearby project mitigation site, which supports about 50 different vascular species, approximately two-thirds of which are non- native. The only species present on the berm extension site that were not present on the project site were coast goldenbush, California fuschia (Epilobium canum), California croton (Croton californicus), and field mustard (Brassica rapa).

Sensitive Wildlife Species

Project Site

Four special-status wildlife species were observed within the project site during the general and focused wildlife surveys: the California horned lark, northern harrier, Lawrence’s goldfinch, and

Tijuana River Valley 3.4-3 December 2008 Wetlands Mitigation Project Environmental Analysis least Bell’s vireo. Five additional sensitive species were observed within habitat adjacent to the project area including white-tailed kite, Cooper’s hawk, yellow warbler, yellow-breasted chat, and merlin (wintering).

The horned lark and northern harrier are California Special Concern species. California horned lark was observed foraging in the agricultural fields within and adjacent to the project area and a northern harrier was observed soaring over the project area during the March 9 and 19, 2007 surveys. Lawrence’s goldfinch is a USFWS Bird of Conservation Concern. This species was observed foraging on various plants on the berms surrounding the project during the March 19, 2007 survey.

The least Bell’s vireo is a state- and federally-listed endangered species that nests within the riparian habitat that is immediately adjacent to the project area. During the 2006 least Bell’s vireo presence/absence surveys, three least Bell’s vireos were observed adjacent to the site. During two of these surveys, a vireo was observed foraging on site in riparian scrub.

White-tailed kite is a USFWS migratory non-game bird of management concern, and a CDFG Fully Protected Species. Cooper’s hawk, yYellow warbler and, yellow-breasted chat ,are also California Species of Special Concern. Cooper’s hawk and merlin are also California Special Concern speciesincluded on CDFG’s list of Special Animals and are protected under Sections 3503 and 3503.5 of the California Fish and Game Code.

Berm Extension Site

Wildlife species present on site are similar to those documented at the project site due to the presence of similar riparian habitat. No additional special status wildlife species are expected to occur on the berm extension site.

Wildlife Corridors and Habitat Linkages

Wildlife corridors are linear features that connect large patches of natural open space and provide avenues for dispersal or migration of animals, as well as dispersal of plants. Wildlife corridors contribute to population viability in several ways: 1) they assure continual exchange of genes between populations which helps maintain genetic diversity; 2) they provide access to adjacent habitat areas representing additional territory for foraging and mating; 3) they allow for a greater carrying capacity; and 4) they provide routes for colonization of habitat lands following local population extinctions or habitat recovery from ecological catastrophes. Habitat linkages are patches of native habitat that function to join two larger patches of habitat. They serve as connections between habitat patches and help reduce the adverse effects of habitat fragmentation.

Tijuana River Valley 3.4-4 December 2008 Wetlands Mitigation Project Environmental Analysis

The project site and berm extension site occur within the Tijuana River Valley regional wildlife corridor, which includes open space and park land associated with the lower Tijuana River Valley. This corridor connects areas of wetlands and riparian habitats associated with the Tijuana River to the upland and wetlands habitats within Border Field State Park, the Tijuana Slough National Wildlife Refuge and the TRVRP. Note that these protected federal, state and local preserve areas and parks are cumulatively referred to as the Tijuana River National Estuarine Research Reserve, which is cooperatively managed by the National Oceanic and Atmospheric Administration (NOAA), California State Parks and the USFWS. The wildlife corridor continues up to four miles inland from the coast and extends south into the Baja peninsula of Mexico. The primary habitat types within the wildlife corridor include coastal sage scrub, maritime succulent and bluff scrubs, riparian woodland and scrub, coastal salt marsh and beaches.

Multi-Habitat Preserve Planning Area (MHPA)

The project site and berm extension site are located on lands within the Multiple Species Conservation Program (MSCP), which is a comprehensive conservation planning program that addresses impacts and preservation of sensitive plants, animals, and habitats. The proposed project occurs entirely within the city of San Diego Multi-Habitat Planning Area (MHPA), in the Tijuana River Valley preserve segment. This area is dominated by riparian wetlands, agricultural lands and coastal sage scrub. Several of the privately owned agricultural parcels located immediately south of the project site are not included within the MHPA, but all other lands located adjacent to and within the general vicinity of the project site are included within the MHPA. Nearby MHPA segments include riparian forest and scrub in the lower Otay River Valley approximately 5 miles northeast of the project site, extensive coastal sage scrub uplands of West Otay Mesa approximately 4 miles east of the project site, and beaches and coastal salt marsh of the South Bay approximately 4 miles north of the project site.

Conditional allowable uses within the MHPA include habitat restoration (city of San Diego 1999c), and those lands restored may be utilized for mitigation (city of San Diego 2004).

The project site and berm extension site also occur within designated critical habitat for the least Bell’s vireo in the MHPA. The designation of Critical Habitat by the USFWS is a requirement of the federal Endangered Species Act designed to ensure that federal actions are adequately reviewed for the potential to adversely affect a species listed as threatened or endangered. USFWS designated Critical Habitat for the least Bell’s vireo in 1994. USFWS is required to review all federal actions (funding, authorizing or actual implementation by a federal agency) on Critical Habitat lands and is prohibited from allowing activities which result in the destruction or adverse modification of Critical Habitat.

The USFWS has developed a Recovery Plan for the least Bell’s vireo (USFWS 1998) which includes evaluation of the vireo population within the Tijuana River Valley as one of 14 population units, representing approximately 7 percent of the known least Bell’s vireo pairs

Tijuana River Valley 3.4-5 December 2008 Wetlands Mitigation Project Environmental Analysis recorded in California in 1996. Recovery goals which would apply to the Tijuana River Valley include control or elimination of threats including “unauthorized clearing activities and placement of fill materials, off-road vehicle use, exotic species, and flood control projects and “channelizations” as well as ongoing monitoring, cowbird control measures, restoration of riparian habitat, and public education and outreach.

3.4.2 Thresholds of Significance

Thresholds used to evaluate potential impacts to biological resources are derived from Appendix G of the State CEQA Guidelines. Significant impacts related to biological resources would occur if the project were to:

• Have a substantial adverse effect, 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 California Department of Fish and Game or U.S. Fish and Wildlife Service. • Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, or regulations or by California Department of Fish and Game or U.S. Fish and Wildlife Service. • Have a substantial adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act (including but not limited to marsh, vernal pool, coastal, etc.) through direct removal, filing, hydrological interruption, or other means. • 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. • Conflict substantially with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance. • Conflict substantially with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan.

3.4.3 Impact Analysis

Would the proposed project have a substantial adverse effect, 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 California Department of Fish and Game or U.S. Fish and Wildlife Service?

Tijuana River Valley 3.4-6 December 2008 Wetlands Mitigation Project Environmental Analysis

Sensitive Plant Species

The proposed project would not result in impacts to sensitive plant species. No sensitive plant species were observed within or adjacent to the project site and berm extension site during the 2007 and 2008 surveys. Impacts to sensitive plant species would therefore be less than significant.

Sensitive Wildlife Species

Project Site

The proposed project would result in permanent direct impacts to 30.40 acres and temporary direct impacts to 3.44 acres of land designated as Critical Habitat for least Bell’s vireo. Of this area, only 3.41 acres support “primary constituent elements” for the species as designated by the Critical Habitat ruling. These 3.41 acres are mapped as disturbed southern willow scrub (disturbed wetlands per the city of San Diego biology guidelines) in the northern most part of the project. This area would be temporarily impacted by the project during the creation of a low-flow surface hydrology connection for the mitigation site to the Pilot Channel in the Tijuana River. However, the project as whole protects and will contribute to the recovery of least Bell’s vireo by creating additional suitable habitat areas with primary constituent elements. As required under Section 7 of the federal Endangered Species Act, the project would not result in adverse modifications that appreciably diminish the value of Critical Habitat for the survival and recovery of the species. Nonetheless, the project would require removal of the understory vegetation and may require removal of much of the limited riparian canopy present within this disturbed wetlands area. These temporary impacts to the vireo occupied habitat would be significant (Impact BIO-1).

The proposed project would also result in direct impacts to approximately 3.63 acres of wetlands (disturbed southern willow scrub, excluding open channel), which may also result in significant direct impacts to nesting and/or foraging habitat for sensitive passerines including the yellow warbler and yellow breasted chat. These impacts to the yellow warbler, yellow breasted chat, and other sensitive passerines would be potentially significant (Impact BIO-2).

Over the long-term, foraging habitat for some sensitive raptors may be reduced in area and/or quality by the project through the conversion of approximately 40 acres of agricultural uplands to riparian wetlands. The agricultural fields are expected to support rodent populations which are prey for sensitive raptor species known or expected to be present on the project site including but not limited to white-tailed kite, Cooper’s hawk, northern harrier, and merlin. The fields also provide foraging habitat for seed and insect specialists such as Lawrence’s goldfinch and California horned lark. The overall agricultural habitat loss resulting from the project is not expected to be appreciable for these species, as agricultural lands of substantial acreage would remain for foraging adjacent to the south and west site boundaries. Also, riparian habitat created

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by the project is likely to support some rodent populations, as well as provide cover, nesting habitat and forage for sensitive riparian species such as yellow warbler and yellow-breasted chat. The project site would continue to provide a dynamic landscape after project implementation consisting of open, cultivated fields and dense riparian scrub for foraging, cover and nesting for a variety of sensitive species. These long-term impacts to sensitive raptors would not be significant.

The proposed project may also result in short-term indirect impacts to the least Bell’s vireo and other nesting birds, as a result of noise disturbance during project grading within or adjacent to riparian scrub dominated wetlands. Least Bell’s vireo nests established within 300 feet or more (500-foot avoidance area for nesting northern harriers, and other raptors) of the project site boundaries may be disturbed during the breeding season and discouraged from nesting in the areas adjacent to the project site. These indirect impacts to sensitive wildlife species, including the State and federally-listed endangered least Bell’s vireo are expected to be of short duration (approximately three months) but would be significant if they disrupt the breeding cycle of sensitive avian species in the area (Impact BIO-3).

Short- and long-term indirect impacts to sensitive wildlife can occur as a result of displacement or predation by increased non-native wildlife species presence. Three non-native species that are known to have negative effects on sensitive wildlife species occur within the vicinity of the site, including brown-headed cowbird, bullfrog and African-clawed frog (county of San Diego 2007b). Brown-headed cowbird, a brood parasite that lays eggs in the nests of many bird species present in the project area including least Bell’s vireo, southwestern willow flycatcher and yellow warbler (Unitt 2004), was observed on the project site during the 2006 and 2007 wildlife surveys. The project is not anticipated to result in any increase of the brown-headed cowbird within the project vicinity. This widespread species can utilize a wide variety of habitats, hence conversion of agricultural land to riparian wetlands is not anticipated to have a significant effect on any sensitive wildlife species through increased parasitism by the brown-headed cowbird. Note that a cowbird trapping project is currently being implemented within the Tijuana River Valley Regional Park which would include habitats within the vicinity of the project (county of San Diego 2007).

Berm Extension Site

Impacts at the berm extension site would result in impacts to 0.003 acre of southern willow scrub that has been designated Critical Habitat for the federally-listed endangered least Bell’s vireo. This impact results from the removal of vegetation where the berm would be constructed. This impact to the vireo habitat would be significant, as previously identified in Impact BIO-1.

The implementation of the berm extension project component would result in impacts to 0.114 acres of wetlands habitat (including southern willow scrub and mulefat scrub), which may also result in significant impacts to nesting and/or foraging habitat for sensitive passerines including

Tijuana River Valley 3.4-8 December 2008 Wetlands Mitigation Project Environmental Analysis the yellow warbler and yellow breasted chat, as well as other migratory species protected under the MBTA. These direct impacts to sensitive wildlife would be potentially significant, as previously identified in Impact BIO-2.

As would occur at the project mitigation site, construction at the berm extension site may also result in short-term indirect impacts to the least Bell’s vireo and other nesting birds, as a result of noise disturbance during project grading within riparian scrub dominated wetlands. These indirect impacts to sensitive wildlife species, including the State and federally-listed endangered least Bell’s vireo are expected to be of short duration (approximately three months) but would be significant if they disrupt the breeding cycle of sensitive avian species in the area (Impact BIO-3).

Would the proposed project have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, or regulations or by California Department of Fish and Game or U.S. Fish and Wildlife Service? Project Site

In the long-term, the project would create approximately 40 acres of jurisdictional wetlands habitat at the mitigation site. These riparian wetlands are anticipated to be under the jurisdictions of ACOE/CDFG/RWQCB/CCC/county of San Diego/city of San Diego. This includes a sufficient area of wetlands habitat to be created, restored and/or enhanced on-site to mitigate the direct, temporary impacts anticipated to occur to existing on-site jurisdictional wetlands during the construction phase of the project.

In the short-term, as shown in Table 3.4-1, construction of the proposed project would result in impacts to approximately 3.66 acres of sensitive habitats, which would be a significant impact (Impact BIO-4). All other impacts would occur within non-sensitive upland habitats and are thus not considered significant.

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Table 3.4-1 Permanent and Temporary Habitat Impacts (Acres)

Temporary Permanent Habitat Type Impacts Impacts Total Upland Habitats Disturbed Habitat (Tier IV Uplands) 0.00 3.70 3.70 Ruderal (Tier IV Uplands) 0.00 4.11 4.11 Agricultural (Tier IV Uplands) 0.00 42.08 42.08 Ornamental (Tier IV Uplands) 0.00 0.60 0.60 Developed (Tier IV Uplands) 0.00 0.25 0.25 Uplands subtotal 0.00 50.73 50.73 Jurisdictional Habitats ACOE/CDFG/CCC/RWQCB/County of SD/City of SD Wetlands and Non-Wetland Water of the U.S. Disturbed Southern Willow Scrub (Disturbed Wetlands per city 3.382.77 0.00 3.382.77 2004) Open Channel (Natural Floodway per city 2004) 0.03 0.00 0.03 Subtotal 3.412.80 0.00 3.412.80 CDFG/CCC/City of SD Wetlands Disturbed Southern Willow Scrub (Disturbed Wetlands per city 0.6403 0.04 0.6807 2004) CCC/Ccity of San Diego Only Wetlands Disturbed Southern Willow Scrub (Disturbed Wetlands per city 0.00 0.18 0.18 2004) Jurisdictional Habitats subtotal 3.44 0.22 3.66 Project Impact Total1 3.44 50.95 54.39 1 The total project site is 60.7 acres; a total of 6.31 acres of the site would not be impacted by the project.

Of the total 3.66 acres of impacts to jurisdictional waters, the proposed project would result in approximately 3.412.80 acres of temporary impacts to wetlands and non-wetland WOUS under the joint jurisdiction of ACOE, CDFG, RWQCB, CCC, county of San Diego and the city of San Diego including 3.382.77 acres of disturbed southern willow scrub and 0.03 acres of open channel. These impacts would result from creation of a surface hydrology connection for the mitigation site to the pilot channel in the Tijuana River. Establishing the connection would require grading throughout the understory of the disturbed wetlands habitat to remove non-native plants, lower the site surface elevations and may require removal of the existing sparse riparian canopy in most of the 3.382.77 acres of disturbed southern willow scrub.

Another portion of the 3.66 acres of temporary impacts to jurisdictional waters includes approximately 0.07 68 acre of direct impacts to disturbed southern willow scrub under the jurisdictions of the CDFG, CCC, county of San Diego and the city of San Diego only; 0.03 64 acres would be temporarily impacted through the removal of berms and 0.04 acres would be

Tijuana River Valley 3.4-10 December 2008 Wetlands Mitigation Project Environmental Analysis

permanently impacted through the establishment of new berms. Note that a portion of the existing berm along the north edge of the site would be preserved in place.

The remainder of the 3.66 acres of temporary impacts to jurisdictional waters includes direct, permanent impacts to 0.18 acres of disturbed southern willow scrub under the jurisdictions of the county of San Diego, city of San Diego and the CCC. These impacts would result from the removal of two relatively large, established arroyo willows within agricultural land near the northeast corner of the proposed project site to accommodate the development of an on-site soil disposal and construction staging area.

Berm Extension Site

A total of 0.11 acres of jurisdictional wetlands would be directly permanently impacted by the proposed berm extension and another 0.09 acres of jurisdictional wetlands would be temporarily impacted. All impacted wetlands are jurisdictional under ACOE, CDGG, CCC, county of San Diego and the city of San Diego. Table 3.4-2 shows the communities and land covers that will be impacted.

Table 3.4-2 Vegetation Communities and Land Covers Impacted by the Berm Extension

Impacts (acres) Vegetation Community/Land Cover Tier Temporary Temporary Permanent (Berm) (Access/Staging) (Dike/Dewatering) Southern Willow Scrub wetlands .003 0 0 Mulefat Scrub wetlands .082 0 .023 Open water wetlands .029 0 .071 Wetlands Subtotal: 0.208 acre .114 0 .094 Ruderal Habitat IV .004 .129 0 Developed Land IV 0 .849 0 Uplands Subtotal: 0.982 acre .004 .978 0 Total 0.118 .978 0.094

The berm extension would result in permanent impacts to a total of 0.114 acre of jurisdictional wetlands or non-wetlands WOUS, including 0.082 acre of mulefat scrub, 0.003 acre of southern willow scrub, and 0.029 acre of open water.

Construction of a temporary dike during project implementation would result in direct temporary impacts to 0.018 acre of jurisdictional wetlands, including 0.007 acre of mulefat scrub and 0.011 acre of open water. Dewatering during project implementation would also result in direct temporary impacts to 0.076 acre of jurisdictional waters, affecting mostly open water in the Tijuana River (0.06 acre), but also 0.016 acre of mulefat scrub.

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Therefore, the berm extension would result in approximately 0.208 acres of direct impacts (which includes permanent and temporary impacts) to jurisdictional wetlands and non-wetland WOUS. Impacts to jurisdictional wetlands would be significant (Impact BIO-5).

The buildout of the berm extension would also result in permanent impacts to less than 0.01 acre of ruderal land cover. Access and staging for construction of the berm extension would temporarily impact an additional 0.98 acres of ruderal and developed land. Ruderal and developed lands are not considered sensitive by the county, city and/or the resource agencies. These impacts to ruderal and developed land would be less than significant.

Would the proposed project have a substantial adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act (including but not limited to marsh, vernal pool, coastal, etc.) through direct removal, filing, hydrological interruption, or other means?

Project Site

As discussed previously in this section, the proposed project would result in direct impacts to approximately 3.66 acres of wetlands and non-wetland WOUS under the jurisdictions of ACOE, CDFG, RWQCB, CCC, county of San Diego and/or the city of San Diego. These impacts would be significant (Impact BIO-4), as analyzed above.

Berm Extension Site

As discussed previously in this section, the proposed project would result in direct impacts to approximately 0.208 acres of wetlands and non-wetland WOUS under the jurisdictions of ACOE, CDFG, RWQCB, CCC, county of San Diego and/or the city of San Diego. These impacts would be significant (Impact BIO-5), as analyzed above.

Would the proposed 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?

The proposed project, including impacts at the wetland site and berm extension site, is not expected to result in significant direct impacts to wildlife corridors or habitat linkages. The project would result in an overall expansion of native riparian scrub habitat adjacent to the lower Tijuana River within the Tijuana River Valley regional wildlife corridor. The project would functionally expand the width of the Tijuana River riparian corridor by increasing the area dominated by native riparian scrub, and ultimately by providing a greater area of dense cover for lateral movement of terrestrial wildlife species within the river valley. Establishment of native wetlands vegetation within the project area would expand the riparian corridor near the project site from an average width of 500 feet south of the pilot channel to an average width of over 1,000 feet south of the pilot channel. The proposed project is not expected to significantly

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increase or decrease the functioning of wildlife corridors or habitat linkages. Impacts would be less than significant.

Also, the multi-use trails established for the project are not anticipated to result in any significant indirect impacts to wildlife corridors or habitat linkages. The project would relocate existing trail segments several hundred feet to the south, on new berms constructed for the project. These trails would accommodate equestrian, pedestrian and bicycle uses and would be available during daylight hours in accordance with county park management directives (county of San Diego 2007). The proposed project also would include removal of several hundred feet of chain-link fence erected along the south boundary of a former ACOE riparian restoration project located along the north project boundary. The removal of this fence segment may indirectly improve mobility for small and large mammals through the project area. The relocation and replacement of existing multi-use trails and fence removal is not anticipated to result in any significant changes to wildlife movement through the Tijuana River Valley. Impacts would be less than significant.

Would the proposed project conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance?

Project Site

The city of San Diego Environmentally Sensitive Lands (ESL) Regulations apply to the project because it contains sensitive biological resources and is located within a floodway. Uses allowed within floodways in the ESLs are those allowed by the Open Space – Floodplain zone, which includes passive recreation and natural resources preservation. Given the proposed use of the project for a wetlands mitigation site, there are no potential significant effects on environmentally sensitive lands. The proposed project does not conflict with any local policies or ordinances protecting biological resources.

Berm Extension Site

The berm extension site footprint is also within the coastal zone, subject to the city’s LCP/LUP designations. As such impacts to wetlands are only permitted where they can be considered unavoidable. The Tijuana River Valley LCP/LUP acknowledges that flood control and mitigation activities are allowable. The berm extension is an integral part of both flood control and mitigation objectives and the function of the structure cannot be accomplished unless it is located within the wetlands; thus the impacts are considered unavoidable. No significant conflicts with local policies or ordinances would result.

Would the proposed project 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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The proposed project would target prior converted agricultural lands located adjacent to the Tijuana River within the MHPA and restore those agricultural lands to native wetlands, in order to more fully contribute to the functioning of the MHPA. The restored wetlands would be utilized for mitigation, including temporary direct impacts associated with project implementation and future Water Authority projects, and would be managed in perpetuity. The project has been developed to be consistent with allowable land uses including wetlands creation and habitat restoration per the Tijuana River Valley Local Coastal Program Land Use Plan.

The proposed project, including the wetlands mitigation site and berm extension site, is not expected to result in any significant short- or long-term indirect impacts to the city of San Diego MHPA preserve. Any potentially significant indirect impacts to sensitive habitats or wildlife within the project MHPA segment would be limited temporally and spatially and would not result in significant indirect impacts to the MHPA preserve. Management of long-term wetlands habitat quality would be implemented with the HMP that would be created for the proposed project, and as a result, MSCP-covered sensitive plant and wildlife species and habitats would be maintained and protected in perpetuity.

3.4.4 Mitigation Measures

Implementation of Mitigation Measure BIO-1 would reduce Impacts BIO-1, BIO-2, and BIO-3 to below a level of significance:

BIO-1 To minimize potentially significant direct impacts to sensitive wildlife species to a level below significance, clearing of habitat on the project site shall be completed prior to the onset of the avian nesting season (January 15 – July 31 for raptors; March 15 - September 15 for riparian avian species) or implementation of the following nest avoidance measures. A nesting bird survey, for species protected under the MBTA and/or California Fish and Game Code, shall be conducted within 10 days of the start of construction over the entire proposed construction area. Any actives nests found within the construction limits to be disturbed by construction clearing shall have a minimum 50-foot buffer from the nest site or an area determined to be adequate by a qualified biologist to protect the nest site(s) from work activities. Weekly surveys to assess nest status shall be conducted until juvenile birds have successfully fledged or the nest becomes inactive. At such time, the nest site and surrounding buffer vegetation may be removed under the direction of a qualified biologist.

To minimize potentially significant indirect impacts to sensitive wildlife species to a level below significance, a nesting bird survey, for species protected under the Water Authority’s draft NCCP/HCP with the potential to occur in the project area, shall be conducted within 10 days of the start of construction or at the onset of the avian breeding season (January 15 – July 31 for raptors; March 15 - September 15 for riparian avian species, annually). The survey shall include a 500-foot buffer from

Tijuana River Valley 3.4-14 December 2008 Wetlands Mitigation Project Environmental Analysis

edge of construction for raptor species. If one or more sensitive species is detected within the species-specific buffer areas, a qualified biologist shall monitor nesting activity to determine if adverse effects from construction occur. If adverse effects are observed that can be attributed to construction, the biologist will recommend changes to the construction process or active work area until breeding activity has ceased to avoid negative impacts. Weekly surveys to assess nest status shall be conducted until juvenile birds have successfully fledged or the nest becomes inactive.

If construction is to occur during the breeding season for the least Bell’s vireo (March 15 – September 15, annually), focused protocol surveys for the least Bell’s vireo shall be conducted prior to construction activities such as clearing, grading, and berm demolition and construction (or at the onset of the breeding season if construction starts before the season and is expected to continue into the season) to determine (1) if this species is present in and/or adjacent to the proposed project impact areas and (2) whether this species is located within 500 feet of the proposed construction areas. If this species is observed or detected within 500 feet of the construction site, mitigation for indirect impacts shall be developed by the project biologist in coordination with the appropriate agencies (e.g., setbacks, monitoring, breeding season construction limitation, sound attenuation walls). If construction activities must occur during the least Bell’s vireo breeding season, human activities would be restricted within a 300-foot radius measured from occupied least Bell’s vireo nest site(s), or a sufficient distance (as determined by the qualified biologist) such that

noise levels at the nest location do not exceed 60 dBA Leq (hourly average) and avoid significant indirect impacts to the least Bell’s vireo.

To minimize potentially significant direct impacts to sensitive wildlife species to a level below significance, clearing of habitat on the project site shall be completed prior to the onset of the nesting season or following successful completion of the nesting season for sensitive avian species known or likely to be on site. These species include but are not limited to least Bell’s vireo, northern harrier, white-tailed kite, Cooper’s hawk, merlin, California horned lark, Lawrence’s goldfinch, yellow warbler and yellow-breasted chat. The completion of the nesting season for sensitive avian species shall be determined by a qualified biologist based on comprehensive nesting bird surveys of the project impact area within 72 hours of initiation of construction. Avoidance of construction between January 15 and July 31 for raptors, and March 15 through September 15 for other sensitive avian species annually would ensure avoidance of direct impacts to any of these species, as well as any other migratory bird species protected under the MBTA.

If construction is to occur during the breeding season for the least Bell’s vireo (April 1 – July 31, annually), focused protocol surveys for the least Bell’s vireo shall be conducted prior to construction activities such as grading and berm demolition and construction (or at the onset of

Tijuana River Valley 3.4-15 December 2008 Wetlands Mitigation Project Environmental Analysis the breeding season if construction starts before the season and is expected to continue into the season) to determine (1) if this species is present in and adjacent to the proposed project impact areas and (2) whether this species is located within 500 feet of the proposed construction areas. If this species is observed or detected within 500 feet of the construction site, mitigation for indirect impacts shall be developed by the project biologist in coordination with the appropriate resource agencies (e.g., setbacks, monitoring, breeding season construction limitations). If active nests are located within 300 feet of the project, noise mitigation measures including noise monitoring and/or placement of temporary noise walls/berms may be required on site to keep noise levels at the nest location to less than 60 dB (average per hour) and avoid significant direct impacts to the least Bell’s vireo.

If construction is to occur during the general non-raptor bird nesting season (March 15 – September 15), general nesting bird surveys shall be conducted within the project disturbance area and within 50 feet of the outer boundary of the disturbance area prior to construction to determine the location of active nests for any non-raptor bird species protected under the MBTA. If nests are detected within this survey area, they shall be flagged and provided a buffer area of at least a 50 feet radius around the nest site, or a buffer determined to be adequate by a qualified monitoring biologist, to protect the nest site(s) from work activities.

If construction is to occur during the general raptor nesting season (January 15 – August 31), nesting raptor surveys shall be conducted within the project disturbance area and within 500 feet of the outer boundary of the disturbance area prior to construction to determine the location of any active raptor nests. If raptor nests are detected within this survey area, they shall be provided a buffer area of at least a 500-foot radius around the nest site, or a buffer determined to be adequate by a qualified monitoring biologist, to protect the nest site(s) from work activities.

A qualified biological monitor shall conduct weekly surveys of all active nest sites during the construction period to assess their status. For both raptors and non-raptors, construction may proceed within the buffer areas once the juvenile birds have successfully fledged and/or the nest is no longer occupied or it has been determined to have failed by a qualified biological monitor.

Implementation of Mitigation Measure BIO-2 would reduce Impact BIO-4 to below a level of significance:

BIO-2 Mitigation for significant direct impacts to sensitive habitat types requiring mitigation (jurisdictional wetlands and WOUS) shall be accomplished through on-site restoration, enhancement and/or creation of wetlands habitat. Prior to the project applicant commencing any activity that will substantially divert or obstruct the natural flow or substantially change the bed, channel, or bank (which may include associated riparian resources) or a river, stream or lake, or deposit or dispose of debris, waster, or other material containing crumbled, flaked, or ground pavement where it may pass into any river, stream, or lake, the applicant shall submit a

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complete Lake or Streambed Alteration Program notification package and fee to CDFG. The proposed mitigation for direct impacts resulting from the project is summarized in Table 3.4-3.

Mitigation ratios are based on City of San Diego Biology Guidelines (City of San Diego 2004) and an evaluation of functions and services provided by existing wetlands and proposed mitigation. Disturbed southern willow scrub is considered a Disturbed Wetland in the City of San Diego Biology Guidelines and supports reduced functions and services values compared with proposed mitigation and therefore the mitigation ratio for these impacts is 2:1. Open channel is considered natural flood channel and supports similar functions and services compared with proposed mitigation and therefore the mitigation ratio for this impact is 2:1.

The project provides that approximately 40 acres of jurisdictional wetlands habitat be created or restored (32.3 acres of wetland acreage available to the Water Authority and adequate acreage to mitigate project impacts). These riparian wetlands are anticipated to be under the jurisdictions of ACOE/CDFG/RWQCB/CCC/ county of San Diego/city of San Diego. The 40 acres of habitat includes a sufficient area of wetlands habitat to mitigate the direct and temporary impacts anticipated to occur to existing onsite and offsite jurisdictional wetlands during the construction phase of the project.

Direct, temporary impacts to 3.382.77 acres of disturbed southern willow scrub under the jurisdictions of ACOE/CDFG/RWQCB/CCC/county of San Diego/city of San Diego will be mitigated at a ratio of 2:1, including 1:1 restoration and an additional 1:1 creation/restoration/enhancement within the Tijuana River watershed.

Direct, temporary impacts to 0.03 acre of open channel under the jurisdictions of ACOE/CDFG/RWQCB/CCC/county of San Diego/city of San Diego shall be mitigated at a ratio of 2:1, including 1:1 restoration and an additional 1:1 creation/restoration/enhancement within the Tijuana River watershed.

Direct temporary impacts to 0.03 64 acre of disturbed southern willow scrub under the joint jurisdiction of CDFG/CCC/county of San Diego/city of San Diego shall be mitigated on site at a ratio of 2:1 through the restoration in-place at a 1:1 ratio and an additional 1:1 creation/restoration/enhancement of riparian scrub wetlands habitat within the Tijuana River watershed.

Direct, permanent impacts to 0.04 acre of disturbed southern willow scrub under the jurisdictions of CDFG/CCC/county of San Diego/city of San Diego and direct, permanent impacts to 0.18 acres of disturbed southern willow scrub under the jurisdictions of CCC/county of San Diego/city of San Diego shall be mitigated on site

Tijuana River Valley 3.4-17 December 2008 Wetlands Mitigation Project Environmental Analysis

through the creation/restoration of 0.44 acre of riparian scrub wetlands habitat (at a 2:1 ratio).

Overall, a total of 7.32 acres of wetlands mitigation (3.44 acres of restoration of temporary impacts in-place and 3.88 acres of additional creation/restoration/enhancement of riparian scrub) shall be provided on site for significant impacts associated with implementation of this project; the remainder of created/restored wetlands (approximately 32 acres) would be available for use as mitigation credits for Water Authority projects.

Table 3.4-3 Mitigation Summary

Mitigation in Impact Inside Required Acres (Inside Habitat Type/Land Cover MHPA (Acres) Mitigation Ratio MHPA) Disturbed Southern Willow Scrub1, 2 3.382.77 2:1 6.765.54 (ACOE/CDFG/RWQCB/CCC/county/city) Open Channel 0.03 2:1 0.06 (ACOE/CDFG/RWQCB/CCC/county/city) Subtotal 3.412.80 6.825.60 acres (ACOE/CDFG/RWQCB/CCC/county/city) Wetlands Disturbed Southern Willow Scrub1 0.073683 2:1 0.141.36 (CDFG/CCC/county/city) Disturbed Southern Willow Scrub1 0.18 2:1 0.36 (CCC/county/city) Wetlands Mitigation Total 3.66 7.32 acres Disturbed Habitat (Tier IV Uplands) 3.70 0:1 0.00 Ruderal (Tier IV Uplands) 4.11 0:1 0.00 Agricultural (Tier IV Uplands) 42.08 0:1 0.00 Ornamental (Tier IV uplands) 0.60 0:1 0.00 Developed (Tier IV Uplands) 0.25 0:1 0.00 Uplands Mitigation Total 50.73 0.00 acre 1 Disturbed Wetlands per City of San Diego Land Development Code Biological Guidelines 2Least Bell’s vireo occupied habitat. 3Includes 0.04 acre of permanent impacts

Implementation of Mitigation Measure BIO-3 would reduce Impact BIO-5 to below a level of significance:

BIO-3 Mitigation for significant direct permanent impacts to sensitive habitat types (jurisdictional wetlands and WOUS) at the berm extension site shall be accomplished through creation of riparian wetlands habitat at the mitigation site. Mitigation for direct impacts resulting from the project is summarized in Table 3.4-4 based on ratios

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established in the city of San Diego Biology guidelines for impacts and mitigation within the MHPA and coastal zone.

Table 3.4-4 Permanent Direct Impacts and Required Mitigation

Required Mitigation Mitigation in Acres Vegetation Community/Land Cover Tier Impact (Acres) Ratio (Inside MHPA) Southern Willow Scrub wetlands 0.003 3:1 0.009 Mulefat Scrub wetlands 0.082 3:1 0.246 Open Water wetlands 0.029 2:1 0.058 Wetlands Subtotal 0.114 0.313 Ruderal Habitat IV 0.004 0:1 0 Uplands Subtotal 0.004 0 Total 0.118 0.313

A total of 0.313 acre of wetlands will be created to mitigate the 0.114 acre of direct impacts to sensitive vegetation communities and jurisdictional waters. The permanent impacts to southern willow scrub and mulefat scrub will be mitigated at a 3:1 ratio and the permanent impacts to open water will be mitigated at a 2:1 ratio. The created wetlands are anticipated to be under the jurisdictions of ACOE, CDFG, RWQCB, CCC, county of San Diego, and the city of San Diego.

With regards to temporary impacts to 0.023 acre of mule fat scrub and 0.071 acre of open water, mitigation shall consist of restoration of pre-construction conditions within these work areas. A construction monitoring report shall establish pre-existing conditions, conditions during construction, and conditions up to 90 days post-construction. Due to the limited nature of the temporary impacts, it is expected that vegetation communities and waters will be visibly restored to pre-construction conditions within 90 days.

3.4.5 Residual Impacts after Mitigation

No significant impacts would remain after implementation of the recommended mitigation measures.

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Tijuana River Valley 3.4-26 December 2008 Wetlands Mitigation Project Environmental Analysis 3.5 CULTURAL RESOURCES

This section evaluates the potential impacts of the proposed project on cultural resources within the project site. This evaluation is based on a cultural resources study (Brian F. Smith and Associates 2008) prepared for the project. The survey program was conducted in accordance with CEQA and the county and city of San Diego guidelines to determine the presence of any archaeological or historical cultural resources that would be affected by the proposed project. Records searches were requested from the South Coastal Information Center (SCIC) at San Diego State University and the San Diego Museum of Man. A Sacred Lands File (SLF) search from the Native American Heritage Commission (NAHC) was also conducted to document any sacred, ceremonial, or religious sites on or near the project. The Museum of Man and SCIC records searches were requested to determine what previously recorded cultural resources were located within a one-mile radius of the project area, and specifically within the project boundaries. Archaeologists conducted a survey of the project site on January 8, 2008 with the assistance of a Kumeyaay Nation Native American representative. Following the survey, a subsurface testing program was implemented to identify cultural resource sites.

For reference purposes, the cultural resources study for the project is included as Appendix F to this EIR. Methods used in the preparation of this report are contained therein.

3.5.1 Existing Conditions

Cultural History

The cultures that have been identified in the general vicinity of the project consist of the possible Paleo-Indian manifestation of the San Dieguito Complex, the Archaic and Early Milling Stone horizons represented by the La Jolla Complex, and most prominently, the Late Prehistoric Kumeyaay culture. Some areas in the region were used for ranching following the Hispanic intrusion into the region (1769). A brief discussion of the cultural elements in the project area is provided in the following subsections.

Prehistoric Period

The San Dieguito Complex was a cultural group that occupied sites in the southern California region between 10,000 and 8,000 years before present (YBP) and believed to have been related to or contemporaneous with the Paleo-Indian groups in the Great Basin area. The artifacts recovered from San Dieguito sites duplicate the typology attributed to the Western Pluvial Lakes Tradition. These artifacts generally consist of scrapers and scraper planes, choppers, and bifacially flaked knives, but few or no milling tools. The absence of grinding or milling stones suggests that cereal grains and nuts were not a primary part of the subsistence pattern. Tools recovered from sites of the San Dieguito Complex and the general pattern of site locations indicate that they were a wandering hunting and gathering society.

Tijuana River Valley 3.5-1 December 2008 Wetlands Mitigation Project Environmental Analysis The San Dieguito Complex is the least understood of the cultures that have inhabited San Diego county. This is due primarily to the fact that San Dieguito sites rarely contain stratigraphic information or datable material. There is a current controversy among researchers centering on the relationship of the San Dieguito and the subsequent cultural manifestation in the area, the La Jolla Complex. Firm evidence has not yet been discovered to indicate whether the San Dieguito “evolved” into the La Jolla Complex, the La Jolla Complex moved into the area and assimilated the San Dieguito people, or the San Dieguito retreated from the area because of environmental or cultural pressures. Very little evidence of the San Dieguito Complex has been identified within the region of the project area. It is probable that environmental changes associated with climatic change affected the subsistence base of the San Dieguito Complex, resulting in their exodus from this area sometime before 9,000 YBP.

The La Jolla Complex. Approximately 9,000 to 8,500 YBP, a second major cultural tradition was established in the San Diego region along the coast as well as in the inland valleys. Locally, this cultural tradition has been called the La Jolla Complex, and radiocarbon dates from sites attributed to this culture span a period of over 7,000 years in this region (between 9,000 and 2,000 YBP). The La Jolla Complex is best recognized for its pattern of shell middens, grinding tools closely associated with marine resources, and flexed burials.

The Late Prehistoric Kumeyaay Indians. The last major migration into the coastal zone occurred approximately 1,500 YBP, when Yuman- and Shoshonean-speaking people moved from the Colorado River Basin to the coast in search of a more plentiful food supply. This group is known locally as the Late Prehistoric Diegueño, or Kumeyaay, culture. Fortunately, ethnographic evidence is available from the period of the earliest Spanish contact to the late 1800s, providing a record of the nonmaterial aspects of this group.

Sites associated with the Kumeyaay are typically focused in the foothills and mountains, including the area of the proposed project. Their subsistence pattern was based on the collection of seeds (especially acorns), berries, and bulbs, and the hunting of small game. Artifact collections from late prehistoric occupations include milling tools, ceramics, projectile points, beads, shaft straighteners, and hammerstones. Ethnographic information indicates that the culture of the Kumeyaay Indians consisted of a close clan system with definitive religious beliefs and complex trade associations with relatives living in the Colorado River Basin.

Although the project lies near the international United States/Mexico border, this geographical distinction is a political boundary dating back to the mid-nineteenth century Mexican War. Prehistoric and protohistoric populations would not have been subjected to the same boundary. When contacted by the Spanish in the sixteenth century, the Kumeyaay occupied a territory bounded on the west by the Pacific Ocean, on the east by the Sand Hills, on the north by Agua Hedionda Lagoon, and on the south by Todos Santos Bay in what is now Baja California. Therefore, the archaeological record for any possible pre-contact resources located within the

Tijuana River Valley 3.5-2 December 2008 Wetlands Mitigation Project Environmental Analysis project area will have to be examined as part of a larger settlement and subsistence pattern that transcends modern political boundaries.

Historic Period

Exploration Period (1530-1769). The historic period in the San Diego vicinity began with the landing of Juan Rodríguez Cabrillo and his men in 1542. Sixty years after the Cabrillo expeditions, an expedition under Sebastian Viscaíno made an extensive and thorough exploration of the Pacific Coast. Although the voyage did not extend beyond the northern limits of the Cabrillo track, Viscaíno had the most lasting effect on the nomenclature of the coast.

Spanish Period (1769-1821). The Spanish occupation of the claimed territory of Alta California took place during the reign of King Carlos III of Spain. The representative of the King in Mexico was Jose de Galvez, who conceived of the plan to colonize Alta California and thereby secure the area for the Spanish crown. The effort involved both a military and a religious contingent, with the overall intent of establishing forts and missions to gain control of the land and its native inhabitants through conversion. Missions were constructed from San Diego to as far north as San Francisco. The mission locations were based on a number of important territorial, military, and religious considerations. Grants of land were given to persons who made applications, but many tracts reverted to the government for lack of use. As an extension of territorial control by the Spanish empire, each mission was placed so as to command as much territory and as large a population as possible.

Mexican Period (1821-1846). By 1821, Mexico had gained independence from Spain, and the northern territories were subject to political repercussions. By 1834, all the mission lands had been removed from the control of the Franciscan Order under the Acts of Secularization. Without proper maintenance, the missions quickly began to disintegrate, and after 1836, missionaries ceased to make regular visits inland to minister the needs of the Indians. Large tracts of land continued to be granted to persons who applied for them or to persons who had gained favor with the Mexican government. Grants of land were also made to settle government debts.

Anglo-American Period (1846-Present). California was invaded by United States troops during the Mexican War of 1846-1848. The acquisition of strategic Pacific ports and California land was one of the principal objectives of the war. At the time, the inhabitants of California were practically defenseless, and they quickly surrendered to the United States Navy in July 1847.

The mid-nineteenth century saw the end of the Mexican War, at which point the United States government sought to quickly authenticate its newly acquired property in the southwest by officially marking its southernmost boundary with Mexico. The establishment of complimentary border commissions within each county to survey, map, and define the international border with

Tijuana River Valley 3.5-3 December 2008 Wetlands Mitigation Project Environmental Analysis border monuments was initiated with the 1848 Treaty of Guadalupe Hidalgo and later, the Gadsen Treaty of 1853.

The cattle ranchers of the “counties” of southern California prospered during the cattle boom of the early 1850s. They were able to “reap windfall profit...pay taxes and lawyer’s bills...and generally live according to custom.” Cattle-raising soon declined, however, contributing to the expansion of agriculture. With the passage of the “No Fence Act,” San Diego’s economy changed from stock-raising to farming. The act allowed for the expansion of unfenced farms, which was crucial in an area where fencing material was practically unavailable. Five years after its passage, most of the arable lands in San Diego county had been patented as either ranchos or homesteads, and growing grain crops replaced raising cattle in many of the county’s inland valleys. By 1870, farmers had learned to dry-farm and were coping with some of the peculiarities of San Diego county’s climate. Between 1869 and 1871, the amount of cultivated acreage in the county rose from less than 5,000 acres to more than 20,000. Of course, droughts continued to hinder the development of agriculture. Large-scale farming in San Diego county was limited by a lack of water and the small size of arable valleys; also, the small urban population and poor roads restricted commercial crop growing. Nevertheless, cattle continued to be grazed in inland San Diego county. For example, in the Otay Mesa area east of the proposed project, the “No Fence Act” had little effect, because ranches were still spaced far apart, and natural ridges kept the cattle out of growing crops.

During the first two decades of the twentieth century, the population of San Diego county continued to grow. The population of the inland county declined during the 1890s, but between 1900 and 1910, it rose by about 70 percent. The pioneering efforts were over; the railroads had broken the relative isolation of southern California, and life in San Diego county became similar to other communities throughout the west. After World War I, the history of San Diego county was primarily determined by the growth of San Diego Bay. In 1919, the United States Navy decided to make the bay the home base for the Pacific Fleet. During the 1920s, the aircraft industry also established itself at the bay. The establishment of these industries led to the growth of the county as a whole; however, most of the growth occurred in the north county coastal areas, where the population almost tripled between 1920 and 1930. During this time period, the history of inland San Diego county was subsidiary to that of the city of San Diego, which became a Navy center and industrial city. In inland San Diego county, agriculture became specialized, and recreational areas were established in the mountain and desert areas. Just before World War II, urbanization began to spread to the inland county.

Record Search Results

Several archaeological studies have been conducted in the area of the project site. The records search results indicate that approximately 38 previous investigations have been conducted within one mile of the project site, four of which overlap the project site. In 2004, an archaeological

Tijuana River Valley 3.5-4 December 2008 Wetlands Mitigation Project Environmental Analysis survey for the TRVRP Trails and Habitat Restoration Project was conducted, which included the entire current project area. Numerous artifacts and lithic scatters were identified, however none were located within the current project site. Another survey, conducted by EDAW in 2003 for an earlier inception of the proposed project, covered the majority of the central and northern portions of the current project site. Within the current project site, EDAW identified elements of a previously recorded prehistoric lithic and shell scatter (SDI-10,967), one historic farmhouse with associated outhouses (P-37-025705), and one historic pump house and water storage basin (P-37-025704). Additionally, two archaeological overview projects, consisting solely of records search reviews, overlapped the current project site.

The SCIC and San Diego Museum of Man records searches conducted for the proposed project indicate that 63 resources have been recorded within a one-mile radius of the project, four of which are located within the project site. These four resources are identified below.

The eastern half of Site SDI-10,967 is located in the northwestern portion of the project site. This site has been described as a prehistoric shell and lithic scatter, and a possible component of the ethnographically recorded Kumeyaay village of Mellejo.

Also, a portion of site SDI-10,669 is located in the southeast portion of the project area. This site is also associated with the Kumeyaay village of Mellejo. These two recorded archaeological sites (SDI-10,669 and SDI-10,967) represent prehistoric components of the recorded Village of Mellejo that was situated along the banks of the Tijuana River. This prehistoric habitation area is not well understood, as it appears the majority of the sites along the Tijuana River have been buried beneath flood debris deposited over thousands of years. The current site boundaries were delineated by the patterns of surface artifacts observed; however, the location and importance of any subsurface cultural deposits have never been established.

Two recorded historic sites are located on the project site (listed as Site P-37-025705 and Site P- 37-025704). Site P-37-025705 is located in the north-central portion of the project site and consists of a complex of farm structures, including a historic house and other buildings of more modern construction. The residential structure is projected to have been built between 1928 and 1953, based upon aerial photographic surveys of those dates. Site P-37-025704 is located in the northwest portion of the project boundary and consists of a historic pump house/well with a wooden water storage tank.

Field Survey Results

The archaeological field survey of the project was conducted by Brian F. Smith and Associates on January 8, 2008, and included 60 acres of relatively level terrain. Ground surface visibility was good due to sparse introduced vegetation. A previous investigation conducted by EDAW (2003) resulted in the determination that historic resource P-37-025705, a historic farmhouse

Tijuana River Valley 3.5-5 December 2008 Wetlands Mitigation Project Environmental Analysis complex, did not retain integrity. This resource was relocated in the field, and a field check of P- 37-025705 was conducted to confirm the previous determination.

Additionally, the EDAW investigation resulted in the determination that historic resource P-37- 025704, a historic pump house, well, and water storage tank, possessed relatively good integrity. This resource was relocated, and a field check of P-37-025704 was conducted. The location of this water supply system is on one of the many linear berms that were created to protect vicinity small farms from periodic flooding of the Tijuana River. EDAW reported that the water well, pump house, and storage tank were in relatively good condition in 2003. However, the present condition is poor, and it was determined that this resource holds no further research potential (Brian F. Smith and Associates 2008).

The survey also resulted in the relocation of two previously recorded shell and lithic scatters, corresponding to the mapped locations of portions of Sites SDI-10,669 and SDI-10,967 in the southeast and northwest portions of the project, respectively. Based on the survey results and exploratory trenching in and around SDI-10,669, the site boundaries have been expanded north. Based on the survey results and exploratory trenching in and around SDI-10,967, the recorded site boundaries have been slightly expanded to the east and west. The results of the field and laboratory studies for Sites SDI-10,669 and SDI-10,967, as well as the results of exploratory trenching conducted for the project, are provided in Appendix F to this EIR.

3.5.2 Thresholds of Significance

Thresholds used to evaluate potential impacts to cultural resources are based on applicable criteria in the CEQA Guidelines, Appendix G. A significant impact to cultural resources would occur if the proposed project would:

• Cause a substantial adverse change in the significance of a historical resource as defined in §15064.5 of the State CEQA Guidelines. • Cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5 of the State CEQA Guidelines. • Disturb any human remains, including those interred outside of formal cemeteries.

3.5.3 Impact Analysis

Would the project cause a substantial adverse change in the significance of a historical resource as defined in §15064.5?

Two recorded historic sites are located on the project site (listed as Site P-37-025705 and Site P- 37-025704). Site P-37-025705, a historic farmhouse complex, is deteriorating and exhibits graffiti, broken windows, and loss of structural integrity. A previous investigation resulted in the determination that this resource was not significant (Water Authority 2003), and the current

Tijuana River Valley 3.5-6 December 2008 Wetlands Mitigation Project Environmental Analysis reassessment conducted by Brian F. Smith and Associates in 2008 supports the previous determination. As a result, the site is not a significant historic resource according to CEQA Guidelines, and impacts to this resource would be less than significant.

Site P-37-025704 consists of a historic pump house, well, and water storage tank. A previous investigation of this resource indicated that it possessed relatively good integrity (Water Authority 2003). The current reassessment by Brian F. Smith and Associates in 2008 contradicts the previous determination, in that the site is dilapidated and has not functioned in some time. The pump has not been operational for an unknown period of years, the electrical system has been stripped of parts, modern lumber has been added to reinforce the frame and wall of the pump house, and the water storage tank is no longer functional. The site was likely an ancillary feature to the farm complex (P-37-025705) located directly east, and should have been originally recorded as an associated feature of that site. Due to the lack of integrity, the site is not a significant historic resource according to the CEQA Guidelines, and impacts to this resource would be less than significant.

Would the project cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5 of the State CEQA Guidelines?

Two archaeological sites have been identified on the project site, both of which have been associated with the Kumeyaay village of Mellejo. Site SDI-10,669 is a resource processing site for marine shell and lithic resources. Resource processing sites such as this portion of SDI-10,669 are often referred to as “dinner camps” where food resources were processed along daily forays to and from the coast. Shell scatters are the most common prehistoric site types found along the immediate coastline and bays, demonstrating the focused subsistence pattern of both Archaic and Late Prehistoric populations located adjacent to marine environments. The 2008 subsurface testing throughout the eastern half of the project area revealed various disturbed deposits consisting of a mixture of modern trash, fill, and elements associated with the prehistoric occupation of the site. Because the portion of the site within the project site is disturbed in its entirety, the resource does not have the potential to yield additional information important to the history of the Tijuana River Valley area. Therefore, Site SDI-10,669 is not a significant cultural resource according to the CEQA Guidelines, and impacts to this resource would be less than significant.

Similar to SDI-10,669, Site SDI-10,967 is a resource processing site for marine shell and lithic resources dating to AD 340 to AD 720. The site is categorized in the same fashion as SDI- 10,669, being a temporary camp where shellfish were processed as part of the exploitation of marine resources. The subsurface testing throughout the far western portion of the project area revealed various disturbed deposits consisting of a mixture of modern trash, fill, and elements associated with the prehistoric occupation of the site. The excavation results and the artifact analysis have resulted in the conclusion that the portion of SDI-10,967 located within the

Tijuana River Valley 3.5-7 December 2008 Wetlands Mitigation Project Environmental Analysis northwest corner of the project site is a largely disturbed resource with occasional pockets of possibly intact remnants. Additionally, the lead Native American monitor indicated that the deposits were largely disturbed and did not convey any interpretations of significance to the Native American community. For these reasons, Site SDI-10,967 is not a significant cultural resource according to the CEQA Guidelines, and impacts to this resource would be less than significant.

All recovered artifacts have been curated by Brian F. Smith Associates at the San Diego Archaeological Center in May and June 2008. While impacts to known on-site cultural resources would be less than significant, construction of the proposed project has the potential to uncover significant cultural resources that have not been previously documented because the floodplain contains a high probability of containing resources. The potential for discovery of cultural resources during construction is high and would be a potentially significant impact (Impact CR-1).

Would the project disturb any human remains, including those interred outside of formal cemeteries?

No evidence of human remains has been discovered on the project site through a literature search and an intensive site survey. However, construction of the proposed project has the potential to uncover human remains that have not been previously documented. Although a low probability, the discovery of human remains during construction would be a potentially significant impact (Impact CR-2).

3.5.4 Mitigation Measures

Implementation of Mitigation Measures CR-1 and CR-2 would reduce Impacts CR-1 and CR-2 to below a level of significance:

CR-1 A county-approved archaeological monitor shall be required on-site during grading or excavation of previously undisturbed soil in order to identify any previously unrecorded resources that might be uncovered during the construction process. Prior to approval of grading permits or improvement plans, or prior to the recordation of the final map, the Water Authority shall provide evidence to the satisfaction of the county Director of Planning and Land Use that the cultural resource evaluation of the San Diego County Water Authority prepared by Brian F. Smith and Associates for this project, dated April 24, 2008, has been submitted to the South Coastal Information Center. Evidence shall be in the form of a letter from the South Coastal Information Center identifying that the cultural resource evaluation has been received. Furthermore, all prehistoric artifacts and a sample of historic artifacts shall be curated in accordance with county guidelines.

Tijuana River Valley 3.5-8 December 2008 Wetlands Mitigation Project Environmental Analysis Prior to approval of grading or improvement plans, a grading monitoring plan shall be implemented to mitigate potential impacts to undiscovered buried archaeological resources on the project to the satisfaction of the Planning Director. This program shall include, but shall not be limited to, the following actions:

Provide evidence to the Department of Planning and Land Use that a county- certified archaeologist has been contracted to implement a grading monitoring program to the satisfaction of the Director of Planning and Land Use. A letter from the project archaeologist shall be submitted to the Director of Planning and Land Use. The letter shall include the following guidelines:

a. The consulting archaeologist shall contract with a Native American monitor to be involved with the grading monitoring program. b. The county-certified archaeologist/historian and Native American monitor shall attend the pre-grading meeting with the contractors to explain and coordinate the requirements of the monitoring program. c. The consulting archaeologist shall monitor all areas identified for development. d. An adequate number of monitors (archaeological/historical/Native American) shall be present to ensure that all earth-moving activities are observed and shall be on-site during all grading activities. e. During the original cutting of previously undisturbed deposits, the archaeological monitor(s) and Native American monitor(s) shall be onsite full-time. Inspections would vary based on the rate of excavation, the materials excavated, and the presence and abundance of artifacts and features. The frequency and location of inspections shall be determined by the principal investigator (i.e., project archaeologist). f. During the cutting of previously disturbed deposits, the archaeological monitor(s) and Native American monitor(s) shall be onsite as determined by the principal investigator of the excavations. Inspections shall vary based on the rate of excavation, the materials excavated, and the presence and abundance of artifacts and features. The frequency and location of inspections shall be determined by the principal investigator in consultation with the Native American monitor. g. Isolates and clearly non-significant deposits shall be minimally documented in the field and the monitored grading can proceed.

Tijuana River Valley 3.5-9 December 2008 Wetlands Mitigation Project Environmental Analysis h. In the event that previously unidentified potentially significant cultural resources are discovered, the archaeologist shall have the authority to divert or temporarily halt ground disturbance operations in the area of discovery to allow evaluation of potentially significant cultural resources. The archaeologist shall contact the county archaeologist at the time of discovery. The archaeologist, in consultation with the county staff archaeologist, shall determine the significance of the discovered resources. The county archaeologist must concur with the evaluation before construction activities can be allowed to resume in the affected area. For significant cultural resources, a Research Design and Data Recovery Program to mitigate impacts shall be prepared by the consulting archaeologist and approved by the county archaeologist, then carried out using professional archaeological methods. i. If any human bones are discovered, the principal investigator shall contact the county coroner. In the event that the remains are determined to be of Native American origin, the most likely descendant, as identified by the Native American Heritage Commission, shall be contacted in order to determine proper treatment and disposition of the remains. j. Before construction activities are allowed to resume in the affected area, the artifacts shall be recovered and features recorded using professional archaeological methods. The principal investigator shall determine the amount of material to be recovered for an adequate artifact sample for analysis. k. In the event that previously unidentified cultural resources are discovered, all cultural material collected during the grading monitoring program shall be processed and curated at a San Diego facility that meets federal standards per 36 CFR Part 79, and therefore would be professionally curated and made available to other archaeologists/researchers for further study. The collections and associated records shall be transferred, including title, to an appropriate curation facility within San Diego county, to be accompanied by payment of the fees necessary for permanent curation. Evidence shall be in the form of a letter from the curation facility identifying that archaeological materials have been received and that all fees have been paid. l. In the event that previously unidentified cultural resources are discovered, a report documenting the field and analysis results and interpreting the artifact and research data within the research context shall be completed and submitted to the satisfaction of the Director of Planning and Land Use prior to the issuance of any building permits. The report will include

Tijuana River Valley 3.5-10 December 2008 Wetlands Mitigation Project Environmental Analysis Department of Parks and Recreation Primary and Archaeological Site forms. m. In the event that no cultural resources are discovered, a brief letter to that effect shall be sent to the Director of Planning and Land Use by the consulting archaeologist that the grading monitoring activities have been completed.

The principal investigator shall be responsible for ensuring that all artifacts associated with the survey, testing, data recovery and/or monitoring for this project are permanently curated with an appropriate institution. For discoveries on city-owned land, this shall be completed in consultation with qualified city staff and the Native American representative, as applicable. For curation of materials collected from city-owned land, the principal investigator shall submit the Accession Agreement and catalogue record(s) to the city Resident Engineer for donor signature with a copy submitted to the City Mitigation Monitoring Coordination (MMC) Section. The city Resident Engineer shall obtain signature on the Accession Agreement and shall return to the principal investigator with a copy submitted to MMC. The principal investigator shall include the Acceptance Verification from the curation institution in the Final Monitoring Report submitted to the city Resident Engineer and MMC.

CR-2 Prior to approval of grading or improvement plans, evidence shall be provided to the Director of Planning and Land Use that the following notes have been placed on the grading plan, with respect to the potential discovery for human remains::

a. The county-certified archaeologist/historian and Native American monitor shall attend the pre-construction meeting with the contractors to explain and coordinate the requirements of the monitoring program. b. During the original cutting of previously undisturbed deposits, the archaeological monitor(s) and Native American monitor(s) shall be onsite full-time to perform full-time monitoring as determined by the principal investigator of the excavations. The frequency of inspections will depend on the rate of excavation, the materials excavated, and the presence and abundance of artifacts and features. c. During the cutting of previously disturbed deposits, the archaeological monitor(s) and Native American monitor(s) shall be onsite as determined by the pPrincipal iInvestigator of the excavations. Inspections willshall vary based on the rate of excavation, the materials excavated, and the presence and abundance of artifacts and features. The frequency and

Tijuana River Valley 3.5-11 December 2008 Wetlands Mitigation Project Environmental Analysis location of inspections willshall be determined by the principal investigator in consultation with the Native American monitor. d. In the event that previously unidentified potentially significant cultural resources are discovered, the archaeological monitor(s) shall have the authority to divert or temporarily halt ground disturbance operation in the area of discovery to allow evaluation of potentially significant cultural resources. The pPrincipal iInvestigator shall contact the county archaeologist at the time of discovery. The principal investigator, in consultation with the county staff archaeologist, shall determine the significance of the discovered resources. The county archaeologist must concur with the evaluation before construction activities will be allowed to resume in the affected area. For significant cultural resources, a Research Design and Data Recovery Program to mitigate impacts shall be prepared by the consulting archaeologist and approved by the county archaeologist, then carried out using professional archaeological methods. e. The consulting archaeologist shall monitor all areas identified for development. f. If any human bones are discovered, the principal investigator shall contact the county coroner. In the event that the remains are determined to be of Native American origin, the most likely descendant, as identified by the Native American Heritage Commission, shall be contacted in order to determine proper treatment and disposition of the remains. g. Prior to rough grading inspection sign-off, provide evidence that the field grading monitoring activities have been completed to the satisfaction of the Director of Planning and Land Use. Evidence shall be in the form of a letter from the project archaeologist. h. Submit to the satisfaction of the Director of Planning and Land Use a final report that documents the results, analysis, and conclusions of all phases of the Archaeological Monitoring Program. The report shall also include the following: ƒ Department of Parks and Recreation Primary and Archaeological Site forms. ƒ Evidence that all cultural materials collected during the grading monitoring program has been curated at a San Diego facility that meets federal standards per 36 CFR Part 79, and therefore would be professionally curated and made available to other archaeologists/researchers for further study. The collections and associated records shall be transferred, including title, to an

Tijuana River Valley 3.5-12 December 2008 Wetlands Mitigation Project Environmental Analysis appropriate curation facility within San Diego county, to be accompanied by payment of the fees necessary for permanent curation. Evidence shall be in the form of a letter from the curation facility identifying that archaeological materials have been received and that all fees have been paid. i. In the event that no cultural resources area discovered, a brief letter to that effect shall be sent to the Director of Planning and Land Use by the consulting archaeologist that the grading monitoring activities have been completed.

CR-1 A qualified archaeological monitor shall be onsite during grading or excavation of previously undisturbed soils. The archaeological monitor shall work with the Native American community to provide an opportunity for Native American monitoring. The archaeological monitor shall coordinate with the Water Authority’s construction manager to stop or divert work to implement measures necessary to protect cultural resources discovered during construction.

CR-2 The archaeological monitor shall ensure that any human remains are treated in accordance with applicable state laws and regulations. The archaeological monitor shall contact the county coroner as necessary. In the event that the remains are determined to be of Native American origin, the most likely descendant, as identified by the Native American Heritage Commission, shall be contacted in order to determine proper treatment and disposition of the remains.

3.5.5 Residual Impacts After Mitigation

With implementation of the mitigation measures listed above, no significant cultural resources impacts would result.

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Tijuana River Valley 3.5-14 December 2008 Wetlands Mitigation Project Environmental Analysis 3.6 GEOLOGY AND SOILS

This section evaluates the potential impacts of the proposed project on geology and soils, including seismic hazards. This evaluation is based on a review of geologic maps of the project area, as well as existing site documentation.

3.6.1 Existing Conditions

Regional Geologic Setting

The proposed project site is situated in the floodplain of the Tijuana River. The general topography of the area consists of the broad floodplain and the relatively steep hillside area between the floodplain and international border. In the project site vicinity, ground surface elevations range from approximately 25 feet AMSL in the eastern portion of the project to approximately 19 feet AMSL on the western portion of the project.

The project site is located within the TRVRP. The TRVRP’s geologic composition consists of fill, alluvium, recent and old alluvial fan deposits, and terrace deposits (county of San Diego 2006). Rocky zones are also found in these alluvial deposits, consisting of large amounts of gravels, cobbles, and localized boulders. Higher elevations within the Tijuana River Valley have conglomerates consisting of San Diego Formation materials.

Soils

According to Bowman (1973), two soil types are mapped on the proposed project site: the saline Chino silt loam on 0 to 2 percent slopes (CkA) and the Tujunga sand on 0 to 5 percent slopes (TuB). The location of these soil types within the project site is shown in Figure 3.6-1. The Initial Study for the proposed project (Water Authority 2007) identifies the Visalia sandy loam (VaA) as a third soil type that is present on the project site, however upon further review, this soil type is located just south of the site. The Chino series consists of moderately well drained, fine sandy loams derived mainly from granitic alluvium. The Chino silt loam is slightly saline and is silt loam to loam throughout. The Tujunga series consists of very deep excessively drained sands derived from granitic alluvium. The Tujunga sand is found on alluvial fans and flood plains.

The project site has been extensively disked for agricultural purposes on an annual basis since the mid 1950s. Due to this long history of intensive land management for agriculture, these distinct soil types may no longer be distinguishable on the project site. Soils observed on the project site during the general field investigations and the wetlands delineation included deep, well-drained, fine-grained sandy loams with slightly saline characteristics. In addition, salt accumulation was noted within portions of soils that have been disked in the recent past.

Tijuana River Valley 3.6-1 December 2008 Wetlands Mitigation Project Environmental Analysis Groundwater

Groundwater was encountered less than 30 inches below ground surface along the most northern edge of the project site, and especially on the northwestern portion of the site during soil ripping activities conducted by the Integrated Waste Management Board (IWMB 2000). In the vicinity of the site, groundwater is reported to occur from ground surface (artesian wells) to 15 feet bgs. Additional discussion related to groundwater conditions is presented in Section 3.3 of this EIR.

Geologic Hazards

Ground Shaking

As defined by the California Geological Survey, an active fault is one that has had surface displacement within Holocene time (about the last 11,000 years). The state geologist has defined a potentially active fault as any fault considered to have been active during Quaternary time (last 1.6 million years). This definition is used in delineating Earthquake Fault Zones under the Alquist-Priolo Geologic Hazards Zones. The project site is not included within any Earthquake Fault Zones as created by the Alquist-Priolo Act (CDC 2007). There are no known major or active faults on or in the immediate vicinity of the site. The fault capable of producing the largest acceleration at the site is the Rose Canyon Fault Zone, located approximately 5 miles northwest of the project site (CDC 2007).

Liquefaction

Liquefaction is a phenomenon in which soils lose strength when subjected to ground shaking during an earthquake. The soils at risk of liquefaction are typically uniform, granular, and saturated with groundwater. Due to the site’s location in the Tijuana River Valley and the near- surface groundwater conditions, the potential for liquefaction on the project site is considered to be relatively high.

Landslides

Landslide hazard areas are generally considered to exist when substantial slopes are located on or immediately adjacent to a subject property. The nearest substantial slopes are located approximately 0.25 miles to the south, near the international border. The potential for effects associated with landslides is considered low given the relatively level terrain of the project site and distance to steep slopes.

3.6.2 Thresholds of Significance

Thresholds used to evaluate potential geology and soils impacts are based on applicable criteria in the State CEQA Guidelines, Appendix G. A significant impact to geology and soils would occur if the proposed project were to:

Tijuana River Valley 3.6-2 December 2008 Wetlands Mitigation Project Environmental Analysis • Expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving: o Rupture of a known earthquake fault, as delineated 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; o Strong seismic ground shaking; o Seismic-related ground failure, including liquefaction; o Landslides. • Result in substantial loss of topsoil. • 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. • Be located on expansive soils, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial risks to life or property. • Have soils incapable of adequately supporting the use of septic tanks or alternative wastewater disposal systems where sewers are not available for the disposal of wastewater.

3.6.3 Impact Analysis

Would the proposed project expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving:

• Rupture of a known earthquake fault, as delineated 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 shaking? • Seismic-related ground failure, including liquefaction? • Landslides?

As noted in Section 3.6.1, no active earthquake faults have been identified as occurring on or directly adjacent to the site. The site is not located within an Alquist-Priolo Earthquake Fault Zone, and as a result ground surface rupture is considered unlikely. The project would not expose people or structures to surface rupture, and impacts would be less than significant.

The Rose Canyon Fault Zone, which consists of several faults, is considered active and is located less than 5 miles away from the project site (CDC 2007). Due to the proximity of the project site

Tijuana River Valley 3.6-3 December 2008 Wetlands Mitigation Project Environmental Analysis to this seismic area, ground shaking and other seismic activities may occur. Primary earthquake hazards include damage from ground displacement along a fault zone, severe ground shaking, and induced secondary hazards such as liquefaction and rapid differential settlement (county of San Diego 2006). While the project area is susceptible to ground shaking, liquefaction, and settlement, the proposed wetlands mitigation project (including the berm extension) would not expose people or structures to these hazards once it has been completed, since no structures are proposed and no people would permanently occupy the site. Additionally, existing berms would be made taller in height, which would serve to provide 100-year flood protection. It is not anticipated that impacts relating to seismicity would be significant. Impacts would therefore be less than significant.

The potential for effects associated with landslides is considered low given the relatively level terrain of the project site and distance to steep slopes. As a result, impacts resulting from landslides would be less than significant.

Would the proposed project result in substantial loss of topsoil?

Project grading would extend approximately nine months. During construction, grading activities may take place during the rainy season and soil erosion may potentially occur. However, substantial soil erosion or loss of topsoil during construction would be avoided by implementation of the standard specifications and project design features described in Section 2.4, including erosion control BMPs developed for the SWPPP. Following project construction, over time the site would become vegetated with wetlands, which would serve to reduce soil erosion; impacts would be less than significant. The impact of potential erosion and loss of topsoil would therefore be less than significant.

Would the proposed 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?

Given the proposed intended use of the project site, soil instability would not present significant hazards related to on- or off-site landslides, lateral spreading, subsidence, liquefaction, or collapse. Therefore, impacts would less than significant.

Would the proposed project be located on expansive soils, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial risks to life or property?

For the proposed wetlands mitigation uses, expansive soils would not present a substantial hazard. Any disruptions to the site as a result of expansive soils would not create substantial risks to life or property. Impacts would less than significant.

Tijuana River Valley 3.6-4 December 2008 Wetlands Mitigation Project Environmental Analysis Would the proposed project have soils incapable of adequately supporting the use of septic tanks or alternative wastewater disposal systems where sewers are not available for the disposal of wastewater?

Implementation of the proposed project would not result in any need for a septic tank or alternative wastewater disposal system. Impacts would be less than significant.

3.6.4 Mitigation Measures

Impacts to geology and soils would be less than significant. Therefore, no mitigation measures are required.

3.6.5 Residual Impacts After Mitigation

No significant impacts would occur.

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Tijuana River Valley 3.6-6 December 2008 Wetlands Mitigation Project Legend

Proposed Project Site Soil Types: Chino silt loam, saline, 0 to 2 percent slopes Tujunga sand, 0 to 5 percent slopes

Fe et AERIAL SOURCE: DIGITAL GLOBE, MARCH 2007 0 400 Z:\Projects\j509302\Figs\EIR\Section 3\EIR509302_Fig3-6_01_soils.mxd 3\EIR509302_Fig3-6_01_soils.mxd Z:\Projects\j509302\Figs\EIR\Section

Tijuana River Valley Wetlands Mitigation Project - EIR FIGURE Onsite Soils 3.6-1 Environmental Analysis

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Tijuana River Valley 3.6-8 December 2008 Wetlands Mitigation Project