IV. Environmental Impact Analysis G. Hydrology, Surface ... › ... › DEIR › files ›...

City of Los Angeles Archer Forward: Campus Preservation and Improvement Plan SCH. No. 2012011001 February 2014

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WORKING DRAFT – Not for Public Review

IV. Environmental Impact Analysis G. Hydrology, Surface Water Quality, and

Groundwater

1. Introduction

This section describes the existing surface water and groundwater hydrology and quality within the Project area and provides an analysis of the Project’s potential impacts with regard to these resources. This analysis is based on the Water Resources Technical Report prepared by KPFF Consulting Engineers (April 2013), included as Appendix L of this Draft EIR.

2. Environmental Setting

a. Regulatory Framework

(1) Federal

(a) Clean Water Act

The Clean Water Act was first introduced in 1948 as the Water Pollution Control Act. The Clean Water Act authorizes federal, state, and local entities to cooperatively create comprehensive programs for eliminating or reducing the pollution of state waters and tributaries. The primary goals of the Clean Water Act are to restore and maintain the chemical, physical, and biological integrity of the nation’s waters and to make all surface waters fishable and swimmable. As such, the Clean Water Act forms the basic national framework for the management of water quality and the control of pollutant discharges. The Clean Water Act also sets forth a number of objectives in order to achieve the above-mentioned goals. These objectives include regulating pollutant and toxic pollutant discharges; providing for water quality that protects and fosters the propagation of fish, shellfish and wildlife; developing waste treatment management plans; and developing and implementing programs for the control of non-point sources of pollution, including the

IV.G Hydrology, Surface Water Quality, and Groundwater


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issuance of National Pollutant Discharge Elimination System (NPDES) permits for point source discharges to surface waters.1

Since its introduction, major amendments to the Clean Water Act have been enacted (e.g., 1961, 1966, 1970, 1972, 1977, and 1987). Amendments enacted in 1970 created the United States Environmental Protection Agency (USEPA), while amendments enacted in 1972 deemed the discharge of pollutants into waters of the United States from any point source unlawful unless authorized by a USEPA National Pollutant Discharge Elimination System permit. Amendments enacted in 1977 mandated development of a Best Management Practices (BMPs) Program at the state level. Amendments enacted in 1987 required the USEPA to create specific requirements for discharges.

In response to the 1987 amendments to the Clean Water Act and as part of Phase I of its NPDES permit program, the USEPA began requiring NPDES permits for: (1) municipal separate storm sewer systems generally serving, or located in, incorporated cities with 100,000 or more people (referred to as municipal permits); (2) 11 specific categories of industrial activity (including landfills); and (3) construction activity that disturbs 5 acres or more of land. Phase II of the USEPA’s NPDES permit program, which went into effect in early 2003, extended the requirements for NPDES permits to: (1) numerous small municipal separate storm sewer systems;2 (2) construction sites of 1 to 5 acres; and (3) industrial facilities owned or operated by small municipal separate storm sewer systems. The NPDES permit program is typically administered by individual authorized states.

In California, the NPDES stormwater permitting program is administered by the State Water Resources Control Board (SWRCB). The SWRCB was created by the Legislature in 1967. The joint authority of water distribution and water quality protection allows the Board to provide protection for the State’s waters, through its nine Regional Water Quality Control Boards (RWQCBs). The RWQCBs develop and enforce water quality objectives and implement plans that will best protect California’s waters, acknowledging areas of different climate, topography, geology, and hydrology. The

1 Non–point sources of pollution are carried through the environment via elements such as wind, rain, or

stormwater and are generated by diffuse land use activities (such as runoff from streets and sidewalks or agricultural activities) rather than from an identifiable or discrete facility.

2 A small municipal separate storm sewer system is any municipal separate storm sewer system not already covered by the Phase I program as a medium or large municipal separate storm sewer system. The Phase II Rule automatically covers, on a nationwide basis, all small municipal separate storm sewer systems located in “urbanized areas” as defined by the Bureau of the Census (unless waived by the NPDES permitting authority), and on a case-by-case basis, those small municipal separate storm sewer systems located outside of urbanized areas that the NPDES permitting authority designates.



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RWQCBs develop “basin plans” for their hydrologic areas, issue waste discharge requirements, enforce action against stormwater discharge violators, and monitor water quality.3

In addition to regulating non-stormwater discharges, the Clean Water Act sets forth water quality standards and criteria based on a water body’s designated beneficial uses. Section 305(b) of the Clean Water Act requires preparation of a 303(d) list (list of water quality limited or impaired water bodies), which requires identification and listing of water-quality limited or “impaired” water bodies where water quality standards and/or receiving water beneficial uses are not met. Once a water body is listed as “impaired,” total maximum daily loads (TMDLs) must be established for the pollutants or flows causing the impairment (33 United States Code Section 1313(d)(c)). Once established, the TMDL allocates the loads among current and future pollutant sources to the water body. In general, where urban runoff is identified as a substantial source of pollutants causing the impairments and is subject to load allocating, implementation of, and compliance with the TMDL requirements are administered through a combination of individual Industrial Stormwater Permits, the General Industrial and General Construction Stormwater Permits, and the County of Los Angeles’ municipal stormwater NPDES program, specifically through the municipal separate storm sewer system permit, which are described below.

The USEPA delegated the responsibility for administration of portions of the Clean Water Act to state and regional agencies, including the State of California. Therefore, the primary regulations resulting from the Clean Water Act (i.e., NPDES Permit program) are discussed in the discussion of State, regional, and local regulations below.

(2) State and Regional

(a) Porter-Cologne Water Quality Act (California Water Code)

The Porter-Cologne Water Quality Control Act (embodied in the California Water Code) established the principal California legal and regulatory framework for water quality control. The California Water Code authorizes the SWRCB and the Regional Boards to implement the provisions of the federal Clean Water Act. Under the California Water Code, the State of California is divided into nine regions governed by regional boards that under the guidance and review of the SWRCB, implement and enforce provisions of the California Water Code and the Clean Water Act. The Project Site is located within Region 4, also known as the Los Angeles Region, and governed by the Los Angeles RWQCB (LARWQCB). The SWRCB’s principal responsibility is the development and

3 USEPA. Clean Water Act. Website www.epa.gov/lawsregs/laws/cwa.html, accessed October 19, 2012.



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implementation of California water quality policy and development of programmatic water quality control procedures to be followed by the RWQCBs. Accordingly, each RWQCB is required to formulate and adopt a local water quality control plan or Basin Plan for its region, which is ultimately incorporated into the California Water Plan (discussed below). This Plan must adhere to the policies set forth in the California Water Code and established by the SWRCB. The RWQCB is also given authority to include within its regional plan water discharge prohibitions applicable to particular conditions, areas, or types of waste.

Section 13050 of the California Water Code defines what is considered pollution, contamination, or nuisance. Briefly defined, pollution means an alteration of water quality such that it unreasonably affects the beneficial uses of water. Contamination means an impairment of water quality to the degree that it creates a hazard to the public health. Nuisance is defined as anything that is injurious to health, is offensive to the senses, or is an obstruction to property use, and which affects a considerable number of people.

(b) California Antidegradation Policy

The California Antidegradation Policy, otherwise known as the Statement of Policy with Respect to Maintaining High Quality Water in California was adopted by the SWRCB (State Board Resolution No. 68-16) in 1968. The California Antidegradation Policy applies to all waters of the state, not just surface waters. The policy states that whenever the existing quality of a water body is better than the quality established in individual Basin Plans, such high quality shall be maintained and discharges to that water body shall not unreasonably affect present or anticipated beneficial use of such water resource.

(c) California Toxics Rule

The USEPA has established water quality criteria for certain toxic substances via the California Toxics Rule. The California Toxics Rule establishes acute (i.e., short-term) and chronic (i.e., long-term) standards for bodies of water such as inland surface waters and enclosed bays and estuaries that are designated by the LARWQCB as having beneficial uses protective of aquatic life or human health.

(d) Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties

As required by the California Water Code, the LARWQCB has adopted a plan entitled Water Quality Control Plan, Los Angeles Region: Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties (Basin Plan). Specifically, the Basin Plan designates beneficial uses for surface waters and groundwater, sets narrative and numerical objectives that must be attained or maintained to protect the designated beneficial uses and conform to the State’s Anti-Degradation Policy, and describes



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implementation programs to protect all waters in the Los Angeles Region. 4 In addition, the Basin Plan incorporates (by reference) all applicable State and Regional Board plans and policies and other pertinent water quality policies and regulations. Those of other agencies are referenced in appropriate sections throughout the Basin Plan. The Basin Plan is a resource for the RWQCB and others who use water and/or discharge wastewater in the Los Angeles Region. Other agencies and organizations involved in environmental permitting and resource management activities also use the Basin Plan. The Basin Plan also provides valuable information to the public about local water quality issues.

(e) Santa Monica Bay Restoration Plan

The Santa Monica Bay Restoration Plan is an outgrowth of the efforts of the Santa Monica Bay Restoration Commission, an organization established by the California Legislature in 2002 to monitor, assess, coordinate and advise the activities of state programs and oversee funding that affects the beneficial uses, restoration and enhancement of the Santa Monica Bay and its watersheds. The Santa Monica Bay Restoration Plan provides a review of the existing water quality and establishes goals and objectives to help restore and enhance the Santa Monica Bay through actions and partnerships that improve water quality, conserve and rehabilitate natural resources, and protect the Santa Monica Bay’s benefits and values.

(f) National Pollutant Discharge Elimination System Permit Program

The NPDES permit program was first established under authority of the Clean Water Act to control the discharge of pollutants from any point source into the waters of the United States. As discussed above, in California, the NPDES stormwater permitting program is administered by the SWRCB through its nine RWQCBs.

The LARWQCB issues combined NPDES Permits under the Clean Water Act and Waste Discharge Requirements (under the California Water Code) to point dischargers of waste to surface waters. To ensure protection of water quality, NPDES Permits may contain effluent limitations for pollutants of concern, pollutant monitoring frequencies, reporting requirements, schedules of compliance (when appropriate), operating conditions, BMPs, and administrative requirements. NPDES Permits apply to publicly owned treatment works discharges, industrial wastewater discharges, and municipal, industrial and construction site stormwater discharges. Further discussion of the LARWQCB stormwater discharge permitting activities is provided below.

4 LARWQCB, LARWQCB Basin Plan, www.waterboards.ca.gov/losangeles/water_issues/programs/basin_

plan/, accessed November 5, 2012.



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The SWRCB has issued a statewide NPDES General Permit for stormwater discharges associated with construction activities (known as the Construction General Permit [SWRCB Order No. 2009-0009-DWQ]). Order No. 2009-0009-DWQ was amended by 2010-0014-DWQ and modified on November 16, 2010.5 Any project that disturbs an area more than one acre, as well as linear underground/overhead projects disturbing over one acre require a Notice of Intent to discharge under the Construction General Permit. The Construction General Permit includes three levels of risk for construction sites based on calculated project sediment and receiving water risk. The Construction General Permit includes measures to eliminate or reduce pollutant discharges through implementation of a Stormwater Pollution Prevention Plan (SWPPP), which describes the implementation and maintenance of BMPs to reduce or eliminate pollutants in stormwater discharges and authorized non-stormwater discharges from the site during construction. The Construction General Permit contains receiving water limitations that require stormwater discharges to not cause or contribute to a violation of any applicable water quality standard. The permit also requires implementation of programs for visual inspections and sampling for specified constituents (e.g., nonvisible pollutants). In addition, based upon particular project risk levels, monitoring is required for stormwater discharges. Any construction activities under the Project that disturb more than one acre are subject to requirements of the Construction General Permit. The main objectives of the Construction General Permit are to:

1. Reduce erosion;

2. Minimize or eliminate sediment in stormwater discharges;

3. Prevent materials used at a construction site from contacting stormwater;

4. Implement a sampling and analysis program;

5. Eliminate unauthorized non-stormwater discharges from construction sites;

6. Implement appropriate measures to reduce potential impacts on waterways both during and after construction of projects; and

7. Establish maintenance commitments on post-construction pollution control measures.

On December 13, 2001, the LARWQCB adopted Order No. 01-182 under the Clean Water Act and the Porter-Cologne Act. This Order is the NPDES Permit or Municipal Separate Storm Sewer System Permit for municipal stormwater and urban runoff

5 SWRCB, Construction General Permit Fact Sheet, www.waterboards.ca.gov/water_issues/programs/

stormwater/docs/constpermits/wqo_2009_0009_factsheet.pdf, accessed November 5, 2012.



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discharges within Los Angeles County. The requirements of this Order (the “Permit”) cover 84 cities and most of the unincorporated areas of Los Angeles County. Under the Permit, the Los Angeles County Flood Control District (LACFCD) is designated as the Principal Permittee. The Permittees are the 84 Los Angeles County cities (including the City of Los Angeles) and Los Angeles County. Collectively, these are the “Co-Permittees.” The Principal Permittee helps to facilitate activities necessary to comply with the requirements outlined in the Permit but is not responsible for ensuring compliance of any of the Permittees.

In compliance with the Los Angeles County municipal separate storm sewer system permit, the Co-Permittees are required to implement a Stormwater Quality Management Program with the goal of accomplishing the requirements of the Permit and reducing the amount of pollutants in stormwater runoff. The municipal separate storm sewer system permit includes the following relevant provisions for implementation of the Stormwater Quality Management Program by the Co-Permittees:

General Requirements:

– Each Permittee is required to implement the Stormwater Quality Management Program in order to comply with applicable stormwater program requirements.

– The Stormwater Quality Management Program shall be implemented and each Permittee shall implement additional controls so that discharge of pollutants is reduced.

Best Management Practice Implementation:

– Permittees are required to implement the most effective combination of BMPs for stormwater/urban runoff pollution control. This should result in the reduction of stormwater runoff.

Revision of the Stormwater Quality Management Program:

– Permittees are required to revise the Stormwater Quality Management Program in order to comply with requirements of the RWQCB while complying with regional watershed requirements and/or waste load allocations for implementation of TMDLs for impaired water bodies.

Responsibilities of Co-Permittees—Each Co-Permittee is required to comply with the requirements of the Stormwater Quality Management Program as applicable to the discharges within its geographical boundaries. These requirements include:



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– Coordinating among internal departments to facilitate the implementation of the Stormwater Quality Management Program requirements in an efficient way;

– Participating in coordination with other internal agencies as necessary to successfully implement the requirements of the Stormwater Quality Management Program; and

– Preparing an annual Budget Summary of expenditures for the stormwater management program by providing an estimated breakdown of expenditures for different areas of concern, including budget projections for the following year.

Legal Authority:

– Co-Permittees are granted the legal authority to prohibit non-stormwater discharges to the storm drain system including discharge to the municipal separate storm sewer system from various development types.

Under the Los Angeles County Municipal NPDES Permit, Permittees are required to implement a development planning program to address stormwater pollution. These programs require project applicants for certain types of projects to implement Standard Urban Stormwater Mitigation Plans (SUSMP) throughout the operational life of their projects. The purpose of SUSMP is to reduce the discharge of pollutants in stormwater by outlining BMPs which must be incorporated into the design plans of new development and redevelopment. A project is subject to SUSMP if it falls under one of the categories listed below:

1. Single-family hillside homes;

2. Ten or more unit homes (including single family homes, multifamily homes, condominiums, and apartments);

3. Automotive service facilities;

4. Restaurants;

5. 100,000 or more square feet of impervious surface in industrial/commercial development;

6. Retail gasoline outlet;

7. Parking lots with 5,000 square feet or more of surface area or with 25 or more parking spaces;



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8. Redevelopment projects in subject categories that meet redevelopment thresholds; and

9. Location within or directly adjacent to or discharging directly to an environmentally sensitive area if the discharge is likely to impact a sensitive biological species or habitat and the development creates 2,500 square feet or more of impervious surface.

Permittees are required to adopt the requirements set forth herein in their own SUSMP. Additional BMPs may be required by ordinance or code adopted by the Permittee and applied in a general way to all projects or on a case by case basis.

(g) California Water Plan

The California Water Plan provides a framework for water managers, legislators, and the public to consider options and make decisions regarding California’s water future. The California Water Plan, which is updated every five years, presents basic data and information on California’s water resources including water supply evaluations and assessments of agricultural, urban, and environmental water uses to quantify the gap between water supplies and uses. The California Water Plan also identifies and evaluates existing and proposed statewide demand management and water supply augmentation programs and projects to address the State’s water needs.

(3) Local

(a) County of Los Angeles Hydrology Manual

The Project Site is located within the City of Los Angeles; drainage collection, treatment, and conveyance of surface water are regulated by the City. Per the City’s Special Order No. 007-1299, December 3, 1999, the City has adopted the Los Angeles County Department of Public Works Hydrology Manual as its basis of design for storm drainage facilities. The Los Angeles County Department of Public Works’ Hydrology Manual requires projects to have drainage facilities to meet the Urban Flood level of protection, which is defined as runoff from a 25-year frequency storm falling on a saturated watershed.6 A 25-year frequency design storm has a probability of 1/25 of being equaled or exceeded in any year.

6 Los Angeles County Department of Public Works, Hydrology Manual, January 2006, http://dpw.lacounty.

gov/wrd/Publication/engineering/2006_Hydrology_Manual/2006%20Hydrology%20Manual-Divided.pdf, accessed November 5, 2012.



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(b) Los Angeles County Municipal Stormwater NPDES Program

The County of Los Angeles and the City are Co-Permittees under the municipal stormwater NPDES Permit for Los Angeles County. The Project Site is within the region covered by the Municipal Separate Storm Sewer System Permit (NPDES Permit No. CAS004001). The Municipal Separate Storm Sewer System Permit was issued by the LARWQCB on December 13, 2001, amended on April 14, 2011 pursuant to the peremptory writ of mandate in Los Angeles Superior Court Case No. BS122724. The amendment voided and set aside Order No. R4-2006-0074, which included requirements to implement the Santa Monica Bay Beaches Dry Weather Bacteria TMDL. The Municipal Separate Storm Sewer System Permit was originally issued for a five year period through 2006, but has been administratively amended to remain in effect since that time, with periodic amendments primarily to incorporate various TMDLs that affect municipal separate storm sewer system dischargers. A major update of the entire Municipal Separate Storm Sewer System Permit is currently being undertaken by the LARWQCB and the Second Revised Tentative Municipal Separate Storm Sewer System Permit was posted on November 5, 2012.7

Under the Municipal Separate Storm Sewer System Permit, the County and City are required to implement development planning guidance and control measures that control and mitigate stormwater quality and quantity impacts to receiving waters as a result of new development and redevelopment. The County and the City also are required to implement other municipal source detection and elimination programs as well as maintenance measures.

The Municipal Separate Storm Sewer System Permit contains provisions for implementation and enforcement of the stormwater quality management program. The objective of the Stormwater Quality Management Program is to reduce pollutants in urban stormwater discharges to the “maximum extent practicable,” to attain water quality objectives and protect the beneficial uses of receiving waters in Los Angeles County. Special provisions are provided in the Municipal Separate Storm Sewer System Permit to facilitate implementation of the Stormwater Quality Management Program. In addition, the Municipal Separate Storm Sewer System Permit requires the Permittees to implement a SUSMP, discussed above, that designates BMPs that must be used in specified categories of development projects to infiltrate, filter, or treat stormwater runoff; control peak flow discharge; and reduce the post-project discharge of pollutants from stormwater conveyance systems.

7 LARWQCB, Stormwater—Municipal Permits, www.waterboards.ca.gov/losangeles/water_issues/programs/

stormwater/municipal/index.shtml, accessed November 7, 2012.



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One of the key requirements in the SUSMP is the requirement that certain kinds of projects install structural BMPs that treat, filter, or infiltrate stormwater and meet volume or flow-based design/sizing standards. The SUSMP requires significant redevelopment projects to provide BMPs if land disturbance results in the creation or addition or replacement of 5,000 square feet or more of impervious surface area on an already developed site.

The area subject to post-development water quality control requirements is dependent upon the fraction of existing development that is redeveloped. If a project alters more than 50 percent of existing impervious surfaces, then post-development water quality control is required for the entire project. If a project alters less than 50 percent of impervious surfaces, only the altered area must be treated by post-construction water quality controls, and not the entire development.

Projects subject to the SUSMP requirements must select source control and, in most cases, treatment control BMPs from the list approved by the RWQCB. The BMPs must control peak flow discharge to provide stream channel and overbank flood protection, based on flow design criteria selected by the local agency. Further, the source and treatment control BMPs must be sufficiently designed and constructed to collectively treat, infiltrate, or filter stormwater runoff from one of the following:

The 85th percentile 24-hour runoff event determined as the maximized capture stormwater volume for the area, from the formula recommended in Urban Runoff Quality Management, WEF Manual of Practice No. 23/ASCE Manual of Practice No. 87, (1998);

The volume of annual runoff based on unit basin storage water quality volume, to achieve 80 percent or more volume treatment by the method recommended in California Stormwater Best Management Practices Handbook—Industrial/Commercial, (1993);

The volume of runoff produced from a 0.75-inch storm event, prior to its discharge to a stormwater conveyance system; or

The volume of runoff produced from a historical-record based reference 24-hour rainfall criterion for “treatment” (0.75-inch average for the Los Angeles County area) that achieves approximately the same reduction in pollutant loads achieved by the 85th percentile 24-hour runoff event.

The SUSMP also requires that all stormwater treatment/management facilities be designed such that, “post-development peak stormwater runoff discharge rates shall not exceed the estimated pre-development rate for developments where the increased peak stormwater discharge rate results in increased potential for downstream erosion.”



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Interpretations of the SUSMP requirements by the LARWQCB have emphasized that redevelopment projects evaluate and implement stormwater quality control features or BMPs starting with minimization of impervious surfaces and maximization of percolation followed by treatment of the remaining flow.

In addition to the treatment BMP and peak flow control requirements, the SUSMP contains specific BMP requirements including the following:

Conserve vegetated areas, if/as applicable (e.g., clustering development, maximizing trees and other vegetation).

Minimize stormwater pollutants of concern (e.g., through site design and treatment controls).

Protect slopes and channels.

Provide storm drain system stenciling and signage.

Properly design outdoor material storage areas (e.g., through cover, containment, and/or spill protection controls).

Properly design trash storage areas (e.g., diverting drainage around trash storage areas, and protection from off-site transport of trash).

Provide proof of ongoing BMP maintenance.

Also, the SUSMP includes general design specifications for individual priority project categories, such as 100,000-square-foot commercial developments, restaurants, and parking lots. For example, commercial developments must design loading and unloading dock areas, repair and maintenance bays, and vehicle equipment wash and fueling areas to limit potential contamination of any runoff and control possible spills. Restaurants are required to have properly designed equipment and accessory wash areas. Parking lots must be properly designed to limit oil contamination and have regular maintenance of any parking lot stormwater treatment systems.

The City of Los Angeles supports the policies of the Construction General Permit through the Development Best Management Practices Handbook, Part A Construction Activities, 3rd Edition, and associated ordinances which the City of Los Angeles adopted in September 2004. The handbook and ordinances also have specific minimum BMP requirements for all construction activities and require dischargers whose construction projects disturb one acre or more of soil to prepare a SWPPP and file a Notice of Intent (NOI) with the SWRCB. The NOI informs the SWRCB of a particular project and results in



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the issuance of a Waste Discharger Identification number, which is needed to demonstrate compliance with the General Permit.

The City of Los Angeles supports the requirements of the Los Angeles County Municipal NPDES permit through the City of Los Angeles’ Development Best Management Practices Handbook, Part B Planning Activities, 4th Edition, which the City of Los Angeles, Board of Public Works adopted on July 1, 2011, as authorized by Section 64.72 of the Los Angeles Municipal Code approved by Ordinance No. 173,494.8 The Handbook provides guidance for developers in complying with the requirements of the Development Planning Program regulations of the City’s Stormwater Program.

The City of Los Angeles implements the requirement to incorporate stormwater BMPs into the SUSMP through the City’s plan review and approval process. During the review process, project plans are reviewed for compliance with the City’s General Plans, zoning ordinances, and other applicable local ordinances and codes, including stormwater requirements. Plans and specifications are reviewed to ensure that the appropriate BMPs are incorporated to address stormwater pollution prevention goals.

(c) City of Los Angeles Water Quality Compliance Master Plan for Urban Runoff

On March 2, 2007, City Council Motion 07-0663 was introduced by the City of Los Angeles City Council to develop a water quality master plan with strategic directions for planning, budgeting and funding to reduce pollution from urban runoff in the City of Los Angeles. The Water Quality Compliance Master Plan for Urban Runoff was developed by the Bureau of Sanitation, Watershed Protection Division in collaboration with stakeholders to address the requirements of this Council Motion. The primary goal of the Water Quality Compliance Master Plan for Urban Runoff is to help meet water quality regulations. Implementation of the Water Quality Compliance Master Plan for Urban Runoff is intended over the next 20 to 30 years to result in cleaner neighborhoods, rivers, lakes, and bays, augmented local water supply, reduced flood risk, more open space, and beaches that are safe for swimming.

8 City of Los Angeles, Development Best Management Practices Handbook Low Impact Development

Manual: Part B Planning Activities, June 2011, 4th Edition, www.lastormwater.org/wp-content/files_mf/lidhandbookfinal62212.pdf, accessed November 5, 2012.



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(d) City of Los Angeles Proposition O

On November 2, 2004, City of Los Angeles voters passed Proposition O.9 The $500 million bond authorizes the City to fund projects that protect public health, capture stormwater for reuse and meet Clean Water Act requirements through removal and prevention of pollutants entering regional waterways. A number of projects targeted at improving water quality have been authorized using Proposition O funds, including but not limited to: the Temescal Canyon Park Stormwater BMP; Los Angeles Zoo Parking Lot; the Westchester Stormwater BMP; and the Echo Park Lake Rehabilitation Project.10

In addition, Proposition O funds were used for the Catch Basin Screen Cover and Insert Project, which provided for the installation of catch basin inserts and screen covers throughout the City beginning in 2005 with completion on September 30, 2007 (Phase I and Phase II). Phase III includes the retrofit of approximately 24,000 catch basins with opening screen covers and 2,600 inserts.11 Phase III is expected to be completed in December of 2016.

(e) Los Angeles Municipal Code

Any proposed drainage improvements within the street right-of-way or any other property owned by, to be owned by, or under the control of the City requires the approval of a B-permit (Los Angeles Municipal Code Section 62.105). Under the B-permit process, storm drain installation plans are subject to review and approval by the City of Los Angeles Department of Public Works Bureau of Engineering. Additionally, any connections to the City’s storm drain system from a property line to a catch basin or a storm drain pipe requires a storm drain permit from the City of Los Angeles Department of Public Works, Bureau of Engineering.

Earthwork activities, including grading, are governed by the Los Angeles Building Code, which is contained in Chapter IX, Article 1 in the Los Angeles Municipal Code. Section 64.70 of the Los Angeles Municipal Code sets forth the City’s Stormwater and Urban Runoff Pollution Control Ordinance. The ordinance prohibits the discharge of the following into any storm drain system:

9 City of Los Angeles Stormwater Program, Proposition O Background, www.lapropo.org/index.htm,

accessed November 5, 2012. 10 City of Los Angeles Stormwater Program, Major Prop O Projects, www.lapropo.org/index.htm, accessed

November 5, 2012. 11 Bureau of Engineering, Prop O Bond Division, September 2012 Monthly Report, www.lapropo.org/

sitefiles/docs/engineering/MonthlyReport_Sept_2012.pdf, accessed November 5, 2012. This is the most recent monthly report available.



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Any liquids, solids, or gases which by reason of their nature or quantity are flammable, reactive, explosive, corrosive, or radioactive, or by interaction with other materials could result in fire, explosion, or injury.

Any solid or viscous materials, which could cause obstruction to the flow or operation of the storm drain system.

Any pollutant that injures or constitutes a hazard to human, animal, plant, or fish life, or creates a public nuisance.

Any noxious or malodorous liquid, gas, or solid in sufficient quantity, either singly or by interaction with other materials, which creates a public nuisance, hazard to life, or inhibits authorized entry of any person into the storm drain system.

Any medical, infectious, toxic, or hazardous material or waste.

Additionally, unless otherwise permitted by a NPDES permit, the ordinance prohibits industrial and commercial developments from discharging untreated wastewater or untreated runoff into the storm drain system. Furthermore, the ordinance prohibits trash or any other abandoned objects/materials from being deposited such that they could be carried into the storm drains. Lastly, the ordinance not only makes it a crime to discharge pollutants into the storm drain system and imposes fines on violators, but also gives City public officers the authority to issue citations or arrest business owners or residents who deliberately and knowingly dump or discharge hazardous chemicals or debris into the storm drain system.

(f) Low Impact Development

In October 2011, the City of Los Angeles passed an ordinance (Ordinance No. 181899), the Low Impact Development (LID) Ordinance, amending Chapter VI, Article 4.4, Sections 64.70.01 and 64.72 of the Los Angeles Municipal Code to expand the applicability of the existing SUSMP requirements by imposing rainwater LID strategies on projects that require building permits. The LID Ordinance was adopted in November 2011 and officially became effective on May 12, 2012.12 LID is a stormwater management strategy with goals to mitigate the impacts of increased runoff and stormwater pollution as close to its source as possible. LID consists of site design approaches and BMPs that are designed to address runoff and pollution at the source. The goal of these LID practices is to remove nutrients, bacteria, and metals from stormwater while also reducing the quantity and intensity of stormwater flows. The LID ordinance requires rainwater from a 0.75-inch

12 LA Stormwater, Low Impact Development (LID) 2-Sided Brochure, www.lastormwater.org/wp-content/

files_mf/lidbrochure4.19.12.pdf, accessed November 5, 2012.



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rainstorm to be captured, infiltrated, and/or used onsite at most developments and redevelopments where more than 500 square feet of hardscape is added.

The City of Los Angeles adopted LID standards and practices in future developments and redevelopments encourage the following:13

Beneficial use of rainwater and urban runoff;

Water quality improvement;

Rainwater harvesting;

Reduction of offsite runoff and provide increased groundwater recharge;

Reduction of erosion and hydrologic impacts downstream; and

Enhancement of recreational and aesthetic values in our communities.

(g) Water Master Service for the Santa Monica Basin

The Project Site is underlain by the Los Angeles Coastal Plain’s Santa Monica Basin (Santa Monica Basin). The Santa Monica Basin is currently unadjudicated and the management of water resources in the Santa Monica Basin is provided by the City of Santa Monica. The California Department of Health Services and the RWQCB provide additional oversight of the Santa Monica Basin's groundwater quality and help monitor contaminant levels. Water production is recorded monthly by the City of Santa Monica and reported annually to the California Department of Water Resources.14

b. Existing Conditions

(1) Surface Water Hydrology

(a) Regional

As shown in Figure IV.G-1 on page IV.G-17, the Project Site is located within the Santa Monica Bay Watershed Management Area in the Los Angeles Basin. The Santa

13 LA Stormwater, Why did the city of Los Angeles adopt LID standards and practices?, www.lastormwater.

org/green-la/low-impact-development/faqs/why-did-the-city-of-los-angeles-adopt-lid-standards-and-practices/, accessed November 5, 2012.

14 City of Santa Monica. 2010 Urban Water Management Plan, www.smgov.net/uploadedFiles/Departments/Public_Works/Water/Final%202010%20UMWP_July%202011.pdf; accessed November 12, 2012.

State of the Watershed - Report on Water Quality Santa Monica Bay Watershed Management Area 2nd Edition

Figure 1

Most land areas of the WMA are located in Los Angeles County, except for a small portion of eastern Ventura County. The cities of Los Angeles and Santa Monica, along with twenty other cities, are located either completed or partially within the watershed. There are also land areas under the jurisdiction of Los Angeles County as well as State and Federal jurisdictions (primarily park lands in the Santa Monica Mountain area) (CRWQCB, 1997).

Approximately 9.86 million people live in Los Angeles County (2008 U.S. Bureau of Census estimate). It is estimated that approximately 2.5 million live within the 414 square mile watershed. In addition, approximately 8.8 million live within the so-called "wasteshed", the area that is served by the large wastewater treatment plants that discharge into the Bay (CRWQCB, 1997).

SCAG land use data from 2005 shows 62% of the area is open space, high density residential is 17% of the area, and low density residential is 2.3% of the area. Commercial and industrial land uses total 6% of the area and are found in all but a handful of the subwatersheds These land uses are shown in the

PROJECT SITE

Figure IV.G-1Santa Monica Bay Watershed Management Area

Source: Los Angeles Regional Water Quality Control Board. State of the Watershed – Report of Water Quality, the Santa Monica Bay Watershed Management Area, 2nd Edition. November 2011.

N

NORTH

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Monica Bay Watershed Management Area encompasses an area of 414 square miles. The northern boundary of the Santa Monica Bay Watershed extends from the Pacific Ocean at the crest of the Santa Monica Mountains and the Ventura–Los Angeles County line to downtown Los Angeles. The boundary then extends south and west across the Los Angeles plain to include the area east of Ballona Creek and north of the Baldwin Hills. South of Ballona Creek the natural drainage is a narrow coastal strip between Playa del Rey and Palos Verdes.

Surface water flows into the Santa Monica Bay through 28 catchment basins that are further grouped into nine subwatershed areas. As shown in Figure IV.G-1 on page IV.G-17, these nine subwatershed areas include the North Coast; Malibu Creek; Topanga Creek; Santa Monica Canyon; Pico–Kenter; Ballona Creek; El Segundo–LAX; South Bay; and Palos Verdes. The Project Site is specifically located within the Pico–Kenter subwatershed area. The land use within this watershed comprises approximately 48 percent single family uses, 21 percent multiple family, 6 percent commercial, 3 percent public, and 19 percent open space.15 The Pico–Kenter drain, located where Pico Boulevard intersects the beach in the City of Santa Monica, enters the Santa Monica Bay in a 20-foot-wide by 8-foot-high reinforced concrete box. This storm drain system drains an approximately 4,147-acre area that includes much of the City of Santa Monica and part of the West Los Angeles and Brentwood communities in the City of Los Angeles.

(b) Local

Drainage from the Archer campus is directed to Sunset Boulevard where it is conveyed westerly via surface flow to an underground storm drain pipe owned and maintained by Los Angeles County at the intersection of Sunset Boulevard and Bundy Drive. Drainage from the Barrington Parcel flows south on Barrington Avenue and then west onto Sunset Boulevard following the same path as the drainage from the Archer campus toward the underground storm drain at the intersection of Sunset Boulevard and Bundy Drive. Drainage from the Chaparal Parcel is directed toward Chaparal Street where it is conveyed through surface flow toward the west along Chaparal Street then south on Saltair Avenue towards the City-owned underground storm drain at the intersection of Sunset Boulevard and Bundy Drive. After entering the underground storm drain pipe at Sunset Boulevard and Bundy Drive, the drainage from the Project Site is conveyed through an underground pipe network that flows south and west through various drainage pipes owned by the City of Los Angeles and Los Angeles and subsequently discharging into

15 Percentages are approximate and are based on the Los Angeles Regional Water Quality Control Board.

State of the Watershed—Report of Water Quality, the Santa Monica Bay Watershed Management Area, 2nd Edition, www.waterboards.ca.gov/rwqcb4/water_issues/programs/regional_program/wmi/ws_santamonica.shtml; accessed November 12, 2012.



Page IV.G-19


pipes owned by Los Angeles County before crossing into the City of Santa Monica and ultimately discharging from Pico Boulevard into the Santa Monica Bay.

(c) On-Site

As shown in Figure IV.G-2 on page IV.G-20, the Project Site has been divided into four drainage areas.16 These drainage areas are determined by the drainage patterns and flow paths of stormwater that are tributary to a common point or area. As described in Section II, Project Description, of this Draft EIR, the Project Site’s overall topography slopes downward from north to south with a fall in grade of approximately 25 feet from Chaparal Street to Sunset Boulevard. Accordingly, as described further below, the existing drainage pattern of the Archer campus is generally from north to south. In addition, the existing 7.31-acre Project Site, including the Archer campus and the Barrington and Chaparal Parcels, is approximately 59 percent impervious surfaces including buildings and impervious pavements for pedestrian and vehicular circulation. The remaining 41 percent of the existing Project Site is pervious surfaces consisting of athletic fields, landscaped areas, and lawns. Based on the Los Angeles County Hydrology Manual, the Project Site is underlain by soil type 013.17 As this type of soil has a limited capacity to absorb stormwater during an intense rain event (i.e., a 25-year storm event), existing site soils are anticipated to runoff in a similar manner as runoff from paved surfaces.

As shown in Figure IV.G-2, stormwater runoff from the north part of the campus (drainage area 1) is currently collected by on-site catch basins on the west side of the Main Building and then piped to a 12-inch-diameter PVC storm drain system located along the west side of the campus, which connects to a transition structure located in the southwest corner of the campus adjacent to Sunset Boulevard. Discharge from the transition structure occurs via a curb drain connection to the existing curb and gutter on Sunset Boulevard. Roof drains from the existing Main Building and the southern part of the campus (drainage area 2) discharge to the adjacent asphalt surfaces and flow overland toward Sunset Boulevard. Stormwater runoff from the northern portion of the Chaparal Parcel (drainage area 3) sheet flows to Chaparal Street. The southern portion of the Chaparal Parcel and the entire Barrington Parcel (drainage area 4) sheet flow to Barrington Avenue. As described above, all on-site stormwater flows from the Project Site are conveyed towards the County-owned underground storm drain at the intersection of Sunset Boulevard and Bundy Drive before ultimately discharging from Pico Boulevard into the Santa Monica Bay. Existing runoff flows for each drainage area during a 50-year storm

16 The drainage areas tributary to each discharge location were determined from a topographical survey. 17 Los Angeles County Department of Public Works. Hydrology Manual, Appendix B, Hydrologic Maps.

January 2006. Available at http://ladpw.org/wrd/publication/, accessed September 12, 2013.

Figure IV.G-2Existing Hydrology and Storm Drain System

Source: KPFF Consulting Engineers, 2012.

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event are shown in Table IV.G-1 on page IV.G-22. As shown therein, under existing conditions, the runoff flow rate for the Project Site is 28.26 cubic feet per second.

(2) Surface Water Quality

(a) Regional

As discussed above, the Project Site is located within the Santa Monica Bay Watershed Management Area of the Los Angeles Basin, which includes several subwatershed areas. The Project Site is specifically located within the Pico–Kenter Subwatershed area. As previously described, the Project Site ultimately drains to the Santa Monica Bay via a network of City and County storm drains within the Pico–Kenter Subwatershed.

(i) Beneficial Uses of the Pico–Kenter Watershed

According to the LARWQCB Santa Monica Bay Watershed Report, almost every beneficial use defined in the Basin Plan is identified in water bodies within the Santa Monica Bay Watershed Management Area.18 Specifically, twenty beneficial uses for surface waters and four beneficial uses for ground waters in the Santa Monica Bay Watershed Management Area are designated in the Basin Plan. Of these, the existing and potential beneficial uses for the waters within the Pico–Kenter Subwatershed, where surface water flows from the Project Site ultimately discharge are shown in Table IV.G-2 on page IV.G-23 and are described below. Beneficial uses for waterbodies in the Pico–Kenter Subwatershed are primarily identified for coastal waters that receive discharges from the storm drains. Beaches in the area include the Santa Monica Beach and Venice Beach.

Navigation (NAV): Uses of water for shipping, travel, or other transportation by private, military, or commercial vessels.

Water Contact Recreation (REC-1): Uses of water for recreational activities involving body contact with water, where ingestion is reasonably possible. These uses include, but are not limited to, swimming, wading, water-skiing, skin and scuba diving, surfing, white water activities, fishing, or use of natural hot springs. For REC-1 and REC-2 uses (discussed below), the LARWQCB has adopted a “High-Flow Suspension” provision for engineered channels such as the Los Angeles River such that the requirement to protect these uses and their associated water quality objectives are temporarily suspended during periods of

18 Los Angeles Regional Water Quality Control Board. State of the Watershed—Report of Water Quality,

the Santa Monica Bay Watershed Management Area, 2nd Edition, www.waterboards.ca.gov/rwqcb4/water_issues/programs/regional_program/wmi/ws_santamonica.shtml; accessed November 12, 2012.



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high flow determined by days of rainfall of 0.5 inch or greater and the 24 hours following.

Water Contact Recreation (REC-2): Uses of water recreational activities involving proximity to water, but not normally involving body contact with water, where ingestion of water is reasonably possible. These uses include, but are not limited to, picnicking, sunbathing, hiking, beach combing, camping, boating, tidepool and marine life study, hunting, sightseeing, or aesthetic enjoyment in conjunction with the above activities.

Commercial and Sport Fishing (COMM): Uses of water for commercial or recreational collection of fish, shellfish, or other organisms including, but not limited to, uses involving organisms intended for human consumption or bait purposes.

Marine Habitat (MAR): Uses of water that support marine ecosystems including, but not limited to, preservation or enhancement of marine habitats, vegetation such as kelp, fish, shellfish, or wildlife (e.g., marine mammals, shorebirds).

Wildlife Habitat (WILD): Use of water that support terrestrial ecosystems including, but not limited to, preservation and enhancement of terrestrial habitats, vegetation, wildlife (e.g., mammals, birds, reptiles, amphibians, invertebrates), or wildlife water and food sources.

Rare, Threatened, or Endangered Species (RARE): Uses of water that support habitats necessary, at least in part, for the survival and successful maintenance of plant or animal species established under state or federal law as rare, threatened, or endangered.

Table IV.G-1 Existing 50-Year Storm Event Flow Rate

Drainage Area Area

(acres)a Existing Flow Rate

(cfs)

Area 1 3.47 13.43

Area 2 2.73 10.57

Area 3 0.18 0.70

Area 4 0.92 3.56

cfs = cubic feet per second




Page IV.G-23


Table IV.G-2 Beneficial Uses of the Waters within the Pico–Kenter Subwatershed Area

Beneficial Use Santa Monica Beach

Designation Venice Beach Designation

Navigation (NAV) E E

Water Contact Recreation (REC1) E E

Water Contact Recreation (REC2) E E

Commercial and Sport Fishing (COMM) E E

Marine Habitat (MAR) E E

Wildlife Habitat (WILD) E E

Rare, Threatened, or Endangered Species (RARE) — E

Migration of Aquatic Organisms (MIGR) E E

Spawning, Reproduction, and/or Early Development (SPWN)

E, as E, as

Shellfish Harvesting (SHELL) E E

E: Existing Beneficial Use

as: Most frequently used grunion spawning beaches. Other beaches may be used as well.

Source: Los Angeles Regional Water Quality Control Board. State of the Watershed—Report on Water Quality for the Santa Monica Bay Watershed Management Area, 2nd Edition. November 2011.

Migration of Aquatic Organisms (MIGR): Uses of water that support habitats necessary for migration, acclimatization between fresh and salt water, or other temporary activities by aquatic organisms, such as anadromous fish.

Spawning, Reproduction, and/or Early Development (SPWN): Uses of water that support high quality aquatic habitats suitable for reproduction and early development of fish.

Shellfish Harvesting (SHELL): Uses of water that support habitats suitable for the collection of filter-feeding shellfish (e.g., clams, oysters, and mussels) for human consumption, commercial, or sports purposes.

(ii) Impairments and TMDLs in the Pico–Kenter Subwatershed

Pursuant to Section 303(d) of the federal Clean Water Act, the State and RWQCBs identify impaired bodies of water that do not meet water quality standards and prioritizes and schedules them for development of TMDLs. A TMDL specifies the maximum amount of a pollutant that a water body can receive and still meet water quality standards. Those facilities and activities that are discharging into the water body, collectively, must not exceed the TMDL. The USEPA approved the most recent Section 303(d) list in November



Page IV.G-24


2010.19 TMDLs in effect within the Pico–Kenter Subwatershed include the dry- and wet-weather bacteria TMDLs for Santa Monica Bay beaches and the Santa Monica Bay nearshore and offshore debris TMDL.

Based on the LARWQCB Santa Monica Bay Watershed Report, the pollutants of concern identified for the Pico–Kenter Subwatershed include pathogens; heavy metals such as lead, copper, zinc, cadmium, and silver; debris; oil and grease; polycyclic aromatic hydrocarbons; and chlordane.20 Implementation strategies for reducing the impacts of the effluent of the Pico–Kenter storm drain have primarily involved the construction of the Santa Monica Urban Runoff Recycling Facility, which treats effluent from the Pico–Kenter and the Santa Monica Pier storm drains. This facility became active in 2001 and began diverting and treating 500,000 gallons per day to recycled water quality. Additionally, dry-weather runoff from several storm drains within this subwatershed is currently being diverted away from storm drain systems or waterways and redirected into the sanitary sewer system where the contaminated runoff receives treatment and filtration before being discharged.

Santa Monica Beach and Venice Beach are listed in the Section 303(d) list as impaired for indicator bacteria. These TMDLs, approved by the USEPA in 2003, require reduction of bacteria loadings from urban runoff to the Santa Monica Bay to meet the REC-1 bacteria standards for water-contact recreation in marine waters as defined by the Basin Plan.21 The wet-weather bacteria TMDL specifies a threshold number of exceedance days based on daily monitoring activities and implements a reference/anti-degradation approach to ensure that bacteriological water quality is at least as good as that of a reference site and that no degradation of existing bacteriological water quality is permitted where existing bacteriological water quality is better than that of a reference site.22 The dry-weather bacteria TMDL includes a two-phase compliance approach. The first phase requires that within three years of the effective date of the TMDL, there may be no exceedances at any location during the summer dry weather (April 1 to October 31). 19 State Water Resources Control Board, 2010 Integrated Report, www.swrcb.ca.gov/water_issues/

programs/tmdl/integrated2010.shtml, accessed November 15, 2012. 20 Los Angeles Regional Water Quality Control Board. State of the Watershed—Report of Water Quality,

the Santa Monica Bay Watershed Management Area, 2nd Edition, www.waterboards.ca.gov/rwqcb4/water_issues/programs/regional_program/wmi/ws_santamonica.shtml; accessed November 12, 2012.

21 City of Los Angeles Watershed Protection Division and City of Los Angeles Bureau of Sanitation. Assessment of Santa Monica Bay Shoreline Monitoring Program and BMP Mitigation Measures for TMDL Compliance, http://stormwaterconference.com/App_Data/indooGrid/Abstracts/205.AbstractTextFile.CASQA2009Coxsession3trackA0345pm.pdf, accessed November 13, 2012.

22 Los Angeles Regional Water Quality Control Board. State of the Watershed—Report of Water Quality, the Santa Monica Bay Watershed Management Area, 2nd Edition, www.waterboards.ca.gov/rwqcb4/water_issues/programs/regional_program/wmi/ws_santamonica.shtml; accessed November 12, 2012.



Page IV.G-25


The second phase requires that within six years of the effective date of the TMDL, compliance with the allowable number of exceedance days, which varies by beach, during the winter dry weather must be achieved. A Coordinated Shoreline Monitoring Plan was developed by the County and City of Los Angeles and representatives from many of the bacteria TMDLs’ responsible agencies to comply with the monitoring requirements of both the dry- and wet-weather bacteria TMDLs.

The Santa Monica nearshore and offshore debris TMDL was adopted by the LARWQCB in 2010 and requires that industries that manufacture, store, transport, or otherwise handle plastic pellets as raw material comply with a waste load allocation of zero plastic pellets. The TMDL requires a 20-percent reduction of trash from the baseline waste load allocation within four years of the effective date of the TMDL and a 100-percent reduction within eight years.23 Implementation strategies for compliance with the waste load allocation include appropriate containment systems, sealed containers, vacuum devices for cleaning, and frequent inspection and cleaning at operational areas and outlets of water discharge, to effectively control and prevent discharges of pre-production plastic pellets.24

(b) Local

In general, urban stormwater runoff occurs during and shortly following precipitation events. The volume of water ultimately directed into the drainage system depends on such things as the intensity and duration of the rainstorm and soil moisture. In addition to sediment, contaminants that may be found in stormwater from developed areas include trash, bacteria, metals, nutrients, and potentially, organics and pesticides. The source of contaminants is diffuse and includes all areas where precipitation falls, as well as the air it falls through. Therefore, contaminants on roads, maintenance areas, parking lots, and building tops, which are not usually contained in dry weather discharges, may be carried with rainfall drainage into the drainage system. In addition to the wider-reaching projects the City has contributed to, such as the Santa Monica Urban Runoff Recycling Facility discussed above, the City has installed catch basins to capture debris before entering the storm drain system. In addition, the City conducts routine street cleaning operations as well as periodic cleaning and maintenance of catch basins to reduce stormwater pollution within the City.

23 Ibid. 24 Los Angeles Regional Water Quality Control Board. Santa Monica Bay Nearshore and Offshore Debris

TMDL, www.waterboards.ca.gov/losangeles/board_decisions/basin_plan_amendments/technical_documents/72_New/SMB%20Debris%20Staff%20Report%20073010.pdf, accessed November 13, 2012.



Page IV.G-26


(c) On-Site

While the Project Site currently does not have structural BMPs for the treatment of stormwater runoff from the existing impervious surfaces such as building roof areas and pavements, there are a range of non-structural BMPs and environmental water quality policies that are currently used at the Project Site to minimize the impact of pollutant sources. These include general housekeeping practices such as regular trash collection and street sweeping; spill prevention and response activities within the chemistry and photography laboratories; proper storage of hazardous materials and wastes; and substituting environmentally friendly products for environmentally hazardous products, such as soaps, solvents, and pesticides. In addition, stormwater runoff from existing pervious surfaces such as the athletic fields, landscaped areas, and lawns is naturally treated to some extent by existing vegetation and the absorptive properties of the existing soils. Based on the existing operations within the Project Site, the on-site runoff likely contains the following pollutants of concern: sediment, nutrients, pesticides, metals, pathogens, and oil and grease.

(3) Groundwater Hydrology

(a) Regional

Groundwater use for domestic water supply is a major beneficial use of groundwater basins in Los Angeles County. The City of Los Angeles overlies the Los Angeles Coastal Plain Groundwater Basin. As shown in Figure IV.G-3 on page IV.G-27, the Los Angeles Coastal Plain Groundwater Basin comprises the Hollywood, Santa Monica, Central, and West Coast Basins. Groundwater flow in the Los Angeles Coastal Plain Groundwater Basin is generally south-southwesterly and may be restricted by natural geological features. Replenishment of groundwater basins occurs mainly by percolation of precipitation throughout the region via permeable surfaces, spreading grounds, and groundwater migration from adjacent basins, as well as injection wells designed to pump freshwater along specific seawater barriers to prevent the intrusion of salt water.

(b) Local

Within the Los Angeles Coastal Plain Groundwater Basin, the Project Site specifically overlies the Santa Monica Basin, which is located in the northwestern part of the Los Angeles Coastal Plain Groundwater Basin. The Santa Monica Basin is bounded on the north by impermeable rocks of the Santa Monica Mountains, the Newport-Inglewood fault to the east, the Pacific Ocean to the west, and the Ballona Escarpment to the south. As shown in Figure IV.G-4 on page IV.G-28, extensive faulting within the Santa Monica Basin further separates the Basin into five subbasins. These include the Arcadia, Olympic, Coastal, Charnock, and Crestal subbasins. The Santa Monica Basin is a natural

Figure IV.G-3Coastal Plain of the Los Angeles Groundwater Basin

Source: U.S. Geological Survey, 2012.

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Figure IV.G-4Santa Monica Groundwater Basin

Source: The Metropolitan Water District of Southern California. Groundwater Assessment Study, Santa Monica Basin, September 2007.

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groundwater basin that encompasses a surface area of approximately 50.2 square miles and is estimated to have a total storage capacity of approximately 1.1 million acre-feet.

Groundwater in the Santa Monica Basin is replenished naturally by percolation from precipitation, receiving an average annual precipitation of approximately 14 inches, and by surface runoff from the Santa Monica Mountains. The Newport-Inglewood fault to the east of the Santa Monica Basin restricts some of the groundwater inflows from the Central Basin that would have otherwise replenished the Santa Monica Basin. In addition, the Santa Monica Basin is mostly urbanized and soil surfaces have been paved to construct roads, buildings, and flood channels. As a result, the surface area open to direct percolation has decreased substantially and, therefore, replenishment to the Santa Monica Basin’s water formations is limited to only a small portion of soils in the Basin. The Santa Monica Basin currently does not receive any artificial recharge through injection wells or spreading basins.25

The primary water-bearing formations of the Santa Monica Basin include the Ballona and Silverado aquifers underneath the Bellflower aquiclude. The Lakewood Formation, which includes the Ballona Aquifer, is also present within the Arcadia and Olympic subbasins in the northern half of the Santa Monica Basin. The Ballona Aquifer has a thickness of up to 90 feet with a yield of 800 gallons per minute. The Silverado Aquifer within the San Pedro Formation is the main potable production aquifer within the Santa Monica Basin with a thickness of up to 280 feet and a yield of 4,700 gallons per minute.26

The groundwater in the Santa Monica Basin generally flows southward from the Santa Monica Mountains on the north to the West Coast Basin on the south. Groundwater outflows to the West Coast Basin are estimated to be about 1,000 acre-feet per year. However, there are no formal agreements governing this outflow. Additional outflow to the Hollywood and Central Basins is restricted by the Newport-Inglewood Uplift.27

As described above, the Santa Monica Basin is an unadjudicated groundwater basin and is managed by the City of Santa Monica. While no formal safe yield has been adopted for the Santa Monica Basin, the United States Geological Survey estimated an average safe yield of approximately 7,500 acre-feet per year.28,29

25 City of Santa Monica. 2010 Urban Water Management Plan, www.smgov.net/uploadedFiles/Departments/

Public_Works/Water/Final%202010%20UMWP_July%202011.pdf, accessed November 13, 2012. 26 Ibid. 27 Ibid. 28 Ibid.



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The City of Santa Monica is the primary producer from the Santa Monica Basin and currently extracts groundwater from ten active groundwater wells with a combined production capacity of 12,300 gallons per minute. Two of these wells are located in the Arcadia subbasin (Nos. 4 and 5), three are located in the Olympic subbasin (Nos. 1, 3, and 4), and five wells are located in the Charnock subbasin (Nos. 13, 15, 16, 18, and 19).

(c) On-Site

As previously discussed, the Project Site is located above the Santa Monica Basin of the Coastal Plain of the Los Angeles Groundwater Basin. The Project Site slopes generally to the south at varying gradients with an elevation of approximately 495 feet above mean sea level on the northern boundary of the Project Site to approximately 465 feet above mean sea level on the southern boundary, adjacent to Sunset Boulevard.

Based on on-site explorations conducted as part of the Geotechnical Engineering Investigation for the Project Site, encountered fill materials varied between 1 and 5 feet in depth. Fill materials consisted of mixtures of sand, silt, and clay, which ranged from light brown to orange brown to dark brown in color, slightly moist to moist, loose to medium dense or medium firm to stiff, and fine grained with occasional gravel, slate fragments, and concrete fragments. The fill was found to be underlain by older alluvial soils consisting of interlayered mixtures of sand, silt, and clay. The older alluvium ranged in color from brown to reddish brown to dark brown, and was slightly moist to moist, dense to very dense, stiff to very stiff, and fine to coarse grained with occasional gravel. Slate fragments were also found, varying from occasional to abundant.

As discussed in the Water Resources Technical Report, including in Appendix L, of this Draft EIR, and summarized in Section IV.E, Geology and Soils, of this Draft EIR, the historic highest groundwater level was established by review of California Geologic Survey Seismic Hazard Evaluation Report 023 Plate 1.2 entitled Historically Highest Ground Water Contours. Review of this plate indicates that the historically highest groundwater level was on the order of 40 feet below grade. In addition, groundwater was not encountered during recent on-site explorations conducted to a maximum depth of 60 feet below the existing grade. Furthermore, there are no groundwater production wells or public water supply wells within 1 mile of the Project Site.30

29 Safe yield refers to the annual amount of water that can be taken from a source of supply over a period of

years without depleting that source beyond its ability to be replenished naturally in wet years. 30 State Water Resources Control Board Groundwater Ambient Monitoring and Assessment GeoTracker,

http://geotracker.waterboards.ca.gov/gama/gamamap/public/?CMD=runreport&myaddress=11725+los+angeles%2C+ca, accessed December 11, 2012.



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(4) Groundwater Quality

In general, due to historical activities and practices, groundwater quality in the City of Los Angeles has been substantially degraded. The degradation of regional groundwater is a result of seepage into the subsurface of fertilizers and pesticides from agricultural uses, nitrogen and pathogenic bacteria from septic tanks, and various hazardous substances from leaking aboveground and underground storage tanks and industrial-type operations. In addition, historic over-pumping has led to falling groundwater levels resulting in seawater intrusion in the lower aquifers of the Central and West Coast Basins. However, this issue has been largely mitigated through operation of an artificial recharge system consisting of spreading basins and injection wells that form fresh water barriers along the coast. Groundwater quality in the upper aquifers of the Central and West Coast Basins has been impacted by both organic and inorganic pollutants from a variety of sources, such as leaking aboveground and underground storage tanks, leaking sewer lines, and illegal discharges.

As discussed above, the Project Site is located within the Santa Monica Basin of the Coastal Plain of the Los Angeles Groundwater Basin. As described in the City of Santa Monica’s 2010 Urban Water Management Plan, groundwater extracted from the Santa Monica Basin contains various levels of contaminants, which include total dissolved solids, nitrate, volatile organic compounds, and methyl tertiary butyl ether. Other common groundwater contaminants of the region such as nitrates and perchlorate either meet drinking water standards or have not been detected. In addition, as groundwater levels within the Santa Monica Basin are typically at or above mean sea level, seawater intrusion does not pose a significant risk within the Santa Monica Basin.

(5) Flood Zone

Based on the Federal Emergency Management Agency Flood Insurance Rate Map for the Project Site, the Project Site is not located within a 100-year flood zone.31 In addition, according to the City of Los Angeles General Plan Safety Element, the Project Site is not located in a potential inundation area.32

31 Federal Emergency Management Agency. Map Service Center—Flood Maps. Website https://msc.fema.

gov/webapp/wcs/stores/servlet/FemaWelcomeView?storeId=10001&catalogId=10001&langId=-1&userType=G, accessed October 19, 2012.

32 City of Los Angeles General Plan Safety Element, Exhibit G, adopted November 26, 1996.



Page IV.G-32


3. Environmental Impacts

a. Methodology

The analysis of potential impacts to surface water hydrology, surface water quality, and groundwater, is based on the Water Resources Technical Report, prepared by KPFF Consulting Engineers. This report is provided in Appendix L of this Draft EIR.


The surface water hydrology analysis included below evaluates the change in surface water runoff patterns and quantity for the Project Site associated with the Project and the impact of these changes on the existing downstream stormwater system.

As discussed in the Regulatory Framework Section above, the City has adopted the Los Angeles County Department of Public Works Hydrology Manual as its basis of design for storm drainage facilities. The Hydrology Manual requires projects to have drainage facilities to meet the Urban Flood level of protection, which is defined as runoff from a 25-year frequency storm falling on a saturated watershed. As described below, the City of Los Angeles CEQA Thresholds Guide, however, establishes the 50-year frequency design storm event as the threshold to evaluate potential impacts on surface water hydrology. Thus, to provide a more conservative analysis of the ability of storm drain infrastructure to accommodate the demand generated by the Project, the larger 50-year storm event threshold was used.

As the non-peak runoff flow rate varies from 0.0 cubic feet per second (cfs) up to the peak flow rate, it is only necessary to consider peak runoff in determining the impact to drainage systems. Consequently, as part of its Hydrology Manual, the Los Angeles County Department of Public Works developed a time of concentration calculator, Tc Calculator,33 to automate time of concentration, peak runoff rate, and total volume calculations using the Modified Rational Method design criteria as outlined in its Hydrology Manual. The Tc Calculator can be used for single subareas and small watersheds. The Tc Calculator was used to calculate the stormwater peak runoff flow rate for the Project Site with implementation of the Project by evaluating the changes within the individual drainage areas as described below.

33 The time of concentration (Tc) is defined as the time it takes for rain in the most hydrologically remote

part of the basin area to reach the outlet.



Page IV.G-33



The analysis of surface water quality impacts identifies the types of pollutants associated with construction and operation of the Project and considers their potential effects on surface water quality.

As described above, in October 2011, the City of Los Angeles passed the Low Impact Development Ordinance, amending Chapter VI, Article 4.4, Sections 64.70.01 and 64.72 of the Los Angeles Municipal Code to expand the applicability of the existing SUSMP requirements by imposing rainwater LID strategies on projects that require building permits. The LID Ordinance requires rainwater from a 0.75-inch rainstorm to be captured, infiltrated and/or used on-site at most developments and redevelopments where more than 500 square feet of hardscape is added. The LID Ordinance prioritizes the selection of BMPs with infiltration systems as the first priority type of BMP. As described further below, in accordance with the requirements of the LID Ordinance, the Project proposes the implementation of two infiltration systems within the Project Site. To determine the appropriate size of the infiltration system for the Project Site, the five-step process outlined in the LID Manual was used.34 This five-step process includes calculating the design volume of the infiltration system, determining the design infiltration rate, calculating the BMP surface area, calculating the total storage volume, and calculating the media storage depth. For additional details regarding this analysis, please refer to the Water Resources Technical Report, included in Appendix L of this Draft EIR and the Percolation Testing and Stormwater Infiltration Memorandum prepared by Geotechnologies, Inc. and included in Appendix M of this Draft EIR.

(3) Groundwater

The analysis of the Project’s potential impacts associated with groundwater was based on a review of existing groundwater levels, conditions, and groundwater uses and an evaluation of the potential impacts for construction and operation of the Project to affect those uses and groundwater quality. Construction and operational activities evaluated include any potential dewatering activities during construction; changes in groundwater recharge based on proposed land use changes; infiltration capacity of the underlying soil; permanent dewatering; potential soil or shallow groundwater exposure to construction materials, wastes, or spilled materials, handling and storage of hazardous materials; and any potential groundwater remediation activities.

34 The “LID Manual” refers to the Development Best Management Practices Handbook, Part B Planning

Activities, 4th Edition, which was adopted by the City of Los Angeles, Board of Public Works on July 1, 2011, to reflect Low Impact Development requirements that took effect May 12, 2012.



Page IV.G-34


b. Significance Thresholds

Appendix G of the CEQA Guidelines provides a set of sample questions that address impacts with regard to surface water hydrology and water quality and groundwater. These questions are as follows:

Would the project:

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 (e.g., the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted)?

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 that would result in flooding on- or off-site?

Create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff?

Otherwise substantially degrade water quality?

Place housing within a 100-year flood hazard area as mapped on federal Flood Hazard Boundary or Flood Insurance Rate Maps or other flood hazard delineation maps?

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

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?

Expose people or structures to a significant risk of loss, injury or death involving inundation by seiche, tsunami, or mudflow?



Page IV.G-35



In the context of these questions from Appendix G of the CEQA Guidelines, the City of Los Angeles CEQA Thresholds Guide states that a project would normally have a significant impact on surface water hydrology if it would:

Cause flooding during the projected 50-year developed storm event which would have the potential to harm people or damage property or sensitive biological resources;

Substantially reduce or increase the amount of surface water in a water body; or

Result in a permanent, adverse change to the movement of surface water sufficient to produce a substantial change in the current or direction of water flow.


In the context of the above questions from Appendix G, the City of Los Angeles CEQA Thresholds Guide states that a project would normally have a significant impact on surface water quality if it would:

Result in discharges that would create pollution, contamination or nuisance as defined in Section 13050 of the California Water Code or that cause regulatory standards to be violated, as defined in the applicable NPDES stormwater permit or Water Quality Control Plan for the receiving water body.

As defined in the California Water Code:

“Pollution” means an alteration of the quality of the waters of the State to a degree which unreasonably affects either of the following: (1) the waters for beneficial uses; or (2) facilities which serve these beneficial uses. Pollution may include contamination.

“Contamination” means an impairment of the quality of the waters of the State by waste to a degree which creates a hazard to the public health through poisoning or through the spread of diseases. Contamination includes any equivalent effect resulting from the disposal of waste whether or not waters of the State are affected.

“Nuisance” means anything which meets all of the following requirements: (1) is injurious to health, or is indecent or offensive to the senses, or an obstruction to the free use of property so as to interfere with the comfortable enjoyment of life or property; (2) affects at the same time an entire community or neighborhood, or any considerable number of persons although the extent of the annoyance or



Page IV.G-36


damage inflicted upon individuals may be unequal; and (3) occurs during or as a result of the treatment or disposal of wastes.

(3) Groundwater

In the context of the question from Appendix G, the City of Los Angeles CEQA Thresholds Guide states that a project would normally have a significant impact on groundwater if it would:

Change potable water levels sufficiently to:

– Reduce the ability of a water utility to use the groundwater basin for public water supplies, conjunctive use purposes, storage of imported water, summer/winter peaking, or to respond to emergencies and drought;

– Reduce yields of adjacent wells or well fields (public or private); or

– Adversely change the rate or direction of flow of groundwater;

Result in demonstrable and sustained reduction of groundwater recharge capacity

Affect the rate or change direction of movement of existing contaminants;

Expand the area affected by contaminants;

Result in an increased level of groundwater contamination (including that from direct percolation, injection or salt water intrusion); or

Cause regulatory water quality standards at an existing production well to be violated, as defined in the California Code of Regulations (CCR), Title 22, Division 4, Chapter 15 and in the Safe Drinking Water Act.

With regard to the above questions from Appendix G of the CEQA Guidelines, as evaluated in the Initial Study included as Appendix A of this Draft EIR and discussed above, the Project Site is not located within a Federal Emergency Management Agency–defined flood plain. In addition, the Project Site is not located within a potential inundation area. Furthermore, the Project does not include the development of residential uses. Accordingly, the Project would not place housing within a 100-year flood plain or place structures within a 100-year flood plain that could impede or redirect flood flows. Additionally, the Project would not 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 or inundation by seiche. Further, based on the Project Site’s distance from the ocean and hillside soils to the north as well as its elevation above sea level, the Project Site would



Page IV.G-37


not be susceptible to tsunamis and mudflow. Therefore, as concluded in the Initial Study, no significant impacts with regard to these issues would occur and further analysis of these issues in this Draft EIR is not required.

c. Project Design Features and Regulatory Compliance Measures

(1) Project Design Features

No specific project design features beyond those set forth in Section II, Project Description, of this Draft EIR are proposed with regard to hydrology, surface water quality, and groundwater.

(2) Regulatory Compliance Measures

Regulatory Compliance Measure G-1: Earthwork activities, including grading, shall be performed in accordance with Chapter IX, Article 1 in the Los Angeles Municipal Code.

Regulatory Compliance Measure G-2: In accordance with NPDES and City requirements, prior to the issuance of a grading permit, the Applicant shall provide evidence to the City of Los Angeles Department of Public Works, as appropriate, that a Notice of Intent has been filed with the State Water Resources Control Board for coverage under the Construction General Permit and a certification that a Storm Water Pollution Prevention Plan has been prepared. Such evidence would consist of a copy of the Notice of Intent stamped by the State Water Resources Control Board or Regional Board, or a letter from either agency stating that the Notice of Intent has been filed. The Stormwater Pollution Prevention Plan would include a menu of Best Management Practices to be selected and implemented based on the phase of construction and the weather conditions to effectively control erosion. BMPs to be implemented as part of the Project could include, but not be limited to, the following:

Erosion Control BMPs to protect the soil surface and prevent soil particles from detaching. Selection of the appropriate erosion control BMPs would be based on minimizing areas of disturbance, stabilizing disturbed areas, and protecting slopes/channels;

Sediment Control BMPs, which are treatment controls that trap soil particles that have been detached by water or wind. Selection of the appropriate sediment control BMPs would be based on keeping sediments on-site and controlling the site boundaries;



Page IV.G-38


Wind Erosion Control BMPs, which consist of applying water to prevent or minimize dust nuisance;

Tracking Control BMPs, which consist of preventing or reducing the tracking of sediment off-site by vehicles leaving the construction area. These BMPs include street sweeping and vacuuming. The construction site would have a stabilized construction entrance to prevent off-site tracking of sediment and debris;

Non-Stormwater Management BMPs, which are also referred to as “good housekeeping practices” involve keeping a clean, orderly construction site; and

Waste Management and Materials Pollution Control BMPs consist of implementing procedural and structural BMPs for handling, storing, and disposing of wastes generated by a construction project to prevent the release of waste materials into stormwater runoff or discharges through the proper management of construction waste.

Regulatory Compliance Measure G-3: In accordance with NPDES and City requirements, prior to issuance of a building permit, the Applicant shall prepare and submit for review and approval a Standard Urban Stormwater Mitigation Plan that would include Best Management Practices and demonstrate compliance with Low Impact Development Ordinance requirements to the City of Los Angeles Department of Public Works or Department of Building and Safety, as applicable. Specific BMPs to be implemented as part of the SUSMP for the Project to manage post-construction stormwater runoff would include, but not be limited to, the following:

Installation of catch basins, planter drains, and building roof drain downspouts throughout the Project Site to collect roof and site runoff and direct stormwater away from structures and to proposed infiltration systems.35

Installation of filter inserts to catch basins to improve the quality of stormwater runoff from the Project Site.

Installation of an infiltration system. The infiltration system proposed for the Project would consist of storage pipes and/or

35 Infiltration refers to the physical process of percolation, or downward seepage, of water through a soil’s

pore space. As water infiltrates, the natural filtration, adsorption, and biological decomposition properties of soils, plant roots, and micro-organisms work to remove pollutants prior to the water recharging the underlying groundwater. Infiltration BMPs include infiltration basins, infiltration trenches, infiltration galleries, bioretention without an underdrain, dry wells, and permeable pavement. Infiltration can provide multiple benefits, including pollutant removal, peak flow control, groundwater recharge, and flood control.



Page IV.G-39


tanks equipped with deep auger shafts that penetrate into the underlying soils.

Additionally, the implementation of the following LID BMPs would be included as part of the SUSMP:

Promote evapotranspiration and infiltration, and the use of native and/or drought tolerant plants;

Provide storm drain system stenciling and signage to discourage illegal dumping;

Design material storage areas and loading docks within structures or enclosures to prevent leaks or spills of pollutants from entering the storm drain system;

Provide evidence of ongoing BMP maintenance as part of a legal agreement with the City of Los Angeles. Recorded covenant and agreements for BMP maintenance are part of standard building permit approval processing; and

Design post-construction structural or treatment control BMPs to infiltrate stormwater runoff. Stormwater treatment facilities and systems would be designed to meet the requirements of the SUSMP and LID Manual.36

Also refer to Section IV.F, Hazards and Hazardous Materials, of this Draft EIR for regulatory compliance measures related to the appropriate handling, storage, and disposal of hazardous materials, which would serve to minimize potential impacts to surface water quality.

d. Analysis of Project Impacts

(1) Construction

(a) Surface Water Hydrology and Water Quality

Construction activities for the Project would include the demolition of the existing North Wing and construction of an entirely new North Wing. During the North Wing construction, Archer proposes to establish a Temporary Classroom Village on the existing outdoor athletic fields. The Project also proposes demolition of the residence on the Chaparal Parcel and the vacant residence on the Barrington Parcel. In addition, the

36 The “LID Manual” refers to the Development Best Management Practices Handbook, Part B Planning

Activities, 4th Edition, which was adopted by the City of Los Angeles, Board of Public Works on July 1, 2011, to reflect Low Impact Development requirements that took effect May 12, 2012.



Page IV.G-40


Project proposes the development of new athletic, performing arts, and visual arts facilities. The existing outdoor athletic fields would be improved to allow for regulation-size soccer and softball fields and would be developed with artificial turf. In addition, parking is proposed to be provided in a new underground parking structure. The Project would also include associated landscaped plazas, courtyards, and pedestrian paths. It is anticipated that the Project would result in the excavation of approximately 98,853 cubic yards of soil, of which approximately 258 cubic yards would be used for fill on-site and the remaining 98,595 cubic yards would be exported off-site.

Construction activities would have the potential to temporarily alter existing drainage patterns and flows within the Project Site by exposing the underlying soils and making the Project Site temporarily more permeable. Exposed and stockpiled soils could be subject to erosion and conveyance into nearby storm drains during storm events. In addition, construction activities such as earth moving, maintenance/operation of construction equipment, and handling/storage/disposal of materials could contribute to pollutant loading in stormwater runoff. On-site watering activities to reduce airborne dust could also contribute to pollutant loading in runoff. The main pollutant of concern during construction would be sediment or soil particles that would become detached by water and wind. However, as the construction site would be greater than one acre, Project construction activities would be regulated per the NPDES Construction General Permit.

As discussed in the Regulatory Framework Section above, the Construction General Permit is a risk-based permit that establishes three levels of risk (Risk Level 1 being the lowest and Risk Level 3 the highest) for construction sites based on calculated project sediment risk and receiving water risk. The Construction General Permit risk level determination quantifies sediment and receiving water characteristics and uses these results to determine a project’s overall risk level.

The sediment risk is specifically calculated by using the Revised Universal Soil Loss Equation to obtain soil/sediment erosion expressed in tons/acre. This equation includes factors such as rainfall-runoff erosivity, soil erodibility, slope length, and slope steepness. Based on the calculated amount of erosion, a sediment risk level is assigned. A construction site is considered to have a low sediment risk if the total sediment loss is less than 15 tons/acre; medium sediment risk if the total sediment loss is greater than or equal to 15 tons/acre but less than 75 tons/acre; and a high sediment risk if the total sediment loss is greater than or equal to 75 tons/acre. Receiving water risk is either high or low and is based on whether a project would discharge directly to a sediment-sensitive waterbody. A sediment-sensitive waterbody is considered a waterbody that is either on the most recent 303(d) list for waterbodies impaired for sediment, has a TMDL implementation plan for sediment, or has the beneficial uses of COLD, SPWN, and MIGR. A project that would



Page IV.G-41


discharge directly to a waterbody that meets at least one of these three criteria would be considered to have a high receiving water risk.

In order to determine the sediment risk level associated with the Project, a preliminary erosion calculation was performed. Based on this evaluation, the total predicted sediment loss from the Project Site was determined to be 854.50 tons/acre. Based on the sediment risk criteria described above, the Project would be considered to have a high sediment risk. However, drainage from the Project Site would continue to discharge to the municipal storm drainage system via an underground storm drain pipe at Sunset Boulevard and Bundy Drive which connects an underground pipe network owned by both the City of Los Angeles and Los Angeles County. Therefore, as drainage from the Project Site would not discharge directly to any waterbody, the Project would be considered to have a low receiving water risk. Based on a high sediment risk and a low receiving water risk, the Project would have an overall Risk Level 2 risk to water quality. As described further in the Water Resources Technical Report included in Appendix L of this Draft EIR, the requirements associated with a Risk Level 2 project include, but are not limited to, effluent sampling, non-stormwater inspection, pre- and post-rain inspection, and sampling of contained rain water.

In accordance with the requirements of the Construction General Permit, the Project would implement a SWPPP that would specify BMPs and erosion control measures to be used during construction to manage runoff flows and prevent pollution. BMPs such as the ones listed above would target pollutants of concern and be designed to reduce runoff and pollutant levels in runoff during construction to the maximum extent feasible. In addition, Archer would be required to comply with all applicable City grading permit regulations that require necessary measures, plans (including a wet weather erosion control plan if construction occurs during the rainy season), and inspections to reduce sedimentation and erosion. Furthermore, the existing drainage flow paths and discharge points would be maintained and would prevent cross-lot drainage to neighboring properties during construction. Implementation of BMPs such as sandbag barriers, earthen drainage dikes, swales, and sediment traps during construction would further ensure that the existing drainage pattern is maintained. Additionally, stormwater from the roof areas of the Temporary Classroom Village would be collected and dispersed onto the existing athletic fields. Therefore, as the existing pervious athletic fields would be maintained around the Temporary Classroom Village biofiltration of stormwater from the roof areas would naturally occur. In addition, stormwater around the Temporary Classroom Village would be managed as part of the SWPPP to be implemented in accordance with the requirements of the Construction General Permit.

Through compliance with all NPDES Construction General Permit requirements, including the preparation and implementation of a SWPPP, implementation of BMPs, and



Page IV.G-42


compliance with applicable City grading regulations, construction of the Project would not substantially alter the existing drainage pattern of the Project Site and surrounding area, would not substantially reduce or increase the amount of surface water in a water body, and would not substantially increase the rate or amount of surface runoff in a manner that would result in flooding or in a permanent, adverse change to the movement of surface water. The Project also would not result in discharges that would cause: (1) pollution that would alter the quality of the waters of the State to a degree which unreasonably affects beneficial uses of the waters; (2) contamination of the quality of the waters of the State by waste to a degree which creates a hazard to the public health through poisoning or through the spread of diseases; or (3) nuisance that would be injurious to health, affect an entire community or neighborhood or any considerable number of persons, and occurs during or as a result of the treatment or disposal of wastes. Furthermore, construction of the Project would not result in discharges that would cause regulatory standards to be violated in the Santa Monica Bay.

Based on the above, impacts to surface water hydrology and water quality during construction would be less than significant.

(b) Groundwater Hydrology

As described above, no water supply wells are located at the Project Site or within 1 mile of the Project Site that could be impacted by construction, nor would the Project include the construction of water supply wells. Development of the Project would include excavations with average depths ranging from 4 feet to approximately 38 feet below ground surface (plus an additional 5 feet of local excavation for footings). As described in the Geotechnical Engineering Investigation prepared for the Project Site included as Appendix J of this Draft EIR, the historic high groundwater level in the vicinity of the Project Site was on the order of 40 feet below grade. However, as provided in the Geotechnical Engineering Investigation, borings drilled to depths of 50 to 60 feet below ground surface throughout the Project Site, including in the area of the proposed underground parking structure and the Multipurpose Facility, did not report groundwater above those depths. Accordingly, it is not expected that groundwater would be encountered during construction that would require temporary or permanent dewatering operations. Therefore, as Project development would not adversely impact the rate or direction of flow of groundwater and no water supply wells would be affected, the Project would not result in a significant impact on groundwater hydrology during construction.

(c) Groundwater Quality

As discussed above, the Project would include excavations at a maximum depth of 38 feet below ground surface (plus an additional 5 feet of local excavation for footings). The Project would also result in a net export of existing soil material. Although not



Page IV.G-43


anticipated at the Project Site, any contaminated soils found would be captured within that volume of excavated material, removed from the Project Site, and remediated at an approved disposal facility in accordance with regulatory requirements.

During on-site grading and building construction, hazardous materials, such as fuels, paints, solvents, and concrete additives, could be used and would therefore require proper management and, in some cases, disposal. The management of any resultant hazardous wastes could increase the opportunity for hazardous materials releases into groundwater. Compliance with all applicable federal, state, and local requirements concerning the handling, storage and disposal of hazardous waste, would reduce the potential for the construction of the Project to release contaminants into groundwater that could affect existing contaminants, expand the area or increase the level of groundwater contamination, or cause a violation of regulatory water quality standards at an existing production well. In addition, as there are no groundwater production wells or public water supply wells within 1 mile of the Project Site, construction activities would not be anticipated to affect existing wells. Therefore, the Project would not result in any substantial increase in groundwater contamination through hazardous materials releases and impacts on groundwater quality would be less than significant.

(2) Operation

(a) Surface Water Hydrology

As previously discussed, the Project Site, including the Archer campus and the Barrington and Chaparal Parcels, is covered by approximately 59 percent impervious surfaces, including buildings and impervious pavements for pedestrian and vehicular circulation. The remaining 41 percent of the existing Project Site is pervious surfaces consisting of athletic fields, landscaped areas, and lawns. The Project would include development of new buildings, paved areas, and landscaped areas. In addition, development of the new athletic fields would replace the natural turf on the existing athletic fields with artificial turf. With implementation of the Project, the amount of impervious area would increase from approximately 59 percent to 70 percent. However, as described above, the type of soils found beneath the Project Site currently have a limited capacity to absorb stormwater during an intense rain event (i.e., a 25-year storm event). As such, once the soils become saturated, runoff from pervious areas of the Project Site behaves in a similar manner as paved or impervious surfaces. Thus, while existing landscaped areas and the natural turf of the existing athletic fields would be replaced by impervious surfaces, from a hydrological perspective, these areas would be considered to have the same properties as existing pervious surfaces during an intense rain event.

As discussed above, based on the drainage patterns and flow paths of stormwater that are tributary to a common point or area within the Project Site, the Project Site has



Page IV.G-44


been divided into four drainage areas. The boundaries of these four drainage areas with implementation of the Project are illustrated in Figure IV.G-5 on page IV.G-45. As shown, the boundaries of the drainage areas would remain as under existing conditions. Therefore, the flow patterns and discharge points under existing conditions would be maintained with the Project. In addition, expected peak runoff flows for each drainage area during a 50-year storm event with Project buildout are shown in Table IV.G-3 on page IV.G-46. As shown in Table IV.G-3, a comparison of the future peak runoff flows at the discharge points from the campus to the public right-of-way with the existing peak runoff flows shown in Table IV.G-1 on page IV.G-22 demonstrates that based on the limited capacity of the Project Site soils to absorb stormwater during an intense rain event, an increase in impervious surface within the Project Site would not result in an increase in the peak flow rate within the Project Site. In addition, as described above, as part of the SUSMP for the Project to manage post-construction stormwater runoff, the Project would include the installation of catch basins, planter drains, and building roof drain downspouts throughout the Project Site to collect roof and site runoff and direct stormwater away from structures through a series of underground storm drain pipes. This on-site stormwater conveyance system would serve to prevent flooding and nuisance water within the Project Site. Further, with implementation of the proposed infiltration system described below, the volume of water leaving the Project Site would be further reduced compared to existing conditions. Additionally, as stated above, the Project Site is not located within a FEMA or City of Los Angeles designated 100- or 500-year flood plain or within a potential inundation area as designated by the City of Los Angeles General Plan Safety Element.

Based on the above, the Project would not result in an incremental impact on either on-site or off-site flooding during a 50-year storm event, would not substantially reduce or increase the amount of surface water in a water body, or result in a permanent adverse change to the movement of surface water that would result in an incremental effect on the capacity of the existing storm drain system. As such, operation of the Project would result in a less-than-significant impact on surface water hydrology.

(b) Surface Water Quality

As is typical of most urban developments, stormwater runoff from the Project Site has the potential to introduce pollutants into the stormwater system. Anticipated and potential pollutants generated by the Project are presented in Table IV.G-4 on page IV.G-47.

As previously described, Archer would be required to implement SUSMP and LID requirements throughout the operational life of the Project. As part of these requirements, Archer would prepare a SUSMP which would outline the stormwater treatment measures or post-construction BMPs required to control pollutants of concern associated with storm

Figure IV.G-5Proposed Hydrology and Storm Drain System


jeremy.buck

Rectangle

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Typewritten Text

Page IV.G-45



Page IV.G-46


Table IV.G-3 Post-Project 50-Year Storm Event Flow Rate

Drainage Area Area

(acres)

Proposed Flow Rate

(cfs)

Existing

Flow Rate

(cfs)

Incremental Increase from Existing to

Proposed Condition (%)a

Area 1 3.47 13.43 13.43 <0.5

Area 2 2.73 10.57 10.57 0

Area 3 0.18 0.70 0.70 <0.5

Area 4 0.92 3.56 3.56 <0.5

cfs = cubic feet per second

a As previously described, the soil type underlying the Project Site has a limited capacity to absorb stormwater. Thus, the runoff during the peak intensity of a 50-year storm event would runoff existing Project Site soils in a similar manner as runoff from paved surfaces. Therefore, an increase in impervious surfaces within the Project Site would not result in an increase in the peak flow rate of the Project Site. In addition, BMPs would be implemented such that post-development peak stormwater discharges would not exceed the estimated pre-development flow rates.


events up to the 0.75-inch precipitation level. BMPs would include source control and treatment control BMPs such as those listed in Table IV.G-5 on page IV.G-48 to remove pollutants from stormwater discharges. In addition, consistent with LID requirements to reduce the quantity and improve the quality of rainfall runoff that leaves the Project Site, the Project would include the installation of an infiltration system, which is considered the first priority type of BMP as established by the LID Manual. As shown in Table IV.G-5, infiltration/retention has a high performance rating for targeting the anticipated and potential pollutants of concern within the Project Site. Stormwater runoff would be collected via a series of proposed catch basins, planter drains, and building roof drain downspouts and directed to the proposed infiltration systems via underground storm drain piping.

As described in the LID Manual, the implementation of infiltration BMPs may be infeasible at a project site due to the underlying site conditions. As such, the LID Manual establishes infiltration feasibility criteria including but not limited to a seasonal groundwater depth greater than 10 feet from the bottom of the infiltration system, an infiltration rate of 0.5 inch/hour or greater, and the placement of buildings or structures at least 25 feet from the infiltration BMP. To determine the feasibility of infiltration within the Project Site, a percolation test was performed to measure the infiltration rate of the soils underlying the Project Site. The percolation test involved the drilling of two percolation testing wells in the area of the front lawn adjacent to Sunset Boulevard and one percolation testing well in the front of the Barrington Parcel adjacent to Barrington Avenue. The percolation tests yielded



Page IV.G-47


Table IV.G-4 Anticipated and Potential Pollutants Generated by the Project

Project Pollutant Sources Pollutants of Concern

Lawns, Landscaping, and Parks Sediment (coarse and fine), Nutrients (dissolved and particulate), Pesticides, Pathogens, Trash and debris

Parking Lots and Driveways Sediment (fine), Metals (dissolved and particulate), TPH, Trash

Roads and Highways Sediment (coarse and fine), Metals (dissolved and particulate), TPH, PAH, Trash and debris

Food-Related Commercial Pathogens, Oil and grease

Source: KPFF Consulting Engineers, Water Resources Technical Report, 2013.

a 0.5-inch/hour infiltration rate within the Project Site. Based on the infiltration feasibility criteria set forth in the LID Manual, infiltration would be considered feasible within the Project Site.

As set forth in the LID Manual, infiltration facilities shall be sized to capture and infiltrate the design capture volume based on the runoff produced from a 0.75-inch storm event. Based on this requirement, the total storage volume needed within the Project Site was determined to be approximately 16,886 cubic feet. To achieve this storage volume, the Project proposes the installation of two infiltration systems. The primary infiltration system is proposed to be located under the front lawn adjacent to Sunset Boulevard. This system would have a total storage volume of approximately 14,430 cubic feet and serve runoff from drainage areas one and two. An additional infiltration system is proposed along the rear of the Performing Arts Center, adjacent to Barrington Avenue, which would serve runoff from drainage areas three and four. This system would have a total storage volume of approximately 2,456 cubic feet. These locations proposed for installation of the infiltration systems meet the infiltration feasibility criteria as described above.

The infiltration systems are proposed to consist of storage pipes and/or tanks equipped with deep auger infiltration wells that penetrate into the underlying impermeable soils. Pretreatment devices such as catch basin filter inserts and hydrodynamic separators also would be utilized upstream from the infiltration areas. These pretreatment devices would provide an additional level of treatment by removing many pollutants prior to infiltration and would serve to prolong the life of the infiltration system by removing trash and debris that may have the potential to limit infiltration capacity and efficiency. As described above, the Project Site currently does not have structural BMPs for the treatment of stormwater runoff from the existing impervious surfaces. Therefore, implementation of the infiltration system proposed as part of the Project would result in a substantial improvement in surface water quality runoff from the campus. In addition, the



Page IV.G-48


Table IV.G-5 Efficiency of Treatment Control BMPs by Target Pollutanta

Sediments Nutrients Trash Metals Bacteria Oil/Grease Organics

Vegetated Swale Medium Low Low Medium Low Medium Medium

Vegetated Buffer Strip High Low Medium High Low High Medium

Vortex/Hydrodynamic Systemb

Medium Low High Low Low Medium Low

Catch Basins Systemc High Low High Low Low Low Low

Infiltration/Retention High High High High High High High

Media Filtration High Low High High Medium High High

a Data was obtained from the 2003 California Stormwater Quality Association of Stormwater Best Management

Practice Handbook for New Development and Redevelopment, Table 2-1, and modified to include only those pollutant sources and potential pollutants that apply to the Project.

b FloGard® Dual-Vortex Hydrodynamic Separators are designed to effect greater than 80 percent removal of TSS reflective of typical urban runoff. Other similar alternative products would be considered in further detail during the design phase.

c The FloGard+PLUS® is a multipurpose catch basin insert designed to capture sediment, debris, trash and oils/grease from low (first flush) flow. Other similar alternative products would be considered in further detail during the design phase.

Source: KPFF Consulting Engineers, Water Resources Technical Report, 2013.

implementation of BMPs, which would utilize the natural adsorption and filtration characteristics of vegetated swales and pervious surfaces, would allow for more opportunities to direct stormwater to flow through the planting media where pollutants are filtered, absorbed, and biodegraded by the soil and plants, prior to infiltrating to the ground below.

Based on the above, with implementation of BMPs such as those described in Table IV.G-5 and listed above, operation of the Project would not result in discharges that would cause: (1) an incremental increase in pollution which would alter the quality of the waters of the State (i.e., Santa Monica Bay) to a degree which unreasonably affects beneficial uses of the waters; (2) an incremental increase of contamination of the quality of the waters of the State by waste to a degree which creates a hazard to the public health through poisoning or through the spread of diseases; or (3) an incremental increase in the nuisance that would be injurious to health; affect an entire community or neighborhood, or any considerable number of persons; and occurs during or as a result of the treatment or disposal of wastes. Furthermore, operation of the Project would not result in discharges that would cause regulatory standards to be violated in Santa Monica Bay. Thus, operational impacts on surface water quality would be less than significant.



Page IV.G-49


(c) Groundwater Hydrology

The percolation of precipitation that falls on pervious surfaces is variable, dependent upon the soil type, condition of the soil, vegetative cover, and other factors. Implementation of the Project would include both the addition and removal of impervious surfaces throughout the Project Site boundary. Currently, the Project Site is approximately 59 percent impervious surfaces and 41 percent pervious surfaces. As described above, implementation of the Project would increase impervious surfaces to approximately 70 percent. However, the Project would include the installation of infiltration systems, which would infiltrate the first flush or first 0.75-inch of rainfall for any storm event and offset the potential reduction in percolation resulting from Project development. In addition, as infiltration systems are designed to only infiltrate small storm events or the first 0.75-inch of rainfall for any storm event, large storm events would bypass the infiltration systems and would not result in infiltration of a large amount of rainfall which would affect groundwater hydrology, including the direction of groundwater flow.

As discussed above, Project development would require excavations with a depth ranging from 4 feet to approximately 38 feet below grade (plus 5 feet of local excavations for footings). As described in the Geotechnical Engineering Investigation prepared for the Project Site included as Appendix J of this Draft EIR, the historic high groundwater level in the vicinity of the Project Site was on the order of 40 feet below grade. However, based on the absence of groundwater identified as part of the on-site borings drilled to depths of 50 to 60 feet below grade throughout the Project Site, it is not expected that groundwater would be encountered during construction that would require permanent dewatering operations. Furthermore, there are no existing wells or spreading grounds within 1 mile of the Project Site and the Project would not include new injection or supply wells.

Based on the above, operation of the Project would result in a less-than-significant impact on groundwater hydrology, including groundwater levels.

(d) Groundwater Quality

Operational activities which could affect groundwater quality include spills of hazardous materials and leaking underground storage tanks. Surface spills from the handling of hazardous materials most often involve small quantities and are cleaned up in a timely manner, thereby resulting in little threat to groundwater. Other types of risks such as leaking underground storage tanks have a greater potential to affect groundwater. As described in Section IV.F, Hazards and Hazardous Materials, of this Draft EIR, no underground storage tanks are currently operated or will be operated by Archer. In addition, while the development of new school facilities would increase the use of existing on-site hazardous materials, compliance with all applicable existing regulations at the Project Site would prevent the Project from affecting or expanding any potential areas of



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contamination, increasing the level of contamination, or causing regulatory water quality standards at an existing production well to be violated, as defined in the California Code of Regulations, Title 22, Division 4, Chapter 15 and the Safe Drinking Water Act. Furthermore, as described above, operation of the Project would not require extraction from the groundwater supply based on the depth of excavation for the proposed uses and the depth of groundwater below the Project Site. Additionally, the Project would include the installation of infiltration systems as a means of treatment and disposal of the first flush or first 0.75 inch of rainfall for any storm event, which would allow for treatment of the on-site stormwater prior to infiltrating to the groundwater below.

Based on the above, operation of the Project would result in a less-than-significant impact on groundwater quality.

4. Cumulative Impacts


The geographic context for the cumulative impact analysis on surface water hydrology is the Santa Monica Bay Watershed. The Project in conjunction with the cumulative growth in the Santa Monica Bay Watershed (inclusive of the related projects) through 2020 would cumulatively increase stormwater runoff flows potentially resulting in cumulative impacts to surface water hydrology. However, as described above, in accordance with City requirements, related projects and other future development projects would be required to implement BMPs such that post-development peak stormwater runoff discharge rates would not exceed the estimated pre-development rates. Furthermore, the City of Los Angeles Department of Public Works would review each future development project on a case-by-case basis to ensure sufficient local and regional drainage capacity is available to accommodate stormwater runoff. Similarly, other cities located within the boundaries of the Santa Monica Bay Watershed would require projects to implement BMPs to reduce runoff flows and ensure drainage capacity is available to accommodate stormwater runoff from respective sites. Therefore, cumulative impacts on surface water hydrology would be less than significant.


The geographic context for the cumulative impact analysis on surface water quality is the Santa Monica Bay Watershed. As with the Project, cumulative growth in the Santa Monica Bay Watershed (inclusive of the related projects) through 2020 would be subject to NPDES requirements regarding water quality for both construction and operation. In addition, it is anticipated that the related projects and other future development projects would also be subject to SWPPP, SUSMP, and LID requirements and implementation of



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measures to comply with total maximum daily loads. Furthermore, increases in regional controls associated with other elements of the Municipal Separate Storm Sewer System Permit would improve regional water quality over time. Additionally, with implementation of the Project, new BMPs for the treatment of stormwater runoff would be installed, thus improving the surface water quality runoff from the campus compared to existing conditions. Therefore, with compliance with all applicable laws, rules and regulations, cumulative impacts to surface water quality would be less than significant.

(3) Groundwater Hydrology

Cumulative groundwater hydrology impacts could result from the overall use of groundwater basins located in proximity to the Project Site and the related projects. In addition, interruptions to existing injection or supply wells or designated spreading grounds would have the potential to affect groundwater levels. Any calculation of the extent to which the related projects would extract or otherwise directly use groundwater would be speculative. Nonetheless, the cumulative use of groundwater in the region, either as a result of water extraction under the related project sites or extraction from local basins by the local water supply agency to accommodate the related projects, could adversely affect local and regional groundwater hydrology, including groundwater levels. However, as described above, no water supply wells, spreading grounds, or injection wells are located within a 1-mile radius of the Project Site. In addition, Project development would not involve the temporary or permanent extraction of groundwater from the Project Site or otherwise use the groundwater.

Furthermore, while implementation of the Project would result in an increase in impervious surface area, the Project would include the installation of infiltration systems, which would infiltrate the first flush or first 0.75 inch of rainfall for any storm event and offset the potential reduction in percolation resulting from Project development. However, development of the related projects could result in changes in impervious surface area within their respective project sites which would decrease the potential for groundwater recharge. Any calculation of the extent to which the related projects would increase or decrease impervious or pervious surfaces that might affect groundwater hydrology would be speculative. In addition, as the related projects are located in a highly urbanized area, any reduction in groundwater recharge due to the overall net change in impervious area within the related project sites would be minimal in the context of the regional groundwater basin. Additionally, as infiltration systems are designed to infiltrate only small storm events or the first 0.75 inch of rainfall for any storm event, the infiltration of stormwater as a means of stormwater treatment and management within the Project Site and related project sites would not result in a cumulative effect to groundwater hydrology.



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Based on the above, cumulative impacts to groundwater hydrology would be less than significant.

(4) Groundwater Quality

As described above, compliance with all applicable existing regulations at the Project Site would prevent the Project from affecting or expanding any potential areas affected by contamination, increasing the level of contamination, or causing regulatory water quality standards at an existing production well to be violated, as defined in the California Code of Regulations, Title 22, Division 4, Chapter 15 and the Safe Drinking Water Act. As with the Project, the related projects would be unlikely to cause or increase groundwater contamination because compliance with existing statutes and regulations would similarly prevent the related projects from affecting or expanding any potential areas affected by contamination, or increasing the level of contamination, or causing regulatory water quality standards at an existing production well to be violated. Therefore, cumulative impacts to groundwater quality would be less than significant.

5. Mitigation Measures

Impacts to surface water and groundwater hydrology and quality during construction and operation of the Project would be less than significant. No mitigation measures would be necessary.

6. Level of Significance After Mitigation

Surface water and groundwater hydrology and quality impacts would be less than significant.

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