IV. Environmental Impact Analysis I. Hydrology

Transcription

1 IV. Environmental Impact Analysis I. Hydrology 1. Introduction This section of the Draft EIR describes the existing surface water and groundwater hydrology and quality within the Project area and analyzes the Project s potential impacts with regard to these resources. The analysis is based on the Technical Memorandum: Hydrology and Water Quality (referred to in Section IV.I as the Technical Memorandum ) prepared for the Project by Geosyntec Consultants (May 16, 2014) included as Appendix G of this Draft EIR. For analysis of water supply issues, see Section IV.L.1, Utilities and Service Systems Water Supply. 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 abovementioned 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 Page IV.I-1

2 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 NPDES 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. 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 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 RWQCBs develop basin plans for their hydrologic areas, issue waste discharge requirements, enforce action against stormwater discharge violators, and monitor water quality. 2 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. 1 2 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. State Water Resources Control Board, Regulatory Framework: Water and Environmental Legislation, accessed January 19, Page IV.I-2

3 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 waterquality 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. The USEPA approved the most recent Section 303(d) list in November 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. (b) Federal Antidegradation Policy The Federal Antidegradation Policy (40 Code of Federal Regulations ) requires states to develop statewide antidegradation policies and identify methods for implementing them. Pursuant to the Code of Federal Regulations (CFR), state antidegradation policies and implementation methods shall, at a minimum, protect and maintain: (1) existing in-stream water uses; (2) existing water quality, where the quality of the waters exceeds levels necessary to support existing beneficial uses, unless the state finds that allowing lower water quality is necessary to accommodate economic and social development in the area; and (3) water quality in waters considered an outstanding national resource. (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 3 State Water Resources Control Board, 2010 Integrated Report, programs/tmdl/integrated2010.shtml, accessed January 20, Page IV.I-3

4 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 is governed by the Los Angeles RWQCB (LARWQCB). The SWRCB s principal responsibility is the development and 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 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 ) in 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. Page IV.I-4

5 (d) Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties IV.I Hydrology 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 Antidegradation Policy, and describes implementation programs to protect all waters in the Los Angeles Region. 4,5 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) 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 5 Designated beneficial uses of water include, but are not limited to: domestic, municipal, agricultural and industrial supply; power generation; recreation; aesthetic enjoyment; navigation; and preservation and enhancement of fish, wildlife, and other aquatic resources or preserves. Such uses may be past, present and probable future beneficial uses of water. LARWQCB, LARWQCB Basin Plan, plan/, accessed January 17, Page IV.I-5

6 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 DWQ]). Order No DWQ was amended by Order No DWQ and adopted on November 16, ,7 Order No DWQ became effective on February 14, 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: Reduce erosion; Minimize or eliminate sediment in stormwater discharges; Prevent materials used at a construction site from contacting stormwater; Implement a sampling and analysis program; Eliminate unauthorized non-stormwater discharges from construction sites; Implement appropriate measures to reduce potential impacts on waterways both during and after the construction of projects; and SWRCB, Construction General Permit Fact Sheet, stormwater/docs/constpermits/wqo_2009_0009_factsheet.pdf, accessed January 17, SWRCB, Order No DWQ, NPDES No. CAS000002, adopted_orders/water_quality/2010/wqo2010_0014dwq.pdf, accessed January 21, Ibid. Page IV.I-6

7 Establish maintenance commitments on post-construction pollution control measures. On December 13, 2001, the LARWQCB adopted Order No 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 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 Pasadena) 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 the 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 the requirements of the RWQCB while complying with regional watershed requirements and/or waste load allocations for implementation of TMDLs for impaired water bodies. Page IV.I-7

8 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: 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: 9 Single family hillside development. Hillside means property located in an area where the development contemplates grading on any natural slope that is twenty-five percent or steeper. Industrial/Commercial development that creates an area of one acre or more of impermeable area. 9 County of Los Angeles Department of Public Works, Standard Urban Stormwater Mitigation Plan (SUSMP) Review Sheet, Rev. January, 9, 2008, Grading/Plan%20Check%20Documents/SUSMP%20Review%20Sheet% pdf, accessed January 21, Page IV.I-8

9 Retail gasoline outlet, gas station, or fuel dispensing. Automotive repair shop, automotive and/or equipment maintenance areas. Restaurant, outdoor food handling or processing. Parking lot creating 5,000 square feet or more of surface area, or with 25 or more parking spaces and potentially exposed to stormwater runoff. Projects located within, directly adjacent to, or directly tributary to an environmentally sensitive area. Automotive or equipment washing or cleaning area(s). Outdoor hazardous material, waste handling or storage. Commercial or industrial waste. Outdoor manufacturing areas such as equipment or product fabrication including welding, cutting, sawing, metal fabrication, assembly, application of paints, coatings, or finishes, pre-cast concrete fabrication, equipment or machinery repair and/or maintenance, etc. Outdoor horticulture activities. Animal slaughtering, animal confinement, pet care facilities, stables, kennels, etc. Ten or more unit homes. 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. (f) 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. Page IV.I-9

10 (3) Local (a) Pasadena General Plan Open Space and Conservation Element The City s General Plan Open Space and Conservation Element, which was adopted on January 23, 2012, serves as a framework of goals and policies to assure efficient stewardship of the City's green spaces, recreation facilities, and natural resources. The Open Space and Conservation Element includes an inventory of existing open space areas, a summary of existing open space and conservation plans, and agencies that the City partners with to protect and enhance natural open space. The Open Space and Conservation Element also reviews the existing documents related to conservation, including the plans of the City s Green City Program, the Water and Power Integrated Resource Plans (IRPs), and the California Green Building Code. The Open Space and Conservation Element establishes goals and objectives in the areas of Open Space, Wildlife & Native Plants, and Environmental Quality, Conservation & Sustainable Use Practices. The Open Space and Conservation Element also includes a series of implementation measures to achieve these goals and objectives. Some of the implementation measures, particularly in the area of conservation, are restated from existing plans, such as the Water and Power IRPs which serve as implementation documents in these areas. (b) Pasadena General Plan Safety Element The City s General Plan Safety Element, which was adopted in 2002, addresses public safety risks due to natural disasters including seismic events and geologic conditions such as: earthquakes, landslides, mudflows, dam or reservoir failure, wildland and structural fire, and contamination of soil and groundwater resources. The Safety Element works with the current City development review practices under the Federal and State laws discussed above. (c) Pasadena Municipal Code The Pasadena Municipal Code (PMC) adopted the NPDES Permit requirements, which are discussed below. Specifically, Section (D) of the PMC states, Where best management practices guidelines or requirements have been adopted or required by any federal, State of California, regional, county, or city agency for any activity, operation, or facility which may cause or contribute to stormwater pollution or contamination, illicit discharges, or discharges of non-stormwater to the stormwater system, every person undertaking such activity or operation, or owning or operating such facility shall comply with such guidelines or requirements as may be identified by the enforcement official of any such agency. Page IV.I-10

11 (d) Los Angeles County Municipal Stormwater NPDES Program In 2012, the LARWQCB issued an NPDES Permit and Waste Discharge Requirements (Permit No. CAS004001, Order No. R ) under the CWA and the Porter-Cologne Act for discharges of urban runoff in public storm drains in Los Angeles County. The Permittees are the Los Angeles County cities and the County (collectively the Co-Permittees ). The 2012 NPDES Permit includes design requirements for new development and substantial redevelopment in Part VI.D.7.c (New Development/ Redevelopment Project Performance Criteria). These criteria apply to all projects which create or replace more than 5,000 square feet of impervious cover which have not been deemed complete prior to February 8, Where redevelopment results in an alteration to more than fifty percent of impervious surfaces of a previously existing development and the existing development was not subject to post-construction storm water quality control requirements, the entire project must be mitigated. Projects that trigger the Project Performance Criteria are required to retain onsite (by either infiltrating or storing for reuse) the volume of runoff that is generated from the 0.75-inch storm or the 85th percentile, 24-hour storm, whichever is greater. At the Pasadena City Hall rain gage station, the 85th percentile 24-hour storm is reported at 1.00 inch; thus, it is likely that the Project would be required to retain more than the 0.75-inch storm. Alternative compliance measures can be implemented if the Project can demonstrate that retaining the design storm is technically infeasible. Projects that use alternative compliance measures must still implement flow-through BMPs to treat (but not retain) onsite stormwater. Flow-through BMPs must be sized to treat 0.2 inch per hour or the one-year, one-hour rainfall intensity, whichever is greater. 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. 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 large 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 Page IV.I-11

12 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. Interpretations of the SUSMP requirements by the LARWQCB have emphasized that redevelopment projects evaluate and implement stormwater quality control features or BMPs starting with the 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: Page IV.I-12

13 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. b. Existing Conditions (1) Surface Water Hydrology The Project Site has a slight slope of 6 to 8 feet from Walnut Street on the north to Union Street on the south. The Project Site has no inlets or underground stormwater drainage system. Therefore, current runoff flows overland until it reaches offsite storm drain inlets on Holly Street and Union Street. Lateral storm drain lines convey stormwater to the main line that drains southward beneath a rail line to the west of Arroyo Parkway. This main storm drain daylights just south of the Blair High School playing fields into the concrete lined Alhambra Wash. As shown in Figure IV.I-1, Alhambra Wash and Raymond Groundwater Basin, on page IV.I-14, the Project Site is located within the tributary area of the Alhambra Wash, the westernmost tributary to the Rio Hondo. The Alhambra Wash flows through private residences, golf courses and commercial property for approximately 8 miles until it outlets into the Rio Hondo, which shortly thereafter becomes channelized and remains so until joining the Los Angeles River in the City of Downey. Page IV.I-13

14 Project Site Alhambra Wash Los Angeles River Rio Hondo Raymond Basin N Miles Figure IV.I-1 Alhambra Wash and Raymond Groundwater Basin Source: Google Earth, 2013; ESRI, 2013.

15 The Project Site is currently covered by impervious surfaces except for the planting areas located within the existing surface parking lots, a small landscaped plaza located northwest of the intersection of Holly Street and Leonard J. Pieroni Street, and portions of the perimeter of the Project Site. (2) Surface Water Quality (a) Beneficial Uses Beneficial uses are related to the various ways water can be used. The RWQCB designates beneficial uses for surface water and groundwater, which are discussed below. Together with water quality objectives for specific beneficial uses, the beneficial uses form the basis of developing water quality standards. The beneficial uses (potential, existing, and intermittent) for the Alhambra Wash, within the Los Angeles Basin, include: Ground Water Recharge (GWR): Uses of water for natural or artificial recharge of groundwater for purposes of future extraction, maintenance of water quality, or halting saltwater intrusion into freshwater aquifers. Maintaining current local freshwater aquifers, and eventually reversing the trend of local freshwater aquifers. Preservation of rare and endangered species (RARE): Uses of waters that support habitats necessary for the survival and successful maintenance of plant or animal species established under state and/or federal law as rare, threatened, or endangered. Municipal and Domestic Supply (MUN): Uses of water for community, military, or individual water supply systems, including, but not limited to, drinking water supply. Water Contact Recreation (REC1): Uses of water for recreational activities involving body contact with water, where ingestion of water 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. Warm Freshwater Habitat (WARM): Uses of water that support warm water ecosystems including, but not limited to, preservation or enhancement of aquatic habitats, vegetation, fish, or wildlife, including invertebrates. Wildlife Habitat (WILD): Uses of water that support warm water ecosystems including, but not limited to, preservation or enhancement of aquatic habitats, vegetation, fish, or wildlife, including invertebrates. Page IV.I-15

16 Preservation of Rare and Endangered Species (WILD): Uses of waters that support habitats necessary for the survival and successful maintenance of plant or animal species established under state and/or federal law as rare, threatened, or endangered. Fish Spawning (SPWN): Uses of water that support high quality aquatic habitats suitable for reproduction and early development of fish. (b) Pollutants As the Project Site is located in an urbanized area, stormwater runoff from the Project Site and surrounding area is anticipated to contain a number of pollutants including: Sediments (Total Suspended Soils [TSS]): Excessive erosion, transport, and deposition of sediment in surface waters are a substantial form of pollution resulting in major water quality problems. Excessive sediment can impair aquatic life, cause taste and odor problems in drinking water supplies, and block water intake structures. Sources of sediment from commercial properties include: wind-blown dust and particles, and sediment from vehicles. Nutrients (Phosphorus and Nitrogen): Nutrients of concern include the inorganic forms of nitrogen (nitrate, nitrite, and ammonia) and phosphorus. The several sources of nutrients in urban areas, and the likely sources associated with an office building complex are: fertilizers in runoff from landscaped areas, pet wastes, atmospheric deposition from automobile emissions, and soil erosion. Trace Metals (Aluminum, Copper, Lead, and Zinc): The primary sources of trace metals in stormwater are typically commercially available metals used in transportation (automobiles), buildings, and infrastructure but are also found in fuels, adhesives, paints, and other coatings. Pathogens (Bacteria, Viruses, and Protozoa): Runoff that flows over land, such as urban runoff, can mobilize pathogens, including bacteria and viruses. Sources of pathogens in urban areas include pets and other wildlife, leaky sanitary sewer pipes, or human fecal wastes. Petroleum Hydrocarbons (Oil, Grease, and polycyclic aromatic hydrocarbons): The sources of oil, grease, and other petroleum hydrocarbons include spillage fuels and lubricants, discharge of domestic and industrial wastes, atmospheric deposition, and runoff. Runoff can be contaminated by leachate from asphalt roads, wearing of tires, and deposition from automobile exhaust. Pesticides (herbicides, insecticides, and fungicides): Pesticides are chemical compounds commonly used to control insects, rodents, plant diseases, and weeds. Excessive application of a pesticide in connection with landscaping may Page IV.I-16

17 result in runoff containing toxic levels of its active component. Pesticides may be classified as organochlorine pesticides or organophosphorus pesticides, the former of which have been banned and the later are being restricted by the USEPA. Trash and Debris: Trash (such as paper, plastic, polystyrene packing foam, and aluminum materials) and biodegradable organic debris (such as leaves, grass cuttings, and food waste) are general waste products on the landscape that can be entrained in urban runoff. Two segments of the Rio Hondo can be found on California s 303(d) list, which is discussed above. Reach 1 of the Rio Hondo (Los Angeles River to the Santa Ana Freeway) is listed as being impaired with regard to coliform bacteria, copper, lead, ph, toxicity, trash, and zinc. Reach 2 of the Rio Hondo (at the spreading ground) is included on California s 303(d) list due to impairment by coliform bacteria and cyanide. Both Reach 1 and Reach 2 are located approximately 15 miles downstream of the Project Site. (3) Groundwater Hydrology The Project Site is located within the Raymond Groundwater Basin, a sub-basin within the San Gabriel Valley Groundwater Basin. The Raymond Groundwater Basin has an existing beneficial use of municipal and domestic water supply, as discussed below. The Raymond Groundwater Basin comprises approximately 41 square miles in surface area and includes the water-bearing sediments bounded by the contact with consolidated basement rocks of the San Gabriel Mountains on the north and the San Rafael Hills on the southwest. 10 The west boundary is delineated by a drainage divide at Pickens Canyon Wash and the southeast boundary is the Raymond fault. Groundwater use for domestic water supply is a major beneficial use of groundwater basins in Los Angeles County. The Raymond Groundwater Basin underlies the service areas of four Metropolitan Water District (MWD) member agencies, including the City of Pasadena. Approximately 61 percent of Pasadena Water and Power (PWP) water is imported from MWD and approximately 36 percent of the PWP supply is groundwater from the Raymond Groundwater Basin, which is pumped out of 16 deep wells located throughout the. The remaining 3 percent is purchased from neighboring water agencies that combine surface water and groundwater. Average annual depth to groundwater at the Project Site is estimated at approximately 220 feet below ground 10 California Department of Water Resources, California s Groundwater Bulletin 118, pubs/groundwater/bulletin_118/basindescriptions/4-23.pdf, accessed January 20, Page IV.I-17

18 surface, with a minimum of depth of 83 feet over the 83-year period of record. 11 groundwater conditions are not known to occur at the Project Site. Perched Natural groundwater recharge to the Raymond Groundwater Basin occurs through infiltration and percolation of rainfall and surface runoff from the San Gabriel Mountains. The nearest active groundwater recharge area to the Project Site is the Arroyo Seco, which is located approximately 3 miles northwest of the Project Site. (4) Groundwater Quality According to the City s General Plan Open Space and Conservation Element, groundwater contamination is an issue that will require PWP to invest in well treatment over the next few years and potentially beyond. However, groundwater quality in the Raymond Groundwater Basin is generally good to fair in most areas. Groundwater concentrations of total dissolved solids (TDS) typically range from 350 to 700 milligram per liter (mg/l) in the central and southern portions of the Pasadena subarea. Data for 70 public supply wells within the Raymond Groundwater Basin indicate there is an average TDS content of 346 mg/l with a range from 138 to 780 mg/l. Fluoride content occasionally exceeds recommended levels of 1.6 mg/l near the San Gabriel Mountain front. Specifically, the maximum recorded level is 3.1 mg/l and the average recorded level is 1.0 mg/l. High nitrate concentrations are found in water from some wells near the. Volatile organic compounds are detected in wells near the Arroyo Seco. Beneficial uses for groundwater in the Pasadena area of the Raymond Watershed include: Agricultural Supply (AGR): Uses of water for farming, horticulture, or ranching including, but not limited to, irrigation, stock watering, or support of vegetation for range grazing. Municipal and Domestic Supply (MUN): Uses of water for community, military, or individual water. Industrial Service Supply (IND): Uses of water for industrial activities that do not depend primarily on water quality, including, but not limited to, mining, cooling water supply, hydraulic conveyance, gravel washing, fire protection, and oil well repressurization. 11 Annual average water levels for Well No H (approximately 1 mile northeast of the Project Site) were averaged to estimate the approximate depth to groundwater for the Project Site. The ground surface elevation of the Project Site was used as the reference elevation. Page IV.I-18

19 Industrial Process Supply (PROC): Uses of water for industrial activities that depend primarily on water quality. (5) Flood Zone The Federal Emergency Management Agency (FEMA) defines the base flood or 100-year flood as a flood that has a 1 percent or greater chance of being equaled or exceeded during any given year. A base flood has a 26-percent chance of occurring during a 30-year period, generally the length of most home mortgages. However, the recurrence interval represents the long-term average period between floods of a specific magnitude; rare floods could occur at short intervals or even within the same year. Based on the FEMA Flood Insurance Rate Map (FIRM) for the, the Project Site is not located within a 100-year floodplain. Specifically, the Project Site is located within Zone X, which is located outside of the Special Flood Hazard Areas Subject to Inundation by the 1 percent Annual Chance of Flood (100-year floodplain) and is defined as an area outside the 0.2 percent annual chance floodplain (i.e., 500-year floodplain). In addition, according to the City s Dam Failure Inundation Map (Plate P-2 of the adopted 2002 Safety Element of the City s General Plan), the Project Site is not located in a dam inundation area. Furthermore, the Project Site is not located within a Dam Inundation Zone or Landslide Hazard Zone as mapped in the s Local Hazard Mitigation Plan, which was approved by the California Emergency Management Agency. 3. Environmental Impacts a. Methodology To evaluate potential impacts relative to hydrology, surface water quality, and groundwater, the Technical Memorandum was prepared for the Project Site. b. Significance Thresholds The proposed Project may have a significant impact related to hydrology, surface water quality, and groundwater issues if it would:: Directly pollute a public water source or indirectly result in the degradation of the water quality of a public water source. Reduce the beneficial uses of receiving waters. Page IV.I-19

20 Result in a net extraction of known groundwater resources or involve excavation within an active groundwater recharge area. Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, resulting in substantial erosion or siltation. Alter the existing drainage pattern of the site or area, increasing the rate or amount of surface water runoff in a manner that could result in flooding on- or off-site. Create runoff that exceeds the capacity of existing storm water facilities. Locate housing within a 100-year flood hazard area mapped by the Federal Emergency Management Agency or in a dam inundation area as defined in the latest adopted Safety Element. Place a structure within the 100-year flood hazard area mapped by the Federal Emergency Management Agency. Expose people to flood-related hazards. Expose people or property to inundation from seiche or mudflow. As evaluated in the Initial Study included as Appendix A-2 of this Draft EIR and discussed above, the Project Site is not located within a 100-year floodplain identified by the FEMA FIRM. In addition, the Project Site is not located in a dam inundation area. Accordingly, the Project would not place housing within a 100-year floodplain or place structures within a 100-year floodplain 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. Furthermore, the is not located near any inland bodies of water or the Pacific Ocean so as to be inundated by either a seiche or tsunami. Finally, the Project Site would not be susceptible to mudflow due to its relatively flat geography and distance from hillside soils. Therefore, as concluded in the Initial Study (see Appendix A-2 of this Draft EIR), no impact with regard to these issues would occur and further analysis of these issues in this Draft EIR is not required. Page IV.I-20

21 c. Regulatory Compliance Measures and Project Design Features (1) Regulatory Compliance Measures Regulatory Compliance Measure I-1: Consistent with the requirements of the statewide Construction General Permit, the Project Applicant is required to prepare and implement a Stormwater Pollution Prevention Plan designed to reduce potential adverse impacts to surface water quality through the Project construction period. The Stormwater Pollution Prevention Plan must be designed based on the assessed Project Risk Level to address the following objectives: All pollutants and their sources, including sources of sediment associated with construction, construction site erosion and all other activities associated with construction are controlled; Where not otherwise required to be under a Regional Water Quality Control Board permit, all non-storm water discharges are identified and either eliminated, controlled, or treated; Site BMPs are effective and result in the reduction or elimination of pollutants in stormwater discharges and authorized nonstormwater discharges from construction activity to the best available technology/best control technology standard; Calculations and design details as well as BMP controls for site run-on are complete and correct; and Stabilization BMPs installed to reduce or eliminate pollutants after construction is completed. The Stormwater Pollution Prevention Plan must be prepared by a Qualified Stormwater Pollution Prevention Plan Developer. The Stormwater Pollution Prevention Plan must include the minimum BMP s required for the assessed Project Risk Level. The Project Risk Level must be determined as part of the Notice of Intent for coverage under the Construction General Permit. The project s overall risk is determined based on two sets of criteria: (1) project sediment risk (the relative amount of sediment that is expected to be generated from the project without any controls, given the project and location details) and (2) receiving water risk (the sensitivity of receiving waters to sediment and turbidity impacts). There are three possible risk levels with Level 1 as the lowest and Level 3 as the highest. The Project was assessed to have a Risk Level 2. The Project s sediment risk is medium due to relatively high potential rainfall intensities in the area. The sensitivity of the receiving waters is low, because runoff from the property does not reach streams that Page IV.I-21

22 have sediment impairments or assigned beneficial reuses of fish spawning, cold freshwater habitat, or fish migration. Because of the low receiving water sensitivity, the Project cannot be a Risk Level 3 regardless of sediment risk level. Required BMPs include: BMPs for erosion and sediment control, site management/housekeeping/waste management, management of non-stormwater discharges, infiltration and runoff controls, and BMP inspection/maintenance/repair activities. The Stormwater Pollution Prevention Plan must include a construction site monitoring program that identifies requirements for dry weather visual observations of pollutants at all discharge locations, and water quality sampling of the site effluent. A qualified Stormwater Pollution Prevention Plan Practitioner must be responsible for implementing the BMPs at the Project Site and performing all required monitoring and inspection/maintenance/repair activities. Because the Project is Risk Level 2, the Project Applicant must also prepare a Rain Event Action Plan as part of the Stormwater Pollution Prevention Plan. The Project Stormwater Pollution Prevention Plan may include some or all of the identified Best Management Practices (BMPs) listed below: Erosion Control BMPs Scheduling Sequencing construction activities to minimize the amount of time that soils remain disturbed. Stabilizing all disturbed soils as soon as possible following the completion of ground-disturbing work. Installing erosion and sediment control BMP s prior to the start of any ground-disturbing activities. Preserving existing vegetation. Stabilizing soils using hydroseeding, geotextile fabrics and mats, mulch, or soil binders. Constructing earth dikes, drainage swales and slope drains to divert runoff away from exposed soils and stabilized areas, and redirect the runoff to a desired location, such as a sediment basin. Installing outlet protection and velocity dissipation devices at culvert and pipe outlets to drainage conveyances in order to prevent scour of the soil caused by concentrated high-velocity flows. Page IV.I-22