Appendix H Surface Water Quality Control Study

SURFACE WATER QUALITY CONTROL STUDY

USC SPECIFIC PLAN

September 2009

PREPARED BY:

KPFF Consulting Engineers 6080 Center Drive, Suite 750

Los Angeles, CA 90045 (310) 665-2800

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TABLE OF CONTENTS

1.0 Overview ..................................................................................................................... 1

2.0 LA CEQA Thresholds Guide.................................................................................... 2

3.0 National Pollutant Discharge Elimination System (NPDES)................................. 3

3.1 Storm Water Pollution Prevention Plans (SWPPP) ............................................ 3

3.2 Standard Urban Storm Water Mitigation Plans (SUSMP).................................. 4

4.0 Existing Regional Water Quality Issues .................................................................. 6

4.1 Santa Monica Bay Watershed Management Area............................................... 6

4.2 Ballona Creek...................................................................................................... 7

4.3 Pollutants of Concern .......................................................................................... 7

4.4 Water Quality Condition at USC ........................................................................ 9

4.4.1 Example 1: Parkside Housing............................................................ 9

4.4.2 Example 2: Downey Way Improvement Project ............................. 10

4.4.3 Example 3: Watt Way Improvement Project ................................... 11

4.4.4 Example 4: School of Cinematic Arts Project ................................. 12 5.0 USC Specific Plan Project Features ....................................................................... 13

5.1 SWPPP BMPs ................................................................................................... 13

5.2 Source Control BMPs........................................................................................ 14

5.3 Treatment Control BMPs .................................................................................. 15

5.3.1 Flow-Based Treatment Control BMPs............................................. 15

5.3.2 Volume-Based Treatment Control BMPs........................................ 16

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6.0 Analysis and Conclusion ......................................................................................... 18

7.0 References................................................................................................................. 21

APPENDICES

Appendix A – Standard Urban Storm Water Mitigation Plan (SUSMP) Mitigated Flow

and Volume Calculation Appendix B – Storm Water Quality Management Program (SQMP) Implementation; Part

3 of The Los Angeles County Municipal Storm Water Permit, Order No. 01-182, NPDES Permit No. CAS004001.

Appendix C – Special Provisions; Part 4 of The Los County Municipal Storm Water

Permit, Order No. 01-182, NPDES Permit No. CAS004001 Appendix D – Summary of Potential Significant General Permit (Order 99-08-DWQ)

Changes

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1.0 Overview The USC Specific Plan site consists of three subareas on or around University Park Campus with a total area of 207 acres. Subarea 1 (166 acres) of the proposed Specific Plan is bounded by Jefferson Boulevard to the north, Vermont Avenue to the west, Exposition Boulevard and 37th Place to the south and the Harbor Freeway to the east. Subarea 2 (11 acres) is generally defined within the limits of Jefferson Boulevard to the north, Hope to the west, 35th Street to the south and Hill Street to the east. Subarea 3 (30 acres) is defined within 30th Street and 30th Place to the north, Vermont Avenue to the west, Jefferson to the south and Hoover Street to the east.

Figure 1-1: Map of proposed USC Specific Plan

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2.0 LA CEQA Thresholds Guide LA CEQA Thresholds Guide considers a project to have a significant impact on surface water quality if discharges associated with the project would create pollution, contamination, or nuisance as defined in Section 13050 of the California Water Code (CWC) 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. The CWC includes the following definitions: “Pollution” means an alteration of the quality of the waters of the state to a degree which unreasonably affects either of the follow: 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 disease. “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 damage inflicted upon individuals may be unequal; and 3) occurs during, or as a result of, the treatment or disposal of wastes.

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3.0 National Pollutant Discharge Elimination System (NPDES) Any discharge of pollutants to the waters is prohibited by the Clean Water Act unless the discharge is in compliance with a National Pollutant Discharge Elimination System (NPDES) permit. The phase I of the NPDES permit program outlines municipal and industrial storm water discharge requirements for 1) municipal storm drain system serving population of 100,000 or more, 2) storm water discharge associated with industrial activities, and 3) storm water discharge from construction activities greater than five acres. The phase II of the permit program, which went into effect in early 2003, set requirements for discharges caused by 1) municipal storm drain systems serving population of 100,000 or less, 2) construction activities between one to five acres, and 3) commercial, light industrial, and institutional activities. In the State of California, the NPDES permit is issued through the State Water Resources Control Board (SWRCB) and the nine Regional Water Quality Control Boards (RWQCBs). In addition, per Section 303(d) of the Clean Water Act, the SWRCB also prepares a list of impaired waters and develops Total Maximum Daily Loads (TMDLs) for these waters. As one of the eighty three incorporated cities within the County of Los Angeles, the City of Los Angeles is one of the permittees covered by the Los Angeles County Municipal Storm Water Permit (NPDES No. CAS004001) from the Los Angeles RWQCB. Because stormwater from USC University Park Campus discharges into the city’s stormwater system, the USC Specific Plan area is also covered by the same NPDES permit. Part 3 and 4 of the Los Angeles County Municipal Storm Water Permit is attached in Appendices B and C. 3.1 Storm Water Pollution Prevention Plans (SWPPP) The General Construction Activity Storm Water Permit, adopted by the SWRCB in 2004, requires all construction that disturbs one acre or more to develop and implement a Storm Water Pollution Prevention Plan (SWPPP) in accordance with the SWRCB Order No. 99-08-DWQ (NPDES Permit No. CAS000002). The purposes of the SWPPP are to identify potential pollutant sources that may affect the quality of discharge associated with construction activity, to identify non-storm water discharges, and to design the use and placement of Best Management Practices (BMP) to effectively prohibit the entry of pollutants from the project site into the public storm drain system during construction. As construction progresses and as conditions warrant, the SWPPP will require modification by the contractor. Prior to commencement of construction activities, a Notice of Intent (NOI), and the appropriate fees must be filed with the Regional Water Quality Control Board (RWQCB). Once the construction is complete, a Notice of Termination needs to be filed

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with the RWQCB certifying that all State and local requirements have been met in accordance with Special Provisions for Construction Activity, C.7, of the General Permit. Currently USC has six active construction storm water permits for University Park Campus filed with the Water Quality Control Board as listed in Table 3-1. The State Water Board has proposed significant changes to Order 99-08-DWQ and the potential upcoming changes are listed in Appendix D. In addition, implementations of SWPPP BMPs for the USC Specific Plan are discussed further in Section 5.0 USC Specific Plan Project Features.

WDID Number Facility Name 419C334828 Parkside Residential Housing Phase II 419C354270 School of Cinematic Arts Phase II 419C333430 Parking Structure 2 419C351481 USC Campus Center 419C345324 USC School of Cinematic Arts 419C337233 USC Bldg Shell & Core Data Center Utility Yard

Table 3-1: List of USC Active Construction Stormwater Permits for University Park Campus 3.2 Standard Urban Storm Water Mitigation Plans (SUSMP) As one of the permittees covered by the Los Angeles County Municipal Storm Water Permit, the City of Los Angeles implements Standard Urban Storm Water Mitigation Plans (SUSMP). The purpose of SUSMP is to reduce the discharge of pollutants of concern by outlining the necessary Best Management Practices (BMPs) which must be incorporated into design plans of new development and redevelopment. A project is subject to SUSMP if it falls under one of the categories listed below:

a) Single-family hillside residential developments of one acre or more of surface area;

b) Housing developments (includes single family homes, multifamily homes, condominium, and apartments) of ten units or more;

c) A 100,000 square feet or more impervious surface area industrial/ commercial development;

d) Automotive service facilities [5,000 square feet or more of surface area]; e) Retail gasoline outlets [5,000 square feet or more impervious surface area

and with projected Average Daily Traffic (ADT) of 100 or more vehicles]; f) Restaurants [5,000 square feet or more of surface area]; g) Parking lot [5,000 square feet or more of surface area or with 25 or more

parking spaces]; h) Projects located in, adjacent to or discharging directly to an

Environmentally Sensitive Area (ESA) that meets the following threshold conditions: (1) Discharge storm water and urban runoff that is likely to impact a

sensitive biological species or habitat; and

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(2) Create 2,500 square feet or more of impervious surface area. i) Redevelopment projects in subject categories that meet Redevelopment

thresholds. An example SUSMP flow rate and volume calculation is shown in Appendix A. In addition, SUSMP design guidelines and BMP requirements are discussed in Section 5.0, USC Specific Plan Project Features.

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4.0 Existing Regional Water Quality Issues The University of Southern California – University Park Campus is located within the Santa Monica Bay Watershed Management Area (WMA) designated by the Los Angeles Regional Water Quality Control Board (RWQCB). The WMA includes several watersheds with Malibu Creek and Ballona Creek being the two largest. USC University Park Campus is a part of the Ballona Creek watershed.

Fig 4-1: Santa Monica Bay Watershed Management Area 4.1 Santa Monica Bay Watershed Management Area According to the Santa Monica Bay WMA Summary (December 2007) prepared by the Los Angeles RWQCB, many of the beneficial uses of the WMA have been impaired or threatened to be impaired due to the pollutant loadings originated from human activities. National Pollutant Discharge Elimination System (NPDES) permitted discharges in the Santa Monica Bay WMA include the following:

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193 NPDES discharges including: seven major NPDES permit discharges, three Publicly Owned Treatment Works (two direct ocean discharge), one refinery, and three generating stations; 18 are minor discharges.

175 dischargers covered under general permits 87 dischargers covered by an industrial storm water permit 401 dischargers covered by the construction storm water permit

A majority of the 193 NPDES permitted facilities are located in the Ballona Creek watershed. Moreover, a large number of the general industrial storm water permitted facilities drain to Ballona Creek as well. 4.2 Ballona Creek A majority of Ballona Creek is channelized and surrounded by highly developed residential and commercial areas. The list of 2006 Clean Water Act Section 303(d) impaired water bodies indicates cadmium (sediment), coliform bacteria, dissolved copper, cyanide, silver (sediment), toxicity, trash, and viruses (enteric) as the major pollutants in Ballona Creek. At the mouth of Ballona Creek, bacterial levels frequently exceed the standard which resulted in permanently posted warning signs on each side of the Creek. In addition, the Bay Protection and Toxic Cleanup Program (BPTCP) identifies the sediments in the Ballona Creek Entrance Channel as one of the Toxic Hot Spots. A study conducted by the U.S. Army Corps of Engineers (USACE) in conjunction with the Los Angeles Basin Contaminated Sediment Task Force shows that both dry weather runoffs and storm runoffs in the Creek are toxic to marine organisms. The USACE is currently conducting a feasibility study of restoring natural streams and riparian habitats in the lower Ballona Creek. 4.3 Pollutants of Concern Pollutants that are expected to be present in stormwater can be generally grouped into seven categories. Impacts of each pollutant category on water quality are present below. Sediment Sediment is a common component of stormwater, and can be a pollutant. Sediment can be detrimental to aquatic life (primary producers, benthic invertebrates, and fish) by interfering with photosynthesis, respiration, growth, reproduction, and oxygen exchange in water bodies. Sediment can transport other pollutants that are attached to it including nutrients, trace metals, and hydrocarbons. Sediment is the primary component of total suspended solids (TSS), a common water quality analytical parameter.

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Nutrients Nutrients including nitrogen and phosphorous are the major plant nutrients used for fertilizing landscapes, and are often found in stormwater. These nutrients can result in excessive or accelerated growth of vegetation, such as algae, resulting in impaired use of water in lakes and other sources of water supply. In addition, un-ionized ammonia (one of the nitrogen forms) can be toxic to fish. Bacteria / Viruses Bacteria and viruses are common contaminants of stormwater. For separate storm drain systems, sources of these contaminants include animal excrement and sanitary sewer overflow. High levels of indicator bacteria in stormwater have led to the closure of beaches, lakes, and rivers to contact recreation such as swimming. Oil / Grease Oil and grease include a wide array of hydrocarbon compounds, some of which are toxic to aquatic organisms at low concentrations. Sources of oil and grease include leakage, spills, cleaning and sloughing associated with vehicle and equipment engines and suspensions, leaking and breaks in hydraulic systems, restaurants, and waste oil disposal. Metals Metals including lead, zinc, cadmium, copper, chromium, and nickel are commonly found in stormwater. Many of the artificial surfaces of the urban environment (e.g., galvanized metal, paint, automobiles, or preserved wood) contain metals, which enter stormwater as the surfaces corrode, flake, dissolve, decay, or leach. Over half the trace metal load carried in stormwater is associated with sediments. Metals are of concern because they are toxic to aquatic organisms, can bioaccumulate (accumulate to toxic levels in aquatic animals such as fish), and have the potential to contaminate drinking water supplies. Organics Organics may be found in stormwater in low concentrations. Often synthetic organic compounds (adhesives, cleaners, sealants, solvents, etc.) are widely applied and may be improperly stored and disposed. In addition, deliberate dumping of these chemicals into storm drains and inlets causes environmental harm to waterways. Pesticides Pesticides (including herbicides, fungicides, rodenticides, and insecticides) have been repeatedly detected in stormwater at toxic levels, even when pesticides have been applied in accordance with label instructions. As pesticide use has increased, so too have concerns about adverse effects of pesticides on the environment and human health. Accumulation of these compounds in simple aquatic organisms, such as plankton, provides an avenue for biomagnification through the food web, potentially resulting in elevated levels of toxins in organisms that feed on them, such as fish and birds.

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4.4 Water Quality Condition at USC USC has been implementing structural Best Management Practices on its projects in compliance with SUSMP on a case-by-case basis. The following four projects provide examples of BMPs implemented on recent USC projects. As a part of SUSMP requirements, USC has filed master covenant and agreements to maintain these structural BMPs. 4.4.1 Example 1: Parkside Housing The Parkside Housing project, located on the northeast corner of the intersection of Exposition Boulevard and McClintock Avenue, was permitted in 2004 and completed in 2006. The project consists of a four-level residential tower and basement, including student and faculty residences. Structural BMPs implemented for this project were CDS Stormwater Treatment Unit (Fig. 4-2) and catch basin filter inserts. In addition, a large detention pipe was installed to reduce the peak runoff from the project site. CDS Stormwater Treatment Unit (PMSU20_15)

A CDS Technologies Inc. storm water treatment unit model PMSU20_15 is effective for the removal of petroleum-based hydrocarbons, silt and debris in storm water runoff. The unit is designed to accommodate up to and including the 85th percentile storm event (the first ¾” of rainfall) and utilizes a non-blocking, non-mechanical screening technique to remove pollutants from storm water flow. Filter pouches are included to remove additional design pollutants. The filters have been also selected to accommodate up to and including the 85th percentile storm event.

Fig. 4-2: Contech CDS

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4.4.2 Example 2: Downey Way Improvement Project The majority of the Downey & Watt Way Improvement project was completed in December 2008. The project included installation of a new 24 inch storm drain retention facility along Downey Way and installation of catch basins along Downey and Watt Way. Structural BMPs for the project included Contech Vortsentry (Fig. 4-3) and a dry well. Both BMPs were designed to treat storm water runoff from all storms up to and including the 85th percentile 24-hour storm event (the first ¾” of rainfall).

Contech Vortsentry The Contech VortSentry Unit is a hydrodynamic separator with a small footprint which makes it an effective treatment option for projects where space is at a premium and efficiency is critical. The internal bypass ensures treatment chamber velocities remain low, which improves performance and eliminates the risk of resuspension. In addition to stand-alone applications, the VortSentry is an ideal pretreatment device. The system is housed inside a lightweight concrete manhole structure for easy installation and unobstructed maintenance access. Dry Well A dry well was also proposed for this project to allow for the infiltration of the first ¾” of rainfall. Dry wells consist of a vertical hole in the ground filled with an open graded aggregate fill, utilizing gravity to infiltrate stormwater into the ground.

Fig. 4-3: Contech Vortsentry

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4.4.3 Example 3: Watt Way Improvement Project The Watt Way improvement project was permitted in 2007 and is currently under construction. The project includes installation of new catch basins with KriStar Flo-GardTM+ Plus Catch Basin filter inserts (Fig. 4-4) along Watt Way and a portion of 37th Place, installation of 36 inch HDPE perforated pipe, and construction of infiltration trench. The structural BMPs were designed to treat storm water runoff from all storms up to and including the 85th percentile 24-hour storm event.

Fig. 4-4: Kristar Flo-Gard

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4.4.4 Example 4: School of Cinematic Arts Project The project is currently under construction and is anticipated to be completed in the summer of 2010. The project includes demolition of existing buildings and construction of a new 130,000 square-foot instructional building. Structural BMPs selected for the project are Flo-GardTM+ Plus Catch Basin Filter Inserts, sand filtration, and Contech ChamberMaxx retention system (Fig. 4-5). All structural BMPs are designed to treat storm water runoff from all storms up to and including the 85th percentile 24-hour storm event. Flo-GardTM+ Plus Catch Basin & Curb Inlet basin filter inserts by KriStar Enterprises, Inc. are effective for the removal of petroleum-based hydrocarbons, silt, and debris in storm water runoff, whereas sand filtration are effective for the removal of nutrients, bacteria and phosphorous.

Contech ChamberMaxx ChamberMaxx is a corrugated, open-bottom domed-shaped system designed to collect, detain, retain, and infiltrate stormwater runoff. Typically, installation of a pretreatment water quality unit upstream of the infiltration system is recommended to reduce the maintenance costs and extend the performance life of the infiltration system. For the School of Cinematic Arts project, Contech CDS was selected as a pretreatment system.

Fig. 4-5: Contech ChamberMaxx

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5.0 USC Specific Plan Project Features New development proposed by the USC Specific Plan includes 2,500,000 square feet of academic use, 350,000 square feet of retail/commercial use, 2,135,000 square feet of housing, 165,000 square feet of hotel, and 80,000 square feet of educational academy. During course of design, construction and operation of the project, the USC Specific Plan will implement BMPs in accordance with regulatory standards. 5.1 SWPPP BMPs As discussed in Section 3.1, all construction that disturbs one acre or more needs to develop and implement a SWPPP. The USC Specific Plan will implement SWPPP BMPs in accordance with the general construction permit issued by the RWQCB. Erosion Control Erosion control is any source control practice that protects the soil surface and prevents soil particles from being detached by rainfall, flowing water, or wind. Erosion control is also referred to as soil stabilization. Examples of erosion control BMPs include, but not limited to, preservation of existing vegetation, hydraulic mulch, hydroseeding, soil binders, straw mulch, earth dikes, and drainage swale. Sediment Control Sediment control is any practice that traps soil particles after they have been detached and moved by rain, flowing water, or wind. Sediment control measures are usually passive systems that rely on filtering or settling the particles out of the water or wind that is transporting them. Examples of sediment control BMPs include, but not limited to, silt fence, sediment basin, sediment trap, check dam, gravel bag berm, sandbag barrier, and storm drain inlet protection. Non-Stormwater Management and Material Management Non-stormwater management BMPs are source control BMPs that prevent pollution by limiting or reducing potential pollutants at their source or by eliminating off-site discharge. These practices involve day-to-day operations of the construction site and are usually under the control of the contractor. These BMPs are also referred to as “good housekeeping practices” which involve keeping a clean, orderly construction site. Non-stormwater management BMPs also include procedures and practices designed to minimize or eliminate the discharge of pollutants from vehicle and equipment cleaning, fueling, and maintenance operations to stormwater drainage systems or to watercourses. With proper selection, design, and maintenance of SWPPP BMPs, the USC Specific Plan is not expected to create pollution, contamination, or nuisance, as defined in Section 13050 of the CWC, or cause regulatory standards to be violated.

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5.2 Source Control BMPs Post-Construction Best Management Practices (BMPs) can be divided into source control and treatment control BMPs. The difference between source control BMPs and treatment control BMPs is that source control BMPs are used to prevent pollutants from entering into stormwater discharges, whereas treatment control BMPs are used to remove pollutants that have already entered the stormwater. The following menu of source control BMPs will be considered for each project proposed by the USC Specific Plan. More detailed information of these BMPs including design consideration can be found in the California Stormwater Quality Association BMP Handbook. Effective Site Design & Landscape Planning Each project site possesses unique topographic, hydrologic, and vegetative features, some of which may be more suitable for development than others. Integrating and incorporating appropriate landscape planning methodologies into the project design is an effective action that can be done to minimize surface and groundwater contamination from stormwater. Project plan designs will conserve landscape areas where appropriate, maximizing natural water storage and infiltration opportunities. In addition, project design will also include application methods of irrigation water that minimize runoff of excess irrigation water into the stormwater conveyance system. Storm Drain Signage Storm drain messages have become a popular method of alerting the public about the effects of and the prohibitions against waste disposal. The stencil or affixed sign with a brief statement that prohibits dumping of improper materials into the urban runoff conveyance system is recommended at all storm drain inlets within the boundary of the USC Specific Plan area. Proper Design of Maintenance Bays & Docks Several measures can be taken to prevent operations at maintenance bays and loading docks from contributing a variety of toxic compounds, oil and grease, heavy metals, nutrients, suspended solids, and other pollutants to the stormwater conveyance system. Preventative measures include overflow containment structures, dead-end sumps, and engineered infiltration systems. Proper Design of Trash Storage Area Stormwater runoff from areas where trash is stored or disposed of can be polluted, and loose trash and debris can be easily transported by water or wind into nearby storm drain inlets, channels, and/or creeks. Waste handling operations such as dumpsters, litter control, and waste piles may be sources of stormwater pollution. As preventative measures, trash container areas will be screened or walled to prevent off-site transport of trash, and drainage from adjoining roofs and pavement will be diverted around the area.

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Proper Design of Outdoor Material Storage Areas Proper design of outdoor storage areas for materials reduces opportunity for toxic compounds, oil and grease, heavy metals, nutrients, suspended solids, and other pollutants to enter the stormwater conveyance system. Materials with the potential to contaminate stormwater will be: (1) placed in an enclosure such as, but not limited to, a cabinet, shed, or similar structure that prevents contact with runoff or spillage to the stormwater conveyance system; or (2) protected by secondary containment structures such as berms, dikes, or curbs. In addition, the storage area will be paved and sufficiently impervious to contain leaks and spills and have a roof or awning to minimize collection of stormwater within the secondary containment area. Proper Maintenance of Structural/Treatment Control BMP Improper maintenance is one of the most common reasons why water quality controls will not function as designed or which may cause the system to fail entirely. It is important to consider who will be responsible for maintenance of a permanent BMP, and what equipment is required to perform the maintenance properly. As part of project review, if a project applicant has included or is required to include, Structural or Treatment Control BMPs in project plans, the applicant will be required to provide verification of maintenance provisions through such means as may be appropriate, including, but not limited to legal agreements, covenants, and/or CEQA mitigation requirements. With proper selection, design, and maintenance of source control BMPs, the USC Specific Plan is not expected to create pollution, contamination, or nuisance, as defined in Section 13050 of the CWC, or cause regulatory standards to be violated. 5.3 Treatment Control BMPs Treatment control BMPs will be implemented in accordance with performance standards established by the City of Los Angeles SUSMP. 5.3.1 Flow-Based Treatment Control BMPs The following is a menu of potential flow-based treatment control BMPs that will be considered for feasibility during design of the new development proposed by the USC Specific Plan. In accordance with SUSMP, flow-based treatment control BMPs will be designed to treat the flow of runoff produced from a 0.75 inch storm event or as described below:

1. The flow of runoff produced from a rain event equal to at least 0.2 inches per hour intensity, or

2. The flow of runoff produced from a rain event equal to at least two times the 85th percentile hourly rainfall intensity for Los Angeles County, or

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3. The flow of runoff produced from a rain event that will result in treatment of the same portion of runoff as treated using volumetric standards above.

Vegetative Systems Vegetative systems are designed to treat runoff through filtering by the vegetated surface, filtering through a subsoil matrix, and/or infiltration into the underlying soils. They trap particulate pollutants (suspended solids and trace metals), promote infiltration, and reduce the flow velocity of stormwater runoff. Vegetative system BMPs include vegetative filter strips, vegetated swale, green roof, and bioretention (Bioretention can be also considered as a volume-based treatment control BMP). Vortex / Hydrodynamic System Vortex separators are gravity separators, which the water moves in a centrifugal fashion before exiting. Unlike wet vault, by having the water move in a circular fashion, it is possible to obtain significant removal of suspended sediments and attached pollutants with less space. Catch Basins Systems Drain inserts are manufactured filters or fabric placed in a drop inlet to remove sediment and debris. There are a multitude of inserts of various shapes and configurations, typically falling into one of three different groups: socks, boxes, and trays. The sock consists of a fabric, usually constructed of polypropylene. The fabric may be attached to a frame or the grate of the inlet holds the sock. Socks are meant for vertical (drop) inlets. Boxes are constructed of plastic or wire mesh. Typically a polypropylene “bag” is placed in the wire mesh box. The bag takes the form of the box. Most box products are one box; that is, the settling area and filtration through media occur in the same box. Some products consist of one or more trays or mesh grates. The trays may hold different types of media. Filtration media vary by manufacturer. Types include polypropylene, porous polymer, treated cellulose, and activated carbon. 5.3.2 Volume-Based Treatment Control BMPs The following is a menu of volume-based treatment control BMPs that will be considered for feasibility during design of the new development proposed by the USC Specific Plan. In accordance with SUSMP, volume-based treatment control BMPs will be designed to treat:

1. The 85th percentile 24-hour runoff event determined as the maximized captured storm water 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), or

2. 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), or

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3. The volume of runoff produced from a 0.75 inch storm event, prior to its discharge to a storm water conveyance system, or

4. 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.

Infiltration/Retention The infiltration type of BMPs utilizes the natural filtering ability of the soil to remove pollutants in stormwater runoff. Infiltration facilities store runoff until it gradually exfiltrates through the soil and eventually into the water table. This practice has high pollutant removal efficiency and can also help recharge groundwater, thus helping to maintain low flows in stream systems. Infiltration basins can be challenging to apply on many sites because of soils requirements. Pretreatment using buffer strips, swales, or detention basins is important for limiting amounts of coarse sediment entering the trench which can clog and render the trench ineffective. Examples of infiltration and retention BMPs include infiltration basins, cisterns, drywells, and extended detention ponds. Pervious Pavement Pervious paving may be considered for light vehicle loading in parking areas and pedestrian areas. The term describes a system comprising a load-bearing, durable surface together with an underlying layered structure that temporarily stores water prior to infiltration or drainage to a controlled outlet. The surface can itself be porous such that water infiltrates across the entire surface of the material (e.g., turf and gravel surfaces, porous concrete, and porous asphalt), or can be built up of impermeable blocks separated by spaces and joints, through which the water can drain. This latter system is termed ‘permeable’ paving. Advantages of pervious pavements are that they reduce runoff volume while providing treatment, and are unobtrusive resulting in a high level of acceptability. Asphalt porous pavements, concrete block porous pavements, and structural soil are part of pavement BMPs. Media Filtration Stormwater media filters are usually two-chambered including a pretreatment settling basin and a filter bed filled with sand or other absorptive filtering media. As stormwater flows into the first chamber, large particles settle out, and then finer particles and other pollutants are removed as stormwater flows through the filtering media in the second chamber. There are a number of design variations including the Austin sand filter, Delaware sand filter, and multi-chambered treatment train (MCTT). The new development proposed by the USC Specific Plan will be designed to meet the 0.75-inch flow and volume criteria of SUSMP. and as a result the Specific Plan is not expected to create pollution, contamination, or nuisance, as defined in Section 13050 of the CWC, or cause regulatory standards to be violated.

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6.0 Analysis and Conclusion In general, anticipated and potential pollutants generated for a new development can be determined per the proposed land use types. Anticipated and potential pollutants associated with the USC Specific Plan are summarized in Table 6-1. As the USC Specific Plan includes many different types of new development, almost all categories of pollutants are anticipated to be generated. In addition, construction activities such as earth moving, maintenance/operation of construction equipment, and handling/storage/disposal of construction materials are potential sources of short-term storm water pollution.

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Table 6-1: Anticipated and Potential Pollutants Generated by Land Use Type

General Pollutant Categories

Land Use Type Pathogens Metals Nutrients Pesticides

Organic Compounds

Sediments Trash & Debris

Oxygen Demanding Substances

Oil & Grease

Detached Residential Development

X X X X X X X

Attached Residential Development

P X X X X P P

Commercial / Industrial Development

P P P P P X P X

Restaurants X X X X

Parking Lots X P P P X P X

Streets, Highways & Freeways

X P X X X P X

Notes: X = Anticipated P = Potential Source: California Stormwater Quality Association, 2003.

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Table 6-2: Treatment Control BMPs

Sediment 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 System1

Medium Low Unknown Low Unknown Unknown Unknown

Catch Basin System1 Unknown Unknown Unknown Unknown Unknown Unknown Unknown

Infiltration/Retention High High High High High High High

Media Filtration High Low High High Medium High High

Notes: 1Performance of each system varies per manufactures and model. The USC Specific Plan, however, will comply with regulatory standards such as SWPPP and SUSMP by implementing various BMPs and manage potential pollutants. As listed in Section 5.0, the USC Specific Plan proposes to incorporate source control BMPs and minimize potential pollutants. Moreover, single or combination of treatment BMPs will be implemented and designed to treat the first 75-inch rainfall in compliance with SUSMP as discussed in Section 5.0. As different types of treatment control BMPs target different pollutants and have different removal efficiencies as shown in Table 6-2, appropriate treatment control BMPs will be individually selected for each project. With proper selection, design, and maintenance of BMPs, the USC Specific Plan is not expected to create pollution, contamination, or nuisance, as defined in Section 13050 of the CWC, or cause regulatory standards to be violated. Therefore, the USC Specific Plan’s impact on surface waters is anticipated to be less than significant.

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7.0 References Los Angeles Regional Water Quality Control Board. Santa Monica Bay Watershed

Management Area Summary. December 2007. Los Angeles County Department of Public Works. A Manual for the Standard Urban

Storm Water Mitigation Plan (SUSMP). September 2002. City of Los Angeles. L.A. CEQA Thresholds Guide. 2006. California Stormwater Quality Association. New Development and Redevelopment

Handbook. January 2003.

APPENDIX A

STANDARD URBAN STORMWATER MITIGATION PLAN (SUSMP) MITIGATIED FLOW AND VOLUME CALCULATION BASED ON 0.75 INCHES OF RAINFALL

NOMENCLATURE AI = Impervious Area (acres)

AP = Pervious Area (acres)

AU = Contributing Undeveloped Upstream Area (acres)

ATotal = Total Area of Development and Contributing Undeveloped

Upstream Area (acres)

CD = Developed Runoff Coefficient

CU = Undeveloped Runoff Coefficient

IX = Rainfall Intensity (inches/hour)

QPM = Peak Mitigation Flow Rate (cfs)

TC = Time of Concentration (minutes, must be between 5-30 min.)

VM = Mitigation Volume (ft3)

EQUATIONS ATotal = Al + AP + AU

AI = (ATotal * % of Development which is Impervious)

AP = (ATotal * % of Development which is Pervious)

AU = (ATotal * % of Contributing Undeveloped Upstream Area***)

CD = (0.9 * Imp.) + [ (1.0 – Imp.) * Cu ] If CD < Cu, use Cu = Cu

QPM = CD * IX * ATotal * (1hr/3,600 seconds) * (1ft /12inches) * (43,560 ft2 / 1acre)

= CD * IX * ATotal * (1.008333 ft3-hour / acre-inches-seconds)

Tc = 10-0.507 * (CD * IX)-0.519 * Length0.483 * Slope-0.135

VM = (0.75in) * [(AI)(0.9) + (AP + AP)( CU)] * (1ft/12ins)*(43,560ft2/1acre)

= (2,722.5 ft3/acre) * [(AI)(0.9) + (AP + AP)( CU)]

*** Contributing Undeveloped Upstream Area is an area where storm water

runoff from an undeveloped upstream area will flow directly or indirectly to the

Post-Construction Best Management Practices (BMPs) proposed for the

development. This additional flow must be included in the flow rate and volume

calculations to appropriately size the BMPs.

APPENDIX B

STORM WATER QUALITY MANAGEMENT PROGRAM (SQMP) IMPLEMENTATION PART 3 OF THE LOS ANGELES COUNTY MUNICIPAL

STORM WATER PERMIT, ORDER NO. 01-182, NPDES PERMIT NO. CAS004001.

APPENDIX C

SPECIAL PROVISIONS; PART 4 OF THE LOS ANGELES COUNTY MUNICIPAL STORM WATER PERMIT, ORDER NO. 01-182, NPDES PERMIT NO. CAS004001

APPENDIX D

SUMMARY OF POTENTIAL SIGNIFICANT GENERAL PERMIT (ORDER 99-08-DWQ) CHANGES

Draft Fact Sheet CGP -5- April 22, 2009

E. How the Panel’s Findings are Used in this General Permit

The State Water Board carefully considered the findings of the panel and related public comments. The State Water Board also reviewed and considered the comments regarding statewide storm water policy and the reissuance of the Industrial General Permit. From the input received the State Water Board identified some permit and program performance gaps that are addressed in this General Permit. The Summary of Significant Changes (below) in this General Permit are a direct result of this process.

F. Summary of Significant Changes in This General Permit

The State Water Board has proposed significant changes to Order 99-08-DWQ. This General Permit differs from Order 99-08-DWQ in the following significant ways: Rainfall Erosivity Waiver: this General Permit includes the option allowing a small construction site (>1 and <5 acres) to self-certify if the rainfall erosivity value (R value) for their project's given location and time frame compute to be less than or equal to 5. Technology-Based Numeric Action Levels: this General Permit includes NALs for pH and turbidity. Technology-Based Numeric Effluent Limitations: this General Permit contains daily average NELs for pH during any construction phase where there is a high risk of pH discharge and daily average NELs turbidity for all discharges in Risk Level 3. The daily average NEL for turbidity is set at 500 NTU to represent the minimum technology that sites need to employ (to meet the traditional Best Available Technology Economically Achievable (BAT)/ Best Conventional Pollutant Control Technology (BCT) standard) and the traditional, numeric receiving water limitations for turbidity. Risk-Based Permitting Approach: this General Permit establishes three levels of risk possible for a construction site. Risk is calculated in two parts: 1) Project Sediment Risk, and 2) Receiving Water Risk. Minimum Requirements Specified: this General Permit imposes more minimum BMPs and requirements that were previously only required as elements of the SWPPP or were suggested by guidance. Project Site Soil Characteristics Monitoring and Reporting: this General Permit provides the option for dischargers to monitor and report the soil characteristics at their project location. The primary purpose of this requirement is to provide better risk determination and eventually better program evaluation. Effluent Monitoring and Reporting: this General Permit requires effluent monitoring and reporting for pH and turbidity in storm water discharges. The purpose of this monitoring is to determine compliance with the NELs and evaluate whether NALs included in this General Permit are exceeded. Receiving Water Monitoring and Reporting: this General Permit requires some Risk Level 3 dischargers to monitor receiving waters and conduct bioassements. Post-Construction Storm Water Performance Standards: this General Permit specifies runoff reduction requirements for all sites not covered by a Phase I or Phase II MS4 NPDES permit, to avoid, minimize and/or mitigate post-construction storm water runoff impacts. Rain Event Action Plan: this General Permit requires certain sites to develop and implement a Rain Event Action Plan (REAP) that must be designed to protect all exposed portions of the site within 48 hours prior to any likely precipitation event. Annual Reporting: this General Permit requires all projects that are enrolled for more than one continuous three-month period to submit information and annually certify that their site is in compliance

Draft Fact Sheet CGP -6- April 22, 2009

with these requirements. The primary purpose of this requirement is to provide information needed for overall program evaluation and pubic information. Certification/Training Requirements for Key Project Personnel: this General Permit requires that key personnel (e.g., SWPPP preparers, inspectors, etc.) have specific training or certifications to ensure their level of knowledge and skills are adequate to ensure their ability to design and evaluate project specifications that will comply with General Permit requirements. Linear Underground/Overhead Projects: this General Permit includes requirements for all Linear Underground/Overhead Projects (LUPs).