Contact EPA Pacific Southwest Water Division
Pacific Southwest, Region 9
Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations
Low Impact Development
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On this page:
- EPA Pacific Southwest’s Support for Low Impact Development
- EPA’s Policies and Tools for the Use of Low Impact Development
- Promoting the Use of Low Impact Development in the Pacific Southwest
- LID provisions in Municipal Separate Storm Sewer System (MS4) Permits
- Other Recommended Resources
Support for Low Impact Development
EPA Pacific Southwest is a strong supporter of the use of Low Impact Development (LID) to protect water quality by managing stormwater as close to its source as possible via infiltration into soils, evapotranspiration via plants, and/or harvesting for use. LID (also known as Green Infrastructure) techniques reduce the opportunity for stormwater to run off, entrain pollutants, and discharge pollutants to waters. LID tools mimic pre-development hydrology to reduce the impact of built areas and promote the natural movement of water within a watershed, thus reducing hydromodification. Stormwater is treated as a resource, rather than a waste, conserving scarce water supplies by replenishing groundwater and capturing stormwater for beneficial use. Ancillary benefits of LID include energy conservation, ecosystem restoration, and flood control.
Policies and Tools for the Use of Low Impact Development
Nationally, EPA has developed policies and guidance encouraging the use of LID. EPA’s Headquarters office has also compiled technical information such as research papers, models and calculations. All of these materials, and more, including links to external resources, may be found at the two EPA-HQ websites for Low Impact Development and Green Infrastructure.
Promoting the Use of Low Impact Development in the Pacific Southwest
Financial Support
Nonpoint Source Program
Related Funding Opportunities: Congress amended the Clean Water Act in 1987 to establish EPA's Section 319 Nonpoint Source Management Program because it recognized the need for greater federal leadership to help focus state and local nonpoint source efforts. Under Section 319, states, territories, and Indian tribes receive grant money which supports a wide variety of activities including technical assistance, financial assistance, education, training, technology transfer, demonstration projects, and monitoring to assess the success of projects that have been implemented.
- The Los Angeles River Street Biofiltration Project, a Green Streets Pilot Project, is one example of LID work funded with NPS funds.
- The Popoia Street Stormwater Retrofit and Rain Garden Co-op are two examples of LID efforts supported with NPS funds in Hawaii. The Rain Garden Co-op project also developed a statewide rain garden manual (PDF) (36 pp, 6.0M).
Urban Waters Small Grants
The goal of the Urban Waters Small Grants program is to fund research, investigations, experiments, training, surveys, studies, and demonstrations that will advance the restoration of urban waters by improving water quality through activities that also support community revitalization and other local priorities.
Green Infrastructure
The Green Infrastructure Technical Assistance program provides assistance to help communities 1) overcome the most significant barriers to green infrastructure, and 2) develop innovative approaches to implementation that meet multiple environmental, social, and economic goals. Technical assistance will be directed to communities with significant water quality impairments associated with urban or suburban stormwater and is expected to produce knowledge or tools that can be transferred to other communities and to a national audience. See additional green infrastructure funding sources.
Clean Water Act State Revolving Fund
The Clean Water Act State Revolving Fund (CWSRF) Program provides financing, typically via below-market rate loans, to eligible entities within state and tribal lands for water quality projects including: nonpoint source control, watershed protection or restoration, estuary management, and municipal wastewater treatment. Our Pacific Southwest Office provides grants to the states of Arizona, California, Hawaii and Nevada to capitalize individual state CWSRFs. The programs are managed by the states. Loans or other types of assistance for projects are distributed according to each state’s program and priorities.
Some examples of completed LID projects funded by the CWSRF include:
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- The Hermosa Beach Strand Infiltration Trench is an innovative way to apply LID to protect water quality that could be a model for other coastal communities.
- The El Cerrito Green Streets Rain Gardens uses LID to address stormwater runoff that would otherwise impact San Francisco Bay.
- The Redondo Beach Alta Vista Park Diversion and Reuse Project is collecting stormwater, treating it, and using it to irrigate the City of Redondo Beach's largest park.
National Estuary Program
The National Estuary Program (NEP) was established in 1987 by amendments to the Clean Water Act to identify, restore and protect estuaries along the coasts of the United States. Currently, there are 28 national estuaries, including three in the Pacific Southwest, that annually receive EPA funding. The NEP focuses not just on improving water quality in an estuary, but on maintaining the integrity of the whole system-- its chemical, physical, and biological properties, as well as its economic, recreational, and aesthetic values. The following are NEP-sponsored LID programs and projects:
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- The Morro Bay National Estuary Program (PDF) (36 pp, 3.24MB) developed an LID Guidance document for local governments. This interactive map includes some LID projects.
- The San Francisco Estuary Partnership has helped local governments utilize LID. This interactive map includes LID projects.
LID provisions in Municipal Separate Storm Sewer System (MS4) Permits
Storm water runoff in urbanized areas is often conveyed through a municipal separate storm sewer system (MS4) before discharging into downstream water bodies. MS4s are used in modern developments to convey storm water separately from sanitary sewage, in contrast with the combined sewer systems which convey both storm water and sewage in some older cities.
The public entities that own and operate MS4s are required to develop storm water management programs and obtain MS4 permits under the National Pollutant Discharge Elimination System (NPDES) of the Clean Water Act (CWA). For more information on NPDES MS4 permits, see the national storm water website. MS4 permittees are increasingly using LID to control storm water discharges to meet CWA requirements.
Many recently renewed MS4 permits contain provisions requiring the use of LID, most commonly for new and redevelopment projects. EPA’s Pacific Southwest Office endorses the following permits containing measurable LID provisions to protect water quality:
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- City of Long Beach
- City of San Diego
- City of Salinas
- California Phase 2 for Small Municipal Separate Storm Sewer Systems
State and Local Initiatives
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- City of San Francisco – The San Francisco Stormwater Design Guidelines require new development and redevelopment disturbing 5,000 square feet or more of the ground surface to manage stormwater on-site. The Guidelines show project applicants how to achieve on-site stormwater management using LID strategies, also known as green infrastructure.
- City of Santa Monica - On July 27, 2010, the City of Santa Monica’s City Council approved an updated Urban Runoff Pollution Ordinance (PDF) (34 pp, 1.8MB) requiring the use of LID for new development/redevelopment projects.
Other Recommended Resources
This section includes material on aspects of LID in the Pacific Southwest that may be valuable for those implementing LID.
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- NRDC's Capturing Rainwater from Rooftops: An Efficient Water Resource Management Strategy that Increases Supply and Reduces Pollution (PDF) (25 pp, 539K) shows rainwater catchment from rooftops can increase water supply and reduce stormwater runoff. With "little, if any" treatment, captured rainwater can be used for domestic uses such as flushing toilets and watering gardens.
- The California Stormwater Quality Association established the California LID Portal in 2010 and includes the Low Impact Development Manual for Southern California.
- Sierra Nevada College in Nevada constructed a LEED Platinum Building that collects storm water to treat and recycle within the building for toilet flushing and floor drain trap primers.
- The Natural Resources Defense Council released A Clear Blue Future, How Greening California Cities Can Address Water Resources and Climate Challenges in the 21st Century (PDF) (53 pp, 2.4MB) August 2009.
- The San Francisco Bay Area developed Bay Friendly Landscaping, a whole systems approach to the design, construction and maintenance of the landscape.
- The California State Water Resources Control recently released Slow the Flow – Make Your Landscape Act Like a Sponge, a half-hour film that brings to life practices and projects that individuals and communities have created to steward our watersheds and slow down the flow of storm water, one of the largest contributors of pollution into our waterways.