Through the Water Augmentation Study, the Council for Watershed Health researches and demonstrates storm water infiltration solutions to increase local supplies of water and reduce water quality impacts.


The Water Augmentation Study (WAS) is a long-term research project led by the Council for Watershed Health, to explore the potential for increasing local water supplies and reducing urban runoff pollution by increasing infiltration of stormwater runoff. The project was initiated in January 2000, as a result of a number of concerns:

1. Impacts of urbanization on the LA region and the resulting increase in runoff over time. Runoff volumes have increased tenfold over the past 75 years.
2. Impacts of runoff-transported pollutants on rivers, coastal waters and beaches.
3. Interest in utilizing this “wasted” resource as a potential addition to local water supplies, in order to reduce reliance on declining supplies of imported water.
4. Uncertainty surrounding the impacts of capturing polluted stormwater for infiltration, in terms of both groundwater quality and quantity.

The Los Angeles basin relies on imported water for two-thirds of its water supply – sources which are becoming increasingly restricted. In 2008, a combination of drought and regulatory restrictions has drastically cut the amount of water available for import. As urbanization has increased the area of paved surfaces over the past several decades, urban runoff has increased tenfold. On average, about 500,000 acre-feet of runoff flows to the ocean annually from the Los Angeles basin, about one-third of our annual water use.

Opportunities for additional surface water storage are limited in the developed LA basin, but the groundwater aquifers have much unused capacity. If the questions surrounding the feasibility of utilizing stormwater runoff for groundwater recharge could be resolved, the result may be greater self-sufficiency for the Los Angeles Basin in terms of water supply reliability.

The Council for Watershed Health has forged a unique partnership between local water, public works, and wastewater agencies, the State of California , and the US Bureau of Reclamation to more fully evaluate capacity and feasibility of new stormwater management practices through infiltration, and whether these can be achieved without impacting groundwater quality. At the same time, we are evaluating the benefits of enhancing environmental health, increasing green space in our neighborhoods, providing jobs, and increasing our water supply reliability.

The Water Augmentation Study has developed through three phases. The Phase 1 Pilot Study completed in 2002 began an investigation of the groundwater quality ramifications of infiltrating stormwater, by monitoring water quality at two sites in the Los Angeles area. Phase 2, completed in 2007, expanded the study by adding four new sites and monitoring surface and groundwater quality at all six locations. The monitoring program was structured to assess infiltration characteristics and water quality ramifications of different land use, soils, and types of Best Management Practices for infiltration. The data from Phase 2 found that storm water infiltration did not negatively impact groundwater.

Phase 3 of our study is taking a closer look at the viability of region-wide infiltration in terms of potential quantity, physical constraints, social and institutional issues, and will compare the costs of developing this water supply relative to other possible sources. Phase 3 incorporates a demonstration project on a neighborhood scale in Sun Valley (The Elmer Avenue Neighborhood Retrofit), to show how existing infrastructure can be retrofit to locally manage stormwater and incorporate a variety of other sustainable watershed management practices. The overall goal of Phase 3 is to develop a regional strategy for developing this potentially significant new source of water for Southern California.

Through the Elmer Avenue Neighborhood Retrofit Project the Council for Watershed Health and its partners have built the first “Complete Green Street” in the City of Los Angeles. Designed to reduce flooding, reduce water pollution, recharge our local groundwater supplies, increase green spaces, and enhance the community, the Project serves as a living laboratory to test and demonstrate multiple alternative storm water best management practices (BMPs).

The Elmer Avenue Neighborhood Retrofit Projects capture, treat, and infiltrate runoff from sixty acres that flows to Elmer Avenue and the Paseo to the south. BMPs that are demonstrated include two under-street infiltration galleries, bioswales along the public right-of-way and in the Paseo, permeable surfaces for walkways and driveways, front yard rain gardens, and rain barrels to utilize and capture water from downspouts, as well as drought-tolerant landscaping and drip irrigation to lower water usage and utility bills.

Construction of the Elmer Avenue Retrofit was completed in 2010 and Elmer Paseo in 2012 (see virtual tour here). The Elmer Projects, during a year with average rainfall, will contribute over 13 million gallons of water to critical water supply stored in the San Fernando Groundwater Basin.

The demonstration projects are being monitored to evaluate surface water quality improvements, quantify groundwater recharge, water conserved on landscapes, changes in property values, and community attitudes, and additional multiple benefits. The Council welcomes collaborations with researchers and utilizes student interns for learning. Contact us if you interested in working with us on studying the Elmer Projects.

Residents, most of whom own their homes, received bilingual maintenance manuals and training in the maintenance and care of their new landscapes over the course of the project. This neighborhood-scale project provides a real-world model of sustainable design and serves as an example to integrate many on-going efforts in the region to address flood management, water quality, local supplies, and environmental restoration.

Check back here for updates on the materials to download including photos, plans, monitoring program and data, and the Elmer Paseo plans.

We want to acknowledge and thank the many partners who worked on the Elmer Projects. Elmer Avenue construction was supported by the City of Los Angeles Bureau of Sanitation, Bureau of Street Services, and Bureau of Street Lighting, U.S. Bureau of Reclamation, Metropolitan Water District of Southern California, Water Replenishment District of Southern California, Los Angeles Department of Water and Power, County of Los Angeles Department of Public Works, TreePeople, City of Santa Monica and California Department of Water Resources. We want to also thank our design and construction teams AMEC, Stivers & Associates, and Pierre Landscaping.

The Elmer Paseo was supported by funding from the California Strategic Growth Council, Santa Monica Mountains Conservancy, Los Angeles Proposition O, and Los Angeles Department of Water and Power. We want to thank our design and construction teams from TetraTech and American Landscape Construction.

Additional supporters and vendors included Urban Semillas, Vulcan Materials, Southern California Gas Company, Dudek, Wilson Environmental Landscape Design, The Toro Company, Rainbird Corp., and The Rain Barrel Company.

Finally, the Projects could not have been completed without the residents of Elmer Avenue, Sun Valley Neighborhood Council, and Los Angeles Councilman Tony Cardenas and his staff (CD 6).


The Ground Water Augmentation Model (GWAM), developed in partnership between the Council for Watershed Health and the US Bureau of Reclamation, estimates the amount of deep percolation (groundwater recharge) and storm water runoff generated within the urbanized portion of the Greater Los Angeles Region. Using runoff-diversion-to-infiltration scenarios, the model shows the potential increase in groundwater recharge given changes to the urban landscape.

Within an average year under baseline conditions, GWAM estimates that 16% of precipitation percolates past the root zone as deep percolation (~194,000 acre/feet) in the modeled area of Greater Los Angeles, while 48% of precipitation becomes runoff which flows into our existing storm systems, rivers, and ocean (~600,000 acre/feet). Further calculations indicate that if the first ¾” of runoff from storms on every parcel was conserved for infiltration there would be a potential increase of ~578,000 acre/feet/year to groundwater recharge, and stormwater runoff volume would potentially decrease to only 17% of precipitation (~206,000 acre/feet/year). This represents 384,000 acre/feet/year of additional groundwater recharge, a volume sufficient for the annual needs of three-quarters of a million (768,000) typical Southern California families (MWD, 2010).
Request for Proposals (RFP) The Elmer Paseo Stormwater Improvements

RFP Package
Bid Proposal Guidelines
General Conditions
General Requirements
Draft Contract
Paseo Plans with Amendment 1 (The plan documents for the Paseo are digitally sent via email. Contact information is required.)

Response to RFP Questions/Comments
REVISED Schedule of Work & Prices
AMENDMENT 1: Elmer Paseo Sheets:L2,L3,L4
Questions regarding the RFP can be emailed to Eileen Alduenda
RFP Schedule
Monday,June 25 RFP Released
Tuesday,July 3 10am Job Walk
Friday,July 13 5pm Close of Questions
Wednesday, July 25 4pm Bids Due
Friday,August 3 Contract Awarded

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