Caruthers Park Stormwater and Urban Runoff Capture Project: Achieving Stormwater Harvest and Use Water Quality Compliance in Los Angeles County
This presentation will delve into our first-hand experiences working with the Los Angeles County Department of Public Health (LACDPH) to obtain approval for on-site use of treated stormwater, including our approach to obtaining approval, hurdles encountered along the way, and how the project team managed to overcome those hurdles. The purpose of the presentation is to inform and educate the audience on the process of obtaining such regulatory approval in Los Angeles County. By using the City of Bellflower’s Caruthers Park Stormwater and Urban Runoff Capture Project (project) as an example, the audience will leave the presentation with tools, ideas, and concepts that they may apply to similar projects in Los Angeles County such as what to expect when working to obtain regulatory approval, what kind of information is needed, and examples of how to meet or exceed the LACDPH requirements. The speaker will engage the audience by periodically posing questions and taking surveys. This will inform the speaker on which topics to cover in more or less depth, thereby creating a fully interactive experience. Finally, the conference theme of “Envision the Future” will be addressed by explaining the goals of the Caruthers Park project, how the project strived to achieve those goals, and how those goals relate to a grander vision of a sustainable future in stormwater management.
The Caruthers Park project is a multi-benefit sustainable stormwater management project, the implementation of which supports a vision of improved water quality, increased local water supply, inter-agency cooperation, and community engagement. The project captures discharges from a tributary area of 3,211 acres, which is derived from two different watersheds (the Lower San Gabriel River and Los Cerritos Channel Watersheds), and then conveys those discharges to a 9.0 acre-feet underground reservoir. The reservoir is divided into two parts: a storage gallery that reserves up to 1.0 acre-feet of captured water for daily irrigation at Caruthers Park (park), and an 8-acre-feet infiltration gallery used to replenish the local groundwater supply. The infiltration gallery will primarily be used during storm events when the storage gallery is at full capacity. However, for the vast majority of the year when there is little to no rainfall, the main function of the project will be to store, pressurize, treat, and deliver dry weather urban runoff to the park’s irrigation system. The project is expected to meet 100% of the park’s irrigation demand with dry weather flows alone – approximately 16 million gallons of water. In addition to the above water quality and quantity benefits, the project will provide improved park amenities for the local community to enjoy for years to come.
Using stormwater runoff for on-site distribution (i.e. irrigation) requires minimum standards of filtration, disinfection, and characterization of the stormwater for toxic contaminate levels, as described in the LACDPH’s “Guidelines for Alternate Water Sources: Indoor and Outdoor Non-Potable Water Uses” – dated February 2016 (Guidelines). In order to use the captured stormwater for spray irrigation, a permit is required from LACDPH’s Cross Connection and Water Pollution Control Program to demonstrate compliance with these guidelines. In addition to a standard plan check review for potential cross connection issues, LACDPH requires the applicant to submit documentation describing the influent water quality characterization conducted for the project, any exceedances encountered during the water quality characterization, the proposed treatment processes that will target those exceedances, an effluent water quality monitoring plan, and a treatment system operations and maintenance plan. LACDPH also requires the capture and use treatment system to undergo a 6-month testing period to demonstrate compliance with the required water quality standards before allowing the treated water to be used on-site.