The One Water Approach in Action: The MacArthur Lake Stormwater Capture Project in Downtown Los Angeles

The objectives of the MacArthur Lake Stormwater Capture Project (Project) are to contribute to regulatory compliance for the Ballona Creek Watershed by treating both dry and wet weather flows from 200 acres of urban watershed in a disadvantaged community in downtown Los Angeles. In addition to water quality benefits, the Project will offset potable water use with treated stormwater, provide water supply benefits through water recycling, and increase the recreational value of the park with a terraced water feature and educational signage. The Project will also aesthetically enhance the Park with a new pedestrian bridge designed in alignment with the park's existing Art Deco style features. The Project was first identified as one of the top 10 One Water integration opportunities in the One Water LA 2040 Plan because it requires multi-agency collaboration and closes the urban water cycle with a variety of water quality, water supply and community benefits. Extensive community engagement efforts conducted during the One Water LA 2040 Plan contributed to broad support for Measure W, a parcel tax to fund the design, construction, and operation/maintenance of stormwater projects in LA County. Since its passing in 2018, Measure W now generates $300 M/year to fund LA County's Safe Clean Water Program (SCWP) projects. This Project received funding in the first round of applications through a competitive process, and is planned for construction in 2026: it is anticipated to become the second of more than 150 SCWP projects to be implemented. Combined with the historic nature of MacArthur Park, the Project has high visibility and is primed to function as a role-model stormwater project. The Project Final Design is currently undergoing final reviews by the City of Los Angeles and is expected to go out to Bid in mid-2025, with Construction anticipated to start in early 2026. This presentation will include an overview of One Water LA and the SCWP, a summary of the Project's design components, and valuable lessons learned during the planning, preliminary design, final design, and CEQA process, such as: - Right-sizing of the stormwater infrastructure to maximize water quality benefits for both dry and wet weather conditions. - Early involvement and close collaboration between LA Sanitation (LASAN), Recreation and Parks (RAP), Bureau of Engineering (BOE), and Los Angeles Department of Water & Power (LADWP) from the start of the feasibility study through final design. - Early and meaningful community engagement with a local non-profit to build community support, employing creative outreach strategies, such as a telenovela with professional actors to educate the community on the project benefits in English and Spanish. - Special design considerations to minimize community impacts to the unhoused community in the Park, local businesses (street vendors), the Park's recreational functionality, and (public) transportation impacts. The presentation will also highlight how the original project concept idea evolved from the One Water LA 2040 Plan to the Project's 2019 Feasibility Study, and the subsequent preliminary design and final design phases. Modifications made to deliver a design that meets the SCWP's regulatory water quality objectives while also enhancing the Park and maximizing community benefits will provide practical ideas for the audience to implement in their own multi-benefit stormwater and One Water projects.