Los Angeles County, California United States
County of Los Angeles Department of Public Works
The Sun Valley watershed is historically plagued with several watershed health issues, such as severe flooding, poor water quality, and industrial and residential urbanization. The watershed lacks a comprehensive storm drain system and consequently suffers from chronic, severe flooding during moderate storm events. During these events, intersections are inundated, and stormwater on major streets resemble river flows. The Sun Valley Watershed Multi-Benefit Project is a first-of-its-kind venture geared toward managing stormwater for the Sun Valley watershed to provide flood protection, improve watershed health, and increase open space and recreational opportunities, as well as increase wildlife habitat.
Triple Bottom Line
Economic: By preventing flooding in the areas surrounding the basin, the project eliminates substantial damage repair costs. More efficient water management and capture techniques also ensures water security for the area and lowers the cost of water for the community.
Social: The project eliminates local street flooding during moderate storm events, which enhances public safety and health. A park was included in the design, providing the community with access to much needed public space to social interaction and recreation. Project components were designed based on key stakeholder involvement, including direct input on the design from community members.
Environmental: The construction of detention basins and wetlands will store and treat stormwater from the affected watershed prior to ground infiltration for recharge of local aquifers. The project also restores native habitat to the project site with native landscaping, and incorporates wetlands, infiltration trenches and basins, bioswales, and treatment trains to reduce pollutant load concentrations prior to ground infiltration. A detailed hazardous material removal plan was developed to contain, handle, and remove contaminated material safely from the project site.
The project earned an ISI Envision Platinum award for its management of the Sun Valley Watershed. It received 67% of the Department of Public Works' applicable Envision credits, which is the most any project has received to date from the rating system. Los Angeles County took a multi-benefit approach with input from multiple public and private stakeholders.