Adventure Park Multi-Benefit Stormwater Capture Project | 2025 Top Projects

This project, which was initiated to support compliance with the Regional Phase I Municipal Separate Storm Sewer System (MS4) permit for Los Angeles and Ventura counties, sought to find the right balance for improving regional water quality while also delivering long-lasting community benefits. The project’s main element is an advanced stormwater capture and treatment system to address persistent pollution challenges, especially targeting zinc, which is the San Gabriel River Watershed’s limiting pollutant.  

The project captures stormwater runoff from a 6,985-acre drainage area through an integrated system designed for performance and sustainability. The system includes a controlled dam diversion structure, pretreatment systems, an underground storage reservoir, pump stations and a filtration system. It has a capture capacity of 19.5 acre-feet per storm event, and captured flows are treated and stored on-site before being conveyed to the sanitary sewer system.  

On top of those stormwater elements, the project also boasts five acres of enhanced park space, including renovated restrooms, baseball fields, fitness equipment, drought-tolerant landscaping, restored walking paths, a bioswale and new trees, benches and educational signage.  

This multifaceted project did not come without challenges. Specifically, high groundwater levels made traditional infiltration for groundwater recharge infeasible. This is when the team decided to capture urban and stormwater runoff for beneficial reuse. This high groundwater table also required innovative site management, which included pumping and onsite treatment systems to remove contaminants before discharging the water into an open channel.  

Additionally, the project involved the community — who attended public engagement sessions where residents requested restrooms and water fountains that were included in the final project.