Pasadena Launches $441,000 Study For Underground Stormwater System To Capture Fire-Zone Runoff

Pasadena is moving forward with plans for an underground stormwater capture system at Jefferson Park designed to intercept polluted runoff from areas burned in the Eaton Fire.

The Department of Public Works will present the project to the Municipal Services Committee at 4 p.m. Tuesday in City Council Chambers at City Hall.

The proposed system would divert storm and dry-weather flows from the Sierra Bonita Drain into an underground infiltration gallery capable of storing roughly 3.5 acre-feet of runoff per storm and up to 38.5 acre-feet annually. All dry-weather flows would be captured and infiltrated into the Raymond Basin.

The city has secured $441,000 for pre-design work—$250,000 from Measure W Local Return funds for the feasibility study and $191,000 from a grant by SCWP and the Water Foundation for community outreach. Design and construction funding remains unsecured.

The project addresses a 567-acre drainage area, though only about 81 acres lie within Pasadena city limits. The remaining 485.7 acres are in unincorporated Los Angeles County, including zones impacted by and downstream from the Eaton Fire.

Surface improvements under consideration include bioswales, vegetated infiltration basins and drywells to slow, treat and infiltrate runoff while targeting zinc, bacteria and trash.

The project is driven by Pasadena’s Municipal Separate Storm Sewer System Permit, which requires cities to manage runoff, reduce pollutants flowing to the Los Angeles and Rio Hondo rivers, and implement capture measures meeting water quality limits. Jefferson Park ranks among 10 Priority 1 projects identified in Pasadena’s 2022 Storm Drain Master Plan for citywide compliance.

The city has hired Craftwater Engineering for feasibility study development and Dudek/Amigos de Los Rios for outreach support. Both firms have Pasadena offices.

Pre-design work began in December and should conclude by August. The feasibility study kicked off in January. A draft design concept is expected in March, with the full study complete by June. The city plans to submit design funding applications in July.

The outreach program will include a community needs assessment, pop-up activities, an open house and bilingual educational materials. A project website will be developed to promote transparency.