Los Cerritos Stormwater Capture Facility


The thousands of miles of concrete channels diverting street water from the San Gabriel and Los Angeles rivers represent the last major water project in Los Angeles County, built almost 100 years ago. Currently, the State of California is focusing on stormwater conservation, and this stormwater capture facility utilizes the network of rainwater captured by these man-made rivers and repurposes it for beneficial use.


Value: $9M
Type: Design-Build
Owner: City of Signal Hill 
Location: Signal Hill, California


The Los Cerritos Channel Storm Water Capture Facility is one of the largest and most important environmental infrastructure projects under construction in Los Angeles County. Phase I of this stormwater capture facility project, which will capture water at a rate of 166 cubic feet per second, is the first of a multi-phase program. The first phase has a capacity of 14 acre-feet of stormwater or about 14.5 million gallons. The second and third phases, once funded, will be built under adjacent airport land and a nearby parking lot. This type of advanced stormwater capture project provides a locally-sourced water supply, weaning cities and water districts from dependence on more expensive, imported water from Northern California and the Colorado River.


This project intercepts channelized stormwater heading to Alamitos Bay by sending it to twin centrifuge-type machines called hydrodynamic separators that remove garbage, sediments, and grime that are taken to a landfill. The cleaner water is sent through a massive pipe into an underground cistern 660-feet long and 14 feet high, where the effluent can slowly percolate through porous gravel into the ground to be pumped out as potable, or drinking, water.


G3 Quality is providing quality control services including on-site concrete sampling, structure backfill testing, compaction control, and geotechnical services.