San Gabriel Reservoir


In spring 2022, Ames Construction began a four-year effort to remove 5 million cubic yards of sediment from the San Gabriel Reservoir, which provides flood control and groundwater recharge for the San Gabriel Valley and Greater Los Angeles. The emergency restoration project was triggered by the 2020 Bobcat Fire and subsequent rains that washed sediment into the reservoir, reducing its capacity.

To begin work, millions of gallons of water from behind the dam were removed by Los Angeles County and Ames in order to expose the saturated sediment for excavation. Additionally, Ames diverted two streams by adding a series of berms and laying approximately 2 miles of pipe. All diversions and pipe crossings are approved by biologists who are working to ensure that fish are safely removed and relocated.

Saturated sediment is excavated and transported to drying stockpiles, where crews work the material to optimum conditions prior to placement and compaction. Once at optimum moisture, the sediment is hauled to the fill placement site. Ames is also rehabilitating the dam’s main outlet and sluiceway tower and tunnel as a part of this project.

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Los Angeles County