San Gabriel Dam Sediment Removal

In the 1990s, a forest fire ripped through the San Gabriel Mountains, sending as much as 6.1 million CY of sediment down into the San Gabriel Reservoir when the annual rains set in. So the County of Los Angeles Department of Public Works set out to restore this water storage and flood control facility by moving the sediment out gradually over five years when reservoir levels were low. They hired Barnard to do the work.

The project wasn’t accomplished without challenges, though. The Santa Ana sucker fish, a nationally Threatened species, finds its home in the San Gabriel River. Our Team worked with the U.S. Fish and Game and the County’s fisheries consultants, two of 12 stakeholder groups to be involved in this cleanup project, to ensure that our construction methods carefully avoided impacting them during our work onsite. We transported the vast amount of sediment during the summer to avoid having to work in the water, hauling it off with trucks, all of which had to travel on newly constructed private roads to avoid impact on the County and State roads. Three miles away up a canyon, we terraced, erosion-matted and seeded the newly formed hills and installed more than a mile of piping, building drainage aspects into the disposal site so LADPW could control future runoff. Capping off these successful efforts was our ability to complete the project two years ahead of schedule!

San Gabriel Dam Sediment Removal