Cogswell Reservoir

Cogswell Dam, San Gabriel Dam, and Santa Anita Dam play a critical role in safeguarding the Los Angeles County flood control system. However, the devastating 2020 Bobcat Fire wreaked havoc on the Angeles National Forest, including the watersheds that feed into Cogswell, San Gabriel, and Santa Anita Reservoirs. The aftermath of the fire left these watersheds devoid of vegetation, significantly increasing the risk of sediment accumulation in the reservoirs over the coming years. Such sediment accumulation would pose a serious threat to the flood control and water conservation capabilities of these dams.

After most of the sediment was removed by the general contractor, our team was entrusted with the challenging task of abandoning the existing old 102” and 84” diameter Corrugated Steel Pipes (CSPs) and Access Shafts in the affected areas.

This innovative approach had multiple advantages. Firstly, it eliminated the need for extensive trucking to transport legacy materials like a 1-sack slurry to the project site. This not only saved significant time and resources but also reduced the project’s environmental impact. Additionally, the project site’s remote location presented communication challenges due to limited cell service. However, our team adapted to these conditions and successfully overcame the obstacles.