Big Tujunga Dam Seismic Retrofit


Los Angeles County Department of Public Works

Project Location

Tujunga, CA 91042

Project Cost


Services Provided

  • Overall Construction Management of Project
  • Clerical/Document Control

Project Features

  • New thickened arch dam
  • New spillway
  • Rock bolting
  • New valves and valve house
  • New control house and generator buildings
  • Low-flow valve to supplement stream flow and support habitat enhancement in Big Tujunga Creek

The Los Angeles County Department of Public Works, as part of a county-wide initiative to upgrade the seismic capacity of critical water conservation and distribution resources, enhanced the capability of the Big Tujunga Dam. Work on the Big Tujunga Dam Seismic Rehabilitation and Spillway Modification Project started in April 2008. The project benefits included: increased flood control, greater water conservation, dry season habitat enhancement for the endangered Santa Ana Sucker fish, and improved dam safety. The water conservation benefits from this project are expected to be 4.500 acre-feet per year – enough to meet the water needs of 20,000 people for a year. The major features of the project included:

  • A thickened arch dam cross section to resist seismic loads
  • Central overtopping spillway/parapet walls to pass probable maximum flood
  • Extensive rock bolting and rock anchoring
  • Application of shotcrete to the steep canyon walls to reduce canyon erosion
  • Construction of a new valve house with new water control valves to provide greater control of water releases for the dam
  • Construction of a new control house and electrical distribution system with generator backup that will maintain operational capability during and after a major earthquake