Lake Isabella Dam Safety Modification Project

Total Value:
Lake Isabella, CA
Description of Project:

The Lake Isabella Dam Safety Modification Project (DSMP) consists of several major modifications which will enhance the structural capability of the existing dam and will serve to increase public safety as well as restore the water storage capacity in Lake Isabella.  Improvements to the Isabella Dam have been contemplated for many years. The original Dam was completed in 1953, although since 2006 there have been concerns about seismic stability. These safety concerns along with ongoing seepage issues have caused the dam to operate at only limited capacity since that time.  The $241 million dollar construction effort to improve the Dam will be performed by the Joint Venture Team of Flatiron, Dragados, and Sukut (FDS) and will take about 3 years to complete.  The basic features of the contract work include:

  • Excavation of 2.95 million CYs of earth and rock for a new emergency spillway;
  • Construction of a 28 foot tall Labyrinth Weir using 56,000 CYs of structural concrete;
  • Buttressing and raising the existing dam structures by 16 feet;
  • Improvement and enhancements of the Dam foundation;
  • Processing and placement of more than 2.3 million CYs of Zoned Fill embankment;
  • Modifications to CA State Route 155 to accommodate the increased dam height;
  • Site work and improvements to several adjacent recreational facilities and roadways.

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