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Calaveras Dam Replacement (WSIP)

Project Updates
Calaveras Road is open to the public, 7 days a week.

Construction began in 2011 to build a new earth and rock fill dam adjacent to the existing dam. To date, the Contractor has moved over four million cubic yards of earth and rock materials and started to construct the new dam. Crews have prepared disposal sites, completed grouting operations on the right abutment, and constructed a new shaft and three adits which connect to the reservoir. We have also started building the upstream shell of the new dam and begun major excavation work on the new spillway. Our teams work daily to protect the environment, to preserve the pristine watershed lands and natural habitats surrounding the project. As of December 2013, the Calaveras Dam Replacement Project was 56% percent complete. Much work still lies ahead to complete this important feature of the Hetch Hetchy Regional Water system.

In June 2012, we discovered unexpected geologic features during excavation of the left abutment area. These uncovered geologic features were not visible at the ground surface during the extensive geotechnical investigation work performed during the planning and design phases of the project. The findings have resulted in over 3 million cubic yards of additional material that needs to be moved in order to ensure the long-term stability of the slope during the performance life of the dam. Due to the additional time needed to excavate these materials, we anticipate a 25-month delay to the original project schedule which would put the completion of construction activity at the end of 2017. At this time, exploratory core borings are being done to further characterize the geology.

Future Road Closure
A future 18 month road closure is scheduled to begin sometime in 2015. During the closure, Calaveras Road will be CLOSED to vehicle, pedestrian, and bicycle traffic between Geary Road to the Alameda / Santa Clara County boundary, weekdays only. To stay updated, please join our road closure notification mailing list by emailing: or calling our 24 hour answer hotline at (866) 973-1476.

Project Description
The project consists of building a new zoned earth and rock fill dam immediately downstream of the existing dam. The replacement dam will have a structural height of 220-feet high and is designed to accommodate a maximum credible earthquake on the Calaveras Fault. The dam will have a crest length of 1,210 feet, a base thickness of 1,180 feet, and crest thickness of 80 feet. The total volume of the dam will be approximately 3.5 million cubic yards. The replacement dam will restore the original reservoir capacity of 96,850 acre-feet, or 31 billion gallons of water.

Project Information

    August 2011
    November 2017
  • COST
    $643 Million

Additional Information

The information shown reflects the current forecast information published in the latest WSIP Quarterly Report.

Fact Sheets
Calaveras Dam Replacement Project
Fact Sheet - January 2014

Naturally Occurring Asbestos Information and Data:
- Air Monitoring Results

Environmental Impact Report:
- Calaveras Dam Replacement Project Final    Environmental Impact Report

- Calaveras Dam Replacement Project Final    Environmental Impact Report Addendum

- Calaveras Dam Replacment Project - Addendum to EIR July 2013

Summary Data Reports from Air Monitoring Events:
- August 2008 through August 2009
- September 2009 through July 2010
- August 2010 THROUGH November 2010


Need More Information? Contact:

Maria Le
Phone: (925) 493-4535 or

Betsy L. Rhodes
Phone: 415-554-3240 or

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