The Bureau of Reclamation has awarded a $1.3 million contract for foundation dewatering work at Echo Dam in Summit County, Utah, to Foothill Engineering & Dewatering Inc. of Corona, Calif.
Foundation dewatering immediately downstream of the dam is necessary to facilitate seismic retrofit work to be done under Reclamation's Safety of Dams Program, which ensures dams are inspected for safety deficiencies and corrective actions are implemented if necessary.
Beginning in May, a pumping discharge system will be constructed and maintained to lower the groundwater level downstream of the dam in preparation for, and throughout subsequent excavation work in which potentially liquefiable foundation material will be removed and replaced with stronger, denser material. This will enhance the dam's ability to withstand a significant seismic event.
Reclamation began installing numerous dewatering and observation wells to facilitate the seismic retrofit work last fall following the completion of a risk-analysis and corrective action study done by Reclamation and reviewed by a board of independent consultants.
The contract for the foundation modification work is anticipated to be awarded in the fall with the work concluding in the winter of 2012/2013. Local traffic will not be affected by the work. Regular reservoir releases will continue with normal water level fluctuations through 2011. Future work on the foundation and spillway will be coordinated between multiple water districts and may affect reservoir operations in 2012 and 2014.
Echo Dam is a 158-foot high zoned earthfill structure on the Weber River, located one mile upstream from the town of Echo and 42 miles southeast of Ogden, Utah. Part of the Weber River Project, Echo Dam was constructed between 1927 and 1931 to help supply supplemental irrigation water to approximately 109,000 acres of land west of the Wasatch Mountains. Echo Dam is operated by the Weber River Water Users Association.
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