Echo Dam Embankment Seismic Modification Contract Awarded
Media Contact: Lisa Iams, (801) 524-3673
For Release: August 26, 2011
The Bureau of Reclamation has awarded an $18.4 million contract to PNK Constructors LLC of Coalville, UT, for foundation and embankment seismic improvement work at Echo Dam, Summit County, UT. The work is being done under Reclamation's Safety of Dams Program to increase the dam's ability to withstand a major earthquake.
"The important work to be done under this contract will greatly improve the seismic stability of this facility which ensures public safety," said Reclamation commissioner Michael Connor. "Under Reclamation’s Safety of Dams Program, upgrading older facilities which pre-date current seismic design standards continues to be a priority."
Under this contract, a large excavation on the downstream side of the dam will remove loose and liquefiable foundation soils, and the excavation will be refilled with dense compacted materials. In addition, a large stability berm will be constructed on the downstream side of the dam; the dam’s crest will be raised three feet; and a second stability berm will be added on the upstream side of the dam. The work is scheduled to take place between October 2011 and winter of 2013.
Prior field investigations at Echo Dam indicated that the foundation soils underlying both the dam and spillway are potentially liquefiable during a substantial earthquake, which could cause the dam and spillway to deform. A second contract to modify the spillway is scheduled to be awarded in September 2012. The entire seismic modification project is scheduled to be completed by the end of 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, UT. 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.
Local traffic and nearby citizens may be affected when the work begins. Reservoir releases will occur as usual and water levels will fluctuate normally through the spring of 2012. However, in the summer of 2012 the reservoir level will be drawn down more rapidly than normal to accommodate the work. Reservoir operations may also be affected by the spillway modification work into 2013 and 2014.
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