The Bureau of Reclamation has awarded a contract worth US$9.1 million to Gerber Construction Inc. for spillway improvement work at Utah’s 4.5-MW Echo Dam.
Reclamation last sought bids for the work in June, which includes: installation of soldier piles on the left side of the spillway and excavation on the left and right sides of the spillway; demolition of the parapet wall atop the dam and portions of the concrete spillway; jet grouting beneath the crest structure; installation of drains and filter material; construction of new crest structure and parapet wall; installation of low-voltage electrical distribution equipment; refurbishment of four gate hoists and four 18- by 17-foot spillway radial gates.
“Improving the seismic stability of the spillway structure is an essential component of the overall modification work under way at Echo Dam,” said Reclamation Commissioner Michael L. Connor. “This seismic improvement work performed under Reclamation’s Safety of Dams Program is vital to ensure the public safety.”
Echo Dam is a 158-foot-high earthfill structure on the Weber River. It was constructed as part of the Weber River Project to help supplement irrigation to about 109,000 acres of land west of the Wasatch Mountains. The project is owned by Reclamation and operated by the Weber River Water Users Association.
Prior studies at Echo Dam indicated the foundation underlying the dam and spillway are potentially liquefiable, which might cause the spillway and dam to deform during a “substantial” earthquake.
HydroWorld.com reported in August 2011 that Reclamation had awarded an $18.4 million contract to PNK Constructors LLC for dam safety excavation at the project that will modify the embankment and downstream foundation. That project is now expected to be completed by the end of 2014.