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Dam Safety & Security

Echo Dam dewatering contract awarded

The Bureau of Reclamation has awarded a $1.3 million contract for foundation dewatering work at Echo Dam in Utah to Foothill Engineering & Dewatering Inc. of Corona, Calif.

Echo Dam is a 158-foot-high zoned earthfill structure on the Weber River in Summit County. Part of the Weber River Project, Echo Dam was completed in 1931 to help supply supplemental irrigation water to about 109,000 acres of land west of the Wasatch Mountains. Echo Dam is operated by the Weber River Water Users Association.

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.

A pumping discharge system was constructed in May to lower the groundwater level 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 after 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. Future work on the foundation and spillway may affect reservoir operations in 2012 and 2014.

GEI Consultants implementing FloodSAFE program in California

The California Department of Water Resources selected GEI Consultants Inc. to act as management engineering consultant on the FloodSAFE California program.

FloodSAFE is a long-term initiative established in 2006 to improve integrated flood management in California through a system-wide approach, while reducing flood risk at regional and local levels. Programs established under FloodSAFE include the Levee Evaluation Program, Floodplain Evaluation and Delineation Program, Flood Projects and Grants, Flood System Operations and Maintenance, Flood Emergency Response, and Flood Management Planning Program.

GEI will provide technical advice and consultation in engineering and environmental program planning and management partnership, program tracking and reporting, policy development activities, and communication and outreach activities. In partnership with the FloodSAFE Program Management Office, GEI will provide specialized expertise and training to prepare FloodSAFE managers for near- and long-term program management responsibilities.

Corps moving forward with Canton Lake Dam work

The U.S. Army Corps of Engineers is recruiting companies to build a concrete weir and hydraulic structures as part of an auxiliary spillway at Canton Lake Dam in Oklahoma.

Canton is a 68-foot-tall, 15,140-foot-long earth-filled embankment structure on the North Canadian River that includes a 778-foot-wide service spillway at the right abutment with 16 tainter gates. Corps hydraulic studies found the existing spillway is unable to discharge a probable maximum flood and the dam is likely to fail during a major flood.

The Corps has begun construction of an auxiliary spillway at the right abutment. A 480-foot-wide auxiliary channel has been partially excavated. Fifty-foot-tall vertical diaphragm walls line the channel. The Corps chose a Fusegate system from Hydroplus Inc. for the new spillway.

The next phase of the work includes placement of a concrete weir about 35 feet deep and 70 feet long spanning the width of the channel. Other work includes a 40-foot-tall water intake monolith with a 47- by 15-foot base; 250 feet of 11-foot-diameter conduit; 30-foot-tall, 50-foot-wide Fusegates, diaphragm walls with anchors; and stoplog manufacture.

The work is valued at $25 million to $100 million.

USSD names new officers; presents awards, scholarships

Officers for the U.S. Society on Dams (USSD) for 2011-2012 are: Michael F. Rogers, MWH, president; Walter L. Davis, Seattle City Light, vice president; and Keith A. Ferguson, HDR Engineering Inc., secretary-treasurer.

Officers were announced at USSD’s 2011 annual meeting and conference in San Diego, Calif. During the meeting, USSD presented multiple awards:

Corps to stabilize bluff at 100-MW Old Hickory

The U.S. Army Corps of Engineers plans to perform bluff stabilization at the 100-MW Old Hickory project on the Cumberland River in Tennessee.

Old Hickory is among nine Corps hydro plants on the Cumberland that a study found need as much as $470 million in repairs.

The Corps’ Nashville District will hire a contractor to stabilize the right abutment bluff by placing reinforced shotcrete in three areas. Work includes scaling the rock bluffs to remove overhangs and irregularities and installing rock dowels, wire mesh reinforcement and fiber-reinforced shotcrete. The work is expected to cost $1 million to $5 million.

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