Work progressing on Bluestone Dam stability project
The U.S. Army Corps of Engineers plans to award a contract in the fall of 2010 for Phases 3 and 4 of its Bluestone Dam stability project and to complete work on Phase 2B in mid-2011.
Phase 4 is scheduled to begin in 2012 or 2013. The Corps anticipates completing work on Phases 3 and 4 in 2014, says Lisa R. Morgan, the Corps' project manager for the Bluestone Dam Safety Assurance Program. The Phase 5 contract is expected to be awarded in 2015, with overall project completion in 2020.
Bluestone Dam is on the New River in West Virginia. The dam, which contains 55 monoliths, began operation in 1948.
The Dam Safety Assurance Program provides for modification of Corps dams that are potential safety hazards in light of present-day engineering standards, Morgan says. Based on current hydrologic and structural criteria, the potential exists for initiation of failure of Bluestone Dam at a water elevation below the existing top of the dam. A downstream hazard assessment indicates there is sufficient justification to modify the project to accommodate 100 percent of the probable maximum flood.
Work to be performed to correct deficiencies is anticipated to cost more than $250 million and includes:
- Raising the dam 8 feet by installing a precast concrete wall;
- Stabilizing the dam with anchors and mass concrete thrust blocks;
- Improving the spillway; and
- Modifying six penstocks to increase discharge capacity, and installing scour protection for the penstocks.
- Phase 1 consists of construction of a temporary access bridge below the dam, construction of a thrust block, extension of three of the penstocks, and installation of sacrificial bulkheads on three of the six penstocks. The construction contractor for this phase was ASI RCC Inc. The contract was awarded in 2000, and work was completed in 2004.
- Phase 2A includes improvements to the access road on the west side of the dam, construction of a fishing pier on the west side, and construction of an additional monolith on the east abutment. The contract was awarded in 2004 to Ahern & Associates, and work was completed in 2007.
- Phase 2B consists of installation of 150 high-strength anchors for critical monoliths and the sacrificial bulkheads on the remaining penstocks. American Recovery and Reinvestment Act (ARRA) funding increased the number of anchors installed to 204, which will increase the elevation of flood waters that can be held by the dam. The installation of apron drains in the stilling basin and reaming of gallery drains in the dam will increase stability. Brayman Construction Corp. began work on this contract in August 2009, and ARRA funding extended the completion date to 2011.
- Phase 3 includes installation of scour protection and training walls for the penstocks.
- Phase 4 includes installation of about 60 high-strength anchors, primarily over the stilling basin.
- Phase 5 includes spillway improvement, installation of an 8-foot pre-cast concrete parapet wall, and mitigation features.
The U.S. Department of the Interior's Bureau of Reclamation plans to hire a firm to serve as a senior dam safety and geology consultant to the agency's Salt Lake City Regional Office.
Reclamation's Upper Colorado Region said it is seeking a consultant to provide dam safety and geology program technical support to the region's Security and Dam Safety Group.
Reclamation seeks a consultant with an expert level of knowledge and experience in geology related to dams and the agency's Dam Safety Program, with particular emphasis on the Safety Evaluation of Existing Dams and Safety of Dams process. The work is valued at between $50,000 and $1 million for one base year and four one-year option years.
For information, contact Louise Hancock, (1) 801-524-3756; E-mail: firstname.lastname@example.org.
FEMA releases fact sheet on reducing dam risk
The Federal Emergency Management Agency (FEMA) offers the Planning to Reduce Dam Risk Fact Sheet.
About 14,000 dams in the U.S. are classified as high hazard potential, meaning that their failure could result in loss of life, the fact sheet says. Other classifications of dams can result in significant property damage, critical utility disruption, and environmental damage.
The fact sheet says the most important steps a dam owner can take to protect from dam failure are to know the risks and to make sure an emergency action plan (EAP) is in place. The fact sheet provides links to resources for preparing an EAP, as well as links to websites that can provide more information.
– To print the fact sheet, visit the Internet: www.fema.gov/library and search for keyword "dam safety," hazard type "dam/levee break."
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