RCC Dam to Provide a Reliable Drinking Water Source

Elkwater Fork Dam is a new roller-compacted concrete (RCC) gravity dam designed to provide a reliable source of drinking water to the 21,500 residents in Elkins, W.V. and surrounding communities. Randolph County has an annual precipitation of nearly 60 inches, making the area an ideal location for a 54-acre water supply reservoir.

At 128-feet high and having a total length of 670 feet, the Elkwater Fork Dam contains 139,000 cubic yards of RCC. Additionally, the upstream face of the dam is formed with 6-foot high by 16-foot long precast concrete panels. Its downstream face is formed with 2-foot high steps constructed with conventional concrete placed concurrently with the RCC within the spillway.

Design of the project began in 2001 with the initiation of construction occurring in 2006. The RCC placement was completed in 2007 and the project, including installation of the grout curtain, is scheduled to be completed this month. The filling of the reservoir is planned to begin in the fall of 2008.

Gannett Fleming, Inc., of Harrisburg, Pa., completed the design of the project and Heeter Construction Company, Spencer, W.V., was the prime construction contractor. The project has been managed by the Natural Resources Conservation Service in Morgantown, W.V.

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Q: Could RCC dams be founded on non-rock foundation?

A: Although most concrete dams—including RCC dams—are founded on sound rock, for small dams, a rock foundation is not always necessary. However, before placing RCC dams on other than high-modulus rock foundation, design engineers need to carefully evaluate several factors including differential settlement, seepage, uplift pressure distribution, piping potential, and hydraulic erosion of the foundation due to spillway or conduit flows.

History has shown that the potential for failure of concrete dams is extremely remote. However, nearly all such failures have occurred through foundation materials rather than the concrete in the dam. Because each potential dam site is unique, engineers experienced in the evaluation of foundations for dams should investigate the site and determine what foundation improvements are needed. More on foundations for RCC dams.

Consultant Hired to Review Seepage at Repaired New Orleans Levee

On July 23, ENR.com reported that the Southeast Louisiana Flood Protection Authority-East decided to hire a consultant to evaluate seepage within the levee T-wall replacement that was built after hurricane Katrina according to the recommendations of the USACE-sponsored forensic team. The Corps believes water is leaking through the T-wall joints or the steel sheetpile interlocks. They also believe that the water leaks are minor and the wall is structurally sound. However, Tim Doody, SLFPA-East president, stated that the authority decided to determine whether or not something needs to be done. Read the ENR.com article.

Future of Acceler8 Unknown

The future of the largest environmental restoration project in the world is unknown or at least on hold. Acceler8 program covers eight projects sponsored by the federal government and the state of Florida to accelerate funding and stepping up the pace to restore America’s Everglades. South Florida Water Management District, the state agency in charge of the project, voted in May of this year to halt work at the program flagship; Everglades Agricultural Area Reservoir A-1. If completed, the reservoir would be the largest of its kind in the world. Approximately $250 million have been already spent.

The decision came after the Natural Resources Defense Council, National Wildlife Federation, and Sierra Club sued U. S. Army Corps of Engineers alleging the reservoir’s construction violated the Comprehensive Everglades Restoration Plan. The plaintiff fears the water could be diverted for purposes other than restoring the Everglades. Mediation to resolve the dispute started in June.

The future of the huge Acceler8 program is also affected by the deal for Florida to buy out the largest U.S. producer of cane sugar, U. S. Sugar Corporation, and make the firm’s 292 square miles of land available for Everglades restoration, as reported by Environment News Services. The land would be used to re-establish a part of the connection between Lake Okeechobee and the Everglades through a managed system of water storage and treatment. These developments not only delay the construction of EAA Reservoir A-1 but also require rethinking of the entire restoration plan, which originally included construction of three large reservoirs in addition to the halted EAA Reservoir A-1. More information from SFWMD.

Ten Years From Now, Who’ll Be Watching the Dams?

ASDSO's Student Employment Opportunities Clearinghouse was created in response to a dwindling supply of college graduates qualified to enter fields in dam engineering and safety.

ASDSO invites all employers who provide internships and co-ops in dam-related fields to post their information at no charge in the Career Center of the ASDSO Web site. Employers who employ students may post profiles and contact information if all positions are currently filled.

ASDSO plans to publicize this Web site tool to universities throughout the U.S. as soon as the database is populated with information about student-friendly companies, agencies and organizations.

Please join the effort to help attract and recruit more young people into this special field of engineering by taking advantage of this free tool. More information on the ASDSO Career Center.

HydroVision 2008

More than 270 organizations including PCA exhibited at HydroVision 2008 conference to showcase their products and services on July 14-18 in Sacramento, Calif. Attendance exceeded a record 2,300 delegates from 57 countries sharing an interest in hydropower, dams, and water resources. They gathered to hear experts and learn about today’s technology during a 3-day program that included 50 panel discussions, 100 technical paper presentations, and 40 poster gallery presentations.

Speakers presented on hydraulic structures, water resources, operation and maintenance, policies and regulations, and more. Fares Abdo of PCA presented “RCC Trends in Early 21st Century Medium-Size Dams.” He covered RCC mixtures, design, quality control, and construction means and methods implemented at five RCC gravity dams built in U. S. between 2004 and 2008. Abdo also discussed positive environmental impact, energy conservation, and sustainable development when building RCC dams with on-site aggregates to reduce hauling distance and when byproduct materials such as non-spec fly ash that is normally not used in conventional structural concrete are incorporated in the RCC mixture.

See/Hear Us at:

ASDSO Dam Safety 2008 Conference
September 7-11, Indian Wells, Calif.

ASDSO's annual conference offers a unique blend of training in both technical and practical dam safety applications, along with the opportunity to network with a variety of professionals representing all aspects of the dam safety community.