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Dam Safety & Security

FERC sets new policy on Part 12D safety inspections

The Federal Energy Regulatory Commission (FERC) announced a new policy for selecting independent consultants for Part 12D dam safety inspections.

The new policy stipulates an engineer or engineers from the same firm will not be approved as the independent consultant for more than two consecutive Part 12D safety inspections of any project. After two consecutive inspections by the same engineer or engineers from the same firm, the next Part 12D inspection must be performed by a different engineer not associated with that firm. Once consecutive inspections have been interrupted, the dam owner may return to the previous independent consultant.

Additionally, first Part 12D independent consultant inspections for newly constructed projects or projects where a major dam safety remediation recently has been completed may be performed by the design engineer or an engineer from the design engineer’s firm. However, the second Part 12D inspection must be performed by a different engineer not associated with either the design or construction firm.

Part 12D of FERC’s dam safety regulations requires projects be “periodically inspected and evaluated by, or under the responsibility and direction of, at least one independent consultant, who may be a member of a consulting firm.” The independent consultant must identify actual or potential deficiencies that might endanger public safety. Inspections typically are conducted every five years.

Limiting the number of consecutive inspections done by the same engineer was under consideration by FERC for some time. A review of the Part 12D program revealed that consecutive inspections by the same engineers is very common, with some projects inspected by the same engineer for five cycles, or 25 years.

Participants in the FERC potential failure mode analysis process noted that some Part 12D reports done by the same engineer tend to become “carbon copies” where, in some cases, incorrect information is carried over for many years. In addition, a panel of dam safety experts who conducted the recent peer review of the FERC dam safety program noted that even qualified consultants can miss an important consideration or make an incorrect judgment, and recommended limiting consecutive inspections by the same engineer.

Based on all of the above, FERC said an occasional inspection by a different engineer with a new perspective and insights can bring value to the Part 12D inspection process.

According to FERC, there is an understanding and appreciation that some dam owners have a preference and comfort level for independent consultants that they believe have done an excellent job over the years. Further, there is an appreciation on FERC’s part that the change might create a short-term inconvenience in the dam owners’ contracting arrangements.

In order to minimize contracting inconvenience, FERC said it would phase in the new requirement that will kick in every ten years. Dam owners who are coming up on the next Part 12D inspection will be informed of the change in the Part 12D inspection reminder letter, which is sent at least one year before the due date of the inspection report. In addition, an informational letter will be sent to all dam owners required to do Part 12D inspections.

Canadian Dam Association to hold annual conference

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The Canadian Dam Association will hold its 2007 annual conference Sept. 21-27 in St. John’s, Newfoundland.

The conference theme, “A Climate of Change,” reflects the evolving environmental, social, economic, and regulatory climates affecting Canadians specializing in dams, CDA said.

The conference will begin with a board of directors meeting Sept. 21, followed by a full-day workshop on practical applications of computational fluid dynamics Sept. 22. A half-day workshop on due diligence for dam industry professionals is scheduled Sept. 23.

Technical sessions are planned Sept. 24-26, and an awards banquet is planned Sept. 25. A technical tour Sept. 27 will include a visit to the Institute of Ocean Technology at the Memorial University of Newfoundland, and stops at the National Park at Cape Spear and Newfoundland Power’s 5.3-MW Petty Harbour Power Generating Station. The station, commissioned in 1900, is a member of Hydro Review’s Hydro Hall of Fame.

Registration information is available on the Internet at www.cdaconference.com.

ASDSO announces plans for 2007 conference

The Association of State Dam Safety Officials (ASDSO) will hold its 2007 annual conference Sept. 8-13 in Austin, Texas. The conference agenda is on the Internet: www.damsafety.org.

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The association’s board of directors will meet Sept. 8. Conference registration opens Sept. 9, and regional caucus meetings are planned that same day. The opening general session is scheduled Sept. 10.

The Dam Safety 2007 agenda features sessions on a variety of topics over three days, Sept. 10-12, including presentations grouped by subjects: application of roller-compacted concrete to dam and rehabilitation design; breach modeling; case studies in dam rehabilitation; dam failures and incidents; dam removal and environmental issues; embankments; embankment protection; emergency preparedness; focus on owners’ issues; geotech- nical issues; inspections; levees; mitigating seepage; risk; seismic issues: liquefaction; spillway hydraulics; structural issues; and tools and tips
for state programs.

The conference will feature an exhibition by companies providing services and equipment to the dam industry. As of May 14, 45 exhibitors had confirmed they would participate.

A field trip is planned Sept. 13 to dams owned and operated by the Lower Colorado River Authority.

Registration information is posted on ASDSO’s Internet site.

National Dam Safety Program approves research projects

The Federal Emergency Management Agency’s (FEMA) National Dam Safety Program is pursuing several new research projects. They include:

– Analyzing indirect means of assessing conditions within embankment dams. This research, being conducted by the U.S. Army Engineering Research Development Center (ERDC), is intended to determine the best available methods for locating seepage and seepage-induced voids within embankment dams. Phase I of this project, completed in fiscal year 2004, consisted of a literature and case history study. Following completion of the current analysis, known as Phase II, Phase III will be launched. Phase III, to be completed in fiscal year 2008, will involve field testing of select methodologies.

– Analyzing state dam safety programs. The U.S. Army Corps of Engineers’ ERDC is collecting and analyzing performance data from state dam safety programs for fiscal year 2006. The information is being compiled into a document that contains individual reports on each state, as well as ranked lists of states showing the greatest improvements in budget, number of inspections, and number of completed emergency action plans.

– Developing a technical manual, Best Practices for Design and Construction of Outlet Works Energy Dissipaters. The manual will consist of results from a study being conducted by the Bureau of Reclamation on the state-of-practice in the use of outlet works energy dissipaters. Topics to be covered include: existing designs, construction techniques, hydraulic and erosion problems, inspection frequency, repair techniques, vandalism, and public safety.

– Preparing “best practices” guidance for monitoring, measuring, and evaluating seepage through and beneath embankment dams. The initial phase of the project, being conducted by the U.S. Army ERDC, involves surveying the methods and knowledge applicable to seepage monitoring and measurement, using case studies and experiences from the Corps, Reclamation, the Natural Resource Conservation Service, state dam safety agencies, industry, private practice, and academia.

– Developing guidance for design and installation of granular filters within embankment dams. This project, also being conducted by the U.S. Army ERDC, is intended to provide guidance in the design and construction of filters for control of pore pressures and control of migration of soil particles in small to moderate-sized dams.

– Investigating best practices for the operation, inspection, and maintenance of gates. The U.S. Army ERDC is studying case histories and experiences of federal and state dam safety agencies and private dam owners to compare and contrast methods of operations and maintenance and their cost-effectiveness, and then will develop recommendations for effective methods for small to moderate-sized embankment dams.

FEMA’s National Dam Safety Program was established more than 25 years ago. This program is a partnership of the states, federal agencies, and other stakeholders to encourage individual and community responsibility for dam safety. The goal of the research work group of the National Dam Safety Program is to expand dam safety research to other institutions and professionals performing research in the field.

– For more information, contact Eugene P. Zeizel, PhD, civil engineer, National Dam Safety Program, (1) 202-646-2802; E-mail: gene.zeizel@dhs.gov.

Midwest Hydro Users Group sponsors dam safety week

The Midwest Hydro Users Group conducted a dam safety awareness week in Wisconsin in May to promote public safety awareness near dams and prevent accidents throughout the boating season.

The Wisconsin Department of Natural Resources, Wisconsin Public Service Corp., and Wisconsin Valley Improvement Co. joined with the Midwest Hydro Users Group to heighten the safety awareness of recreational and fishing enthusiasts. Gov. Jim Doyle proclaimed April 28-May 5 Dam Safety Awareness Week.

The Midwest Hydro Users Group is an association of dam owners promoting safe, efficient, economical, and environmentally friendly use of hydropower. It has organized awareness weeks each year for a number of years. The group said its members want anglers, boaters, and others to enjoy recreational resources on rivers and around dams in the region.

The Midwest Hydro Users Group, Department of Natural Resources, and local safety officials offered common sense tips to the public for staying safe on rivers and near dams:

 

There are about 3,800 dams in Wisconsin. Nearly 60 percent of the dams are owned by a company or by a private individual, 17 percent are owned by a municipality such as a township or county government, and 9 percent are owned by the state. Other ownership types represent 14 percent.

The federal government has jurisdiction over most large dams in Wisconsin that produce hydropower. That number represents about 5 percent of the total, or nearly 200 dams. The Department of Natural Resources regulates the rest of the dams.

Expert panel urges Corps to lower Lake Cumberland

An independent review panel commissioned by the U.S. Army Corps of Engineers urges the Corps to lower Lake Cumberland another 30 to 40 feet, due to “significant potential for failure” of 270-MW Wolf Creek Dam.

Acknowledging the risk of dam failure in January, the Corps announced it would lower the Kentucky reservoir – the largest east of the Mississippi River – to 680 feet above sea level. Normal pool levels are 723 feet in summer and 690 feet in winter.

The agency is conducting a two-year grouting program to strengthen the 5,736-foot-long, 258-foot-tall, rolled earthfill and concrete gravity dam, on the Cumberland River 300 miles upstream of Nashville, Tenn.

However, in a 71-page report released April 24, the Wolf Creek Peer Review Team said it discovered “compelling evidence” a piping failure mode exists at the dam and is advancing. “At this stage of failure mode development, the panel believes there is significant potential for failure of Wolf Creek Dam under the normal operating conditions,” the panel said.

Recognizing that it is difficult to predict when failure might occur, the group said it is essential for the Corps to take immediate short-term actions to avoid failure and to reduce risks to the public. Expedited investigations, design, and construction of long-term repairs also are needed, it said.

Despite the report, the Corps said it intends to maintain the reservoir at 680 feet through the end of 2007 while expediting the grouting program. Power can be generated when the pool elevation is at or above 680 feet.

Keith Ferguson, vice chairman of the peer review panel, told reporters the panel recognized that the Corps might choose a higher elevation than the 640 to 650 feet recommended. “The panel did recognize the potential to choose a higher elevation and has advised in the report that if that happens it is critical to continue to monitor the structure and grout the dam foundation in an accelerated fashion,” Ferguson said.

The Corps said it expects to complete the first part of the grouting program in September or October. The Corps said it would make a decision in the fall about the level for operating the reservoir in 2008.

Panel advances RCC replacement dam option

The peer review panel also said construction of a new concrete dam section might be a better long-term solution than the Corps’ current seepage repair plan. The panel recommends the Corps evaluate building a roller-compacted-concrete dam to replace a 4,000-foot-long earthen embankment versus proposed construction of a concrete cutoff wall through the dam.

The Corps said it would request full funding to $309 million from Congress to accelerate a program of grouting and construction of the diaphragm wall.

“While there are very significant considerations related to the excavation and preparation of a suitable foundation for an RCC alternative, it would offer a significant increase in reliability and safety,” the group said in its report.

The Corps said it already is taking a second look at the concrete dam proposal it once rejected as too costly. The idea was studied and ruled out several years ago, due to estimated costs of $500 million, compared to the current $309 million plan.

The Corps said the independent peer review validated its high-risk classification of the dam and the interim risk reduction measures it is taking.

Corps finds five other dams with high risk of failure

The Corps said it identified high risk of failure at Wolf Creek and five other dams during an initial screening of 130 dams in 2005 and 2006.

Other high-risk structures include:

 

The Corps screening found the six dams to be critically near failure or having an extremely high life and economic risk. All dams determined to be of highest risk are to undergo peer review by an independent external panel to ensure the Corps is taking the best approach to reducing risks to the public.

The Corps said it intends to screen for risks the remainder of the 610 dams it operates by the end of September 2010.


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