Dam Safety & Security

Amendment to dam safety act could enable dam repairs

A proposed amendment to the Reclamation Safety of Dams Act of 1978 by Oregon Sen. Ron Wyden has the potential to lead to improvements at a number of dams, including Scoggins Dam in Gaston, Ore.

The amendment proposed by Sen. Wyden would adjust the spending cap on dam safety-related construction work for 476 dams and dikes that are owned by the U.S. Department of Interior’s Bureau of Reclamation and spread across 17 western states.

Previous revisions to the 1978 act set the limit at US$1.4 billion in annual dam safety spending for these dams and dikes. With that money, 85% of most dam safety improvements are covered by the federal government, while the operator picks up the remaining tab. The changes would allow for additional spending should dam safety projects require more money than the operator is able to contribute.

Scoggins Dam is owned by Reclamation and operated by Tualatin Valley Irrigation District. The dam requires preventative renovation to withstand the risk of seismic activity, which would damage the properties of and endanger 4,000 people. The desired renovations are expected to cost US$340 million. Reclamation is currently investigating the options available to address the concern.

The bill was introduced in the Senate on Jan. 16 and is co-sponsored by Sens. Dianne Feinstein of California and Brian Schatz of Hawaii. It has been passed to the Senate Committee on Energy and Natural Resources for further consideration.

TVA adding personnel to its dam safety review board

The Tennessee Valley Authority recently announced it was seeking candidates for positions on its Dam Safety Independent Review Board (IRB), which serves in an advisory role to TVA’s dam safety officer.

The IRB’s responsibilities include assessing consistency with industry practices and standards; assessing structural, hydrologic and seismic adequacy; suggesting integration of new development and philosophies into TVA’s Dam Safety Program; and recommending solutions to dam engineering problems.

TVA said the board also participates in and provides oversight for periodic reviews of its safety program and analysis, design, construction, operation and rehabilitation of the dams it owns and operates.

The board includes members with expertise in the following:

– Establishing policies and procedures for dam safety;

Development and application of risk-informed decision-making approaches;

Hydrologic analysis of river systems;

Analysis of concrete and embankment dams; and

Geologic/geotechnical engineering.

HydroPlus to perform dam safety improvements

Fusegate system developer Hydroplus Inc. has been awarded contracts for work on two Pennsylvania dams: Pikes Creek Dam and Springton Dam.

The company said it was selected by the Pennsylvania-American Water Company for work on its Pikes Creek project after it was discovered that the dam had several safety deficiencies, including an inadequate spillway capacity.

Hydroplus said it worked with PAWC’s main consultant, Gannett Fleming Inc., to design the Fusegates used for the project. According to Hydroplus, the project includes the removal of existing flashboards at the auxiliary spillway, lowering the spillway sill and installing a 9.33-foot-high by 13.89-foot-wide Fusegate system. The gates will be made in pre-cast concrete with steel inlet wells.

Engineering work on the Pikes Creek project will be completed by the end of the year, with construction taking place in 2016.

Similar dam safety deficiencies were found at Springton Dam, owned by Aqua Pennsylvania Inc., with Gannett Fleming again serving as the main consultant.

The project will see Springton’s spillway sill lowered and 4.5-foot-high by 20-foot-wide Fusegate modules installed along the 300-foot-wide spillway. At Springton dam, unlike the conventional design where each inlet well is located directly on the Fusegate’s crest, they will be gathered in two separate enclosed structures on both spillway abutments in order to cope with hydraulic constraints of the spillway. The inlet wells will be connected to the Fusegates’ chambers by pipes embedded in the spillway sill.

The company will serve as subcontractor to the selected general civil contractor in supplying and installing the Fusegates during the construction stage.

Fusegates are modular units installed side-by-side on a dam’s spillway crest. The modules are held in place by gravity and then linked by sealing joints, creating a watertight wall that increases reservoir capacity or flood discharge potential.

Corps grants contracts for multiple civil works projects

The U.S. Army Corps of Engineers has granted a number of contracts to engineering firms for infrastructure work in the Great Lakes, Ohio River, Louisville, Midwest, and Mississippi river districts.

The Corps granted a $9.5 million contract for architect-engineer services to Woolpert Inc. The contract includes four separate contracted services for Army, Air Force, other military and civil works projects, primarily located within the Great Lakes and Ohio River districts of the eastern U.S.

The work will include civil works projects such as flood damage reduction studies and designs, ecosystem restoration, stream bank erosion control, navigation improvements, additions and repairs to locks and dams, geotechnical investigations to improve dam safety, levee and floodwall evaluation and design.

An additional $9.5 million contract was granted to Tetra Tech/Pond & Co. for a range of military and civil works projects in the Great Lakes and Ohio River Divisions.

Work is to include military projects for the Army, Air Force, and other military customers of the Louisville District, including construction solicitations and preparation of requests for proposals for design-build projects. It is also to include civil works projects such as flood damage reduction studies and designs, ecosystem restoration, stream bank erosion control, navigation improvements, additions and repairs to locks and dams, geotechnical investigations, and levee and floodwall evaluation and design.

Finally, Gestra-Stanley Joint Venture has won a US$9 million contract from the Corps to work on dams and other projects in the Mississippi Valley and Midwestern U.S..

Per the award, Gestra-Stanley will provide structural, civil, geotechnical, hydraulic and hydrologic, mechanical, and electrical engineering services. The group will also perform architecture, landscape architecture, cost engineering, surveying, cartography, and specification writing services, the Corps said. Work on locks and dams, flood risk management, and other civil works would be performed primarily within the St. Paul, Rock Island, and St. Louis districts in Minnesota, North and South Dakota, Wisconsin, Illinois, Missouri and Iowa.

Correction

In the December issue, the caption on page 20 incorrectly described the photo as the original control room of TransAlta Corp.’s 19-MW Kananaskis hydroelectric project. The photo was actually of the head office in the 1980s. The editors regret the error.

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