R&D Forum

Testing reveals promise of silicon foul release coatings

Results of testing at the Bureau of Reclamation’s Technical Service Center indicate silicone foul release coatings may be an important tool for mitigating the impacts of invasive quagga and zebra mussels on water and hydropower infrastructure.

These invasive species have spread to many areas of the U.S., with zebra mussels reported within, or in waters adjacent to the borders of, 30 states as of 2011. Quagga mussels have been reported in 15 states. These mussels can impair or interrupt water delivery and hydropower generation functions and disrupt aquatic food chains by filtering out plankton upon which fish and other organisms feed.

Allen D. Skaja, PhD, tested more than 50 coatings and metal alloys over three years at Parker Dam on the Colorado River. The coatings and metal alloys tested can be divided into six broad categories: conventional epoxies with no fouling control, foul release coatings, antifouling coatings, fluorinated powdered coatings, metallic coatings and metal alloys. The coatings were tested in still and flowing water.

Skaja found that silicone foul release coatings reduced the rate of mussel settlement and made it easy to remove any attached mussels. “In many cases, it was found water flowing at 0.1 feet per second provided sufficient force to remove mussel colonies,” he says.

One problem with silicone foul release coatings is that they are not durable. Initial research found these coatings are soft and easily damaged by floating debris or mechanical abrasion, such as a trashrack being cleaned. Further research is under way to find a silicone foul release technology that will meet the abuse coatings on facilities must take, Reclamation says.

Parker Dam was chosen as a field test site because the quagga and zebra mussels infesting this location reproduce throughout the year and have a high growth rate, Reclamation says.

This research was funded by Reclamation’s Research and Development Office, where research is conducted to develop and deploy successful solutions to improve water management practices, increase water supply and ensure cost-effective power generation operations.

– The complete report is available on the Internet at www.usbr.gov/mussels.

EPRI looking for test sites for fish-friendly Alden turbine

A grant from the U.S. Department of Energy will allow the Electric Power Research Institute to seek an evaluation site for a new turbine.

EPRI says it hopes test the turbine, which was created at Alden Research Laboratory, at an existing or new hydropower development to study fish passage survival and operational turbine testing.

The ideal site for the demonstration site would have an approximate gross head between 30 and 120 feet and available flow for a new turbine between 1,000 and 2,000 cubic feet per second.

Other sites may be considered, assuming they meet other criteria related to engineering, operational and biological performance.

EPRI has US$3 million available for site design engineering and installation planning. The institute says it will seek further funding from industry and government sources.

The institute says the project “presents an opportunity to lead the industry in completion of a strategic research and development initiative, obtain cost-share funds to minimize investment risks, potentially expedited licensing, and enhance opportunities to expand hydropower generation.”

HRF Fellows announce final research findings

Two students have recently completed their thesis work with support from the Hydro Research Foundation.

Research completed by Michael George with the University of California-Berkeley focuses on rock scour evaluation using block theory and the critical key block concept. He found that more accurate predictions of scour at dams, particularly in unlined spillways and on dam abutments, are achievable when the site-specific three-dimensional geologic structure is accounted for. In addition, with detailed field mapping, blocks most susceptible to scour can be targeted such that more efficient remediation measures can be implemented.

George is continuing into a doctoral program at the university.

Katherine Weidner’s masters research into erosion of cohesive sediment due to hydropower releases was performed at Virginia Tech. She determined that computational fluid dynamics can be used to determine the effect of scour hole shape changes on the applied shear stress. However, scour hole shape (in addition to depth) has an impact on the flow conditions near the jet centerline and within the scour hole.

Weidner has begun working in Black and Veatch’s Charlotte, N.C., offices.

Each Hydro Research Foundation fellowship, awarded to masters and doctoral level students to continue their research in the hydropower sector, is worth $44,000 to $66,000. Since the program began in 2010-2011, 33 students from 19 universities have been selected as recipients.

The fellowships are made possible by partnerships with a number of hydro-related foundations and organizations, including: the U.S. Department of Energy’s Wind and Water Power Program, Avista Foundation, Knight Piesold Consulting, U.S. Army Corps of Engineers Hydroelectric Design Center and Weir American Hydro.

Alden expanding with acquisition of AECOM research facility

Alden Research Laboratory Inc. has acquired the AECOM hydraulic engineering and modeling laboratory in Redmond, Wash.

Alden, based in Holden, Mass., says the acquisition creates the largest commercial hydraulic engineering laboratory system in North America.

“This transaction will establish Alden’s presence on both coasts and will enable us to better serve the growing hydraulic design and flow modeling market by bringing together two companies with extensive capabilities and complementary cultures,” says Alden President Stuart Cain.

The AECOM lab was founded by Charles “Chick” Sweeney in 1978, and personnel have since worked to optimize hydraulic structures and fish passage systems associated with hydroelectric power generation. Scientists at the lab work closely with municipal utilities, federal agencies and hydroelectric utilities in the Pacific Northwest.

AECOM acquired the facility in 2005, which was formerly known as the ENSR hydraulics lab.

“It’s a win-win-win arrangement,” Sweeney says. “I am very excited about the evolution of the laboratory, as both teams get to draw on each other’s knowledge base, and our clients will have much more to bear on their challenging projects.”

Alden says the acquisition is part of its geographical expansion plan. The company established a presence in Portland, Ore., in 2011.

Corps to use PIT tags to track fish on Columbia River

The U.S. Army Corps of Engineers’ Northwestern Divisions’s Anadramous Fish Evaluation Program plans to use passive integrated transponder tags over three years to track fish as they travel past radio receivers installed in hydroelectric projects on the mainstem Columbia River.

The tags will be put to use quickly in order to accommodate timing of migrating juvenile salmonids and research activities. The Corps plans to use PIT tags over three years to complete this research.

The National Oceanic and Atmospheric Administration has a series of tests to evaluate how well new tag models would perform in the current network of “interrogation systems.” Tests performed on the tags are physical and electrical parameters, ranges under different noise levels, maximum read speed, and effect of tag grouping on reading efficiencies. Testing is conducted in laboratories and in the field.

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