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Corps begins work to reduce avian predation of salmon

The U.S. Army Corps of Engineers is initiating work to reduce predation by Caspian terns of juvenile salmonids in the lower Columbia River. The work is focused on decreasing the number of Caspian terns nesting and breeding on East Sand Island, near the mouth of the Columbia River.

About 70 percent (9,100 pairs) of the entire western population of Caspian terns in North America nests on this island. The terns consume an average of 4.7 million young salmonids each year as the fish migrate through the Columbia River estuary to the Pacific Ocean.

As part of this work, the Corps will develop six alternative Caspian tern nesting sites in Oregon and California. All of the alternative sites to be developed are on public land, and most already have small populations of terns nesting in the general area or have historically supported nesting terns. By spreading out the habitat, the Corps hopes to both reduce salmonid predation in the area (potentially saving 2.5 million to 3.1 million juvenile salmonids each year) and reduce risk to the birds posed by disease, human disturbance, pollution, predation, and storms.

Hydropower Generation Report
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To encourage the birds to move to alternative sites, the Corps plans to develop habitat in the alternative locations, then reduce habitat on East Sand Island. In addition, the Corps will use decoys and a sound system, called “social facilitation,” to draw birds to the alternative nesting sites. Social facilitation has been used in the Pacific Northwest to attract Caspian terns to other nesting locations.

The Corps says the redistribution effort is expected to be completed by 2015.

Using organic ester-based insulating fluid in transformers

The U.S. Department of the Interior’s Bureau of Reclamation installed a transformer filled with ester-based insulating fluid at its 13.5-MW Nimbus hydro plant in California. This insulating fluid, an organic oil made from rapeseed or soy, is an alternative to traditional mineral oil.

The fluid is denoted by the “K” in the cooling system description for the KNAN/KNAF transformer (as opposed to an ONAN/ONAF transformer – oil natural air natural/oil natural air forced).

Before installing this type of transformer at Nimbus, staff at Reclamation’s Technical Service Center extensively researched ester-based insulating fluid. Reclamation discovered several advantages and disadvantages.

Advantages include:

Disadvantages include:

Installation of the transformer at Nimbus was completed in December 2007. Reclamation plans to monitor the transformer, to determine if this application is viable for its other hydro facilities.

ASCE releases book onrisk and reliability analysis

The American Society of Civil Engineers (ASCE) announces availability of Risk and Reliability Analysis: A Handbook for Civil and Environmental Engineers. Authors of the book are Vijay P. Singh, PhD, P.E., with Texas A&M University; Sharad K. Jain, PhD, with the National Institute of Hydrology in India; and Aditya Tyagi, PhD, P.E., with CH2M Hill.

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The 785- page book is divided into four parts:

Niagara tunnel to featureimpermeable membrane liner

Construction of the Niagara Tunnel Project involves excavating a 10.4-kilometer-long, 12.7-meter-internal-diameter tunnel through rock. To ensure the fresh water flowing through the tunnel does not escape and cause swelling of the surrounding rock, Ontario Power Generation is installing an impermeable membrane liner.

This project involves building a tunnel under the city of Niagara Falls to divert an additional 500 cubic meters per second of water from above Niagara Falls to the three existing Sir Adam Beck generating stations: 498-MW Sir Adam Beck 1, 1,499-MW Sir Adam Beck 2, and 174-MW Sir Adam Beck Pump-Generating Station.

For the Niagara Tunnel Project, there will be a double-layer polyolefin membrane, installed between the shotcrete that is being sprayed onto the existing rock surface and the final concrete lining. The waterproof membrane prevents fresh water flowing through the tunnel from leaking into the surrounding rock and displacing the salt water trapped in the rock. If this were to occur, the rock around the tunnel would swell and over-stress the concrete lining. The polyolefin membrane is being supplied by Sica AG of Switzerland and will be installed beginning in late 2008 by Strabag Inc., the design/build contractor.

An additional benefit of using this type of liner is that the concrete used to build the tunnel can be thinner and does not require reinforcing steel. The concrete will be 60 centimeters thick, based on structural requirements and placement constraints.

Use of this type of waterproof liner is rare in North America, but it is used in many railway and highway tunnels in Europe, says Aaron Laufer, corporate public affairs officer with Ontario Power Generation.

Waterpower XVI announces call for technical paper abstracts

HCI Publications, organizer of the Waterpower XVI hydropower conference and exhibition, is accepting abstracts for the Technical Papers program. The conference will be held July 27-30, 2009, in Spokane, Wash.

Abstracts are requested on all topics of interest to technical professionals in the hydropower field. Preference will be given to abstracts that focus on innovative, practical, and proven technologies and methods.

Abstracts that describe the focus and content of proposed papers (maximum of 400 words) are due September 5, 2008. Submit abstracts through the Internet at: and click on “Waterpower.”

All abstracts will be reviewed by the conference Technical Committee. If accepted, authors will be invited to submit a paper by February 16, 2009, for inclusion in the official conference publication (in CD-Rom format) that will be distributed to all delegates.

– For more information, contact (1) 816-931-1311 or E-mail: techpapers@

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