News Release
| Release Number: | 98-076 |
| Dated: | 9/11/1998 |
| Contact: | Public Affairs Office, 503-808-4510 |
Portland, Ore. -- The navigation lock at the U.S. Army Corps of Engineers' Bonneville Lock and Dam, 40 miles east of Portland on the Columbia River, will not be closed on Sept. 17, 1998, as previously announced.
Contract crews from General Construction Company, Seattle, Wash., were able to disassemble prototype surface bypass devices installed at Bonneville prior to the April 1998 fish passage season more quickly than projected. They completed the work and the locks reopened at 3 p.m. yesterday, Sept. 10.
Surface bypass systems are designed to guide juvenile salmon away from the turbines, and are being studied as a possible alternative to screened bypass systems. The surface bypass system is believed to cause less stress for juvenile salmon as they pass through the dam.
Biological tests of surface bypass prototypes were conducted at the Bonneville first powerhouse during the 1998 juvenile fish passage season, from April through July 1998. Two configurations with different slot widths allowed biologists to compare fish behavior with each, and reach conclusions about potential benefits. Information gathered from those tests will be analyzed this fall and will be used to help the Corps decide what additional tests should be conducted next year.
The results of the tests, and thus the value of surface bypass, will be considered along with other potential fish passage improvement activities, and those currently underway. The information will be coordinated with regional decision-making bodies (made up of federal, state and tribal representatives) to develop informed decisions about the value of surface bypass, and its use at Corps projects on the Columbia-Snake river system.