News Release
| Release Number: | 97-089 |
| Dated: | 8/14/1997 |
| Contact: | Heidi Y. Helwig, 503-808-4510 |
Portland, Ore. -- The U.S. Army Corps of Engineers and regional fisheries agencies are now ready for the Steelhead and Chinook fall runs.
Fish water unit no. 2 at Bonneville Lock and Dam's 2nd powerhouse on the Columbia River was placed into service on Thursday, Aug. 7, after hydroacoustics sampling indicated few, if any, adult salmon are in the project's Auxiliary Water Supply (AWS). Also, special operations over a five-day period designed to attract out any migratory fish that might be in the AWS resulted in only one steelhead and no salmon, said fishery biologist Gary Johnson.
The fish ladders and the fish attraction unit will operate until later this fall when fish counts decline enough to allow safe dewatering of the system. At that time, the Corps will enter the dam's AWS, rescue any fish and clean out the debris. This work will be carefully scheduled with the region.
In the mean time, the Corps has implemented an extensive monitoring program of the grates in the AWS. On Monday, Aug. 11, a dive team checked the integrity of the gratings in the fishway and confirmed that they are all still tightly attached. Divers also indicated that the debris under the gratings was no worse than last week and that the area may even be slightly cleaner.
In ongoing talks between the Corps and regional resource and fisheries agencies, operation of the 2nd powerhouse main units has been a primary topic of discussion. No decision has been made on when those units will be operated. Plans on how to avoid problems with debris and the fishway in the future also are being developed.
The problems with Bonneville Lock and Dam's 2nd powerhouse fishway began when high flows and large amounts of debris brought down in the Columbia River this summer caused gratings on the floor of the fish ladder to dislodge. This provided an opportunity for fish to enter the AWS, which does not allow fish passage over the dam. Adult fish did continue to pass the dam, however, through other ladders on the project.
When divers surveyed the fish collection channel beginning on July 21, they discovered 25 grates had been pushed out of place due to excess pressure caused by debris buildup.