News Release
| Release Number: | 01-158 |
| Dated: | 12/6/2001 |
| Contact: | Public Affairs Office, 503-808-4510 |
Portland, Ore.-A very brief closure of John Day Dam on the Columbia River probably won't be noticed at all by the general public.
The U.S. Army Corps of Engineers' dam will be shut down from 3 a.m. until 6 a.m., Sunday, Dec. 9. There will be no water flow into or through the John Day powerhouse, spillway or lock during those hours so the amount of seepage through the dam can be evaluated. The south fish ladder will remain in operation.
Seepage occurs at every dam. Routine monitoring is being done so that operators know how much seepage is occurring and thus, because water through the turbines generates power, how much power production capability could be affected. Corps contractors will use a boat outfitted with precision hydro acoustical equipment downstream of the dam to assess the amount of flow still apparent with the dam closed. The equipment will be measuring velocities at multiple points across the width of the river to assess flow in those locations.
Stopping water flow means there will be no hydropower generation, and no vessels can move through the locks. The early morning hours were specifically selected for this test because power demand is at weekly minimum levels and can easily be picked up within the generation system, and because few vessels move through the locks at that time of day.
John Day Dam spans the Columbia River from Washington to Oregon about 25 miles east of The Dalles, Ore., 215 miles upstream from the Pacific Ocean. It has a current hydropower generation capability of 2.1 million kilowatts.