D2021-1 D2021-1(Updated February 24, 2021) D2020-2
D2021-1 Top of Page
|1. SOR Request||
The fishery managers recommend cessation of within day load shaping operations at Dworshak Dam.
Within day load shaping operations at Dworshak Dam were implemented January 25 – 29, 2021 (Attachment 1) with likely impacts to treaty and non-treaty fisheries, ESA-listed juvenile fall Chinook, hatchery operations, and riverine ecological function. Daily load shaping operations occur when water releases through turbines are minimized during periods of low power demand (market value), typically nighttime, and subsequently increased when demand (market value) is high, typically daytime. Daily load shaping operations have not been implemented at Dworshak dam since 1986 and consideration for contemporary use was not coordinated with Fishery Managers.
Flow increases were started each day about 4:00am, with peak flows occurring between 8:00am and 5:00pm. Base flows were ~1,600cfs and peak discharges were ~9,700cfs. These flow fluctuations occur in the North Fork Clearwater River with very little delay, however flows in downstream areas (i.e. Spaulding) do not increase until 10:00am, with peak flows reached by 1:00pm (Figures 1 and 2). Flows from the Clearwater River upstream of its confluence with the North Fork Clearwater River were ~2,900cfs. The load shaping releases nearly tripled flows in the lower Clearwater River.
End of month Flood Risk Management (FRM) pool elevation targets have guided project discharges for several decades, increases in discharge are typical over the last several days of the month to reach FRM target elevation. The Dworshak Dam January FRM elevation was 1,533 feet. Holding Dworshak discharge at minimum flows (1,600cfs) for most of January resulted in a pool elevation on January 24 of 1,534.8 feet. After the five days of load shaping operations, Dworshak pool elevation was at 1,531.7 feet (1.3 feet lower than the FRM target).
Corps of Engineers’ January final snowpack estimates for the North Fork Clearwater basin was 117%. Their February final snowpack estimate is 100% of average. The current forecast from the NOAA River Forecast Center (RFC) is 88% of average.
|2. Requester(s)||Oregon Department of Fish and Wildlife, Washington Department of Fish and Wildlife, U.S. Fish and Wildlife Service, National Oceanic and Atmospheric Administration, Nez Perce Tribe, Yakama Nation, Confederated Tribes of the Colville Reservation, Spokane Tribe of Indians, and the Columbia River Inter-Tribal Fish Commission.|
|3. TMT Recommendation||
February 3, 2021, TMT Meeting.
This section will be updated following the February 3, 2021, TMT Meeting.
|4. AA Decision||This section will be updated following the February 3, 2021, TMT Meeting.|
|5. IT Recommendation|
|6. AA decision (post IT)|
|7. Actual Implemented Operation||This section will be updated following the February 3, 2021, TMT Meeting.|
|8. If different from AA decision, why?|