AHSAHKA, Idaho – Releases from Dworshak Dam will increase to match inflow into the reservoir. This operation is intended to maintain the reservoir at its full pool.
Dworshak Dam is currently releasing 1,600 cubic feet per second. Flows will begin increasing the evening of Friday, June 30 to be in the approximate range of 3,000 to 4,000 cfs. Dworshak is currently less than half a foot from full pool, and the increased discharge will keep the reservoir within one foot from full pool.
This operation is expected to result in the Clearwater River near Peck increasing by approximately 1 to 1.5 feet. The rate of change in downstream river stage limit of one foot per hour, as measured at the United States Geological Survey Clearwater River Near Peck, ID (gage #13341050), will not be violated due to project operations.
The current operation will result in total dissolved gas remaining below 110%. The Corps will continue to work with regional water managers, other agencies, tribes, and fish managers and hatcheries in joint efforts to meet reservoir objectives and keep total dissolved gas below the Idaho State maximum threshold of 110%, when possible.
While the increased discharge on Friday, June 30 is intended to balance full pool, further increases may be required in the upcoming week for the initiation of temperature augmentation.
The specific goal of temperature augmentation is to keep the tailwater of Lower Granite Lock and Dam at or below 68 F to support fish populations. Currently, Lower Granite’s tailwater is approximately 63 F. The natural river temperatures in the Clearwater River at Orofino and in the Snake River at Anatone are approximately 63 F and 65 F, respectively.
With temperatures in the region forecasted to hit the high 90s in the next ten days, the natural river temperatures will increase. Releases of cooling water from Dworshak help offset the natural river temperatures, which may be required starting in the first full week of July. For the remainder of the summer, outflows from Dworshak will vary to meet the needs of temperature augmentation at Lower Granite, with Dworshak Reservoir drafting close to 80 feet from full pool by the end of September.
For safety, the public is advised to be aware of the danger associated with fluctuating river flows and elevations. The river at this time of year is deep, cold and fast, so extreme caution should be used near riverbanks. Boaters, anglers and other people using waterways both in Dworshak Reservoir and below the dam on the Clearwater River are advised to be alert to changes in water elevation and volume of flow. Current Dworshak water-management conditions can be viewed on the Walla Walla District website at https://www.nwd.usace.army.mil/CRWM/Water-Control-Data/Project-Data/.