AHSAHKA, Idaho – Dworshak Dam discharge flows will begin increasing 1,500 cubic feet per second (cfs) per hour today, which should result in a less than six inch increase in depth, according to U.S. Army Corps of Engineers officials.
This increase was coordinated with Salmon Managers and at Technical Management Team on Jan. 31, 2018. Current inflow forecasts for the North Fork of the Clearwater above Dworshak are very high due to a warm storm forecasted for this weekend and early next week. Storm totals exceed four inches of precipitation in three days. The runoff forecast has been rapidly changing, but is currently estimated in the range of 40 kcfs or more. We were below our Jan. 31, 2018 flood target elevation by approximately 1.5 feet.
The Feb. 1, 2018 water supply forecast is 2.78 Million Acre Feet with a Feb. 28, 2018 flood target elevation of 1519.9 feet. We are working with Salmon Managers and Northwestern Division Reservoir Control Center to minimize the impact of higher total dissolved gasses on both the Dworshak National Hatchery and local natural fish populations. We plan to increase discharge once Unit 2 returns to service on Feb. 8, 2018. We may also make additional increases based on the observed inflows during the storm.
Background information previously released by the Corps:
Regional water managers are working to control discharge flows from the reservoir into the North Fork of the Clearwater River to meet seasonal flood-risk-management requirements and balance flows with impacts on fish in the river and downstream fish hatcheries.
Water surface elevations on the Clearwater River are expected to fluctuate during the next several weeks. Additional increases or decreases may be necessary as conditions change.
For safety, the public is advised to be aware of danger associated with fluctuating river flows and elevations. Outflow water is deep, cold and fast, so extreme caution should be used near river banks. 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 up or down in water elevation and volume of flow. Current Dworshak water-management conditions can be viewed on the Walla Walla District website at www.nwd-wc.usace.army.mil/nww/rreports.htm.
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Release no. 18-005