There are over 30 species of fish in Lake Roosevelt.

Annually, over 500,000 rainbow trout and 500,000 kokanee are stocked in the lake through the use of hatcheries and net pens. Lake operations, however, are most often affected by the needs of downstream fisheries, particularly anadromous fish (salmon). With 12 species of fish being listed as endangered, the NOAA Fisheries and the U.S. Fish and Wildlife Service began consultations with federal “action agencies” (the Bonneville Power Administration, the Army Corps of Engineers and the Bureau of Reclamation) to determine and address the affects of Columbia River (including Lake Roosevelt) operations on these fish.

Beginning with the 1995 Biological Opinion, which was most recently updated in 2000, the action agencies began developing and implementing an annual Water Management Plan to assist meeting the Biological Opinion’s fishery objectives. In general terms, this includes managing flows to avoid stranding resident fish, speeding downstream migration of juvenile fish, meeting the water temperature needs of fish, and avoiding creation of dissolved gas conditions that can adversely affect fish.

Specific to Lake Roosevelt, guidelines affecting fisheries include:

  • Within the criteria of reducing lake levels to meet flood control rule curves by April 30th, provide water releases to increase available downstream flows for fish during the spring. For instance, lake levels are commonly drawn down for flood control until May 1 or later. Refill is often delayed to provide additional water for downstream fisheries.
  • Spring water releases, however, must also accommodate refill of the lake by approximately July 4th. During the spring period, one sensitive area is the lake level at the end of May, when net pens release rainbow trout and kokanee. Release conditions are best at an elevation of 1265 or higher. At this level, entrainment (loss of fish through Grand Coulee Dam) is reduced because water flows are weaker. Released fish, therefore, can more easily migrate to bays and outlets. In addition, the fish generally need to be released by the end of May to avoid diseases that occur as a result of their reaching a size and maturity that no longer make their retention in a net pen appropriate.
  • During July and August, lake elevations generally fluctuate between 1278 and 1290. Within the guideline of not reducing the lake level below 1280 unless criteria for a below average water year are met (in which case the lake can be reduced an additional two feet) water can be released to assist downstream juvenile salmon migrating to the ocean.
  • In the Fall there is an effort to maintain lake levels between 1283 and 1285 feet during the month of October. This is to assist with Lake Roosevelt’s kokanee fishery, specifically brood stock collection and assuring their access to tributaries.
  • Fall and winter lake levels may be used to support flows for spawning downstream Chum Salmon.
  • Banks Lake, which has water pumped to it from Lake Roosevelt, is lowered to an elevation of 1,565 feet by the end of August to leave additional water in the Columbia River for summer flow augmentation. Currently, an environmental analysis is being conducted to determine if Banks Lake can be drawn down an additional five feet during this time period. Click here for more information.