MILLS, Wyoming -- The Wyoming Area Office of the Bureau of Reclamation in Mills, Wyoming, will be changing normal operations at Seminoe and Gray Reef Dams this summer.
Seminoe Reservoir releases are currently at 2,600 cubic feet per second (cfs) and will continue at this rate into July. Flow releases from Seminoe and Kortes Dams will be reduced to between 530 cfs and 1,000 cfs in mid- to late-July and continue throughout the Summer to facilitate maintenance at Seminoe Power Plant.
Seminoe Reservoir levels are approximately at elevation 6324 ft and are currently expected to increase to approximately 6328 ft by the end of June. Seminoe Reservoir levels are expected to start lowering at the beginning of July as the seasonal inflows begin to diminish. To facilitate a routine full-travel spillway gate test at Seminoe, the level of the reservoir will continue to be gradually reduced until February 2022 when an elevation of 6307 ft will be achieved. Elevation 6307 ft is the crest elevation of the Seminoe spillway; this elevation is required so the gates can be tested without releasing water downstream. To put this elevation in context, the reservoir was at or below elevation 6307 ft in 7 of the past 19 years (2002, 2003, 2004, 2005, 2007, 2008 and 2014) with the lowest of these elevations coming on March 11, 2008, when the reservoir was 21 feet lower than the end of February 2022 target.
Storage water released from Seminoe Reservoir during the coming months in preparation for the spillway gate test will be re-stored in Pathfinder Reservoir and remain available for future delivery to the Casper-Alcova Irrigation District. Once the full-travel spillway gate test is completed, the reservoir will begin to fill in the Spring of 2022. The North Red Hills #3 boat ramp has a minimum launch elevation of 6300.9 ft and will be accessible throughout the gate testing. Other boat ramps will vary in their usability. Releases from Gray Reef Dam will remain at 450 cfs through the end of May and possibly into June. The below-average flows from Gray Reef Dam are due to the higher-than-average reservoir levels at Glendo Reservoir. Expected releases from Gray Reef Dam will gradually be increased to approximately 2,600 cfs by the end of June, depending on downstream irrigation demands and Glendo Reservoir levels. Glendo and Guernsey Dam releases are approximately 3,000 to 3,500 cfs but will fluctuate based on downstream irrigation demands. These releases are expected to decrease considerably in early June as irrigation diversions are decreased to conserve water, and then resume later in June.
Boaters and recreationists should take the flow conditions along the North Platte River and water levels in the reservoirs into consideration throughout the summer and take appropriate safety precautions.
Source: Bureau of Reclamation
