FORT SMITH, Mont. – According to Natural Resources Conservation Service data, on average, the Bighorn River Basin receives 2.74 inches of precipitation during the month of June. June 2023 has seen above average precipitation throughout the southern Montana and northern Wyoming region. Bighorn Basin has already received 3.33 inches of rain as of June 12, not even halfway through the month. Due to the high levels of precipitation, inflows to Yellowtail Dam are expected to peak above 16,000 cubic feet per second and in response, releases are scheduled to increase from the current release of 8,000 CFS to between 11,000-12,000 CFS by June 20, 2023.
“Reservoir levels and river flows were in line with Yellowtail Dam operating criteria through May. Snowpack was melting off early with below average precipitation. However, the precipitation in the last two weeks added a lot of water to actual and forecasted inflows. This increase is needed to manage current and projected inflows, reservoir levels, and utilization of flood control space in coordination with the U.S. Army Corps of Engineers,” said Montana Area Manager, Ryan Newman.
Reclamation has been in contact with partners to discuss the increased flows and potential impacts regarding the needs of the reservoir to safely pass this event. Additionally, if the wet weather pattern continues the rest of June and into July, there is a potential for the flows to increase beyond 12,000 CFS based upon inflow volumes to the reservoir.
“While we understand the increased flows may be a challenge to people recreating, boating or fishing in the area, we must emphasize the importance of managing reservoir operations for flood control and safety. Visitors to the Bighorn River and surrounding areas should use caution and practice water safety recommendations like wearing a life jacket, and not swimming alone,” said Newman.
Reclamation will continue to release updated information concerning flow rates as they are evaluated and changed. For more information about Yellowtail Dam water supply and projected operations visit https://www.usbr.gov/gp/lakes_reservoirs/wareprts/main_menu.html.
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