- Jun 11, 2020

June River Flow Update

Flows to Maintain Despite Dry Conditions

Record heat at the end of May coupled with below average precipitation has led to very, very dry conditions in the Bighorn Basin this June. Contrary to years past, when we had an abundance of water, water managers are now working to balance the risks of low water conditions amongst various stakeholders, both upstream and downstream.

The Bighorn River Alliance (BHRA) has been actively working with the Bureau of Reclamation (BOR) and Montana, Fish Wildlife and Parks (MFWP) in navigating forecasts, inflows and lake elevations to advocate for sustainable river flows on the Bighorn River, while also recognizing the benefits a full reservoir by the end of July brings to the fishery in regards to winter flows, and next summer river flows.

In early June, the Bighorn Alliance participated in a BOR water users stakeholder call and, with MFWP, urged BOR to keep river flows at or above the current river release rate of 2250cfs through mid-July to aid the rainbow trout spawn, and recruitment of young of year trout. While the preferred fishery flow for this time of year (during an average water year) is 3500cfs, the Alliance and MFWP identify flows between 2000cfs and 2500cfs as standard levels for the fishery under low flow conditions. Flows below 2000cfs can impact the fishery by dewatering side channels that are used during the spawn.

From smart water management Bighorn River flows are predicted (pending conditions remain the same) to stay at 2250cfs through June, with the possibility of flow increases to 2500cfs – 3000cfs to come at months end. It is also predicted that Yellowtail Reservoir will fill by the end of July, but the upstream Wyoming dam Boysen Reservoir is not expected to fill.

While lower river flows are a welcome change for anglers and trout who have been challenged by high river flows over the past years, the paradigm shift does present challenges amongst water users who are scrambling to meet the upstream irrigation demands in Wyoming, filling rates of the Bighorn Reservoir, and needs for the Bighorn wild trout fishery, reminding us of the complexities various water years can bring.

Right now, though, things are looking good for the Bighorn River. For the first time in years anglers are relishing the walk wade opportunities and tremendous dry fly action that the Bighorn River brings. Fish health is exceptional, and the water is gin clear and cool. Its time to go back to the Bighorn.