Updated: Dec 21, 2021
- Reese Hodges
"Diminished Priest River flows during the late summer and early fall, due to management practices and seasonal variability, jeopardize fishery habitat and recreation.”
On an early morning in late June, I found myself diving into the Middle Fork of the Salmon to cool off from a hot night’s sleep; quite strange for a time of year that you might expect hail from the sky and water cold enough to wear a dry suit. The temperature gauge on the Salmon River near Shoup peaked at over 77°F on June 30, 2021 - great for swimming, but terrible news for fish. The same gauge recorded a max temperature of 56°F on the same date in 2020. Even as the cool autumn weather sets in, it is hard to forget that summer 2021 was devastating on rivers and fish throughout the west. From Idaho’s panhandle down to the Owyhee, regulated and free-flowing rivers experienced record low flows and warm temperatures.
While we posted a blog in August on the trouble of abnormally warm stream temperatures on fish throughout Idaho, the lower Priest River in the panhandle deserves a closer look to see how both climate warming and management decisions affect wild fish and recreation opportunities. During the late June heatwave, a widespread fish kill event from hot water brought in stories of 40-50 fish found dead, both whitefish and trout, in one pool on the lower Priest River. A local resident measured the water temperature at 83°F on June 30, 2021. The Priest River is home to wild native Westslope cutthroat trout, mountain whitefish, and bull trout - all cold-water dependent species. However, the Priest River doesn’t have nearly as many fish as nearby comparable rivers (90% lower densities than the Coeur d’Alene). Unfortunately, the 2021 heatwave placed extra stress on a river that is already suffering.
The Priest River, from the outlet of Priest Lake to the confluence with the Pend Oreille, is a beautiful meandering stretch that flows 44 miles through the Kalispell Tribes’ traditional territory (much within National Forest) with sections of whitewater and calm pools and adjacent wetlands. Over 30 miles are designated as a State Protected Stream for recreation, and a USFS study found this same stretch to meet the criteria for a recreational Wild and Scenic River. With these characteristics, plus an assemblage of wild native fish species prized by anglers, one would think that the Priest River would be a destination for anglers and paddlers both near and far. However, low stream flows and warm temperatures have made the river unsuitable for cold-water-dependent fish, and recreation opportunities in summer are limited.
Beyond the 2021 heatwave and drought, why is the Priest River unhealthy? The outlet dam on Priest Lake, first constructed in 1950 and managed by the Idaho Department of Water Resources, controls flow into the lower Priest River and causes unnaturally low summer flows and warm stream temperatures. While water years like 2021 make things worse, there is no question that management decisions by the State of Idaho have caused the decline of fisheries and recreation opportunities in the Priest River. According to the Idaho Comprehensive State Water Plan, “diminished Priest River flows during the late summer and early fall, due to management practices and seasonal variability, jeopardize fishery habitat and recreation.”
Since this dam doesn’t produce hydropower or flood control benefits, it seems the simple answer would be to open the gates and restore the river to its natural flow state. However, Idaho statute requires that Priest Lake be maintained artificially at a minimum recreation level of 3 feet throughout the summer season for lakefront homes and resorts, and the outlet dam holds back water to do so. As a result, the Priest River, habitat, and fish suffer from the low minimal releases, especially during dry years like 2021. Past studies by Idaho Fish and Game found that 200 CFS is the minimum flow needed for trout, especially August-October. Unfortunately, nearly every year the river drops far below the 200 CFS minimum to maintain fish habitat. In 2019, outlet flows alarmingly dropped below 35 CFS. To make things worse, once the recreation season ends on Priest Lake, river flows are rapidly released to draw down the lake in the fall, causing erosion downstream and further harming fish habitat.
How will state agencies address these issues for the Priest River and its wild native fisheries, especially coupled with climate change? Idaho Fish and Game hopes to restore the once abundant fisheries of the Priest River and tributaries, and is working with the Kalispell Tribe to identify key thermal refuges for trout. The agency is also conducting a feasibility study of a coldwater bypass to pump cold water from the depths of Priest Lake into the lower Priest River to help restore the fisheries. While this concept has been met with some skepticism over concerns about impacts to the lake’s volume and temperature, a recently published study demonstrates that there would be no physical or biological harm to the lake. This is potentially great news for the river, but cooling the temperature alone won’t solve the low flow issue. The Idaho Department of Water Resources has struggled in recent years to maintain the lake pool and still release even dismal flows from the outlet dam in late summer. Their current plan is to finish up a $5 million project to raise the outlet dam height by 6 inches, which will allow holding back more water to raise the lake during dry years and allow for late summer river flow releases from the outlet. While this might help with flows from August to October, the issue of fall surge during lake drawdown, and resulting erosion, remains unsolved.
What can you do to support the Priest River? Stay tuned with IRU for public comment opportunities that arise with Idaho Fish and Game and the Idaho Department of Water Resources. Consider writing a Letter to the Editor, especially if you live in the panhandle region, to show your support for restoring the Priest River and its wild native fish. Call IDFG and IDWR, and connect with local organizations like the Selkirk Conservation Alliance.
Original article link here: https://www.idahorivers.org/newsroom/2021/10/26/can-we-bring-coldwater-life-back-into-the-priest-river