A conservation group says improper irrigation practices on the St. Mary River east of Glacier National Park have led to the deaths of hundreds of threatened bull trout annually, and has threatened legal action against federal agencies unless they rectify the situation.
Mike Garrity, executive director for Alliance for the Wild Rockies, said the U.S. Fish and Wildlife Service and the U.S. Bureau of Reclamation have failed to adequately protect bull trout under the Endangered Species Act as dams and irrigation systems create warm and shallow waters while cutting off access to upstream migration.
According to Garrity, the problem removes a critical piece of the migration puzzle for bull trout, which rely on cold, clean and connected waters to persist. Instead, he said as many as 600 bull trout that use the system are dying annually.
“This irrigation project takes cold, clean and abundant water coming out of Glacier National Park and diverts it into shallow, sun-warmed irrigation ditches,” Garrity said. “But bull trout require cold, clean, and connected water, which is not found in sun-warmed irrigation ditches from which there is no escape. If we’re ever going to recover bull trout and remove them from the Endangered Species List, we have to take steps to stop needless and easily preventable fatalities, such as being stranded and killed in irrigation ditches.”
Bull trout and other fish are diverted into the unscreened St. Mary Canal, and mostly die in irrigation ditches, first from heat stress and gain when the canal is dewatered in the fall, Garrity said.
Garrity’s group announced a 60-day notice of intent to sue the federal agencies over the declining bull trout numbers in Glacier National Park unless they begin consulting about how to remedy the problems occurring on the Saint Mary Diversion Dam and the Sherburne Dam as part of the Milk River Irrigation Project.
“The U.S. Bureau of Reclamation has been operating the Saint Mary Diversion and Sherburne Dams since bull trout were listed without consulting with U.S. Fish and Wildlife Service under the Endangered Species Act,” Garrity said. “Instead, USFWS and USBOR have been ‘gathering biological information’ on this project for over 20 years.”
According to Garrity’s notice, one agency report from 2011 concluded an estimated annual loss of more than 470 bull trout over the age of two years to canal entrainment, indicating that the unscreened St. Mary Diversion represents a significant threat to a listed population and highlighting the urgent need for improvements to the Milk River Irrigation Project.
“There’s a simple and effective way to keep bull trout out of irrigation ditches by installing self-cleaning fish screens at the point of diversion,” Garrity said. “These fish screens, which are widely used in Montana and across the West, let the water through but keep bull trout and other fish out.”
“It’s well known that the Trump administration has a horrific record on endangered species,” he continued. “We intend to encourage and, if necessary, take the administration to court to stop killing bull trout and start working toward their recovery as required by the Endangered Species Act. Our planet is getting hotter which makes it even more difficult for bull trout to survive. The Trump administration and the Department of Interior don’t need to make their survival any harder by allowing hundreds of bull trout to die annually in warm water irrigation ditches.”