The Idaho Department of Water Resources has deemed a large water diversion along the East Fork of the Big Wood River “unauthorized” after completing an investigation into an unexplained dewatering incident that occurred during the same period last month.
An IDWR report sent to the Mountain Express on Friday named Bob Mitchell of Hyndman View Drive as the property owner who drew over 350,000 gallons from the East Fork during the evening of Sept. 7 until dawn the next day to “maintain fish ponds.” Within that time frame, a 3-mile stretch of the river ran dry, according to the county, leaving thousands of trout stranded.
On Sept. 17, IDWR staff conducted a field investigation of Mitchell’s diversion and property at Hyndman View Drive to understand his uses and collect facts regarding the dewatering event, which was captured by the U.S. Geological Survey’s East Fork stream gauge off Timberline Road. River flows between the evening of Sept. 7 and morning of Sept. 8—when Mitchell said he’d opened the headgate on his concrete diversion box—dropped to undetectable levels, USGS hydrographs show.
Even so, the IDWR stated in its report that it lacked “sufficient evidence” to determine whether the dewatering was caused by Mitchell’s water diversion.
The department did find that Mitchell had “no water right authorizing the diversion or storage of river water in any of his ponds,” and that Watermaster Kevin Lakey and Assistant Watermaster Ryan Fuchs had erred in allowing Mitchell to divert surface water from the East Fork “every 10 days or so.”
After Mitchell’s three irrigation water rights were curtailed on July 13, they should have remained curtailed, the department said.
“Mitchell has no water rights or any other legal authority allowing the diversion of water from the East Fork for fish ponds or any other use, including irrigation once his irrigation priority rights are curtailed,” the IDWR report said.
During a site visit last month, IDWR staff measured Mitchell’s ponds to determine surface area and capacity, examined his point of diversion and walked the length of the conveyance ditch running from the river to his ponds.
“Mitchell admitted to diverting about 0.98 cubic feet per second for 13 hours, from about 5:30 p.m. on Sept. 7 to about 6:30 a.m. on Sept. 8,” the report stated.
Mitchell’s water conveyance system has the capacity to divert more than 0.98 cfs, IDWR said, but the department did not have any evidence indicating that more than that amount was diverted. Multiplying Mitchell’s diversion rate by 13 hours, investigators found that around 358,435 gallons of water was taken to fill his ponds.
“If Mitchell diverted more than 0.98 cfs, or diverted for a longer period, the excess water should have re-entered the [river],” the report states.
Fuchs told IDWR staff that even though Mitchell’s water rights were out of priority, he had given Mitchell permission to take a “trickle” for his fish. No one else along the East Fork received permission to divert water from Fuchs on Sept. 7 or 8, according to the report.
Lakey told the Express in September that he hadn’t been aware of any illegal diversions but took responsibility for the incident.
“It appears there has been a miscommunication between me, my staff and [the homeowner]. The miscommunication was my fault,” he said in an interview.
IDWR’s report recommended that staff issue a curtailment order to Lakey stating that he must lock Mitchell’s diversion headgate from now on to prevent future unauthorized diversions of water from the East Fork.
“[Lakey] or watermaster assistant(s) shall have a key to Mitchell’s headgate and shall be the only person operating the gate,” the report said.
Lakey should also receive instructions from the state on how to handle water user requests once water right cuts are in place and prohibit out-of-priority diversions, and IDWR should send a written cease-and-desist letter to Mitchell notifying him of his unauthorized water uses, the report stated.
Blaine County, the Idaho Department of Fish and Game and the Idaho Department of Environmental Quality were originally made aware of the dewatering by Michael Harrison, a neighbor over 3 miles downstream of the diversion point. Harrison—cited in the IDWR report—reached out the Express with photos documenting the mass fish kill.
“The dead fish behind my house were in a pool as wide as the river and about 40 feet long,” he said.
The Department of Water Resources became aware of the issue on Sept. 14 through the Department of Environmental Quality and Kristine Hilt, floodplain manager and code compliance officer for Blaine County.
In an interview with the Express last month, Mitchell denied involvement in the dewatering event. He said he had regularly received permission from Fuchs to fill his four connected ponds, which he said provided irrigation for 150 trees and 28 cows on his property.
“[In September] I called Ryan to get a little water and he said ‘yes.’ I took it out for irrigation,” he said. “To anyone suggesting that I personally dried up the river, that’s totally impossible. I’ve been running a headgate for 30 years and I’m not going to be accused of things that I didn’t do, killing all these fish.”
Mitchell told the Express that a strong windstorm over the previous weekend may have caused the dewatering event.
“There was a big windstorm that knocked trees down. I know a builder down the river who heard trees falling down,” he said at the time. “The water may have gone low from a [landslide] and then a storm, I don’t know. I’m not going to make any assumptions until I have the exact facts.”