Since mid-October continuing until Thursday, the Shoshone River may be cloudier downstream of Willwood Dam. The potential increase in “turbidity and suspended sediment concentrations” came as the Willwood Irrigation District lowers the water level behind the dam in preparation for winter operations. It’s a necessary step to prevent damage to the canal gates that may occur with freezing temperatures, the Wyoming Department of Environmental Quality (DEQ) said in a news release.

“The late October timeframe is consistent with the current Operating Recommendations for Willwood Dam and is intended to minimize potential impacts of sediment releases to the downstream fishery,” the DEQ said, noting the Oct. 15 to Nov. 15 fall spawning period for brown trout and mountain whitefish.

The Willwood Irrigation District is coordinating the drawdown with the DEQ, Wyoming Game and Fish Department, Wyoming Water Development Office, Wyoming State Engineer’s Office, U.S. Bureau of Reclamation and the U.S. Geological Survey (USGS), so researchers from the University of Wyoming and state and federal agencies can collect data. That information will be used “to inform future operations of Willwood Dam,” the DEQ says.