Wildfire near Rob Roy Reservoir

Published on September 19, 2020


CHEYENNE, WY – On September 17, 2020, the Mullen Fire broke out approximately eight miles west of the City of Cheyenne Board of Public Utilities’ (Board) Rob Roy Reservoir.  The Mullen Fire, located in the Medicine Bow National Forest, grew from 50 acres on Thursday to over 4,000 acres at press time Saturday, September 19, 2020.

 “The location of the fire is by our main drinking water reservoir, Rob Roy,” stated Clint Bassett, Water Treatment Manager. “We do not know the impact of the Mullen Fire at this time, but the location suggests there may be some adverse effects to the City of Cheyenne’s water collection system and water quality.”

The Board collects water from watersheds and streams during snow melt into the Rob Roy Reservoir which is then transported east through large pipelines to Lake Owen. From there, the collected water from Lake Owen is transported via pipelines to Granite and Crystal Reservoirs to be processed Sherard Water Treatment Plant. Using advance treatment methods, the Water Treatment Plant can treat water quality issues associated with forest fires. Cheyenne’s drinking water remains safe.  

 Forest fires, such as the Mullen Fire, have the potential to trigger erosion issues that may damage dams, clog pipelines, shrink water storage capacity in reservoirs and alter water quality characteristics. “We are working closely with the U.S. Forest Service to protect Cheyenne’s watersheds,” Bassett stated. “Safety for the fire teams, residents and visitors is a major concern of the Board along with post-fire effects like erosion, sediment transportation and potential drinking water quality issues.  

 Click here for updates on the Mullen Fire