Cheyenne's Water Supply Depends on a Healthy Forest
Incident: Keystone Fire Wildfire
The City of Cheyenne gets its water supply from the Medicine Bow, Sierra Madre, and Laramie Mountains and thus depends on a healthy forest and watersheds to provide high quantity and quality water for the community. Cheyenne’s water systems cross these three mountain ranges with 222 miles of pipelines, 149 collection structures and several water-supply reservoirs all managed by the Board of Public Utilities (Board).
The largest reservoir that supplies drinking water to the City of Cheyenne is Rob Roy Reservoir at a storage capacity of 35,640 acre-feet. Water from the reservoir is transported by pipelines down the Medicine Bow Mountains to Lake Owen Reservoir, then across the Laramie River Valley and over the Laramie Mountains to Granite and Crystal Reservoirs. If wildfire impacts like soil erosion are seen in Rob Roy Reservoir and nearby collection structures, a domino effect may impact multiple reservoirs and Cheyenne’s water system. Post-fire debris could degrade water quality, diminish reservoir storage capacity and clog or damage pipelines.
The Keystone Fire started on July 3rd and has burned almost 2,500 acres in the watershed of Rob Roy including Horse and Podunk Creek drainages. With all natural fires, watershed effects like soil erosion could have long-lasting effects for the water quality and quantity. Therefore, the Board will be collaborating with the US Forest Service Burned Area Emergency Response (BAER) team to evaluate wildfire effects on the watershed. Later the Board will strategically plan future water operations and mitigate watershed impacts which reduce future risks to water quality and quantity issues for Cheyenne.
Rob Roy Reservoir, Lake Owen Reservoir, the collection structures and the pipeline to Granite and Crystal Reservoirs are vital to the City of Cheyenne. Without these reservoirs, healthy watersheds, and collection structures, the Board would be unable to meet Cheyenne’s water needs. If damage to infrastructure, storage capacities and/or water quality occurs, financial costs to Cheyenne will be significant. Because of the efforts of the Rocky Mountain Incident Management Team, firefighters and Board employees, Cheyenne continues to have safe drinking water and collection structures have been protected.