Lost Man Creek begins in the Hunter-Fryingpan Wilderness of the White River National Forest. Lush willow carrs characterize the valley floor and are sustained by overbanking flows during spring snowmelt and by soil moisture from upland snowmelt later in the season. A reservoir, dam and a diversion canal interrupt this natural flow before the stream reaches the Roaring Fork River. Above the reservoir a natural hydrologic regime sustains the stream-riparian ecosystem. Below the dam stream width and depth is decreased, and vegetation is encroaching into the stream channel with little habitat available for aquatic wildlife.
Threats to a healthy stream include:

• Recreation-induced wildlife disturbance and vegetation trampling.
• Dewatering and stream habitat fragmentation due to the Twin Lake diversion’s dam and reservoir with consequent degradation of stream habitat and harm to cutthroat trout populations.
• Non-native fish species including brook trout and rainbow trout threaten cutthroat with competition and hybridization respectively.
• Highway-induced habitat fragmentation and consequent wildlife mortality.