The Upper Cache Watershed (HUC 18020116) covers an area of 307 square miles in northwest Montana. The hydrology of the area is heavily influenced by snowmelt, with the watershed receiving an average of 50 inches of snow per year. The snowmelt feeds into the Trout Creek and Upper Cache Creek, which provide important surface water resources for the area. The watershed also includes two reservoirs, the Thompson Reservoir and the Lost Creek Reservoir, which are used for irrigation and provide storage for the winter months.
In recent years, the area has experienced warmer temperatures, leading to earlier snowmelt and reduced snowpack. This has implications for the availability of surface water resources later in the year. Additionally, the area has experienced an increase in wildfire activity, likely due to the combination of warmer temperatures and a buildup of forest fuels. Overall, the Upper Cache Watershed is an important resource for both residential and agricultural users, and continued monitoring and management is necessary to ensure its sustainability.