PREDICTING STREAM TEMPERATURES FOR NATIVE FISH HABITAT MANAGEMENT IN WHITE RIVER NATIONAL FOREST, COLORADO

White River National Forest in the Rocky Mountains is home to one of Colorado’s threatened native fish species, the Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus). Habitat for this native cold-water fish is thermally limited. The goal of this study is to create a small-scale empirical stream temperature model for the White River National Forest (WRNF) to help inform Forest Service management decisions for the conservation of Colorado River cutthroat trout and to identify locations where this species can be reintroduced. Identification of key control variables on stream temperature is a vital first step in building a working model. The primary factors influencing stream temperature are local air temperature, residual pool volume and hyporheic and groundwater exchange. Quantifiable secondary factors that influence these primary factors include valley aspect, elevation, riparian shading, substrate type, channel geometry, drainage area and flow regime. An assessment of WRNF divided the Forest watersheds into 6 management scale aquatic and riparian clusters based on four ecological drivers: geochemistry, sediment production (lithology), hydroclimatic regime and stream gradient (Winters et al., 2011). A single drainage from each cluster is included in the analysis to adequately represent the types of watersheds that exist within the Forest. 40 individual pools were chosen in which to monitor stream temperature over the course of a year. Preliminary results suggest that air temperature is a good proxy indicator for stream temperature in pools within pool-riffle stream reaches.