Glacial versus geomorphic controls on stream temperature and conductivity in a temperate watershed

Climate change is impacting mountain systems worldwide, with far-ranging consequences including changing stream temperature and chemistry. In glacier-dominated systems, previous studies have focused on the distance from glaciers as the primary control on stream temperature and chemistry. However, other watershed attributes including groundwater, lakes, topography, and vegetation may also have a strong impact. Here, we quantified the watershed properties that most influence stream temperature and specific conductivity over a summer season. We used spatially distributed 15-minute observations of stream temperature and conductivity in the glaciated Dinwoody Creek watershed in the Wind River Range in western Wyoming. Though the amount of perennial ice and snow was an important predictor for all variables, it was not significant in mid-summer. However, the percentage of the watershed with gneiss bedrock was significant for mean temperature and the terrain ruggedness near the stream channel was significant for conductivity. These results indicate that lithology and topography, both indicators of surface water–groundwater interaction, are important for predicting alpine stream water quality. These findings highlight the need for a broad understanding of how the landscape mosaic influences critical water quality parameters in rapidly changing mountain ecosystems.