Stream Temperature and Thermal Networks:
A GIS and Remote Sensing Approach to Assess Aquatic Habitat

Water temperature is a fundamental determinant of aquatic species distribution, condition, and abundance within stream ecosystems. With the onset of climate warming, rising temperatures may profoundly affect the distribution of cold water habitat for thermally sensitive fish, such as trout and salmon. Although inexpensive thermographs are now routinely used to collect data at point locations, basin-wide, spatially continuous temperature data are currently unavailable. We collected data of summer stream temperatures within a mountainous watershed in southern Idaho, at 518 unique point locations over a 14 year period. We used Thematic Mapper satellite imagery to map riparian vegetation and hence modeled solar radiation at the stream surface for the entire basin. Various other spatial variables such as elevation, valley confi nement, and glaciated morphology were also generated for the study area. Preliminary correlative analyses between the temperature observations and GIS data suggest that elevation and radiation have large effects on water temperature. More detailed analyses are underway to build models that will be used to predict temperature for all stream reaches within the network, under a range of climate scenarios. Thermally suitable habitat networks can be generated from these data. This presentation will summarize our methods for estimating solar radiation and other predictive GIS variables, and will provide a synopsis of our preliminary results.