Stream temperature is one of the most important barometers of stream health. In the Tualatin River basin, these temperatures are influenced by rising air temperatures and reduced summer flows resulting from climate change and urbanization. The extreme air temperatures in summer 2021 have resulted in the highest stream temperatures on records for the watershed. Some stream segments within our study area have been designated as temperature impaired and were recently restored to improve stream conditions. Meanwhile, beavers have become increasingly common within streams in the Tualatin basin. These beaver-impounded streams may result in reach-scale thermal heterogeneity compared to more channelized stream reaches.

While previous local studies examined broad-scale watershed processes that affect stream temperature, or watershed scale temperature trading in the whole basin in the Tualatin River basin, smaller-scale variation in stream temperature as it relates to recent stream restoration or beaver activity have not been thoroughly investigated. Along with other spatial and temporal factors analyzed at the watershed scale, Distributed Temperature Sensing (DTS)-derived data will allow detailed analysis of spatiotemporal variation of stream temperature on both subbasin and reach unit scale.