Stream temperature has long been used as an indicator of ecosystem health and suitability for aquatic species, particularly in sensitive areas crucial to the survival of declining important fish populations. Typically, stream temperature surveys are limited in spatial extent, and often rely on trends in air temperature to predict how stream temperatures will adapt to changes in climate. However, we propose that empirical relationships between stream and air temperature alone cannot be uniformly applied to regions of differing geologic stratigraphy without accompanying physical models to incorporate subsurface heat flow. By coupling stream temperature distributions with subsurface heat flow dynamics we can better understand the resilience of stream temperatures to climate changes in the Northeast. Our proposed research utilizes new technological advances in fiber-optic distributed temperature sensing (DTS) to characterize stream temperature distributions with high spatial and temporal resolution. In conjunction with physical groundwater heat flow models, we will use detailed stream temperature distribution profiles to provide new insight into the temperature dynamics of thermal refugia critical to the growth and energetics of juvenile fish. Our study site is characteristic of a broader region of headwater catchment systems in Massachusetts which represent critical habitats for Juvenile fish. Furthermore, our streams of interest are also co-located with an on-going long term fish movement study conducted by the Turners Falls USGS Fish Ecology Division, allowing us to directly compare our results with well documented behavioral patterns of fish within our study site.