Groundwater is an increasingly important source of drinking water for many Canadian and First Nations communities. However, the groundwater-surface water interactions and possible effects of climate change on groundwater recharge remain poorly understood in many jurisdictions, particularly in cold regions and places with complex geology and topography. In this study, we present data from the Christmas Brook watershed and fault aquifer which serves as the source water for Eskasoni First Nation, Nova Scotia. The objectives of this research are to quantify the main sources of stream flow and groundwater recharge feeding the pumping wells, then use this information to improve watershed management. We employed water sampling, chemical mixing analysis, hydrometric monitoring, and groundwater modelling to achieve our objectives. 134 samples where taken, each sample analyzed for ions, isotopes, and metals. Two stream gauging stations were installed: one near the headwater and another near the watershed output. Level loggers were also installed in bedrock observation wells in the highland plateau. Preliminary hydrochemical mixing results indicate that, on average at the lowest downstream location, groundwater contributes 34.6% of streamflow and the remaining 65.4% comes from ponds, lakes, and wetlands in the headwaters. Groundwater contribution increases in the downstream direction and was markedly higher during spring and fall sampling campaigns. A groundwater flow model is being developed with MODFLOW and particle tracking will indicate areas of higher conservation priority. This improved understanding of groundwater-surface water interactions will help guide collaborative water resource management and future research on climate change impacts.