Groundwater contributes an essential water supply to several communities and ecosystems in the Truckee River Basin. Water resource investigations were conducted through numerical modeling and comparisons to previous work to assess groundwater recharge in the Martis Valley watershed, which is an essential component to the Truckee River hydrographic region. A baseflow analysis was performed to relate annual baseflow to streamflow and precipitation. Results show that changes in groundwater fluctuations are driven by changes in precipitation, and baseflow response is affected by previous precipitation trends. It was estimated that baseflow is roughly one-sixth of mean annual precipitation. A novel method for constructing a hydrogeologic framework model was developed and applied to an integrated surface water-groundwater hydrologic model, GSFLOW, from which groundwater recharge locations and magnitudes were extracted. Model results supplemented previous work and provided enhanced conceptualizations of surface and groundwater interactions, as well as spatial and temporal recharge trends. Results show that the most significant recharge zones are low to mid-elevation stream channel and alluvial areas. During peak snowmelt periods, upper elevation alluvial areas also contribute significant recharge. The findings herein promote a more detailed understanding of groundwater recharge characteristics in high elevation, snow dependent, alpine catchments
