Groundwater plays a crucial role in sustaining streamflow in mountainous, semi-arid areas. A study in Gordon Gulch, Colorado, used field data to create a model showing that groundwater recharge mainly happens during spring snowmelt or intense summer rain. The stream in Gordon Gulch gains more water from groundwater in lower areas and during spring. Groundwater flows through long, deep paths from upper areas and hillslopes, and short, shallow paths in lower areas. The model suggests that groundwater contributes 16 to 34% of the stream's baseflow. This research helps understand how groundwater recharges and interacts with streams in semi-arid mountain regions.