Groundwater mapping helps identify sources of stream baseflow. By analyzing groundwater surfaces and using digital filter and tracer techniques, researchers found that during high flow periods, baseflow from groundwater exceeded actual groundwater discharge. Tracer analysis couldn't distinguish between different sources of flow, but mapping revealed areas where shallow flow paths dominated tributary flow. This study shows that mapping groundwater surfaces is a valuable tool for understanding baseflow sources and when baseflow analysis may overestimate groundwater discharge to streams.