The researchers studied groundwater circulation in an alpine watershed by collecting data from boreholes and shallow groundwater. They found that groundwater deeper than 20 meters is different from shallow groundwater and creek water in terms of chemistry, age, and flow rates. Their findings suggest that the active circulation depth is around 20 meters, with low vertical flow velocities. The study used a numerical model to show that only a small percentage of bedrock recharge flows below 20 meters. This research highlights the importance of detailed data for understanding groundwater circulation in mountainous areas.