Information about the relationship between rivers and creeks and the underlying aquifers can be assembled through gain-loss studies. The goal of a gain-loss study is to identify the segments of the rivers which gain water from the underlying aquifers (termed gaining) and which segments lose water to the underlying aquifer (losing). This is achieved by measuring the volume of water that is flowing in the river at strategic locations throughout the watershed. These volumes are then compared to see where the volume has increased (indication of a gaining segment and potential spring flows) or decreased (indication of a losing segment or recharging of the aquifer).