3 Conceptualizing Groundwater Flow to Wells

This section describes the conceptual framework of the mechanics of groundwater flow to a pumping well. Once a well is installed and the pumping system set up, the pump is started and water flows up the outflow pipe to the land surface. The flow of groundwater to a well is induced because the pump extracts water from the well bore drawing down the water level in the well. This sets up a hydraulic gradient between the water level in the well (lower hydraulic head) and the adjacent groundwater system (higher hydraulic head). Groundwater flows in response to a decrease in the hydraulic head because groundwater moves from areas of the higher hydraulic head to lower hydraulic head (i.e., high groundwater elevations to low groundwater elevations as referenced to a common elevation datum, generally mean sea level). This is discussed by Woessner and Poeter (2020). While this difference in hydraulic head is maintained by pumping, water flows from the adjacent groundwater system into the well.