What is the function of a stilling well in surface water monitoring?

The function of a stilling well in surface water monitoring is to provide a calm and stable water surface for accurate water level measurements, particularly in turbulent or wave-affected environments such as streams, rivers, or lakes. A stilling well is a vertical pipe or chamber with an opening to the surface water body. The water level inside the well is allowed to equilibrate with the water level outside the well, but the well dampens out waves, currents, and other disturbances, creating a still water surface. This allows for more precise and reliable water level measurements using instruments such as pressure transducers, float sensors, or manual gauging. Stilling wells are often used in conjunction with automated water level recorders to continuously monitor water levels over time. By providing a stable measurement environment, stilling wells improve the accuracy and reliability of surface water monitoring data, which is essential for understanding hydrological processes and managing water resources. The size of the opening between the well and the water body must be carefully selected to allow for equilibration without allowing excessive turbulence inside the well.