Apparatus for taking a water depth measurement using a probe, featuring a signal processor configured to receive signaling containing information about a water depth measurement determined from a pressure sensed by a pressure sensor contained in a probe immersed in flowing water, and also containing information about a velocity-dependent offset that is determined and depends on the velocity of the flowing water; and determining corresponding signaling containing information about a corrected water depth measurement of the flowing water by correcting the water depth measurement by the velocity-dependent offset in order to compensate for Venturi effects on the pressure sensor in the moving water.