Wasser und Umwelt - Discharge


Discharge (= volume of water from a catchment area that flows through the outflow cross section per unit of time) measurements are performed to determine flow rates in rivers.



(Foto: D. Franke/J. Bonnell, Humber River Basin, 2009)
Flow meter measurements: The flow rate is measured at individual points in the cross section using a flow meter (point measurement). The discharge can be determined from the measured velocity and the area of the cross section of the profile (graphical and mathematical).

Tracer method (dilution measurement): A defined quantity of a suitable marker substance (tracer) is added at the beginning of a measuring section, e.g. in rivers with steep or uneven river bed or turbulent flow. To calculate the discharge, the concentration of the diluted tracer will then be determined at the end of the measuring section.