For their water management Rijkswaterstaat determines discharge series through mathematical equations of the discharge and water level (Qh/Qf relation). To test and verify the discharge series the permanent current measurement stations need to be calibrated with actual discharge measurements. Since 2014 Aqua Vision is performing discharge measurements with ADCP survey vessels on three different rivers (IJssel, Waal and Maas) for the whole discharge range (including high water conditions).