Measuring instrument: Maisbich basin: V-notch discharge meter Q1 Type: Pressure Sensor Keller DCX-4.0, SN 1454 This instrument is based on differential pressure measurement of two absolute sensors. The sensors measure pressure and temperature. Height of V-notch above sensor: hV=0.145m. The discharge is calculated with the rating curve Q=C*(h-hV)^2.5 where C is a calibration constant and h results from the pressure difference (Willem Luxemburg, Martijn Westhoff).