TUNING THE FLUME EQUATION FINE TUNES CASH REGISTER: IMPROVING FLUME INSTALLED ACCURACY BY EQUATION CALIBRATION

The Flow Metering Task Force (FMTF), composed of sewer and metering professionals from the Detroit Water and Sewerage Department (DWSD) and its suburban customers, evaluated a specific method for adjusting flow data from flumes. The evaluation was executed by calibrating the flume equation parameters, k and x, of the standard flume equation (Q=k*hx) to in-situ conditions using dye dilution testing. Calibrating the flume coefficient and depth exponent corrects the discharge relationship to account for inaccuracies in the field installation of the flume and level sensor, and for hydraulic conditions present at the site. Installation and site hydraulics are the principal causes for flumes operating differently in the field. Calibrating the equation parameters also accounts for the varying accuracy of the meter throughout the range of flows tested as compared to those predicted by laboratory testing.