FLOW ESTIMATION FROM FLAP-GATE MONITORING

The measurement of flows and recording of storm events at combined sew er overflows are a key requirement in effective urban pollution manage ment. Staff of Thames Water Utilities have developed a low-cost system based on monitoring the behaviour of flap valves on numerous major ri ver outfalls. The paper presents the development of a modelling approa ch based on the principle of conservation of angular momentum and its application to experimental data for circular gates. Flow-prediction a ccuracies, based on the measurement of gate inclination and water dept hs, in the range +/- 20-30%, are found to be achievable for wider gate openings (>20 degrees) - the recommended calibration offering conserv ative flow predictions at lower angles.