A UNIT-HYDROGRAPH METHOD FOR STORM OVERFLOW PERFORMANCE SIMULATION

The paper describes a unit hydrograph method, calibrated using the WALLRUS modelling suite, which was employed to simulate the long-term behaviour of storm overflows in combined sewerage systems. It is shown that this procedure synthesizes overflow operation characteristics to acceptable engineering accuracy, measured relative to WALLRUS predictions. This is achieved at only a small fraction of the computer run-time, and therefore makes practicable a wide range of overflow, performance and river impact studies using local rainfall records of unlimited extent.