The Effects of Urbanisation of Flood Magnitude and Frequency

摘要

This report considers the effect of urbanization on flood hydrograph shape and on flood magnitude-frequency distribution. Urbanization causes an increase in volume of runoff and a more rapid response - yielding a flood hydrograph that is faster to peak, faster to recede, and of increased peak discharge. The dependence of these changes on a range of factors is considered, notably the severity of the storm, the original rural response, the rainfall regime, and the location of urban area. The need is recognized for models of a range of complexity to predict urbanization effects, and problems in model development are discussed.