Urbanisation and hydraulic geometry response: a model approach

Abstract

As the process of urbanisation continues within a river basin, the response of river channels within the basin alters, resulting in a variety of responses. This study seeks to understand the impact of urbanisation on the discharge hydrograph of the Ona River using the hydrological modelling system (HEC-HMS). The hydrograph of the basin shows that the present discharge of the channel is 5,177.32 cumecs with a peak time of 10.52 minutes, while the moderated channel response due to increase in the level of urbanisation discharges 5,342.19 cumecs and peaks at 10.45 minutes. This shows that urbanisation contributes to increase the volume of discharge. The exponents (b, f, m) of the downstream hydraulic geometry (DHG) of the river, 0.15, 0.28, 0.57 respectively, indicates the variability within these three variables downstream and supports the view that as f and m increase, b decreases for cross-sections studied within the basin.