A review on reducing the impacts of urbanisation through greener approaches

![CDATA[It is well known that urbanisation has a notable effect on the hydrologic and environmental dynamics of a catchment. The purpose of this paper is to present a brief review on the effects of urbanisation and compare the various approaches taken to minimise these impacts. Urbanisation has been identified to intensify the response of a watershed, increasing the magnitude of storm peak flow, by up to a factor of 12 and reducing post-development lag time to less than half that of the pre-developed state. Large watersheds were found to be less sensitive to urbanisation due to channel transmission losses. Urban catchments are characterised by a lack of infiltration, hence the 'first flush ' of accumulated pollutants is mobilized to the catchment outlet, rather than retained, increasing the magnitude and frequency of pollutant wash-off. In order to respond to post development effects of urbanisation, implementation of greener approaches such as permeable pavement and bio retention systems are encouraged, as well as the implementation of rainwater tanks. Moreover, the concurrent implementation of on-site detention and Water Sensitive Urban Design (WSUD) systems has been found to effectively replicate the response of a natural catchment to a large degree. Overall, this paper acknowledges that whilst on-site detention is necessary to reduce the excessive peak flows of urban catchments, the simultaneous implementation of greener approaches would better mimic natural catchment dynamics.]]