Matching Rainwater Harvesting Strategies with Ecological Flow Needs

A spreadsheet model was developed to examine the capacity of rainwater harvesting (RWH) to mitigate the effects of urbanization on the pre-development water balance of a suburban neighbourhood. Simulations showed that RWH in a residential lot or neighbourhood moved the runoff and evapotranspiration components of the area's water balance toward their pre-development proportions. Other rainwater management strategies are needed in conjunction with RWH to manage runoff volumes and maintain pre-development groundwater recharge for the development scenarios considered. The spreadsheet model was useful in determining the extent of RWH implementation desirable on a water balance (or receiving water) basis. It can also provide input to larger, more sophisticated models capable of simulating the linkages between urban areas and receiving streams.