Analyzing the Effects of Low Impact Development Controls on the Hydrological Balance of a Highly Impervious Catchment Using Stormwater Management Model (SWMM)

Abstract

The continual increase of impervious surfaces in rapidly developing areas poses the risk of altering its natural hydrological cycle and the water balance. To counteract these issues, low impact development (LID) technologies have been adopted in urban areas as they could mimic predeveloped conditions in built-up regions. The objective of this study was to analyze the effects of LID controls on the hydrological balance of a highly impervious catchment using Storm Water Management Model (SWMM). Four different scenarios were defined: a pre-development scenario and three other post-development scenarios based on the historical stage of development in the site and their corresponding increase in impervious area cover. Three LID controls were used in the simulation, namely the infiltration trenches, rooftop disconnection, and permeable pavements. Simulations have shown that the infiltration decreases, and the runoff increases over time across the four development scenarios. The combination of the rooftop disconnection and infiltration trench on the site was effective, increasing infiltration by up to 13 % and decreasing the runoff by 46 %. The application of permeable pavements in the site also showed the same trend in an increase in infiltration by up to 64 % and a decrease in runoff by up to 90 % while allowing more capacity for stormwater storage. This research showed that LID structures can improve the water balance of the developing site, and this could contribute to the development of LID policies in developing countries.