Simulation and evaluation of low-impact development practices in university construction: A case study of Anhui University of Science and Technology

Abstract

The development of “sponge cities” is a new trend in Chinese urban construction that can effectively alleviate urban flood disasters, reduce non-point-source pollution, and promote the recycling of rainwater resources. Constructing a sponge city generally includes the application of low-impact development (LID) practices. In this study, some different LID practices (vegetative swales, sunken green spaces, rain barrels and combined methods) were applied on Anhui University of Science and Technology (AUST) for various rainfall return periods. A framework for simulating LID practices at AUST was created, and the impacts of LID practices on water quantity were simulated with the SWMM model. In the meantime, the cost-effectiveness of different LID facilities was quantified and analyzed in the runoff mitigation and pollutant removal. The results indicate that LID practices can effectively reduce runoff and peak flow and delay peak times. Overall, the constructions of sunken green spaces and combined LID measures greatly reduced peak flow, with a reduction rate >35%. Furthermore, vegetative swales, sunken green spaces, and combined LID practices were all able to effectively remove pollutants by treating and reducing runoff. We found that the cost per unit was the lowest for vegetative swales, making to the most cost-effective and an ideal LID structure for comprehensively removing non-point-source pollutants. Meanwhile, sunken green spaces were the most effective means of pollution control. Thus, our findings can provide guidance for improving the environmental conditions and impacts of university towns. In the construction of such towns in the future, LID practices should be implemented, with preference given to vegetative swales. In areas for which there is a need for high runoff and pollution control, the use of sunken green spaces should be considered.