Urban stormwater simulation and assessment of the control rate of total annual runoff: A case of the Future Science and Technology Park in Beijing

Abstract

Along with the acceleration of urbanization process, urban impervious surfaces have increased, and the urban rainfall and runoff processes have undergone significant changes, resulting in outstanding flooding problems. Urban stormwater simulation is one of the hotspots and challenges in current urban hydrology research. It is also a key technical means for urban flood control and total annual runoff control rate evaluation of“sponge cities.”In this study, the Future Science and Technology Park in Beijing was selected as the research area. We constructed an urban stormwater model using the stormwater management model (SWMM) to simulate surface and pipe network runoff processes under different rainfall conditions. We designed the precipitation processes corresponding to the control rate of total annual runoff according to the characteristics of different field rainfalls. Moreover, we drove the constructed urban stormwater model to assess the achievement of current land blocks with regard to the control rate of total annual runoff. On this basis, the spatial layout of different“sponge city”measures was proposed to achieve the control rate of total annual runoff. The results demonstrate that the model simulation accuracy was high. The peak errors of the three rainfall and runoff processes were between 8%~26%, and the peak time errors were -8%, -1%, and 0, respectively. Under the current land use conditions, the control rate of total annual runoff of the city of Beijing (80%) has not been reached. With the addition of permeable pavements, green roofs, and sunken green spaces of 20%, 40%, and 40%, respectively on roads, buildings, and green spaces, 90% of the land blocks would reach the control rate of total annual runoff, and the maximum amount of available water would reach 17870 m3. This study can provide a reference for the assessment of the control rate of total annual runoff and specific decision-making basis for the optimization of the spatial layout of urban“sponge city”measures.