Optimization Simulation of Sponge City Landscape Pattern based on SWMM Model

With the acceleration of urbanization in China, the impermeable area of cities has increased dramatically, and the problem of urban flooding has become more and more serious, so China has put forward the concept of sponge city based on the concept of low-impact development. In this study, the central urban area of Shenfu New City in Liaoning Province is taken as the study area, the rainfall process of different recurrence periods is constructed by using the storm intensity formula, and the landscape pattern optimization is carried out in the study area based on the concept of sponge city, and the Storm Water Runoff Management Model (SWMM) is used to simulate the differences in surface runoff and rainwater regulation capacity under the two scenarios of the pre-planning scheme and the optimization scheme of the landscape pattern, and to analyse the effects of the optimization scheme of the landscape pattern on the urban surface runoff and rainwater regulation capacity of the city. The results show that the surface runoff and stormwater control capacity of the city are affected by the rainfall reuse scenario. The results show that the total runoff and runoff coefficient in the study area tend to increase with the increase of the rainfall return period; the runoff coefficient of the landscape pattern optimization scenario decreases significantly under the same rainfall return period, and the reduction of the total runoff increases gradually, and the reductions under the return periods of 1 year, 3 years, 5 years, and 50 years are 2.94, 3.58, 3.72, and 4.19 mm, respectively; The corresponding reduction rates are 23.9%, 16.4%, 14.3% and 9.3%, respectively; the optimized scheme can meet the requirements of controlling the rainfall of 20.8 mm at the rainfall return period of p=1, not overloading the stormwater pipe network at p=3 and not overflowing the river at p=50.