The hydrological effect and uncertainty assessment by runoff indicators based on SWMM for various LID facilities

Low Impact Development (LID) facilities are the key to realizing the source control of stormwater. However, there are few studies on the control effects of different LID facilities on runoff volume and runoff quality. In this paper, based on the Storm Water Management Model (SWMM), a Monte Carlo method was used to simulate the runoff process for five LID facilities. The correlation analysis and scoring of the three indicators of runoff coefficient, peak runoff, and Suspended Solid (SS) wash-off in the simulation results were conducted to evaluate the control effects of different LID facilities. The simulation results showed an evident law of decreasing marginal effect in the deployed area of LID facilities. In addition, the uncertainty of the hydrological response of permeable pavement is the smallest among the five types of LID facilities, and the uncertainty of vegetative swales is the largest. Under the suitable combination of parameters, the area percentage of permeable pavement reaching the upper limit of the control effect of three indicators is the smallest; the control effect of three indicators of infiltration trench is the best. Correlation analysis showed that the three indicators of the LID facilities could be estimated from each other through the regression relationship equation.