Abstract:In order to study the hydrological regulation efficiency of bioretention facilities, a bioretention model was established based on HYDRUS-1D, and the model parameters were calibrated through experimental data to verify the reliability of the model. The verified model was used to carry out simulation experiments, and the influence of hydraulic load parameters, aquifer height and initial water content on the hydrological regulation effect of bioretention was quantitatively analyzed by using the total runoff and peak reduction rate, and the delay time of runoff and peak emergence. The results showed that the maximum root mean square error of the simulated and measured values was only 0.134, the relative error was-2.28% to 7.59%, the Nash-Sutcliffe efficiency and R2 were both above 0.8, and the simulation results were reliable. Comprehensively considering the hydraulic load parameters, the bioretention with a confluence ratio of less than 10∶1 have a better control effect on the rainfall process with a return period of less than 1a and a rainfall duration of less than 120min. With the increase of the confluence ratio, return period and rainfall duration, the hydrological control effect of facilities continues to weaken. Increasing the height of the aquifer will improve the hydrological regulation effect of the bioretention. When the height of the aquifer increases from 0cm to 25cm, the total runoff and peak reduction rate increase by 86.16% and 96.74%, respectively, and the runoff generation and peak emergence delay time are extended by 57.8min and 36.0min, respectively. The increase of the initial water content will reduce the hydrological control effect of the bioretention, the total runoff and peak reduction rate ranged from 49.32% to 54.11% and 22.84% to 45.37%, respectively, and the range of runoff generation and peak-occurrence delay time ranged from 24.1min to 25.0min and 1.0min to 2.5min, respectively.