Hydrological regulation simulation of rainwater runoff of bioretention based on HYDRUS-1D

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 ol the model. I he verified model was used to carry out simulation experiments, and the influence ol 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 thai lite 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 A'2 were both above 0.8, and the simulation results were reliable. Comprehensively considering the hydraulic load parameters, the bioretention with a confluence ratio ol less than 10*1 have a better control effect on the rainfall process with a return period of less than la and a rainfall duration of less than 120 min. With the increase of the confluence ratio, return period and rainfall duration, the hydrological control effect of facilities continues to weaken. Increasing the height ol the aquifer will improve the hydrological regulation effect ol the bioretention. When the height ol the aquifer increases from 0 cm to 25 cm, the total run oil 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. 8 mil) and 36. 0 min, 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% , respective!) . and the range ol runofl generation and peak-occurrence delaj time ranged from 24. I min to 25. 0 min and 1.0 min to 2. 5 min, respectively. © 2022, Editorial Board of Water Resources Protection. All rights reserved.