Rapid Assessment Model Of Runoff Control Effect For Stormwater Facilities Research And Application

In recent years,global climate change,frequent extreme rainfall,and accelerated urbanization in my country,hardening of the underlying surface and low design capacity of urban pipe networks have led to frequent urban floods.In order to effectively solve this problem,my country has vigorously promoted the construction of sponge cities.Runoff control rate is one of the important indicators of sponge city construction effect evaluation.It is of great significance to develop a set of runoff control effect evaluation model.Based on this,this paper develops a set of standardized and portable rapid evaluation models for the runoff control effects of stormwater facilities that coordinate pre-processing,hydrological and hydrodynamic core calculations and post-evaluation algorithms.The model considers the various stages of runoff control effect evaluation more completely and in detail:the pre-processing part is based on the RGB color matrix to automatically identify and divide the land use type of the study area,and match it to form a land use matrix;the runoff generation calculation adopts the super-permeability runoff generation method to calculate,Considering the evaporation,plant interception and infiltration process,the evaporation is calculated by the actual measurement method,the calculation of the plant interception is calculated by the Horton method,the calculation of the infiltration process is calculated by the Horton infiltration method,and the confluence part is calculated by Manning’s formula is used to calculate the drainage of the urban pipe network,and the pore flow formula is used to calculate the amount of water discharged from the pipe network based on the nodes of the urban pipe network.The surface runoff evolution calculation is carried out by constructing scientific evolution rules,and the runoff controlled by the study area is calculated,and then the runoff control rate of the study area is calculated by the ratio of the control water volume to the total rainfall volume,so as to effectively control the runoff control effect of the storm flood facilities in the study area Evaluation.Introduce CPU parallel acceleration technology to increase the calculation speed without reducing the evaluation progress.The model coordinates the various stages of runoff control effect evaluation to compensate for the long modeling time of commonly used urban storm flood models,the inconsistency of pre-and post-processing leads to the insufficiency of the difference in evaluation results,and the lack of a complete hydrological and hydrodynamic calculation process in the runoff coefficient method.The construction content is reached.A more comprehensive and more efficient evaluation model is the goal of the rapid evaluation model for the runoff control effect of stormwater facilities.On the basis of the completion of the model construction,the sensitivity analysis of the key parameters of the model is carried out based on the controlled variable method.The results show that the stable infiltration rate is the most sensitive parameter,and the order of other parameters is:orifice discharge coefficient>impervious area depression Storage capacity>sump storage capacity in permeable area.The accuracy and efficiency of the constructed model are verified by simulation comparison between ideal experiments and actual engineering examples.In the ideal experimental example,the experimental results are compared and analyzed with the simulation results of the rapid evaluation model of the stormwater facility runoff control effect.The results show that the model evaluation results are in good agreement with the experimental analysis results under the ideal experimental conditions;In the calculation example,the underlying surface conditions are more complicated,but the simulation results still have high accuracy compared with the traditional urban rain and flood model,which meets the actual engineering needs,and the single evaluation time is shorter,which meets the requirements of rapid simulation.Finally,the model was applied to a typical sponge reconstruction community in the old city of Xi’an,and the runoff control rate of the community under different designed rainfall conditions was evaluated.The results showed that the runoff control rate gradually decreased with the increase of the rainfall return period,which was in line with the actual situation.At the same time,the model is used to study the influence of rainfall duration on runoff control rate.The results show that under the same rainfall conditions,as the rainfall duration increases,the runoff control rate gradually increases,and the study area will control more runoff.It can be seen that the model in this paper has important application value for the evaluation of runoff control effect and the optimization of sponge city planning.