Comprehensive Benefit Evaluation Of Low Impact Development Based On SWMM Model

On account of the rapid rate of urbanization in China,the conditions of urban bedding have changed.Coupled with the fact that rainstorm with short-duration and strong density happens constantly,the natural water circulation is being broken,which has resulted in urban inundation floods frequently,water environment deterioration,and other issues.Traditional discharge system would no longer satisfy the sustainable urban stormwater management requirements,and recently,urban runoff best management practices and low impact development which designed to improve or maintain the natural hydrological state before site development become more and more popular.It is of great significance to carry out the evaluation study on the comprehensive benefit of low-impact development program and provide the basis for the choice of the scheme.First,the current situation of the study area,engineering campus of Wuhan university,was simulated by using the rainwater model SWMM.The sensitivity analysis of the model parameters is carried out by the perturbation analysis method,and the parameters of the runoff parameters are taken as the objective function.Moreover,through tons of simulations under different rainfall reappearance periods,analysis on the flooding conditions including outlet runoff process,peak flow and pollution load of the outlet pipe.According to the study area of the site conditions and LID measures applicable conditions,select LID technologies.The effect of the LID scheme on the water quality and quantity was simulated in SWMM.Secondly,combined with domestic and foreign research results and practical experience,quantified the LID measures carbon reduction benefits calculation,summed up the LID measures infrastructure and maintenance costs,management needs,economic analysis.In addition,qualitative evaluation of rainwater utilization,landscape value and other social benefits.Finally,the AHP method is used to construct the comprehensive benefit evaluation system of LID measures.Judgment Matrix is constructed by Expert questionnaire and normalization method.Using the yahhp,then get the comprehensive weighting of the LID scheme.So as to provide a comprehensive consideration for the application of engineering options.