Design On The SUSTAIN Model Of Low-impact Devel Opm-ent Of Typical Residential Areas

With the rapid urbanization,urban buildings become increasingly dense,and the impermeability of the underlying surface of the city increases,leading to the increase of runoff coefficient.Therefore,in recent years,the frequent occurrence of urban waterlogging,resulting in a large number of human and financial losses.In view of the deficiency of China’s rainfall management measures planning,this study USES foreign advanced concepts for reference and combines with China’s existing theoretical practice to improve China’s rainwater management system and urban rainfall runoff management technology,and will be applied to the actual pilot study.Based on this,a residential community in Chengbei district of Xining city,Qinghai province was selected as the research object in this study.The BMPs-LID measure evaluation comparison system was established by using analytic hierarchy process(AHP),and the rainwater management measures applicable to this region were preliminarily selected.Secondly,this research USES the SUSTAIN model as the planning tool of the research area,adds BMPs-LID measures of different scenarios in the research area,proposes different planning schemes,and analyzes the regulation effect of different scenarios on regional rainfall runoff.Combined with the study area’s rainfall and runoff control objectives,the planning schemes of different scenarios were optimized to obtain the cost-benefit optimization of rainfall and runoff control and management planning scheme.Finally,the environmental impact of the planning scheme on the study area was evaluated.The main research results are as follows:(1)Indicators were selected from three aspects,namely,regional applicability,BMPs-LID runoff control efficiency and cost management input.AHP method was used to establish a measure evaluation comparison system.The comprehensive scores of Biodetention tank,green roof and grass planting ditch were 4.617,4.494 and 4.156,respectively.It provides reference and basis for adding BMPs-LID measures to different scenario plans.(2)The study of regional water catchment area and reasonable drainage pipe network has carried on the generalized,divides the research area of land use types in detail and the permeable and impermeable area,and analyze the research area of terrain elevation,SUSTAIN model in the study area,based on the basic data according to the model validation results analysis,the study area the eliminator control area by 1,2,the coefficient of variation of runoff coefficient simulation and practical comprehensive to meet the requirements of the maximum plus or minus 5%,so the model established in the study area has good applicability and prediction precision.(3)Three different BMPs-LID measures planning scenarios were established with the daily hourly rainfall of 2016 as the front-end input.Simulation analysis shows that the total runoff in scenario 1 and scenario 2 is reduced by 15.98% and 29.96% respectively compared with the current situation.The flood peak value was reduced by 12.0% and 20.9% respectively.Finally the NSGA-Ⅱ algorithm optimize the planning scheme,according to the result of decision-making,the annual runoff in the study area reduction rate and the cost of the optimal combination for(48% or 12.30 million yuan),36%,6.36 million yuan).