Study On Urban Stormwater Management Planning Based On Runoff Yield And Concentration

With the normalization of extreme climate in the world,urban rain and flood disasters occur frequently.Under the new era background,the development demands of cities have changed.Sponge city is the rain and flood management concept put forward in the new stage in China.The planning and construction of sponge city is in full swing,but there are still deficiencies in the exploration at the county level and plain cities and the research on the corresponding spatial hydrological characteristics.Therefore,the research focuses on the planning and construction of plain sponge cities in the county.Firstly,it combs and summarizes the theories and practices related to rain and flood disaster management at all times,at home and abroad,and runoff generation and concentration,and summarizes the research trends and methods of rain and flood disaster management following the natural hydrological mechanism,gradually paying attention to regional watershed management and using hydrological models.Secondly,it clarifies the key issues and research paths of plain sponge city construction,and determines the research perspective,scale,objectives and methods.The feasibility of the research perspective of runoff generation and concentration is elaborated in detail.From the perspective of runoff generation and concentration process,the mechanism relationship among runoff generation and concentration,rain flood disaster and sponge city construction is clarified.By exploring the scale characteristics of research and control of administrative regions and hydrological basins,the cognition and response scale of county rain flood problems are analyzed,the applicable hydrological model and construction method are determined at the county small watershed scale,and the new era Under the background of the new planning,the spatial-temporal two-dimensional goal research of the planning and construction of sponge cities in the County Plain.Taking Xiping County as an example,Swat and other relevant hydrological models are built through the digital elevation model,soil data,land use data and meteorological data in the study area,and the model results are calibrated based on the monthly measured hydrological data.The risk pattern characteristics and time sequence characteristics of spatial rain and flood disasters in the county are analyzed from the three aspects of runoff process,runoff unit and runoff time with the runoff data in the case area,so as to clarify the source of rain and flood disasters in the study area Risk space characteristics of process and end;Taking the hydrological response unit as the runoff and confluence landscape unit,the landscape pattern index was calculated to analyze the spatial pattern characteristics of water ecology in the whole region;The long-term,short-term and periodic characteristics of rain flood disaster are analyzed based on the time series characteristics of runoff generation and concentration.Finally,four countermeasures are put forward,i.e.the spatial governance of the runoff process,the optimization of the overall pattern of runoff and confluence,the response to the timing planning of runoff and confluence,and the construction of the urban rain and flood prevention system.Spatially,based on the medium and high-risk space identified for runoff generation,confluence and accumulation of runoff generation and confluence,the planning zoning and index control of the corresponding disaster process are carried out,focusing on eliminating the source runoff risk,optimizing the process confluence network,improving the terminal protection capacity,and optimizing the overall planning pattern and guiding the planning structure of the region.In terms of time,the planning,construction and implementation guidelines for short,medium and long term and different periods shall be formulated based on the time sequence characteristics of rain and flood disasters.Finally,the urban disaster prevention system including disaster prevention hierarchical structure and spatial structure will be constructed based on the risk characteristics of rain and flood and urban and rural construction.