A Rain-flood Security Pattern Construction Method Based On FLO-2D Model

In the past urbanization process,the urban hydrological pattern was destroyed due to improper urban development and construction,which was mainly manifested as the reduction of the total amount of urban stormwater storage land,the separation of the flood discharge network by construction land,and the overlapping of the confluence land and construction land.In addition to the frequent occurrence of extreme rainfall events caused by global warming,increasingly frequent floods have become an important problem affecting urban development and seriously threatening the safety of people’s lives and property.The existing practice of sponge city planning plays a certain role on a small scale,but lacks quant itative analysis and research on macro level.However,cities do not exist in isolation and are located in the background of the basin environment.Therefore,to fundamentally solve the urban flood disaster in the event of torrential rain in the basin and improve the resilience of cities against flood disaster,it is necessary to build an organic,integrated and connected drainage basin flood safety pattern.This paper starts with the research idea of "finding problems-analyzing problems-constructing methods-empirical analysis".Firstly,by analyzing the causes of urban flood disaster and the limitations of existing research on sponge cities,this paper focuses on the problems to be studied.Then,the paper further analyzes the problems through literature review,summarizes the existing ideas and methods of stormwater safety pattern construction,and analyzes its reference value and areas to be improved.Then,a rain-flood safety pattern construction method based on 2-D flood simulation software FLO-2D is discussed.Finally,taking the Longhe Basin in Wan zai County,Jiangxi Province as an example,the FLO-2D model was used to simulate the rain-flood inundation area under 24-hour rainfall every 100 years,and GIS spatial superposition analysis was conducted on the rain-flood inundation area,construction land and non-construction land.The superposition area of construction land and inundation by rain flood is waterlogging area.For each catchment area,the current stormwater storage land volume and the target storage volume are calculated.After the above preparations,the stormwater and flood safety pattern is constructed in three parts: the first and second parts are the layout of stormwater and flood corridors and patches on the whole basin scale.The specific methods are as follows: the stormwater and flood runoff corridors obtained from the current stormwater regulation and storage land are overlaid with GIS hydrological analysis,and the layout of stormwater patches and corridors is carried out.The third part is the rain flood storage capacity additions scale and space layout planning,the specific method is: will the volume of the status quo of the rain flood to regulate land with the volumetric method,comparing the calculated design goal to regulate volume and combining with the distribution of Yi Lao District,to guide the supplement of each catchment area to regulate volume and the amount of reserve estimates,and supplement to regulate land use planning strategy is given.The construction method of river basin rain-flood safety pattern explored in this paper will be conducive to the combination of urban rain-flood source control and terminal control,provide new ideas for the prevention and control of urban flood disaster,and have certain practical significance for the flood control planning in the future comprehensive urban disaster prevention planning.