Design Of Waterfront Greenbelt In Semi-humid Region From The Perspective Of Rain And Flood Management

Urban green space has begun to assume an increasingly important role in urban rainwater management,especially in the semi-humid areas of China,affected by the temperate monsoon climate.Although the annual rainfall is 400-800 mm,the interannual change of rainfall is obvious.Uneven distribution,dry and dry in winter and spring,concentrated summer rainfall and short-term rainfall,urban flooding disasters,water pollution problems occur from time to time,and uneven rainfall distribution leads to low utilization of rain water resources,urban development The contradiction between the rain and flood disasters has intensified,and the reflection of the above issues constitutes the opportunity and basis of this study.The purpose of this article is to guide the design of urban waterfront green spaces in sub-humid regions through analysis and sorting of related concepts,connotations,and technical means of rain and flood management,and to summarize design methods and processes in order to alleviate urban floods,urban waterlogging,and water resources in sub-humid regions.The "water problem" such as low utilization rate and water resource pollution provides theoretical and practical support.This paper takes the greenbelt of Binhu East Road,Qian'an City,the first batch of sponge pilot cities in Hebei Province as a carrier,and builds an elastic interface of the green ground against the threat of floods and rainstorms on the basis of meeting the recreational needs of the surrounding people.The main design method is to determine the landscape spatial structure of the green space through qualitative analysis and quantitative simulation,and use SWMM software to perform scenario simulation on the designed green land rain and flood management effects.The main simulation objects are runoff,peak flow,and peak time Etc.,to determine the reduction and postponement of green space to the three and the resource utilization rate of rainwater runoff.Through the analysis and summary of the simulation results,it can be found that the construction of a rain and flood management system based on low-impact development facilities has a positive effect on the rainwater regulation and storage of green land and the utilization of rainwater resources.On the basis of meeting the design goals,the east side site reduced by 97.78%,95.56%,93.33% through the low-impact development facilities of 29.93% under the return period of one,two,three,five,and ten years.,83.78%,82.22% of the total runoff,the peak flow reduction rate was 91.49%,82.91%,69.72%,66.67%,65.30%,the peak current time was delayed by 0.7h,0.6h,0.8h,0.6h,0.4h The utilization rate of rainwater resources is between 34.57%-51.53%.The runoff reduction rate of the west side is 100%,97.14%,96.43%,89.05%,78.57%,the peak flow is delayed by 100%,82.03%,79.74%,64.89% and 44.23%,and the delayed peak current time is 3.6h,2.2h,1.3h,0.6h.The area of the constructed wetland in the site is 6.1hm2,and every square meter of wetland can purify 0.2 tons of water per day,and can be circulated and purified once a week to reach Class IV water quality.