Causes Analysis And Planning Countermeasures Of Urban Waterlogging In Hohhot Central District

Urban waterlogging occurs very frequently in recent years,not only the lives and property of residents are threatened,also trouble daily travel and living order.According to the latest survey data published in the Bulletin of flood and drought disaster in china,waterlogging disasters occurred in 83 cities over the country in 2018,cause the direct economic loss of 161.547 billion yuan.The flood disasters in cities of Inner Mongolia Autonomous Region are also frequent and severe.Taking Hohhot as an example,since 2000,waterlogging disaster have occurred in 2002,2008,2012,2013,2014,2015,2016,2018,and 2019,which have caused the city to be paralyzed,causing heavy casualties and huge economic losses.Flood and waterlogging disasters have become a huge hidden danger for the future sustainable development of the cities.It is urgent to grasp the causes of urban waterlogging and its countermeasures.This article takes the urban area of Hohhot as the research area,analyzes the causes of waterlogging by historical waterlogging data collection and field survey,and proposes countermeasures and planning suggestions for waterlogging disasters.First,we collected and sorted out the waterlogging disasters in the study area from 2010 to 2019,and obtained the number and degree of waterlogging disasters.In addition,in order to grasp the specific location and water range of waterlogging water points,field research was conducted in the study area between 2017 and 2019,and a total of 78 actual data such as the specific location,waterlogging range and frequency of waterlogging points were collected.Through the analysis of the spatial and temporal characteristics of the water accumulation point,it is found that the number of waterlogging water points in the study area shows an increasing trend.Among them,about 39.8% of the water accumulation points repeated water accumulation for more than one year,and the waterlogging disasters mostly occur from June to September during July.Has the most times.In terms of spatial distribution,the water accumulation points in the central area of the city are relatively concentrated.The total number of water accumulation points in different administrative regions is Saihan District> Huimin District> XinchengDistrict> Yuquan District,of which 37.1% of the water accumulation points are located in the concave overpass.Or road intersections,etc.,seriously affect the traffic flow in the study area.Secondly,on the basis of the spatial and temporal characteristics of the accumulated water points,the correlation analysis method was used to analyze the causes of waterlogging in the study area from various factors such as precipitation,rainwater network,topography,water system runoff,and underlying surface.In terms of meteorological factors,analysis of rainfall and rainstorm data in the study area for the past 58 years found that the annual precipitation change trend is not significant.Although the number of rainstorm days is small,the ratio of rainstorm day precipitation to total precipitation is high,indicating that heavy precipitation is waterlogging One of the important causes of disasters.In terms of rainwater pipelines,the area with more water accumulation points or larger water accumulation area shows a tendency of the length or flow of the rainwater pipe network.Therefore,when the rainwater pipe network conditions do not meet the drainage requirements,waterlogging will be exacerbated.In terms of topographical factors,through GIS overlay analysis,it was found that more than 90% of the water accumulation points are located in low-lying places,indicating that small-scale low-lying places in the city create conditions for waterlogging and waterlogging,especially tunnels and concave roads under the railway.High incidence of waterlogging disasters.In terms of the runoff pattern of the water system,the study area is affected by the water catchment in the northern mountainous area and has the potential threat of flash flooding.In terms of urban underlay factors,the correlation analysis results show that the larger the green area,or the smaller the impervious surface,the number of water points and the area of water points show a downward trend.It can be seen from this that the underlying factors will change the urban runoff coefficient and provide conditions for the occurrence of waterlogging disasters.Finally,on the basis of the actual waterlogging situation in the study area and the analysis results of the waterlogging causes,specific proposals were put forward for the restoration of 78 easily accumulated water points,optimizationof the rainwater pipe network and increase of the length of branch pipes.From the perspective of sponge city construction,the permeable paved parking lot station was renovated 540,753 square meters,and the urban roof greening was3,219.59 hectares.On this basis,specific planning schemes such as retrofitting of existing urban green spaces were proposed.The above results provide safety guarantee for the safety and sustainable development of the people in the study area,and provide a scientific reference for the analysis of the causes of urban waterlogging in our area and its prevention and control.