Urban Wetland Loss And Waterlogging Response Of Wuchang Area Based On LUCC

Urban wetlands play an important role in regulating urban climate,flood control and drought relief,and maintaining biodiversity.They are an important part of urban ecological environment and human living environment.However,there are a large number of unreasonable development activities in urban construction,resulting in the wet land being filled,degraded or even disappeared.The degradation of urban wetlands will have a serious impact on the urban ecological environment,weaken the role of its stagnant rainwater,increase the probability and danger of the occurrence of internal hesitation,and adversely affect the sustainable development of urban social economy.Taking Wuhan City,which is a fast urbanization development,as an example,this paper takes the Wuchang area of Wuhan as the research area,and uses the Landsat TM remote sensing image and the land use database of the research area as the data source.First,the land use/cover change(LUCC)of the study area.The overall characteristics were analyzed.On this basis,the spatial and temporal characteristics of wetland water information analysis and the driving factors of wetland change were extracted by visual interpretation.Finally,the flood area in the study area were obtained through social media,combined with the wetland loss in the study area.The influence factors such as elevation are used to evaluate the risk status of the intrinsic disaster through a logistic regression model and to create a risk classification map.The main findings are as follows:(1)From the whole research period,the land use/cover in Wuchang area of Wuhan City has changed drastically,and the construction land area has continued to grow.The area of cultivated land,woodland,lawn,water body and unused land has been reduced to varying degrees.On the above,the construction land has changed the most,and the area has doubled.The change range of other land use has been ranked from cultivated land,unused land,water body,woodland and lawn.(2)From 1990 to 2015,the wetland area in Wuchang area of Wuhan City decreased by 5869.06 ha,and the average annual reduction was 234.76 ha.According to the difference of wetland loss,the wetland change can be divided into wetland rapid loss from 1990 to 2005,2005~2010 wetland rapid loss,2010~2015 wetland loss slowed down three stages.The three major lake wetlands in the study area are also the three largest lakes in the downtown area of Wuhan,namely Tangsong Lake,South Lake and East Wetland.The shrinkage rate in the 25 years accounts for about 40% of the wetland shrinkage area of the entire study area.(3)Taking the internal disasters in Wuchang area of Wuhan in 2016 as an example,through the social media to mine the water retention information in the study area,it is concluded that there are 167 stagnant water points mentioned in the social media information within the research area.According to the analysis of the risk factors affecting urban disasters,combined with the actual situation of the study area,select 8 factors of elevation,slope,curvature,LUCC,NDVI,rainfall,flow accumulation and wetland loss.Risk assessment within the region and mapping of the susceptibility index.It is obvious from the figure that most of the high-risk areas are located in areas with frequent population activities such as residential or commercial gathering areas within the central ring of the city;wetland loss is more obvious for the distribution of volcanic areas,and internal disasters occur within the original wetland.The risk is higher.(4)From the wetland loss and the response of the internal disasters in Wuchang area of Wuhan,it can be seen that as the wetland in the study area is continuously converted into other land types,the effect of the regional wetland regulation and distribution diversion rainwater decreases,while the urban wetland elevation is lower,and the original wetland is located in the area.The probability of infighting increases.Based on this,the restoration and protection measures of wetlands should be proposed to strengthen the anti-mite effect of urban wetlands.At the same time,in the future,in the urban planning process,we should change the traditional concept,build a sponge city based on the long-term,and combine the actual conditions of the region to create a city “sponge body” to enhance the regional flood control capacity.