The Strategy Research Of Stormwater In Shanghai In Response To Climate And Land Use Change

Climate and land use change are the main factors influencing the urban flood disaster. The urban flood disaster coping strategy should not only mechanical engineering measures, the strategy must transfer the research perspective from the water itself to land and water overall,and put forward urban river and built environment comprehensive coping strategies. In this paper, the land area of Shanghai city as the research object, First,we systematically analyse the characteristics of climate and land use change and identify the current situation of environmental change. Then, the influence mechanism of different environment on hydrological process is analyzed. On the basis of the environmental identification and mechanism analysis,we analyse the flood and waterlogging safety pattern of Shanghai city.At last,we put forward coping strategy in response to the flood disaster. The main research content of this paper can be divided into three parts.The first part is the analysis of the characteristics of meteorological hydrology and land use change. About the evolution law of climatic factors, The Mall-Kendall statistical method was used to analyze the changes of temperature, precipitation, evaporation and other meteorological elements in the recent 40 years. The statistical results show that the temperature of Shanghai city is significantly increased, While the precipitation at different time scales is different, annual precipitation show a slight fluctuation upward trend. In space dimension, we use GIS spatial interpolation method to reflect spatial distribution characteristics of the climatic factors. The results show that Shanghai has a significant phenomenon of the heat island and rain island. Analysis of the characteristics of land use change is based on remote sensing image interpretation combined with statistical yearbook data. A land use classification system based on the impervious surface was established. Analysis results showed that the city impervious area increased year by year and the land use degree in high utilization level. We select the index of river density,river surface rate, River frequency to reflect the characteristics of river network change. In recent years, the situation of continuous reduction of Shanghai river network has eased, but the suburban distribution differences remained significant, area of the river in the center of the city rate is still the lowest.The second part is the study of the impact mechanism of climate and land use change on hydrological process. The influence of climate change on regional runoff is analyzed by linear correlation due to the limitation of data precision. Precipitation is the dominant factors which have a direct impact on the regional runoff, temperature and evaporation indirectly affect the regional runoff process. SCS model is used to simulate the hydrological effect of urban impervious surface. We found that with the increase of impervious area, the urban surface runoff showed an increasing trend. The urban impervious area ratio has a significant positive correlation with the growth rate of runoff. River network structure and storage function have high relevance, the rate is an important index of the river flood storage functionThe third part is the research of regional flood safety strategy. Based on the theory of landscape security pattern, the security pattern of urban flood and waterlogging namely key areas affected by flood and waterlogging in the city was determined, including the storage function area and flood risk area. The risk area of urban flood and waterlogging disaster is determined by the way of establishing the comprehensive evaluation of disaster factors. Based on environmental analysis, mechanism analysis and result evaluation, we put forward the coping strategies including updating the concept of urban construction, building regional water ecological security pattern, planning and designing reasonably city function area and improve rainwater storage system, integrating application of the safeguard measures of economic, legal and other non engineering measures.