Strategies for coastal Cities to Cope with Flood disaster and Urban Heat Island Effect in the Context of climate Change- A Case study of Shanghai, China

With the global warming and the acceleration of urbanization, China's climate has also undergone significant changes. Precipitation increased in many areas, and the frequency of extreme events greatly increased. Therefore, people begin to think more about how to deal with climate change in urban planning and how to have stronger disaster resistance in urban functional structure and layout space. With the rapid development of economic construction in Shanghai, the temperature difference between urban and rural areas continues to expand, the intensity and area of heat island continue to increase, the phenomenon of high temperature in summer continues to strengthen, high temperature disasters occur frequently, and the urban thermal environment problems are becoming more and more prominent. Urban heat island is formed under the combined action of human factors (mainly urbanization and industrialization) and local weather and meteorological conditions. With the increasing urban hardening rate and excessive development, the original surface runoff is destroyed and the urban heat island effect is gradually aggravated. Therefore, for urban planning, increasing green space area and reducing urban hardening rate through LID measures can reduce the impact of heat island effect. The rainfall in Shanghai is mainly concentrated from June to October every year. It often rains for several consecutive days. The rainfall is concentrated and lasts for a long time, and the instantaneous rainfall is heavy, which easily causes the water level of the river to rise sharply. At this time, the city due to the original municipal pipe network facilities is not perfect and the design is not reasonable, resulting in rainwater drainage is not smooth, resulting in waterlogging. On the other hand, global warming has accelerated the melting of glaciers and caused sea levels to rise, leading to flooding in coastal areas. By introducing the concept of sponge city into urban waterlogging prevention and control, especially by effectively reducing surface runoff and flood peak through low-impact development measures, the adverse effects and damage caused by urban waterlogging can be alleviated. Therefore, the paper takes the construction concept of "sponge city" and low-impact development measures as an important strategy to alleviate the above problems. The author starts from the theoretical research, and then makes a systematic analysis of the weather of Shanghai in the past 60 years, and concludes that the main climate problems of Shanghai are urban waterlogging and urban heat island effect. Then, according to the pilot project of sponge city construction in Shanghai, four representative pilot projects were selected for planning practice. Systemic strategies and low impact development measures are proposed to alleviate urban waterlogging and urban heat island effect. The present situation of Shanghai and the main problems of sponge city construction are analyzed with the four pilot projects as representatives. In terms of empirical exploration, it mainly analyzes how to construct sponge city system from the perspective of LID layout. Finally, make a summary of the foregoing and put forward deficiencies.