Discovery Early Warning System For The Fresh Water Supply Impacted By Sea Level Rise In Shanghai Municipality

As the most developed areas in our country, the Yangtze River delta and adjacent areas are the most vulnerable regions affected by climate change and sea level rise (SLR). Especially Shanghai, a megacity located in the Yangtze estuary, there are more than23million residents and about70%of fresh water from Yangtze River estuary in the future. Under the background of the climate change, intensifying risk of fresh water supply will occur with the increasing saltwater intrusion caused by the SLR. Therefore, it is necessary to make the further research of the early warning system on the fresh water supply impacted by SLR in Shanghai in order to increase the guarantee of the water supply safety in Shanghai.This paper builds the early warning index system of the fresh water supply in Shanghai and establishes the early warning evaluation model based on the entropy fuzzy matter element. The early warning indexes are determined by analyzing the combined influence of water resources per capita in Shanghai, residual rate of water supply, water consumption per10,000yuan of GDP in Shanghai. The comprehensive early warning levels of the fresh water supply impacted by SLR in Shanghai in the year of2020,2025,2030are divided by calculating the entropy weight of each early warning index and the weighted Euclidean distance between the standard fuzzy matter element model and the early warning evaluation model which is named as the comprehensive evaluation index value to judge the fresh water supply safety in Shanghai. The comprehensive value is calculated as follows:0cm of SLR, in2020, the comprehensive value is0.610and the alert is light; in2025the comprehensive value is1.026and the alert is moderate; in2030the comprehensive value is1.674and the alert is severe.10cm of SLR, it is0.915, moderate alert in2020and it is1.829, heavy alert in2025and it is2.690, severe alert in2030.25cm of SLR, it is0.916, moderate alert in2020and it is1.831, heavy alert in2025and it is2.692, severe alert in2030.Based on the study principles, the paper develops an early warning system for the fresh water supply impacted by SLR in Shanghai. Using C#and JavaScript language, the system has an access to the ACCESS data base by ADO.NET technique, and generates a mid-and-long term early warning tool by ASP.NET technique-Early Warning System for Fresh Water Supply Impacted by SLR in Shanghai(WEWS), which has functions of data management, stimulation, and decision making.WEWS accurately inquires the information of the data of population and water resources in Shanghai by data management function, and it draws charts by the charts analysis function, including bar charts, line charts and pie charts. Based on combination schemes of SLR value and annual runoff chosen individually by the users, WEWS adopts scenarios simulation function to calculate the fresh water supply in Shanghai, and the simulation results are displayed as the hotspots in the map of area of each water source. WEWS leads the users to build SD models of Shanghai water demand, and then predicts the domestic water demand, industrial water demand, agricultural water demand and urban public life water demand. With the results from the stimulations of water supply and demand, WEWS automatically calculates the early warning grades of water supply safety and the comprehensive early warning grades of water supply safety of all the water sources in Shanghai, in2020,2025and2030by the early warning level assessment function which is discovered on the basis of the entropy fuzzy matter element theory.This paper brings the mid-term and long-term early warning function into the process of development of the WEWS and proposes some responses, suggestions and measures of the WEWS, aiming at providing the relevant departments with some policy-making bases to have an effective guarantee and scientific analysis of the fresh water supply in Shanghai. The development of the WEWS is of great application value and promoted meaning in improving the early warning system for the fresh water supply in estuarine megacity and ensuring the industrial, agriculture, domestic and urban public life water safety.