Study on prediction and control of dynamic change of water security in coastal cities.

In order to realise the beautiful vision of Taizhou for the future urban water security, it is necessary to screen out the main factors that affect water security. The traditional analytic hierarchy process has many indicators, large workload and inconvenience to use. On the basis of forecasting the state of water security in Taizhou from 2016 to 2020 by using gray relational theory in the early stage, the main factors affecting water security in Taizhou bay are obtained. In the long-term water security prediction, the water security index system Simplify the water safety assessment of the study area with the main influence factors, so as to reduce the workload and improve the efficiency. The paper discussed the critical value of the index when the water safety status reaches the unsafe status of various combinations of indicators, which is looked as the water environment tends to be unsafe warning value, in order to avoid changes in the impact of environmental factors caused by water safety issues. The results show that The problem of water environmental safety is mainly predicted by the change of the percentage of the main indicators. It is concluded that the proportion of tertiary industry, the percentage of river pollution and the urban water reuse rate reached at 43, 39 and 41%. These three values are the water environment tends to be unsafe warning value.