Research On The Multi-index Grading Evaluation Method Of Water Supply Security

It is well known that water is not only the basic resource for lives, but also one of the strategic foundational resources in human production activities. As a consequence of the expanding scale of economies, human demand for water resources supply has increased rapidly, which leads to the sharp contradiction between the supply and demand. Water supply security affects both the socioeconomic development and the national security. It is not just about the basic human rights and social justice, it has an effect on the stability and sustainability of economic development as well. Whether the water supply is safe or not could be a measure of the social welfare level. Due to the importance of water and water supply security, research on their evaluation has become the hot issues in the field of water resources management and exploitation.Water supply security is the main content of water-related activities all over the world. No exception in China.The national and local governments promote optimal allocation of water resources and urban and rural water supply security actively. And they have made great achievements in both the growing ability of water supply and water penetration. However, owing to the combined effects of many other factors, there are still some undeniable even very prominent problem in China’s present situation of water supply security. For instance, the level of water supply security remains to be further improved, and the capacity and level of regional water supply security are not balanced between regions, especially between the urban and rural regions. The grim situation of water supply security in some of the major city circles, grain producing areas and energy base is also a case in point. It is of great necessity to carry out water supply security evaluation research in China in order to help solve the problems above.As a part of water security evaluation, research on the water supply security evaluation began in the1970s, mainly focus on the urban water supply security. The multi-index comprehensive evaluation method has been used in the existing foreign and domestic studies. Lots of highly targeted evaluation index systems have been established, but none of them has been accepted generally to apply in large-scale regions, with a universal and scientific evaluation index system and standard, which can provide reference and experience for planning the practical work of the national water supply security protection.The basic theory of water supply security is described in this paper, on the basis of the summary of the existed relevant research results. And a index system of universality and practicability for water supply security evaluation is set up, which is applied to evaluate the provincial water supply security in China, using an innovative grading evaluation method. The research mainly includes the following work. (1) Based on studying the foreign and domestic relevant research on the water security and water supply security evaluation, the concept and connotation of water supply security is summarized, the theories and mathematic models and indexes using for water supply security evaluation as well. The applied conditions and advantages and disadvantages of the five commonly kinds of water supply security evaluation method are analyzed, which are Analytic Hierarchy Process(AHP), fuzzy mathematics method, System Dynamics(SD), Set Pair Analysis(SPA) and fuzzy matter-element model. The multi-index evaluation systems and methods are the main objects to study, leading a solid foundation for establishing a evaluation index system of universality and practicability which can be applied to large-scale regions, and providing the reference for the related research in the future.(2) Basic research of the water supply security is carried on systematically, which includes the concept, connotation, characteristics of water supply security, and the structure and influential factors of water supply system. The two different classification of unsafe water supply situation are introducted. One consists of three types according to the structure of water supply system, which are water source shortage, engineering water shortage and excessive-demand water shortage. The other one is divided into the destructive water shortage, passing-on water shortage and restrictive water shortage, depending on the direct reflection consequently. The preliminary explanation for each type of water shortage is given. The theory of water supply security is enriched.(3) According to the theories of water supply security and sustainable development, and following the principles of comprehensiveness, sicence, classification, system, universality and simplicity, the structure of index system for water supply security evaluation is determined. The evaluation indexes are selected with the combination of quantitative and qualitative screening methods. Some indexes are used to assess normal guaranteed ability while the others for the emergency supportive capacity. All indexes are selected from the water source, water-supply engineering, and the water user subsystem. After reviewing the results of research on the index weight calculation and data standardization, a innovative grading evaluation method,with red, yellow, blue and green, is proposed. The new method is similar to equal index weight evaluation and contains qualitative analysis. The four color represent different evaluation results, whose characteristics are also introducted.(4) The historical hydrologic series and statistical yearbooks of water resources and economics are analyzed. The history of water supply in China is divided into four periods, which are the start of water supply, the start of urban water supply, the period of improving quantitative water supply and the period of improving qualitative water supply. The changes of water used for living, farming, industry and environment are investigated. It shows that the amount of supplied water keeps increasing all the time, and that the amount of water for living grows stably, and that the amount of water for industry has segmented growth, and that the amount of water for farming varies from year to year, and that the amount of water for environment presents continuous rising trend. The reasons of all the changes is also investigated.(5) In order to test the universality and practicability of the newly built grading index system for water supply security evaluation, the provinces in our country are chosen to be evaluation objects. The evaluation reslut is constituted of two parts, which are the normal guaranteed ability and emergency supportive capacity. The constraints of water supply security are analyzed. With the analysis of data and evaluation result, the current problem of water supply security in China is summarized. They are the tight balance between water supply and demand, the regional gap and the large gap compared with the developed countries.Water supply is a composite system which is composed of water source, water supply engeineering and water user subsystem. Hence the water supply security evaluation is also a complicated systematic issue. The multi-index water supply security evaluation system proposed in this paper is relatively simple, which focus more on the water source subsystem rather than the other two. Thus the future research should be further perfecting the index selection and data processing, considering the impact of water supply on the ecological environment, evaluating the series of engineerings involved in water supply, and the comprehensive evaluation based on the water the user received which combines the consideration of quantity and quality.