The Evaluation Of Water Security Of Dongting Lake Region Based On Fuzzy Mathematics Method

Water security is an environmental issue resulting from water along with economy development in the contemporary society. Its emergence causes a lot of disasters in the world, such as flood, collapsing of dam, water shortage and pollution, which could do harm to our human society. So far, much attention has been paid to the water security issue worldwide. The Dongting Lake, located in the mid-reach of Changjiang River, with abundant resources and good natural environment and flourishing industry and agriculture, is faced with the serious problem of water security, which is the primary handicap of the economy sustainable development, and may severely threaten the security of the lives and property of the people. In this area, the main problems of water security include sediment, flood, water pollution and environment deterioration. This dissertation studies on the Dongting Lake region to evaluate the water security condition quantitatively and qualitatively, and targets at offering theory instruments for the harness and development of this area. The main research contents are presented as below:Firstly, this thesis analyzes the situation and quality of water security as well as factors affecting water security condition. In Dongting Lake region, every problem of water security has different trait, and flood is the most severe one, which brings about considerable damage annually. Factors influencing water security vary, including natural factors, artificial factors, historical factors, contemporary factors, and so on.Secondly, according to the relationship between all factors and water security, after analyzing these factors' specific impact, this paper brings forward an evaluation index system describing water security, quantifies each index, andcalculates the weight of each index by the use of Analytical Hierarchy Process (AHP).Thirdly, in this article, a fuzzy mathematics method, multi-objective and multilevel fuzzy optimization model, is applied to the evaluation of water security of the three sub-units of Dongting Lake area, and comparative analysis of the result of evaluation ensues after that. Mine while, this paper introduces the fundamental theory and method as well as its application of multi-objective and multilevel fuzzy optimization model in the sector of water security research.Lastly, based on the previous result of evaluation, the paper puts forward water security maintenance systems of the whole Dongting Lake region and its three units respectively. Water security maintenance system consists of the target of water security, the principal measures to be adopted, and the suggestion to harness of the Dongting Lake in future.From the result of evaluation, it is released that, as a whole, the best condition of water security is the east Dongting Lake, and the worst is the west Dongting Lake, with the south Dongting Lake being the second. Therefore, it can be said that, in the Dongting Lake region, water security situation become bad from east to west. However, water security of east Dongting Lake is similar to the south, but the west Dongting Lake are obviously different from them all. Further more, there is much similarity in specific problems of sediment, flood, water pollution and environment degradation among the east, west and south Dongting Lake, and this proves that water security is an integrative issue in Dongting Lake region. Never the less, differences still exist, which are analyzed yet in the article.As this paper demonstrates that, the result of evaluation is consistent with the realities. So Multi-objective andmultilevel fuzzy optimization model, the fuzzy mathematics method, could be used to evaluate water security of Dongting Lake region, and has practical applicable value and prospects in the research of water security evaluation.