Nansi Lake Water Security Estimation Research

Water security is providing ample, superior quality of water and guaranteeing thatthe social economy development of the mankind in the district is free from the restrictof water problem. Lake water security means perfect functions of the lake, providingenough high-quality water to the lake surroundings district, regulating the waterquantity balance of the district, regulating the mini-climate, ecosystem, environmentcondition etc. and guaranteeing the sustainable development of the social economy ofmankind in the lake district. Nansi Lake lies in Jinin City, southwest of ShandongProvince. The natural condition is superior, both the industry and agriculture areflourishing. However, the mankind's unreasonable breakage behaviors and naturaldisasters result in a series of water safety problem such as the lake area atrophy, thesediment, drought or excessive rain disasters, deterioration of the water quality,serious water ecosystem breakage, etc. All these problems seriously affect the watersupply, storage capacity, modulation and ecosystem function, etc. of the lake. And theeconomy development of the lake surroundings is severely restricted. Therefore,combined quantitative with qualitative analysis, the state of Nansi Lake water securitywas fully investigated. Main contents are as follows:(1) Nansi Lake is divided into upper and lower class artificially. There are bothstrong relationship and bigger difference between the upper and lower class.Therefore, the estimation of the Nansi Lake water security is divided into two parts.One is the whole evaluation of the security degree of the Nansi Lake, the other is therelative estimation of the water security between the upper and lower class lake. (2) State of the water security of Nansi Lake and its impact Factors are analyzed.The water problem is mainly due to deterioration of the water quality and ecosystembreakage. Influence factors contain natural, man-caused and historical ones. (3) According to the establishment principles of the water security guidelines andactual circumstance, system of evaluation guidelines is established and theestablishment basis of each index is analyzed. Multi-layer, multi-target fuzzyoptimization model and comprehensive estimation method are put forward to estimatethe water security of internal and whole Nansi Lake, respectively. Analytic hierarchyprocess method is used to computes each index weight.(4) Multi-layer, multi-target fuzzy optimization model is used to estimate relativesecurity degree of the upper and lower class of Nansi Lake. Comprehensiveestimation method is applied to estimate the holistic water security degree of NansiLake, and analysis is conducted according to the estimation results respectively.(5)According to the estimation results, guarantee measures of Nansi Lake watersecurity is put forward, including strengthening wetland management, protectingwetland resources and ecosystem environment, building up water matter supervisionsystem and fast trouble processing system of polluted accident, speeding upcomprehensive cure of pollution source, strengthening management of soil erosion,improving water quality according to engineering measures,etc.Above all,the state of the Nansi Lake water security has close contact with itsvarious functions. Its functions mainly contain district water supply , floodmanagement, regulation of mini-climate ecosystem and environment function. Theynot only distinct mutually, but also contact mutually. If the amount of water of NansiLake is ample, its ecosystem, the environment appearance is relatively good. If itsecosystem, environment is good, shore shoal and water living are flourishing. Thenwater resource is cured, pollution degree is minimized, the air is purified, etc. Inreturn, it will provide with more and more high-quality water resource. This is thedialectical relationship between among them. Therefore, the water safty evaluation istightly enclosing these aspects to establish estimation index system. Among theminvolving the district water supply index includes precipitable water, lake enteringdischarge, water level, etc.. Dynamic equilibrium between district industry water useand lake water supply should also be included in the estimation index. However, thedata of the upper and lower class lake is difficult to obtain, then give it up. Only watersupply index that can be obtained is applied. Index involving flood managementcontains sediment, building the farmland around the lake, drought or excessive raindisasters, etc. Index involving regulation of mini-climate ecosystem and environmentfunction includes production amount of living creature, protection area, natural lakearea, the water pollution condition,etc.. Water problem of Nansi Lake is thedeterioration of the lake functions and a series of social political economic problemscaused by it.Seeing from the multi-layer, multi-target evaluation results, there is close contactbetween the upper and lower class of Nansi Lake. However, their water securitysituation is much different. The excellent degree of the situation is different atdifferent aspects. But in general, the situation of the lower class is better than of theupper class. According to the total evaluation results, the water security degreebelongs to unwillingly qualified, the evaluation value is still below qualified line andthe water safety situation is very rigorous. If comprehensive measurement is notadopted, the water safety situation will worsen, leading to huge threat to district social,economy,environment.