Water Resources Carrying Capacity Evaluation Of Yellow River Downstream Affection Zone (in HeNan)

With increasing of population and the development of economy, waterdemands are increasing rapidly;at the mean time the decrease of running offquantity of Yellow River enhances the contradiction of water demands andwater supply. There are different scales of groundwater depression cone wheregroundwater table are descending because of exploitation blindly, whichresults in a series of zoology environmental problem such as groundwaterresources depletion, land subsidence, aquifer pollution. Because sustainabledevelopment of social economy mostly depends on sustainable exploitation ofwater resources, and some researches show that as long as water resourcesexploitation do not exceed its carrying capacity and environmental capacity,water resources can be used sustainably. Accordingly, make clear about thewater resources carrying capacity of study area is significative to therealization of zoology environment and all the social economy sustainabledevelopment.The paper firstly discusses the conception of water resources carryingcapacity and its evaluation theory and method. On the base of considering itsinfluenced factors, the paper establishes an evaluation indexes system, whichcan reflect the develop scale and quality of "resources-society-economy-environment". On the base of investigation and studying the geology,hydrological geology condition of studied area, the paper founds hydrologicalgeology conception model and mathematical model. Make use of 3-Dnumerical simulation model to evaluate the allowable groundwaterexploitation quantity;Take use of routine trend method to forecast theindustrial, agricultural, life, environmental water needs and water supply of2010 and 2020.Adopt multi-indexes fuzzy comprehensive evaluation model toevaluate water resources carrying capacity of actual and programming years,which provides gist for the department to institute social and economicaldevelop goal. The main results are as follows:Ⅰ Evaluation indexes system of water resources carryingcapacityThe paper discusses water resources carrying capacity conception,connatation and its characteristic, and analyzes every influenced factors ofwater resources carrying capacity roundly. Referring to the indexes system andstandard of balance analysis of water supply and needs or other waterresources evaluation, and considering the independence, representativecharacter and easily obtained, the paper founds an evaluation indexes systemof water resources carrying capacity which contains water resources condition,water supply configuration and engineer condition, configuration of water use,water needs and level of saving water, social economy development, zoologyand water environment.Ⅱ Evaluation water resources quantity of the studied areaThe study area locate in the alluvial plane of Yellow River downstream,the huge loose sedimentation of Quaternary offers the storage condition forgroundwater. With the depth of 350m,the groundwater system can begeneralized into two subsidiary system as follows: shallowunconfined-semi-confined aquifer system and mid-deep confined aquifersystem, there is a regional relative weaken permeable aquifer between thesetwo aquifer syetem, and the groundwater storing in the shallow and mid-deepaquifer system relater by leakage through the weaken permeable layer. Theupper of the shallow aquifer is the phreatic water, and precipitation, surfacewater and phreatic water have consanguineous hydraulic relation. The bottomof mid-deep confined aquifer is the top of Tertiary, which is weak permeableclay stratification, therefore can be generalized water resisting boundary. Thelateral boundaries of different layer are all Newman boundaries except JindiRiver.Based on the above research, the paper builds the heterogeneous, isotropyand unstable mathematic model of groundwater flow system, simulated thegroundwater flow by the three dimensional finite element subsurface flowsystem (FEFLOW) produced by WASY CO. of German. The total element are15738,and the total knots are 11108.The simulation period was selected in1999,the regime data in 1-6 month are used to diagnosis the model, and theregime data in 7-12 month are used to verify the validity of the model. Makeuse of identified and validated model to calculate the allowable groundwaterexploitation quantity, which is 18.38×108m3.further more, the paper gives thesurface water quantity which is 21.93×108m3, therefore the total waterresources is 40.31×108m3.Ⅲ Comprehensive evaluation of water resources carryingcapacityThe paper introduces routine trend method to forecast the industrial,agricultural and life water needs, further more, the paper calculate the zoologyenvironmental water needs in detail. The results are as follows: The total waterneeds of 2010 in 28.66×108m3,thereinto the zoology environmental waterneeds is 0.225×108m3,which occupies 0.79 % of total water needs;The totalwater needs of 2020 is 30.80×108m3,thereinto the zoology environmentalwater needs is 0.306×108m3 which occupies 0.99 % of total water needs;Thepaper forecasts total water supply in 2010 is 29.46×108m3,thereinto usage ofwaste water and sewage occupies 1.91%.Total water supply in 2020 is 34.80×108m3,thereinto usage of waste water and sewage occupies 2.46%. The resultsof forecast shows: Water resources in Zhengzhou and Xinxiang is abundantrelatively, and water supply can satisfy water needs basically. However, thereis contradiction in Kaifeng ,Puyang and Anyang city.Based on the founded evaluation indexes system of water resourcescarrying capacity, the paper uses gray-associated model to analyze and filterthe indexes. Considering other factors such as easily handled, Finally wechoose water resources quantity of every person, water supply of every person,percent of water resources utilization, percent of infield irrigated, water supplymodulus, water need modulus, water needs ration of life, and percent ofzoology environmental water needs as the comprehensive evaluation factors ofwater resources carrying capacity;Introduce AHP to decide the weights ofevery factors, which is 0.1949,0.1767,0.1298,0.0752,0.1520,0.1076,0.0742,0.0896.The paper founds multi-indexes fuzzy comprehensive evaluation model,and apply the model to evaluate water resources carrying capacity of actualand programming years. The results show that: there is certain exploitationpotential in the studied area in the actual year, and the maximal carryingcapacity is in Xinxiang City, and Zhengzhou City is in the next place;With thedevelopment of society and economy, water needs are increasing sostenuto.Accordingly water resources carrying capacity is weakening gradually, and thecomprehensive evaluation number decreases from 0.4668 to 0.3773.In order todevelop social economy and zoology environment synchronously, we mustsforzando bring the stratagem of saving water resources in effect roundly,exploit water resources reasonably, and make sewage into usable waterresources;Strengthen water resources protection and scientific managementconstantly, allocate water resources correctly, so that we can increase waterresources carrying capacity ,and make both of social economy and zoologyenvironment to become sustainable development.