Study On Evaluation And Regulation Of Groundwater Pumping Risk In Perched Section Of Down-Yellow River

Owing to the covered groundwater and the complexity of aquifer medium,it is difficult to resolve groundwater pollution and exploitation problemreasonably. We should adopt prevention and cure policy, the latter is moreimportant. Risk Evaluation of Groundwater Pumping emerges as the timesrequire. According to the study on the risk of groundwater pollution andexploitation, we can provide advice for governor to constitute police ofgroundwater using and protect in order to realize constitute realizinggroundwater.Water resources problem is one of the most notable influences on thesurvival and development of mankind, especially in north China, which bearsthe peculiar condition of geographical climate and social-economiccharacteristic. Despite, along thousands of years, Chinese people haveobtained lots of glorious achievement by their own cleverness and wisdom ingroundwater pumping. And yet, owing to the finite of groundwater andincreased of groundwater needs, the control and mitigation risk ofgroundwater will also be a long-term and complicated task forever.At present, in regard to the state of domestic and international research,all most study on integrated risk management of groundwater still is staying atexploring stage whether on the theory or method. Based on the extensivereading and research of concerning domestic and international literature,relying on the National Key Foundation Developing and Programming the 6thproject "study on the law of Groundwater Renewability in the Yellow RiverBasin"(G1999043606 ).Regarding down-Yellow River as the background, itactively adopts system theory. Under a research clew of basis research, methodfor risk analysis, theory and method for risk evaluation(including environmentand social factor)and measurement for risk management, a theoreticalframework for integrated risk management for groundwater pumping risk isprimarily established. The conclusion as follows:(1)Through the study on the manifold definition of the risk, We think thatthe risk of groundwater pumping is losing degree, at the condition ofgroundwater system, environment and mankind activity. Simultaneity, Wedefine the conception of system of groundwater pumping risk. It is constitutedby water resources, environment, social, economy, ecology, which havefunction to exchange matter, energy, information. Analyzing currentlydevelopment and evolvement law of system, and Analyzing the factors, whichhave effect on the development of system. Put forward the basic content ofevaluation of groundwater risk, definitude the theory and method ofgroundwater risk.(2)Based on the risk theory, composed the target system of groundwaterrisk evaluation, which is composed of three levels: aim level, rule level andsingle target level. The single target include: nature status target covey,exploitation and using status covey, groundwater exceed and ecology status,social and economy development covey. explaining the meanings of target,which established the base of study on groundwater risk.(3)Introduce the evaluation model of integrated risk of groundwaterexploitation by Catastrophe Theory. The subjectivity has been relativelyreduced when working on the establishment and measurement of index. So,the model makes decision or evaluation tend to reality and has someadvantages, such as shortcut calculation, precise outcome and convenientapplication.(4)Analysis the geography, geology and hydrology conditions,understanding the aquifer's distribution, recharge, disrecharge, runoff andhydrochemistry. Study the evolvement and environment problem ofgroundwater.(5)Based on catastrophe theory, the catastrophe evaluation model forgroundwater pumping risk was proposed and applied in groundwaterdevelopment risk evaluation of Yellow River downstream. The risk evaluationindexes for groundwater development and utilization of study area was builtup, the index values was organized, worked and calculation. According tofuzzy mathmatics method,the initial index value was changed into catastropheseries which range is 0-1 by membership grade methods. Fourthermore, gotthe highest layer evaluation values by normalization formular. The evaluationresult showed the following conclusion: the synthesis risk value forgroundwater development in Yellow River downstream is 0.63～0.81,belongto middle risk area which risk value is 0.5～0.85. The order of groundwaterpumping risk is: Dongying→Binzhou→Heze→Tai'an→Xinxiang→Dezhou→Zhengzhou→Kaifeng→Liaocheng→Puyang→Jining→Zibo→Jinan.(6)In order to reduce the groundwater pumping risk in YellowRiver downstream, the three-dimensional transient numerical model ofgroundwater flow was built up and solved by Finite Element gorundwaterFLOW system (FEFLOW). In model calibration process, the groundwaterregime resiudal between long term observation water level andcalculation water level can meet the matching standard. The modelcalibration result showed that the aquifer structure,hydrogeologyparameters, boundary conditions and source sink terms in study area wasreasonable, and the numerical simulation model of groundwater flow canbe used to simulate and forecast the groundwater regime.(7)The regulation scheme of groundwater pumping risk in Yellow Riverdownstream was proposed. Water resources uitilization mode should bechanged, the main manner of water uitilization should changed from surfacewater to groundwater, this not only can reduce the groundwater pumpingrisk,but also can get the benefits of society, economic and environment. Thenumerical simulation of groundwater flow under different condictions showedfollowing conclusions: under the pumping near the Yellow River, themaximum lateral seepage quantity of surface water is 10.58×108m3/a,whichquantity is 4.11%, 3.00%, 2.92% of runoff in Jiahetan Station in year 1999,50% precipitation frequency and perennial average precipitation. Whereas thegroundwater pumpint rate of groundwater pumping station is 6.059×108m3,which quantity only 1.67% of runoff in Jiahetan Station under perennialaverage precipitation. Fourthermore, the affect scope of pumping near the riveris partial area. Therefore, if the groundwater pumping rate can be controlled inreasonable quantity, some recharge project and other prevent means forenvironment can be taken, the stable groundwater supply can be realized andthe environment can be improved.(8)Put forward a synthetic risk management framework, which includeselimination of risk, bearing of risk, abatement of risk and diversion of risk ongroundwater risk. Subsequently, concrete content is discussed in detail withinfour aspects, which involve the structural and non-structural measure,alterative risk transfer and risk management criterion.