Research On The Stimulation Effect By Exploitation For Highly Permeable Open Karst Water System

Shandong Shuangcun karst water system, with an area of 553 km~2, is situated inShandong province, and characterized by its high permeability and opening nature. Itis one of the 68 typical karst water systems in North China. A karst water yield of27,000 m~3/d is extracted from the system. This paper discusses and studies thestimulation effect by exploitation in case of this system. The main research results areas the following:(1) In respect of the characteristics of karst water system, the characteristics ofhigh permeability and opening nature of the Shandong Shuangcun karst water systemare discussed after the classification of permeability and open degree is established.(2) In the stimulation effect by exploitation of karst water system, the historicaldata comparison, regression analysis and cluster analysis of karst water level,chemical component and water quantity in the natural and exploitation conditionillustrate that the stimulation effect by exploitation for Shandong Shuangcun karstwater system is mainly shown in karst water level depression cone developing, lagerkarst water level vibration, quicker water quality deterioration and pluralistic karstwater recharge. 'The karst water level is controlled by different factors in differentexploitation stages. The exploitation changes not only the karst water dynamic field,but also its chemical field.(3) In respect of the numerical simulation of karst water dynamic system,acknowledging the non-linear property of rainfall infiltration recharge andestablishing the rainfall infiltration recharge function, the non-linear problem ofrainfall infiltration recharge is resolved, the dual layer water flow mathematic modelof the Shandong Shuangcun karst water system is improved, and the precision of themodel is raised further more. The model simulated and reappeared the evolution ofthe water dynamic system and water cycle system of the Shandong Shuangcun karstwater system during 1985-1998.(4) In respect of the karst geochemistry, the formation and zonation of waterchemical components are summarized. Calculations for the hydrochemicalequilibrium show that there exists obvious difference in the plan distribution of karstwater saturation indexes of main minerals for natural and exploitation condition,namely the saturation indexes drop and dissolution ability of the karst water rises inthe mountain area, and on the contrary, the saturation indexes rise, dissolution abilitydrops in the plain area.(5) In respect of the research method on the stimulation effect by exploitation ofkarst water system, the Uranium isotope method is applied, and the area-coordinateprinciple is used to calculate the mixing ratio of a triple-source recharge groundwatersystem. On the basis of that, some new viewpoints in the regional hydrogeologicalcondition have been obtained. The karst water for Shuangcun groundwater well field is mainly recharged from the southern mountain area, as for Liangcheng groundwaterwell field the main recharge source is the upper Quarternary pore water. About 10%of karst water in the west area now is from the Baima river.(6) In respect of the evaluation of karst water resource, according to the idea ofgroundwater sustainable utilization, the principles for the evaluation of karst waterresource are discussed, the indexes of karst water sustainable utilization areestablished, the permissible yield of karst water are calculated, and the rationalexploitation suggestions are raised.