Qujing City Emergency Groundwater Source Evaluation And Optimization

Qujing is a new industrialization city,of population and economy hypo-Kunming. At present,urban water-supply source is the surface water. But, with the rapid social development and surface water pollution, lack of water resource is serious day by day. Thus, it is necessary and urgency to establish the urban emergency groundwater sourec field, to deal with extraordinary incidents, such as great drought, water-supply source pullution, and reservoir destruction.Qujing City lies in the fault basin of the southwestern karst area of China. Its regional hydrogeological situation is complex,and eco-environment is frangible. According to groundwater supply,flow and excretion character, Qujing Basin is divided into ten hydrographic cells. The water resources ofⅠ,Ⅲ,Ⅶ,Ⅷ,Ⅸhydrographic cells are abundant,holding good exploitable potential.There are three groundwater types:pore water, fissure water and karst water.The pre-investigative result reveals the pore water has been contaminated seriously,and the fissure water resources is lack, thus, these two water types are unfitted for urban water-supply. So, the karst water in Dongshan Miuntain, of fine quality and enormous quantity, is fit for urban emergency water source.Based on the hydrogeological characteristics of Qujing Basin,this article combines the factors which general water source selection should be taken into account,then follows the pertinently,universal and comparable principle, we constructed an evaluating index system for urban emergency groundwater source field,for the city in the kast fault basin.The index system contains two hierarchies:the first one contains four indexes,including the hydrogeological condition, environmental hydrologic condition, exploitative condition and engineering condition;the second involves such indexes as groundwater type, aquifer aquiferous capability, aquifer penetrability, aquifer thickness, aquifer deepth, supply area, groundwater quality grade, groundwater frangibility, vegetation type, factory amount, geo-disaster probability, emergent exploitable quantity, emergent exploitable potential, exploitation mode, terrain, transportation distance and electric condition.Based on the analysis of all kinds of the evaluationg methods, this article detemines the weight of each evaluating index, adopting AHP; and evaluate the candidates of urban emergency groundwater source field, applying FCE. The result shows:Jiancaoba, Shuicheng subterranean stream and Hujiafen are optimal as urban emergency groundwater sourec field. In addition, the author suggests exploitation project for these groundwater source fields.