Numerical Prediction Of The Effects On The Spring Flow For Exploiting The Karst Water In Xujiagou Spring Site

In order to meet the needs of electric power to the economic development of Hebi city,the secondary project will be established on the base of the first project to enlarge the capacity of the Hebi power plant. The first and secondary construction of Hebi power plant depend on the water of Qihe river,through the southern ditch of Gong nong-canal to convey the water resource,and make the Xujiagou spring area that locate at the north bank of the Qihe river for the auxiliary water source. In the normal condition,the water source of Qihe river can satisfy with the power plant. The power plant will reuse Xujiagou water source when Qihe river can't supply enough water source during the low water period. Xujiagou spring is the drainage center of the karst water,Hebi power plant water site is near the spring.Yet long-period exploiting karst water will produce many ecological and geology-environmental problems,for example,the eubiosis will be distroyed around the spring, water well dry up and spring water cut off. To avoid these problems,it is necessary to predict and analyse the water level dynamic state and the seepage field.Based on the comprehensive analysis of geologic condition and hydrogeologic condition of Xujiagou spring site in Hebi,the hydrogeologic conceptual model is generalized. Applying the Visual Modflow software which is popular and universal in international , the three-dimensional numerical simulation model of groundwater seepage is built. The stability and reliability of the model is proved through model verification and parameter estimation,and the model fits the hydrogeological conditions of Xujiagou water resource site. Using the model,the karst water level and flow dynamic of Xujiagou are predicted under various precipitation recharge conditions when the first and second-stage construction of Hebi power plant total exploiting quantity reach 0.87m3/s in Xujiagou spring area in future. The results indicate that the effect is not obvious to Xujiagou spring karst water between the recharge and drainage quantity when the total developing quantity reach 0.87m3/s on the base of existing developing quantity. In the normal flow year or partial low flow year the spring water is still outpouring and in the low flow year the spring water cut off.