Karst Groundwater Resource Evaluation In Spring Area Of Lancun,Shanxi Province

Shanxi Province is the main province where karst great springs are distributed in China.Due to the wide distribution of ordovician extremely thick limestone and the fact that quartz sandstone and sandstone of the lower Cambrian series are at the bottom of the province as a good waterproof layer,karst is developed.It not only provides water for local production and life,but also is an important part of Shanxi's tourism resources.However,lancun spring was cut off in the 1980s due to overexploitation.In order to better study the local hydrogeological situation,the local competent department conducted supplementary hydrogeological field survey,which made up for the fact that the previous data were old and could not accurately describe the current situation.Therefore,this paper aims to carry out allowable groundwater withdrawal resource evaluation through the analysis of each equilibrium term of groundwater,and judge the future trend of water level change in lancun spring based on this,and put forward reasonable development Suggestions and measure.Based on the predecessors'research results,combined with hydrogeology survey and drill hole?observation well data,redelimited the scope of the lancun spring.The western border is xiqiwan-dabu village-liulin village-liulin river-wang feng horst,and the eastern border includes the xipan village-xiyan basin-yu county,the area of lancun spring is determined as 2610km~2.In addition,rainfall and runoff data collected from 1956 to 2016 are used to analyze and calculate all equilibrium terms in the research area:analyzing the leakage of fenhe river and its tributaries in lancun spring domain by using the relation curve of leakage rate-water quantity and water balance principle,the average leakage amount of fenhe main stream is calculated as 2070thousand m~3/a?the average leakage amount of fenhe tributary stream is calculated as8706 thousand m~3/a;the annual average rainfall infiltration is 1253.96 million m~3/a by Thiessen polygon partition.According to the statistics of mining wells,the total extraction amounts is 158.31 million m~3/a,The main recharge sources are rainfall infiltration recharge and river seepage.After calculation,the total supply quantity of lancun spring area at present136.17 million m~3/a,the total emissions 158.31 million m~3/a,which shows a negative equilibrium state,the annual equilibrium difference is 22.13 million m~3/a.The recoverable capacity is subtracted from the lateral exchange capacity and the annual average flow of lancun spring,which is calculated as 67 million m~3/a.In the future,the water level will continue to decline slowly,and the reflow cannot be realized.Finally,some suggestions and feasible engineering and non-engineering measures are put forward.