Impact Studies On The Mechanism And Quantitative Model Of Coal Mining On River Runoff In Gujiao City Of Shanxi Province

As a result of large-scale coal mining activities in Fenhe River Basin,the underlying surface conditions were changed,thereby causing changes of the surface and the groundwater circulation process,these had occurred a significant change on river runoff.It has an important theoretical and practical significance for the reasonable utilization of water resources that doing research on the effect of coal mining on river runoff.According to the special subject of national key technonlogy R&D pillar program in the 12 th five year plan of China(2012BAB02B0407): "Analyze the reason of runoff drop into the Yellow River from Fenhe river",this paper selected Gujiao city as the typical study area of Shanxi province,from the mechanism and modeling quantitative analysis these two aspects,carried out the study of coal mining with river runoff.The main contents and results were as follows:(1)On the basis of a large number of basic data,the impact of coal mining on surface water and groundwater system were refined.Combining with the collection datum,such as the weather,hydrology,geology,DEM,land use,soil type and the yield of coal mine, this paper started from surface runoff and ground water pathway these two aspects, analyzed the influence of coal mining on the surface water system, cleared the main reasons and ways that leading to surface water reduce of coal mining; also this paper analysed the mechanism from the aquifer system,groundwater recharge,runoff and drainage these aspects,cleared the the effect of coal mining on groundwater.(2)Combined with the water cycle process,this paper carried on the analysis from water circulation system,water quantity and runoff change these three aspects before and after coal mining,the influence of coal mining on water circulation system was analyzed. According to the influence of coal mining on water and water cycle process,the subsidence,cracks and pits were added to the water cycle process,and then constructed the water cycle process figure before and after coal mining,cleared the mine regulating was another element of water cycle; the typical year of rainfall and runoff were selected,and then this article analyzed the rainfall,runoff,peak flow and frequency with statistical methods.(3)This paper established the quantitative analysis model of mining influence on river runoff in Gujiao.In the anlysis of the mechanism of coal mining on river runoff,the model that refleted the underlying surface conditions before and after coal mining were established by coupling MIKE SHE with MIKE 11,after calibration and validation,then simulated the natural and actual water relationship of mining period with the model of before and after coal mining,according to coal production, calculated the influence of coal mining on runoff by comparing with the actual runoff in Gujiao,and analysed the parameters of underlying surface and the change of water process before and after coal mining.The results showed that:mining made annual average river runoff reduce 16.7mm from 1981 to 2008,namely 26.45 million cubic meters,which reduce surface runoff 2.22 million cubic meters and base flow reduction 24.23 million cubic meters;through the influence of coal mining on river runoff in different stages,found that ming coal to reduce the runoff showed an increasing trend;the parameters of underlying surface conditions in model and the process of water content were changed greatly.