Study On The Groundwater Resources In Yingditang Water Source,Jingbian County,Shaanxi Province

Jingbian County is located in southwest of Yulin City,Shaanxi Province,which is the economic and cultural center of northern Shaanxi.With the expansion of urban construction,Sibaishu water source of Jingbian County has been not meet the demand of water supply.In order to ease the water problems of urban as well as ensure the water demand and water security,we investigated the Yingditang water source,and then intended to choose a reasonable water resource exploiting program to build a new water resource.In this paper,a few research methods of domestic and foreign were studied.According to the basic situation of the study area,meteorological data,hydrogeological exploration and pumping test,we obtained the hydrogeological parameters of the study area.Then we described the geological and hydrological conditions of the study area.And through contrastive analysis,the numerical simulation of groundwater was finally selected as the study method.We used groundwater dynamics as the theoretical foundation,determined the model range,initial conditions,boundary conditions and other hydrogeological parameters,and then we set up the three-dimensional hydrogeological model.In the model,for the actual simulation area,the north boundary as the drainage boundary would affect the exchange of groundwater the inner and outer area.And the selection of boundary conditions and the determination of simulation range were both important for the accuracy and reliability of the model.Through we established ideal models which had the single lateral runoff drainage way,and studyed north boundary types(i.e.used constant head and general head to describe north boundary conditions,respectively)and different simulated area.We could draw several conclusions: Firstly,using two kinds of boundary conditions to describe the drainage boundary,their maximum drawdowns were similar.But,by contrast,using the genery head boundary,its influence area of the cone of depression and the variation of two aquifers storage capacity were both small,which was more iconforms with the simulation requirements.But the overall results of using the two different boundary conditions were similar.Secondly,theoretically,the larger the simulation range of the model,the better the simulation results,and the simulation results were more realistic.But,according to the ideal models of the comparison results,we could choose the appropriate boundary condition and simulation range,which could meet the model forecast requirements.At the same time,the reasonable choice would reduce unnecessary resources and capital investment in field exploration.According to the analysis of different boundary conditions,we adjusted the boundary conditions of the original model,got 12 Mining plans of the proposed water source,and then compared the calculation results.According to the scheme of the groundwater table and the maximum groundwater level drawdown,and with the principle of "the smaller maximum drawdown,the larger groundwater exploitation,the larger small range of drawdown,the smaller big range of drawdown ",we chose reasonable mining scheme.And then,we analyszed the change of the groundwater flow field,and put forward the reasonable development plan and protection measures.