Numerical Simulation Research Of Groundwater With GMS In The Upper Reaches Of Qingshui River Plains In Ningxia

The south area of Ningxia hui autonomous region is located in the loess plateau which is situated in the North-west of China, with little raining, limited surface water and shortage of drinking water, it is one of the most droughty areas in China. Confined by the regional tectonic conditions, the landforms present the situation which the mountains and the basins arrange alternately, and how the groundwater originating and preserving are complex. Furthermore, the salted water is distributed widely in the area which has the characteristic of water-quality water deficiency. Therefore, in-depth investigation into the hydrogeology study of this area is time-pressing and significant.This essay focuses on the valuation of the groundwater, especially the current situation and new updates about both domestic and international researches of the groundwater numerical model. On the basis of fully collecting and analyzing relative materials such as geology, hydrology and hydrogeology of the south area of Ningxia hui autonomous region, the paper explains systematically the cause, era and lithology of the main stratum in the research area, and analyzes the law of recharge, runoff, drainage and dynamic characteristics of the groundwater. After confirming the range of simulation district and target layer for calculation and generalization hydraulic characteristics, vertical and lateral boundary, a groundwater mathematical model is set up, according to the hydrogeological conceptual model. And GMS which is based on finite difference method is employed to solve the numerical equations.This simulation select June of2006-June of2007as the testing period which present better match backed by determination of aquifer structure and hydrogeological parameter, and boundary condition generalization, therefore the model established is applicable to evaluate the groundwater volume in this area. According to result from the modified model and during the simulation period, the total supply volume of the groundwater in the plains is2736.11×104m3/a and total discharge volume is4211.65×104m3/a which is negatively balanced. During the simulation period, the discharge volume in conserved layer is1475.54×104m3/a. The total size of the simulation area of Qingshui river Plains is722.54km2, the groundwater level for the whole plains decreased by20.4cm/a if specific yield is0.1.This paper also briefly assesses the quality of the groundwater in this area. Volume of the conserved water can be computed by the size of the area with different total dissolved solids, thickness of water layer etc. Also to compute the volume of mineralized groundwater in each layer according to groundwater quality and size of distribution area and its proportion.The discharge volume in the area under research out-beat the supply volume, meaning the groundwater is severely over explored with continuously decreased water level. Suggestions are aiming to rationally and scientifically explore the groundwater resources with better management on water usage, adjustment of usage structure and combination of searching-for-new and current water mortification, to strictly control and manage the groundwater exploration volume.