Numerical Simulation Of The Groundwater Environment In South Boxing Area

Taking groundwater source in south Boxing county as a case, the 3D groundwater flow and solute transport numerical models are constructed by using survey data and the groundwater numerical simulation software GMS.The water source protection areas are delineated under different time standards by using the technology of reverse trajectory tracking and hydraulic capturing called numerical method based on the calibrated flow model.On the basis of fully collecting and analyzing relative materials such as geology, hydrogeology and environment of the study area, the paper explaines 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 object layer for calculation and generalizating hydraulic characteristics, vertical and lateral boundary, a groundwater mathematical model is set up. GMS which is based on finite difference method is employed to solve thenumerical equations.The simulation takes the groundwater flow from 1998 to 2002 as the steady flow,the groundwater flow field is thought as the initial flow field,and the main hydrogeological parameters is adjusted in the process. This simulation used the water level observed value of selecting July of 2002 to July of 2004 to identify and inspect the model, the fitting effect is all right, and it explains that the determination of aquifer structure and hydrogeological parameter, the model can be used in forecast. The analysis shows groundwater in the area continued to decline, the funnel area has reached 210 square kilometers, regional drawdown funnel is more than 10 meters, the deepest water level has reached -35 meters but the drawdown is less than 5 meters..Select both chloride and sulfate ions as a typical representative pollutants.The groundwater solute transport model was established on the base of flow model.After fitting the model parameter adjustment to achieve the accuracy requirements which can be used to predict.The results show that the risk of future industrial pollution is still high concentration zone, and the most serious region is Xingfu where the chlorideconcentration will reach 440mg/L or more, sulfate ion concentration will reach 360mg/L,but the circumjacent area will not be polluted by the influence of groundwater flow field.Delineating water sources protection areas for groundwater is one of the best way to protect the water sources. According to the purposes,principles of the delineation of groundwater protection areas,with the state of domestic and international research and quoting"Technical Guideline for Delineating Source Water Protection Areas",the paper shows us the time criterion of delineation of Groundwater source protection areas:the time criterion of the primary protection area is 60 days,the time criterion of thesecondary protection areas is10 years,the time criterion of and the terriary protection areasis 25 years.Over-exploitation groundwater is the main reason of shallow groundwater levels falling,and small drainage enterprise pollutants discharge is the main reason for existing pollution risk.Carry out of water pollution risk analysis and study the corresponding preventive measures are helpful for environmental managers making correct decisions to ensure sustainable use of water resources.