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| DOI：10.13522/j.cnki.ggps.20190035 |
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| Application of Numerical Method and Analytical Method in Groundwater Environmental Impact Assessment |
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MEI Jie, LIU Guodong, XIA Chengcheng, HU Yue, LIU Wen
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State Key Laboratory of Hydraulics and Mountain River Development and Protection, Sichuan University/Institute of Water Conservancy and Hydro-electric Power, Chengdu 610065, China
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| Abstract: |
| 【Objective】The aim is to explore the differences between numerical method and analytical method in environmental impact assessment of groundwater, and find a more appropriate calculation method. 【Method】Taking a Chlorinated Titanium Dioxide Project in Yibin, Sichuan Province as an example, three computing methods：one-dimensional convection-diffusion model of instantaneous point source, two-dimensional diffusion model of instantaneous point source and GMS numerical model, were used to study the influence of pollutants on groundwater when benzene tank leaks under abnormal conditions. The central migration distance, maximum concentration and pollution range of pollutants in unconfined aquifer were predicted, and the results of the three methods were analyzed and compared. 【Result】The first method only considers the movement of groundwater flow direction，while its calculation accuracy is not good enough. But this method is simple and convenient, and the parameters are less required. The second method takes into account the distribution of pollutants in the plane, and can predict the range and concentration of pollutants. But the prediction of migration distance is too large, which is inconsistent with the actual boundary conditions. GMS numerical model is a three-dimensional simulation, which is with high accuracy and can accords with the actual situation. But the modeling process is complex and the hydrogeological conditions are more limited.【Conclusion】In summary, it is convenient to use analytic method to predict projects with the simple hydrogeological conditions and low level of groundwater environmental assessment. In areas with abundant hydrogeological data and high level of evaluation, numerical method is more suitable. |
| Key words: groundwater; GMS model; environmental impact assessment; analytical method; numerical method |
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