Application Of Feflow To Groundwater Flow Simulation

The area of the study regions, including Yuci, Taigu and Qixian in Shanxi province, is about 804km2. Recently, due to over-exploitation of groundwater in these areas, the water table has been declining continuously, along with a series of environmental geological problems such as land subsidence, water quality deterioration, drying up springs, water source supply attenuation, and scraping hanging pump wells. Therefore, it's high time we took some measures effectively to optimize the framework of water utilization in these districts. Based on the geological and hydrogeological data of these areas, we combined the GIS data processing technology with specialized software of FEFLOW groundwater numerical simulation, as well as two-dimensional mathematical unsteady flow model, to simulate the number of the groundwater system, and to evaluate the trend of the groundwater in these studied over-exploitation areas. Thus, this will provide an effective method for future groundwater resources assessment and management of the over-exploitation areas and also provide fundamental basis for the optimal allocation of regional water resources. The Main achievements are listed as follows:(1) Systematically we analyzed the research development at home and abroad of the numerical simulation of groundwater, the main numerical methods and main simulation software employed, and had a detailed knowledge of the Feflow computing software system s calculating theory and application.(2) Based on the analysis of annual precipitation characteristics in the past 54 years, from 1954 to 2007, at Taigu Balance experimental station, the study adopts the gray model to predict the precipitation from 2010 to 2020. Besides, the relationship between agricultural exploitation and precipitation in the irrigation area is studied. Here, the study compared the yield and precipitation of the reference year 2006 with that of other years, respectively, conducting the linear regression analysis of the ratio by spss17.0. At last, according to the regression equation, the corresponding agricultural irrigation exploitation could be calculated.(3) Based on the investigation and analysis of relevant data, we summarized the study areas natural geographic conditions, geological conditions, and hydrogeological conditions. According to the geological profile and borehole data, we established the two-dimensional hydrogeologic and mathematical models of these over-exploitation areas, and established the corresponding numerical model by FEFLOW groundwater finite element numerical simulation software. By adjusting parameters of the model number, operation, and identification, we found that the model esssentially simulated well with that of the hydrogeological body.(4) In conditions of current mining Status, improving water utilization efficiency, and replacing groundwater with surface water savings, respectively, we predict the groundwater dynamic process and groundwater exploitation status in both the short term and the long term. The results of the groundwater dynamic forecast showed that, by 2020, the groundwater level will continue to decline under the condition of the current mining Status.Under the premise of improving water utilization efficiency, and in terms of easily implemented, we proposed to replace groundwater with savings of surface water as for the serious over-exploitation areas, as well as to alleviate the contradictions of the water utility in the over-exploitation YuCi and TaiGu areas.