Study Of The Coupling Of Groundwater Modeling Software And GIS For North China Plain

The groundwater numerical modeling has become an important method on the moderngroundwater study. With the development of high-tech it is urgent to integrate the groundwatermodel with the informational groundwater management of our country. Since that thehydrogeologic information mainly is based on the soft of MAPGIS in our country, the researchof how to integrate the groundwater model with GIS has become a focus in the field ofhydrogeology and it is also the trend of the groundwater model development.The principle, methods, structure and flow calculation process of the MODFLOW, which isbased on the method of finite difference, are analyzed in this dissertation. And the feature of thenew version of MODFLOW-2000, the functions of the new program packages, the format andthe significance of the data in variant of input and output files are discussed in detail. On thebasis of analyzing the feature of the GIS data in our country, the relationship between these dataand the input file used in the modeling of groundwater can be found. By calculating with thegroundwater module the result must be visualzed. In the practice, some modifications are madeto the program including three respects. First, the recharge package is modified, which can beused to simulate some recharge or discharge occurring on all layers of the aquifers. Second,combining the input file of sources and sinks with the output files of the exchange flux betweencells, the recharge rate can be obtained. Third, the input and output data formats are improved forfitting to GIS.This study is applied to the North China Plain. It is considered as a heterogeneous, isotropic inthe horizontal, three-dimensional transient groundwater flow system in this dissertation. In theconstruction of groundwater numerical modeling various packages input files are adopted todefine the structure, the parameter, the condition of sources and sinks. Budget analyses ofgroundwater system are made in the simulating period 2002 and 2003. Total recharge is493.74×108m3 and total discharge is 565.30×108m3. It takes on a minus budget in this area.Especially in this model, evapotranspiration segment function is used to calculate theevapotranspiration discharge of the unconfined aquifer and it is obtained that the totalevapotranspiration discharge is 124.31×108m3. By this way the hydrogeologic condition ofevapotranspiration is depicted more accurately than ever. After the identification of the model,defining the information of describing model structure and aquifer feature as the stable items andthe sources and sinks as the dynamic items, then the evaluating and management system can beintegrated with GIS, which can be updated with the change of the sources and sins data.The research indicates that the program soft of MODFLOW has a clear structure, is designedby separate modules which are convenient to modify. And the data in input and output file arefixed providing an important foundation for the integration with GIS. At the same time, it isapplied to the North China Plain with the three dimensional numerical modeling, this integrationis validated.