GIS-based Visualized Numerical Modeling System For Seawater Intrusion In Weihai City

Groundwater plays an important role in water cycle and is one of the indispensable nature resources. It is relatively steady in water quantity and clean in water quality. Groundwater is more and more important for the social development and living. With the rapid development of economics and increase of the population, increase of groundwater withdrawal results in decrease of groundwater level, and thus leads to environmental disaster, such as seawater intrusion in the coast areas. This has become an influence factor in limiting social and economic development.In this paper, a variable density groundwater flow and solute transport model (SUTRA) was selected to simulate the seawater intrusion. The principle, method, model structure and computation processes of the SUTRA model were investigated on the basis of the Fortran programs published by United State Geological Survey. The model structure was modified to enhance its modeling capacity.The 3D model complexity arises from the large number of model parameters and input and output data. We developed a visualized numerical modeling system which integrates GIS and SUTRA to feasibly dealing with spatial analysis and data management.The primary improvement of the model and system development features include: (1) to modify groundwater source and sink subroutines for computing precipitation recharge, evapotranspiration loss and groundwater withdrawal. This modification enables the model to simulate influences of climate and pumping wells on seawater intrusion; (2) to develop visualized modeling system on the basis of spatial analysis function, data management and visual expression of GIS. This visualized system has capacity in visualized model construction, including data input, model simulation and output expression. The developed system provides an efficient tool for simulation and analysis of the seawater intrusion.