Surface Water Interaction Modelling Using Visual MODFLOW and GIS

PHYLARESApproach and methodology / ch.2__________________________________________________________________________________________9errors and uncertainties in a groundwater flow analysis and solute transport analysis make anymodel prediction no better than an approximation. For this reason, all model predictions shouldbe expressed as a range of possible outcomes that reflect the assumptions involved anduncertainty in model input data and parameter values.2.3.9 Performance monitoring PlanGroundwater models can be used to predict the migration pathway and concentrations ofcontaminants in groundwater. Errors in the predictive model, even though small, can result ingross errors in solutions projected forwarded in time. Performance monitoring is required tocompare future field conditions with model predictions.2.4 MethodologyThe model construction is done by using the Visual MODFLOW 3.0 interface. To construct themodel, the study area was divided up into finite difference cells, which have a constant size of 5meter by 5 meter. In the vertical dimension, 3 groundwater layers were represented. Parametersrepresenting physical characteristics and flow conditions were attributed to each cell. VisualMODFLOW stores all of the data in a set of files. Most of the input files are stored in ASCII textformat. As a result, the input files can be manipulated using a text editor or even generated usinga FORTRAN or Visual Basic program. Visual MODFLOW then translates these data files to therequired format prior to running the models. By constructing the model, Visual MODFLOWcreates the modules, basic pieces of the program code, needed by the numeric engine.______________________________________________________________________________________Groundwater – Surface water interaction modeling using visual MODFLOW and GIS