User Guide and Documentation for Five Modflow Ground-Water Modeling Utility Programs

This report documents five utility programs designed for use in conjunction with ground-water flow models developed with the U.S. Geological Surveys MODFLOW ground-water modeling program. One program extracts calculated flow values from one model for use as input to another model. The other four programs extract model input or output arrays from one model and make them available in a form that can be used to generate an ArcGIS raster data set. The resulting raster data sets may be useful for visual display of the data or for further geographic data processing. The utility program GRID2GRIDFLOW reads a MODFLOW binary output file of cell-by-cell flow terms for one (source) model grid and converts the flow values to input flow values for a different (target) model grid. The spatial and temporal discretization of the two models may differ. The four other utilities extract selected 2-dimensional data arrays in MODFLOW input and output files and write them to text files that can be imported into an ArcGIS geographic information system raster format. These four utilities require that the model cells be square and aligned with the projected coordinate system in which the model grid is defined. The four raster-conversion utilities are * CBC2RASTER which extracts selected stress-package flow data from a MODFLOW binary output file of cell-by-cell flows; * DIS2RASTER which extracts cell-elevation data from a MODFLOW Discretization file; * MFBIN2RASTER which extracts array data from a MODFLOW binary output file of head or drawdown; and * MULT2RASTER which extracts array data from a MODFLOW Multiplier file.