TWODAN

TWODAN is a DOS-based multi-functional analytic element model for twodimensional steady-state flow with a user-friendly graphic interface and extensive graphic display of results. This program is well-suited for well-head protection studies. TWODAN 5.0 has a seamless, Windows-standard user interface. It has been designed to be very simple and fast to use. Most modeling operations are executed at the push of a button on the main screen. Instead of using tedious data-entry forms, model input data and plot settings data are accessed directly in spreadsheet-like grids. You can quickly edit all aspects of the model input in the model input screen and all the plot settings from the plot settings screen. The input data for a model is stored in one file while the settings for a particular plot are stored in another. This separation is efficient, allowing you to push one button to repeat a plot with the same contours, pathlines, window coordinates, etc.

TWODAN plots can be output to any device supported by the Windows operating system. Graphic plots may directed to the screen, Windows printer devices, bitmap (*.bmp) files, the clipboard, Surfer GRD files, or to DXF files. In addition, the data contoured and the pathline coordinates may be exported to comma-delimited ASCII files for GIS processing. Plots can include any combination of: (1) contours of head, potential, or stream function; (2) pathlines traced upstream or downstream from a point, line, or circle; (3) DXF basemap; and (4) layout of model elements. Printer plots may be scaled automatically to fit the page, or manually to a specific scale (e.g. 1 inch = 500 ft). You may print a plot with landscape or portrait orientation, and you may add a border box and up to three lines of title text.

TWODAN has a suite of advanced analytic modeling features that allow you to model everything from a single well in a uniform flow field on up to complex remediation schemes with numerous wells, barriers, surface waters, and heterogeneities. The aquifer modeled by TWODAN can consist of one or two hydraulically connected layers, it can be confined and/or unconfined, and it can be homogeneous or heterogeneous. The analytic implementation of barrier elements gives much greater accuracy than is possible with numerical methods. TWODAN is also capable of optimizing discharges of steady wells based on specified head and aquifer discharge conditions. In addition, Both discharge- and head-specified linesinks are implemented and Vertical infiltration or leakage to or from the aquifer can be modeled as uniform or as locally variable.

TWODAN gives the usual compilation of calibration statistics, but it also plots the spatial distribution of (observed head - modeled head). Each difference is plotted at the coordinate of the observation, with different colors for positive and negative values so you can quickly see spatial patterns.

SYSTEM REQUIREMENTS

Intel 80486 based computer
Windows95/NT

CLICK HERE TO DOWNLOAD TWODAN DEMO

Authors: Charles Fitts (University of Southern Maine)