The UN-GW software package consists of two parts: 1) data bases and utilities, and 2) mathematical models. Part 1 includes programs for permeability calculations and conversions, ground-water chemistry, pumping tests, well hydraulics and construction, water level data base and hydrographs, well logs and lithological cross-sections. Part 2 consists of models for transient flow in a confined aquifer, in an unconfined aquifer, in a small oceanic island, and in a two-layered aquifer system. Various options are available for graphic post-processing of results. The programs in the package are:

• GW1:Permeability calculations and conversions: units conversions; empirical formulas (Hazen, USBR, Slichter, Kozeny, Zamarin, Terzaghi); average values in layered media (horizontal and vertical flow); permeameter tests (constant head, falling head, no discharge); pumping tests (steady- state); tables with look-up values for hydraulic conductivity and intrinsic permeability.
  
• GW2:Ground-water chemistry: data base with input, editing and report capabilities; Stiff diagram, Piper diagram, Wilcox diagram.
  
• GW3:Pumping tests: Jacob, Theis, Hantush, recovery, dug wells; interac tive data entry, editing and reporting; screen graphics, printing and plotting.
  
• GW4:Well hydraulics and construction: well functions (Theis, Hantush-Jacob), Bessel functions, error function; pump tests (step-drawdown with well loss, orifice weir, flowing well discharge); well construction (recommended well diameter, optimum screen length).
  
• GW5:Water level data base and hydrographs: data entry, editing, analys is, display, printing, plotting; depth-altitude conversion.
  
• GW6:Well logs and lithological cross sections: drilling data base; dis play, print and plot lithological cross-sections.
  
• GW7:Confined aquifer model - areal; finite difference method: 2D transient flow in an isotropic confined aquifer; spatially varying transmissivity and storage coefficient; time variable recharge in outcrop areas; dynamic (time-varying) prescribed head boundaries; space and time variable pumping; inflow/outflow across model boundaries; uniform type steps; uniform spacing; output includes maps, contours, hydrographs, and water balance.
  
• GW8:Unconfined aquifer model - areal; finite difference method: 2D steady- state/transient flow in an unconfined aquifer; change between confined and unconfined condition; spatially variable hydraulic conductivities and storage coefficients; time and space dependent recharge, evaporation from water table, constant head stage (streams, lakes), and discharge/ recharge wells; uniform type steps; uniform spacing; dynamic (time- varying) prescribed head boundaries; inflow/outflow across model boundaries; output includes maps, contours, hydrographs, and water balance.
  
• GW9:Model of a small island - cross-section; finite difference: 2D steady- state/transient flow in fresh water part of an isotropic unconfined aquifer with stagnant salt water; change between confined and unconfined condition; spatially variable hydraulic conductivities and storage coefficients; time and space dependent recharge, constant head stage (streams, lakes), and discharge/recharge wells; uniform type steps; uniform spacing; space and/or time dependent Ghyben-Herzberg ratio for salt/fresh water used to determine transmissivities; dynamic (time- varying) prescribed head boundaries (fluctuating sea level); inflow/ outflow across model boundaries; output includes cross-sections, hydrographs, and water balance.
  
• GW10:Analytical and graphical data analysis for two-layer aquifer system: analyze, transform, display or print data used in or produced by the modeling of a two-layer ground-water system, modeled by GW7, GW8, or GW9; detect discrepancies in data files.
  
• GW11:Graphics: used by all previous programs to create contour maps showing wells, boundaries, roads, streams, etc.
  

The program is distributed on a set of HD DOS-formatted diskettes containing runtime versions of each program, and example data sets, and includes installation instructions, user's manual and example problems.

SYSTEM REQUIREMENTS

• Intel 80i86 based computer
• 640 Kb conventional RAM
• DOS 2.11 or higher
• CGA, EGA, VGA (recommended), Hercules, AT&T/Olivetti SGA WYSE graphics
• hard drive with about 7 Mb free disk space to install program and example files
  
• math coprocessor strongly recommended
• Microsoft compatible mouse for graphics
• Epson compatible printer optional
• HPGL accepting plotter optional

Authors: J.K. Karanjec and D. Braticevic (U.N. Dept. of Techn. Co-op. for Developm.)