Wellhead Protection Area (WHPA) Model
WHPA is a semi-analytical groundwater flow simulation program used for delineating capture zones in a wellhead protection area. The program consists of four computational modules: RESSQC, MWCAP, GPTRAC, and MONTEC. WHPA is applicable to homogeneous aquifers exhibiting two-dimensional, steady groundwater flow in an areal plane and appropriate for evaluating multiple aquifer types (i.e., confined, leaky-confined, and unconfined). The model is capable of simulating barrier or stream boundary conditions that exist over the entire depth of the aquifer. WHPA can account for multiple pumping and injection wells and can quantitatively assesses the effects of uncertain input parameters on a delineated capture zone. The program can be used as a postprocessor for two dimensional numerical models of groundwater flow.
Specifications
| Version | 2.2 |
|---|---|
| Release Date | September 1993 |
| Operating System | DOS |
Minimum System Requirements
- IBM PC/AT or compatible
- DOS version 2.1 (or higher)
- CGA, EGA, VGA, or Hercules graphics capability
- 640 KB of RAM
Downloads
Program and Installation files 1 (zip) (416 K)
Program files 2 (zip) (364 K)
Addendum
This document is an addendum to the Version 2.0 WHPA Code User’s Guide (Blandford and Huyakorn, 1991). WHPA is a user-friendly microcomputer model developed by the U.S. Environmental Protection agency (EPA) to assist State and local technical staff with the delineation of wellhead protection areas (WHPAs) as mandated by the 1986 Amendments to the Safe Drinking Water Act. Previous versions of the WHPA code (2.1 or less) have the capability to delineate time-related, steady-state, or hybrid capture zones using ground-water flow pathline delineation techniques. To determine pathlines and times of travel, ground-water flow velocities and some physical aquifer properties are required. Since ground-water flow velocities are a function of the difference in hydraulic head (or potentials), rather than the head values themselves, it is not necessary to determine hydraulic heads in order to determine pathlines and capture zones.
Calculation of the hydraulic head values, however, can be useful for visualization and model calibration purposes, and in some cases may serve as a “reality check” for a simulation scenario. For these reasons, options to compute hydraulic head fields were implemented into the RESSQC, MWCAP, and semi-analytical GPTRAC modules of the WHPA code. The purpose of this addendum is to document the implementation and proper application of the new options.
Chapter 2 outlines the implemented changes in the preprocessor and postprocessor modules. It presents several demonstration and verification examples and provides some rules of thumb for model calibration. For interested readers, the mathematical formulations are presented in Chapter 3.
Installation Instructions
To download and install WHPA, the following procedures must be followed:
- Refer to the user's manual for further instructions.
- Download program and installation files (1 and 2).
- Unzip program and installation files (1) from your hard drive to a blank formatted 3.5-inch high-density diskette labeled "WHPA Disk 1."
- Unzip program files (2) to a blank formatted 3.5-inch diskette labeled "WHPA Disk 2."
- Insert the disk labeled "WHPA Disk 1" into the 3.5-inch drive.
- At the DOS prompt, change drives to the 3.5-inch drive.
- Type INSTALL.
- Follow the on-screen directions and refer to the user's manual.