Skip Links

USGS - science for a changing world

Techniques and Methods 3–B9

Groundwater Resources Program

WTAQ Version 2—A Computer Program for Analysis of Aquifer Tests in Confined and Water-Table Aquifers with Alternative Representations of Drainage from the Unsaturated Zone

By Paul M. Barlow and Allen F. Moench


Thumbnail of and link to report PDF (1.39 MB)

The computer program WTAQ simulates axial-symmetric flow to a well pumping from a confined or unconfined (water-table) aquifer. WTAQ calculates dimensionless or dimensional drawdowns that can be used with measured drawdown data from aquifer tests to estimate aquifer hydraulic properties. Version 2 of the program, which is described in this report, provides an alternative analytical representation of drainage to water-table aquifers from the unsaturated zone than that which was available in the initial versions of the code. The revised drainage model explicitly accounts for hydraulic characteristics of the unsaturated zone, specifically, the moisture retention and relative hydraulic conductivity of the soil. The revised program also retains the original conceptualizations of drainage from the unsaturated zone that were available with version 1 of the program to provide alternative approaches to simulate the drainage process. Version 2 of the program includes all other simulation capabilities of the first versions, including partial penetration of the pumped well and of observation wells and piezometers, well-bore storage and skin effects at the pumped well, and delayed drawdown response of observation wells and piezometers.

First posted April, 2011

For additional information contact:
U.S. Geological Survey
Office of Groundwater
411 Federal Center
Reston, VA 20192

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

Barlow, P.M., and Moench, A.F., 2011, WTAQ version 2—A computer program for analysis of aquifer tests in confined and water-table aquifers with alternative representations of drainage from the unsaturated zone: U.S. Geological Survey Techniques and Methods 3-B9, 41 p.




Representation of Drainage From the Unsaturated Zone

Overview of the Analytical Model of Mathias and Butler

Implementation of the Analytical Solution in WTAQ

Evaluation of Revised Program

Sample Problem


References Cited

Appendix 1. Data-Input Instructions for WTAQ Version 2

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo logo U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: Contact USGS
Page Last Modified: Friday, 02-Dec-2016 15:49:59 EST