Slug Test Analysis

The program 'SLUGT2' is an updated version of program 'SLUGT' and computes hydraulic conductivity values based on the analysis of slug-test data.

Three models commonly used for slug-test analysis included in SLUGT2 are:
(1) Method of Cooper, Bredehoeft and Papadopulos;
(2) Method of Bouwer and Rice; and
(3) Modified Hvorslev Method.

In addition, effects due to air entrapped in the completion region of a piezometer or well are estimated using the method of Keller and van der Kamp as a computation option. The program is intended to be run in batch mode, but there is an option to enter the input data from the keyboard as prompted one by one on the monitor. The batch mode involves the preparation of a data file that may include data for a series of slug tests. Data input and output may be in metric (SI) units (centimeter-meter) or inch-feet units. SLUGT2 executes in a Microsoft Runtime Windows Environment (MRWE) with a windows-style interface.

Output includes:
(1) a detailed results file including input and output values;
(2) an Excel-compatible table summarizing the results for all the tests analyzed in the run, and
(3) an Excelcompatible output file containing displacement (H) vs. time data for each case to facilitate preparation of graphs of log(H) vs. time.

The user may find it valuable to plot the reduced data to determine if certain data points should be excluded in a possible second run. In many cases the observation points all fall close to a best-fit straight line and the results of the slug-test analysis are ready for use. In other cases, the early-time points may fall on one straight line, and the later-time points on another straight line, the latter often having a flatter slope. In that case, the user will have to decide whether or not to rerun the program using only the earlier-time points or the later-time points for computation of K and T.

Distribution of the public domain SLUGT2 program includes source code, executable image, and example data sets. The user's manual includes installation instructions and program documentation.


Modifications to SLUGT in Developing SLUGT2

1. General Changes in Code

2. Changes to Code in Calculating T using Cooper, Bredehoeft and Papadopulos (CBP) Method

3. Changes to Code in Calculating K using Bouwer and Rice (B&R) and Hvorslev Methods



Author: A.C. Mills (AMEC E&I, Inc.)