Tutorial 4: Slug Test Analysis

During a slug test, a slug of known volume is lowered instantaneously into the well. This is equivalent to an instantaneous addition of water to the well, which results in a sudden rise in the water level in the well (also called a "falling head" test). The test can also be conducted in the opposite manner by removing water from a well (called a "bail" or "rising head" test). For both types of tests, the water level recovery is measured (i.e. the difference between the water level measured over the course of the test and the initial water level before the addition or removal of the known volume). In the tutorial, we will use two of the more commonly used methods for evaluating slug test data:

•Hvorslev method

•Bouwer & Rice method

Creating a Slug Test

To create a new slug test:

[1] If you have not already done so, double-click the AquiferTest icon to start an AquiferTest session.  At the Welcome page ensure that the "Create Slug Test" box is checked and choose the "Create a new project" button.  
 
 

 
A blank project with the Slug Test tab active loads automatically. The loaded page should look similar to the one shown below:

[2] Enter the following information in the upper portion of the Slug Test tab:

•In the Project Information section:

•In the Slug Test section:

•In the Units frame fill in the following:

•In the Aquifer Properties frame enter the following:

Next, you need to add the well at which this test was performed.

[3] Click Click here to create a new well link under the Wells table. Define the following well parameters for this well:

•Name: OW-11 •Type: Test Well (set by default) •X: 0 •Y: 0 •Elevation: 0	•R: 0.075 •L: 3.0 •r: 0.025

[4] Click on the Water Level tab to enter the water level data for the slug test. (Note: there is no Discharge tab since there is no discharge in a slug test.)

[5] Enter Static Water Level of 13.99

[6] Enter a WL at t=0 of 14.87

[7] Enter the following data into the Water Levels table:

[8] You will see the calculated change in water level data appear in the graph displayed on the right. If the data do not appear in the graph, click the Refresh button in the toolbar.

You have now entered all the required data for this test.

Slug Test Data Analysis - Hvorslev Method

[9] Click on the Analysis tab. Similar to the pumping test, the top portion of the tab contains the analysis information. Fill in the following fields:

•Analysis name: Hvorslev

•Performed by: Your Name

•Date: choose current date from the drop-down calendar

[10] In the Analysis method frame of the Analysis Navigator choose Hvorslev.

[11] Select the Fit button to autofit the data and the Analysis Graph should resemble the picture below:

The Hydraulic Conductivity value is calculated and displayed in the Results frame of the Analysis Navigator:

Similar to the pumping test analysis, you can use the Parameter Controls to adjust parameters in the slug test analyses. The parameter controls dialog is dynamic, changing to suit every test. In the Theis analysis, the transmissivity (T) and storativity (S) were calculated. In Hvorslev analysis, it is conductivity (K). If you choose to switch to another test, the available parameters will change accordingly.

Slug Test Data Analysis - Bouwer & Rice Method

You can perform a Bouwer & Rice Analysis on the same data.

[12] From the main menu, select Analysis > Create a New Analysis or click Create a New Analysis in the Additional Tasks frame of the Navigation Panel

[13] Select Bouwer & Rice from the Analysis method frame of the Analysis Navigator.

Complete the information for the analysis as follows:

•Name: Bouwer & Rice

•Performed by: Your Name

•Date: choose current date from the drop-down calendar
 

[14] Click the Fit button above the graph to autofit the straight line to your data.

Your analysis window should look similar to the following:

The conductivity values calculated for Bouwer & Rice (14.9 ft/d) is similar to that calculated using the Hvorslev method (19.5 ft/d).

Creating a Report

Now that you have entered your test data and conducted the appropriate analyses you may want to print out a report. Using AquiferTest, you can print out the information from any part of the AquiferTest that is currently active, or you can choose which reports to print at the same time using the Reports tab.

[15] Click on the Reports tab.

[16] Expand the nodes in the Report navigator tree. Check the box beside Tutorial 4: Slug Test and your report will include pages for the tabulated Measurements, Analysis Graphs for each analysis (e.g. Hvorslev and Bouwer & Rice) and a summary of all Analysis Results as shown below.

Note that you can define your company information and logo in the Report section of the Options window, which is accessed by clicking Tools > Options from the main menu.

[17] To print the selected reports select File/Print or simply click the Print button in the toolbar.

This concludes the Quick Start Demo Tutorials (1 through 4) for AquiferTest.  You may close AquiferTest or continue by exploring the Demonstration Exercises and Benchmark Tests.

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