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Recommended Book:
Butler (1998)
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Design of a Constant-Rate Pumping Test in an Unconfined Aquifer
This tutorial shows you how to use AQTESOLV for Windows
to design a pumping test in an unconfined aquifer. In the example, a partially
penetrating test well pumps at a constant discharge rate of 750 gallons-per-minute
(gpm). Drawdown is monitored in a partially penetrating observation well screened
near the water table and located 82 feet (ft) from the test well. The thickness of
the aquifer is 94 ft.
Start the AQTESOLV for Windows
application (v. 3.0 or higher) and follow the steps below.
- Choose File | New and select Pumping Test Wizard from
the list to create a new data set for a pumping test. Click OK to
proceed with the Pumping Test Wizard.
- Enter units of measurement as shown and click Next.
- Click Next to skip the step for project information.
- Enter aquifer data as shown and click Next.
- Click Next twice to skip the steps for fractured aquifer data.
- Enter pumping well information as shown. The default X and Y coordinates place the
pumping well at the center of the coordinate system. Click Next.
- Choose the option for a Partially Penetrating Well, enter depths as
shown, and click Next.
- Enter pumping rate data in the spreadsheet as shown. Click Next.
- Enter observation well data as shown and click Next.
- Choose the option for a Partially Penetrating Well, enter depths as
shown, and click Next.
- Enter two pairs of time and displacement into the spreadsheet to define the duration of
the test and the range of displacement for plots. The exact values that you enter
are not important; you can change the range of the x and y axes later. Click Next
to continue.
- Click Finish to complete the Pumping Test Wizard.
- If you entered all of the data into the Pumping Test Wizard correctly, the Error
Log displayed on the screen should show no errors in the data set. If the
Error Log identifies any mistakes, you can correct them by choosing options from the Edit
menu.
- Choose File | Save As to save your work. Choose a folder and
enter Neuman Forward Solution for the name of the file. AQTESOLV for Windows saves the data set with an
.aqt extension.
- Choose View | Displacement-Time to display the Neuman type curve on a
plot of displacement as a function of time. Right click the mouse over the plot and
select Log to display the plot with log-log axes.
- Choose Match | Toolbox and click Parameters to enter
aquifer properties for the Neuman solution. Enter the following estimated values for
the parameters: T=100,000 gal/day/ft, S=0.0001, Sy=0.1 and b=0.3.
Click Apply to update the position of the type curve.
- Click the Tweak tab in the Match Toolbox dialog to perform interactive
sensitivity analysis. For example, select T in the Parameter
list and slide the tab on the scroll bar to adjust the transmissivity value. AQTESOLV for Windows automatically updates the
type curve on the screen so you can view the effect of parameter changes.
 Click here to view
a plot that benchmarks the Neuman solution in AQTESOLV for
Windows against WTAQ, a program from the USGS developed
by Barlow and Moench (1999). |
