GGU-PUMPTEST: Theis type curve method

The theoretical principles are described in Langguth/Voigt on pages 153 to 164. The example file "Theis Typ Gauge 6b.pvs" can be found in the program's example folder.

This method entails a drawdown in a well with a constant pumping rate. At the same time, the course of the drawdown is measured in a nearby monitoring well.

The graphical representation of the test results is in a double-logarithmic scale (drawdown against t/r², t = time, r = distance between gauge and extraction well). The following data is required:

• the distance between the extraction well and the monitoring well;

• the constant pumping rate in the extraction well;

• the aquifer thickness H;

• the specification of confined or unconfined aquifer;

• the drawdown h in the monitoring well against time.

After defining the input values they are entered against time and the best-fit curve determined. The permeability can then be determined.

Example:

This is the example for Gauge 6b in Langguth/Voigt. The measured data for Gauge 6b are shown in Table 3 on page 16. The pumping rate in the extraction well is 0.02667 m³/s. Gauge 6b is 139.60 m from the extraction well. The aquifer is 10.0 m thick. It is a confined aquifer.

In the menu item "File/New", press the "Theis type curve" button and then go to the menu item "Edit/Edit values". Change the number of values to "14" and enter the measured data from Table 3 on page 16.

Go to the "Evaluation/Theis type curve" menu item:

Enter the values in the dialog box and confirm with "OK". The "Displacement to type curve" values are determined automatically or manually afterwards. After input, the measurement curve must be made congruent with the type curve. Two methods can be used to do this