ProgramS for slug test in an unconfined aquifer considering unsaturated flow

By Hongbing Sun, Rider University, New Jersey

The readme file for the setup of slug program readme

Slug test source code zipped file slug9src.zip

Executable file slug9.exe

Example input zipped files

Article: Sun, H., 2016. A semi-analytical solution for slug tests in an unconfined aquifer considering unsaturated flow. Journal of Hydrology. 532, 29-36

 

This slug test program is designed for a test in an unconfined aquifer utilized a new semi-analytical solution which considers the vertical unsaturated flow in the groundwater. The new solution incorporates the effects of partial penetrating, anisotropy, vertical unsaturated flow, and a moving water table boundary. Compared to the Kansas Geological Survey (KGS) model, the new solution can significantly improve the fittings of the modeled to the measured hydraulic heads at the late stage of slug tests in an unconfined aquifer, particularly when the slug well has a partially submerged screen and moisture drainage above the water table is significant. The radial hydraulic conductivities estimated with the new solution are comparable to those from the KGS, Bouwer and Rice, and Hvorslev methods. In addition, the new solution also can be used to examine the vertical conductivity, specific storage, specific yield, and the moisture retention parameters in an unconfined aquifer based on slug test data.

 

The solution paper is in Journal of Hydrology, 2016. 532, 29-36.

 

Readme file: Instruction for files in the slug9src.zip and the input.zip

1. The slug9src.zip has 5 files: two files are for setup, the other three files are the source code files.

Two setup files:

1). g77setup.bat is a batch file for setting up the path for the g77 Fortran Compiler.

2). g77slug8.bat is the batch file that compiles the three source files and creates the executable file called slug6.exe

 

Three source files are:

slugtest9.f, laplace9.f besellsub.f

 

2. The input.zip file has four example input files and one well data file

 

texas1403_9.txt

texasa027_9.txt

texasmw12.txt

butler66_2.txt

 

texasmw12_old.txt is an early calibrated data file used for sensitivity analysis.

 

welldata.xls has the four measured wells' H/Ho data and their measuring time (in seconds) for the input wells.

 

It seems butler66_2.txt data does not have significant unsaturated flow and was added to compare with the KGS model in this situation.

 

3. Other notes

 

The input file in the examples is self-explanatory. The rows above the numbers are the explanatory rows. The program skips these rows no matter what you enter there.

One only needs to change numbers in the example file and save it as a different file to run your own data.

You only need to change the numbers underneath the lines **Your data line. User specified time for the slug test time is underneath line 5+.... For the number of user specified time, one needs to count how many time steps you have and enter your time. Then copy the time of the time steps over.

 

4. To run the executable program, just type in slug9.exe in the command line.

When the program prompts for the input file, one needs to enter the full file name, including the suffix

The input file will have to be in the same directory as slug9.exe file.

 

5. The output file is called the outfile.txt

The file has three columns. One is the time column, another one is the H/Ho, and the third one is the actual water level column(H/Ho)*Ho. These three columns also are displayed on the screen.

 

 

Comparison with traditional models: KGS and Bower and Rice Model

For articles: see link

Figure 1. Left underneath picture, log time vs. normalized head, right underneath picture, time vs. log normalized head plots for well ST14-03 showing the best fit curves from the new solution, the KGS model, and the Bouwer & Rice model to the measured slug test data. Notice the significant improvement of the new solution for fitting the late slug test data which were affected by unsaturated drainage.

Figure 2. Left underneath picture, log time vs. normalized head, right underneath picture, time vs. log normalized head plots for well WSAICTA027 showing the best fit curves from the new solution, the KGS model, and the Bouwer & Rice model to the measured data.

Figure 3. Left underneath picture, log time vs. normalized head, right underneath picture, time vs. log normalized head plots for well MW-12 showing the best fit curves from the new solution, the KGS model, and the Bouwer & Rice model to the measured data.

Figure 4. Left underneath picture Log time vs. normalized head; Right underneath picture, time vs. log normalized head plots for well Butler_6.2 showing the best fit curves from the new solution, the KGS model, and the Bouwer & Rice model to the measured data (The measured data and well parameters were from Butler, 1998, Tables 6.1 and 6.2).

 

Table 2. Comparison of hydraulic parameters estimated from the new solution and traditional

models.

Well ST14-03*

 Models\Parameters

Kr (m/day)

Kz (m/day)

Ss (m-1)

Sy

ac (m-1)

ak (m-1)

Sun (2016) model

2.76

1.78

2.5*10-5

0.1

1.5

250

KGS Model

2.06

1.21

7.52*10-5

Bouwer & Rice Model

2.27

Hvorslev

2.95

WSAICTA027*

 Models\Parameters

Kr (m/day)

Kz (m/day)

Ss (m-1)

Sy

ac (m-1)

ak (m-1)

Sun (2016) model

2.24

2.16

5*10-5

0.10

1.2

350

KGS Model

2.39

0.286

6.84*10-5

Bouwer & Rice Model

1.89

Hvorslev

2.71

MW-12*

 Models\Parameters

Kr (m/day)

Kz (m/day)

Ss (m-1)

Sy

ac (m-1)

ak (m-1)

Sun (2016) model

2.51

2.24

2*10-4

0.12

0.8

400

KGS Model

1.55

1.08

1.8*10-3

 

 

 

Bouwer & Rice Model

2.01

 

 

 

 

 

Hvorslev

2.85

 

 

 

 

 

Butler-6.2

 Models\Parameters

Kr (m/day)

Kz (m/day)

Ss (m-1)

Sy

ac (m-1)

ak (m-1)

Sun (2016) model

5.18

1.3

2*10-4

0.17

10

100

KGS Model

4.73

1.89

2.5*10-4

 

 

 

Bouwer & Rice Model

4.39

 

 

 

 

 

Hvorslev

5.44

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*Hydraulic heads for slug testwells ST14-03, WSAICTA027, and MW-12 were obtained from Houston and Braun, USGS. Hydraulic parameters and heads for slug test well Buter-6.2 were obtained from Butler (1998) Table 6.1 and 6.2 on p.111-113. ac moisture retention exponent (L-1 ), ak relative conductivity exponent (L-1 ), Kr hydraulic conductivity in the radial direction (L/T), Kz hydraulic conductivity in the vertical direction (L/T), Ss specific storage coefficient (L-1 ), Sy the specific yield (dimensionless).

 

 

Email contact: hsun@rider.edu, phone: 609-896-5185

Department of Geological, Environmental, and Marine Sciences

Rider University, Lawrenceville, NJ 08648

Updated by Hongbing Sun 2/12/2016