Data Logger File Format

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Both single column and multiple column data logger files can be read by Super Slug. In most cases, header information does not need to be removed before loading.

Single Column File Format

In single column format, data is in a single column of alternating time and drawdown, as shown below.

0.00

0.01

0.12

0.02

0.14

0.03

0.16

0.04

0.17

Multiple Column File Format

Multiple column data logger files can be read by Super Slug. The data should be in columns separated by either commas, spaces, or tabs. Each individual column can be independently assigned to time or drawdown.

Here is an example of a six column data logger file. Time is in the first column and drawdown in the remaining five columns.

0.00 0.00 0.00 0.00 0.00 0.00

0.01 1.12 0.98 0.68 0.45 0.03

0.02 1.26 1.20 0.75 0.52 0.05

0.03 1.35 1.28 0.82 0.55 0.10

0.04 1.42 1.35 0.84 0.58 0.10

Other data logger include columns for data such as temperature, or clock time.

Automatic Adjustments to Data

Before analyzing slug test data, Super Slug automatically adjusts all values so that the largest drawdown value occurs at time = 0.0. This drawdown will be the first trial for the tests. This adjustment allows the data logger to run for several seconds before the slug is withdrawn or injected. The user can also specify a different trial for the first trial of the test. This is done from Options | Graph Options or during graphical analysis.

The value of drawdown can be either the depth to water in the well or the height of the water column in the well. However the measurements must be consistent with the Static Water Level measurement.

Here are some example files, and how they are interpreted by Super Slug. The first column is time and the second is drawdown.

Example 1

0.00 10.0

0.01 12.0

0.02 11.0

0.03 10.5

In Example 1, the slug was inserted at t = 0.01. The static water level is at 10.0. During the calculations, all time values will be adjusted by subtracting 0.01 so that drawdown at t = 0 is 12.0.

Example 2

0.00 13.0

0.01 12.0

0.02 11.0

0.03 10.5

0.04 10.5

1.00 10.5

In Example 2, the data logger was switched on just as - or slightly after - the slug was withdrawn. It would appear that the test ran until the static water level was reached, however a measurement of the static water level before the slug test should have been made. Because the maximum drawdown value occurs at t = 0, there will be no time adjustment.

Example 3

-0.02 0.0

-0.01 3.6

0.0 3.5

0.01 3.4

0.02 3.2

0.03 3.0

In Example 3, the first time value is negative as sometimes occurs with some data loggers. This will not be a problem for Super Slug. Also note that the maximum drawdown value occurs at t = -0.01. In this case all time values will be increased by 0.01 so that the maximum drawdown occurs at t = 0.0 (a drawdown of 3.5 will occur at t = 0.01).

Also note that the static water level has been adjusted by the data logger to a zero reference. This is acceptable. In the final reports, or in the complete input data file, the drawdown values and the Head values will be the same. Super Slug will calculate the static water level to be zero.

Example 4

0.0 10.0

0.1 14.5

0.2 14.4

0.3 14.6

0.4 14.5

0.5 14.2

0.6 14.0

In Example 4, the maximum drawdown does not occur until the fourth data point at t = 0.3. This sometimes occurs as a result of splashing within the well. All time values will be adjusted by subtracting 0.3. The static water level will be 10.0, and the maximum drawdown will be 14.6.

All default adjustments can be overridden by specifying the First Trial value from Options | Graph Options.