Determining Transmissivity

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From a step-drawdown test, transmissivity can be determined with the Eden-Hazel method and the Birsoy-Summers method.

For the Eden-Hazel method, drawdown in the well is described by the equation:

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b is the slope from Part 1 of the Eden-Hazel method. Aquifer transmissivity will be displayed over the graph of Part 1 of the Eden-Hazel method.

For the Birsoy-Summers method, the slope of the line (actually change in specific drawdown per log cycle of adjusted time) is used to determine transmissivity with the equation:

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Storativity is calculated from:

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