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:
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:
Storativity is calculated from: