8.1 Introduction
Section 7 discusses the radial flow of water to a well and introduces the Theis equation. We show how, given a transmissivity and storativity, the Theis equation can be used to calculate the amount of drawdown that would occur in the aquifer at some distance from a well (pumping at a constant rate) after some period. The Theis equation, however, is more commonly used to do the opposite—that is, to use drawdown data from a pumped well to estimate transmissivity and storativity of the formation. This section focuses on aquifer tests4: tests that involve pumping from a well, measuring drawdown in the aquifer during pumping, then using those data and the Theis equation to estimate aquifer parameters.
4 It is acceptable to refer to these types of tests as aquifer test, hydraulic test, or pumping test. It is not, however, appropriate to use the term pump test, as that implies that one is testing the pump rather than the aquifer.