Deviations from Classical Behaviour in Pumping Test Analysis

This paper discusses certain of the reasons for deviations from the classical type curve behaviour during pumping tests. A particular series of pumping tests in a confined limestone aquifer is considered; the tests include a step test, a 3-day test and a 71-day test. Using a radial flow numerical model, the influences of transmissivity, storage coefficient altering with radius, a neighbouring baseload borehole and a distant unconfined boundary are each considered. The baseload borehole is shown to have a significant effect on both abstraction and recovery response for the 3-day test, while both the baseload borehole and the unconfined boundary modify the response for the 71-day test.