Eden-Hazel Assumptions

From Eden and Hazel (1973)

The aquifer is confined (for unconfined aquifers, release from storage must be instantaneous and drawdown small compared to the total thickness of the aquifer.
The aquifer is isotropic, homogeneous and infinite areal extent
Field data lie within the region that the Cooper-Jacob approximation is valid.
The discharge measured at each observation has been constant since the time of the previous observation.
Turbulent head loss is proportional to Q^2.

Kruseman and de Ridder (1990) add:

The aquifer is of uniform thickness over the area influenced by the test
Prior to pumping, the piezometric surface is horizontal (or nearly so) over the area that will be influenced by the test
The well penetrates the entire thickness of the aquifer and thus receives water by horizontal flow

Kruseman and de Ridder (1990) incorrectly state that the pumping must rate must increase for consecutive steps. This is incorrect. The Eden-Hazel method is suitable for increasing or decreasing rates, (as with the data set Kawecki), or pumping tests followed by recovery.