California State University, Sacramento

Geology 500- M.S. thesis project

Week 7:  Step tests, well efficiency



We will use three hour step tests to examine the appropriate pumping rate for the confined aquifer


We will also a 25 hour aquifer test to estimate well efficiency.



Step tests:

Driscoll, F. G., 1986, Groundwater and wells, 2nd ed., pp. 555- 559


Well efficiency:

Driscoll, F. G., 1986, Groundwater and wells, 2nd ed., pp. 244-245, 554- 555 and 630 - 670.


Specific capacity:

Fetter, C. W., Applied Hydrogeology, 4th ed., pp. 205-207


Data sets:

24 hour aquifer test:  use for well efficiency calculation (contains EX-1 data)

24 hour test


Step test:  Plot to show change in drawdown with time, evaluate qualitatively.  Watch for the % change in drawdown with each step.

Step test MW-1A

Step test MW-3A


Distances between wells were measured with a steel tape:

Extraction well to MW1A = 133.0 ft

Extraction well to MW2A = 138.9 ft

Extraction well to MW3A = 30.05 ft



Plot the results of the step test, and discuss whether the aquifer is capable of supplying water at a rate of 150 gpm for an extended period of time.


Estimate the well efficiency by projecting drawdown and the cone of depression from nearby wells.


Include methods sections with appropriate references, results and discussion.  Use thesis format.