TM 5-818-5/AFM 88-5, Chap 6/NAVFAC P-418
U.S. Army Corps of Engineers
Figure C-13. Drawdown versus pumping rate for a step-drawdown test.
mined from the drawdown versus distance plots for a
c. Recovery test.
step-drawdown pump test as illustrated in figure
(1) A recovery test may be made at the conclusion
C-14. The difference in drawdown between the ex-
of a pumping test to provide a check of the pumping
tended drawdown-distance curve and the water eleva-
test results and to verify recharge and aquifer boun-
tion measured in the well represents the well-entrance
dary conditions assumed in the analysis of the pump-
loss and can be plotted versus the pumping rate as
ing test data. A recovery test is valid only if the pump-
shown in figure C-15. Curvature of the Hw versus QW
ing test has been conducted at a constant rate of dis-
line indicates that some of the entrance head loss is the
charge. A recovery test made after a step-drawdown
result of turbulent flow into or in the well.
test cannot be analyzed.
U. S. Army Corps of Engineers
Figure C-14. Drawdown versus distance for a step-drawdown test for determining well-entrance loss.