MIL-HDBK-1005/7A
4.4
Groundwater Collection Works
4.4.1
Wells. Selection of the type of well is to be guided
by AWWA Manual M21 and AWWA Standard A100, Water Wells, or FGS.
4.4.1.1
Test Well Pumping . After investigation has indicated
the best location for groundwater development, a test well is
generally used to determine well capacity and appropriate well
spacing. A test well may be a small diameter temporary
installation in a test hole or, if preliminary data is very
promising, it may be a permanent installation. Pumping tests
require one pumped well and one or more observation wells. For
a permanent installation, at least one observation well should
be 10 to 15 ft from the pumped well, with others 50 ft or more
away. The pumped well should be either in the best test hole or
not more than 10 ft from it.
a) Duration of Test. The test should run a minimum
of 24 hours after development of well, or as long as required by
any applicable regulations. Longer tests, up to several weeks
duration, may be desirable to verify adequacy of the
information.
b)
Records Required.
Secure the following data:
(1)
Initial static water level in each well
(2) Pumping rates; at least every hour.
Pumping
should be maintained at a constant rate.
(3) Drawdown data. Measure water levels in
pumping well and also in all observation wells.
(4)
Rate of recovery
(5) Where the formation's capability is
doubtful, register water levels at each observation well with an
automatic recorder accurate to 0.02 feet.
(6) Water samples and analyses. For a major new
development, or one of uncertain mineral quality, at least five
samples should be taken at periods approximating 0.01, 0.05,
0.10, 0.5 times the test duration, and at the end of the test.
c) Analysis of Tests. Where the formation capacity
is in question, use Theis' non-equilibrium formula. Refer to
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