MIL-HDBK-1005/7A
Groundwater and Wells, by Driscoll, and AWWA Manual M21 for a
description of the formula.
4.4.1.2
Characteristics
a)
Number.
Provide at least two wells, if possible.
b) Yield. After making allowance for standby wells
and reserve for future needs, the total yield should be no less
than the maximum daily consumption at the Military activity.
c) Diameter. Determine the size of each well using
the total yield required, the number of wells to be constructed,
and the capacity of wells at different diameters. The
dimensions may be governed by the construction facilities
available. Use the following as a preliminary guide for sizing
the diameter of deep -drilled wells according to the anticipated
yield.
ANTICIPATED CAPACITY (gpm)
CASING DIAMETER (in.)
50
6
50-300
8
300-500
10
500-750
12
750-1,000
16
1,000-2,000
20
2,000-3,000
24
Over 3,000
30
d)
Depth.
Drill wells deep enough to:
(1) Penetrate an adequate depth into the
water-bearing aquifer.
(2) Allow for installation of an adequate length
of screen (refer to requirements in par. 4.4.1.3, Well
Construction).
(3) Allow for installation of pumping equipment
below depth of maximum drawdown.
e) Specific Capacity. This factor equals the yield
divided by the drawdown, as determined by the pumping test. It
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