TM 5-818-5/AFM 88-5, Chap 6/NAVFAC P-418
well, calcium hypochlorite shall be added to evenly dis-
(b) The pump shall be capable of pumping at the
tribute a minimum of 2 pounds per ton of filter. Upon
rate of 1500 gallons per minute, over a period of time
completion of development of the well and prior to in-
sufficient to satisfactorily perform the pumping test
stalling the well cover, a minimum of 5 pounds of
specified. An approved means for accurately determin-
granular 70 percent calcium hypochlorite shall be
ing the water level in the well and a calibrated flow
dropped in the well and allowed to settle to the bot-
meter or orifice of standard design for the purpose of
tom.
measuring the discharge from the well during the
(h) Covers. The top of a well shall be sealed im-
pumping test shall be provided. The Contractor shall
mediately after completion of installation with a wa-
furnish and install the necessary discharge line so that
tertight seal which shall be kept in place at all times,
the flow from the well can be pumped into an adjacent
except during cleaning and pumping operations, until
area approved by the C.O.R. The pumping and sand in-
the pump and gear drive are installed.
filtration test shall be conducted in the presence of the
(i) Abandoned wells. Holes for wells abandoned
C.O.R., who will record the following test data: well
prior to placement of well screen and riser pipe shall
number, location, top of riser (mean sea level), date
be filled with sand and cement grout. Wells abandoned
and time test started and stopped, depth to water in
after placement of well screen and riser pipe may be
well before and at end of pumping, elevation of water
pulled and the remaining hole filled with sand to with-
in well immediately before and at the end of pumping,
in 25 feet of the surface. The remaining 25 feet should
rate of sanding at end of pumping period, and depth of
then be backfilled with an approved cement grout.
sand in well after cleaning.
Bentonite may be added to the grout to improve its
(c) The Contractor shall test each well by pump-
pumpability. If the Contractor elects to leave an aban-
ing continuously for a minimum of 2 hours. Pumping
doned well screen and riser in place, it shall be plugged
shall be at a constant rate sufficient to produce either
as described above. Wells which are abandoned as a re-
a drawdown of 20 feet, or a constant rate of flow of
sult of alignment or plumbness being outside of these
1500 gallons per minute, whichever occurs first. The
specifications, or wells which produce sand in excess of
computed rate of sanding shall take into consideration
5 parts per million after development and pump test-
the pumping rate, the rate of sand emerging from the
ing, shall be replaced by the Contractor at no cost to
pump, and the amount of emptying or buildup of sand
the Government.
in the bottom of the well during the (sand) testing peri-
(j) Well records. The following information re-
od as determined accurately with a flat-bottom sand-
garding the installation of each well will be recorded
ing device. No test pumping of a well will be permitted
by the C.O.R. The Contractor shall cooperate and as-
concurrently with drilling, surging, or pumping of any
sist the C.O.R. in obtaining the following informa-
other well within 300 feet thereof.
tion: well number, location, top of riser (mean sea lev-
(d) In the event that sand or other materials in-
el), date and time test started and stopped, depth to
filtrate into the well during the pumping test, the fol-
water in well before and at end of pumping, elevation
lowing procedure will be followed: If the rate of sand
of water in well immediately before and at end of
infiltration during the last 15 minutes of the pumping
pumping, flow in gallons per minute, depth of sand in
test is more than 5 parts per million, the well shall be
well before and after completion of pumping, rate of
resurged by manipulation of the test pump for 15 min-
sanding at end of pumping period, depth of sand in
utes after which the test pumping shall be resumed
well after cleaning, screen length, depth of hole, inside
and continued at the rate specified above until the
depth of well, depth to sand in well after cleaning, top
sand infiltration rate is reduced to less than 5 parts
of well screen (mean sea level), top of filter (mean sea
per million. If at the end of 6 hours of pumping the
level), bottom of well (mean sea level), top of well,
rate of infiltration of sand is more than 5 parts per
method of surging, material surged into well (last cy-
million, the well shall be abandoned unless the C.O.R.
cle) in feet, total material surged into well in feet, rate
requests the Contractor to continue to test pump and
of pumping and drawdown, total pumping time, and
perform such other approved remedial work as he con-
rage of sand infiltration at end of pumping in parts per
siders desirable. If, after such additional test pumping
million.
and other remedial measures, the sand infiltration
rate of the well is reduced to less than 5 parts per mil-
(4) Pumping test on each well.
(a) Upon completion of installation, surging,
lion, the well will be accepted. Upon completion of the
and developing pumping, each well shall be subjected
pumping test, any sand or filter material in the bottom
to a pumping test. Prior to commencement of the
of the well shall be removed by pumping or with a pis-
pumping test, and again after completion of the pump-
ton-type bailer.
ing test, the depth of the well shall be measured when
(5) Installation of pump and chlorination. Each
the C.O.R. is present by means of an approved flat-bot-
dewatering well shall be chemically treated with cal-
tom sounding device.
cium hypochlorite (chlorine) within 24 hours after the
G-14
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