Current through Register Vol. 50, No. 9, September 20, 2024
A.
Geologic conditions in Louisiana permit the use of two methods of drilling: the
rotary method and reverse circulation method. Regardless of the method used,
every precaution should be taken to prevent ground water contamination during
drilling operations.
B. Water used
in drilling operations shall be potable or chlorinated to prevent contamination
of water-bearing formations.
C.
When drilling a hole the contractor shall:
1.
prior to the commencement of any construction on a new water well, the drilling
contractor shall confirm that the office of conservation has received and
responded to water well installation notification as required in LAC
43:VI.701.B;
2. record the hole
diameter and any changes in size of hole;
3. record (driller's log) the depth and
thickness of the formations penetrated;
4. record any unusual occurrences, such as
loss of circulation, cave-ins, etc. (In the event the unusual occurrence is
observable evidence of naturally occurring methane gas, natural gas or similar
sub-surface gas, such as bubbling drilling mud or gas venting at the well bore
or other nearby surface location or feature, the contractor shall report such
event verbally to the Environmental Division of the Office of Conservation
within 24 hours.); and
5. collect
representative samples (drill cuttings) from each potential aquifer.
D. The contractor shall properly
maintain all materials, tools, and drilling equipment and shall take all
measures necessary to minimize health and safety hazards and to prevent
movement of surface water and contaminants into the drilled hole or
well.
E. An approved portable
toilet shall be located at the drilling site if other restroom facilities are
not available.
F. The mud pit shall
be so constructed and maintained as to minimize the contamination of the
drilling mud.
G. During a temporary
shutdown for more than 24 hours, safeguards shall be taken to prevent possible
contamination and damage. The well or hole shall be covered or capped to
prevent entry by other than the contractor; it shall be clearly marked, and
shall not be a safety hazard.
H.
Alignment and Plumbness. The hole shall be drilled reasonably straight and
plumb in order to:
a. avoid encroachment on
neighboring property;
b. prevent
intersection with other wells and holes;
c. prevent damage to screen while being
set;
d. prevent damage to pumping
equipment; and
e. allow for
lowering the pump to the desired depth.
I. The contractor shall exercise reasonably
straight and plumb. Testing for plumbness and alignment are described in
Section 8 and Appendix C of the current American Water Works
Association Standards for Water Wells (AWWA A-100), as well as in
Article 51 of the United States Environmental Protection Agency's
Manual of Water Well Construction Practices.
J. Drilling of Test Holes and Pilot Holes
1. A test hole is usually drilled to the base
of the fresh water or to the bottom of the sand to be tested. Test holes are
drilled primarily to:
a. determine the exact
depth and thickness of the fresh-water bearing sands (aquifers);
b. collect drill cuttings for determining
screen slot openings and the best location for the screen; and
c. collect quality and quantity of water data
that can be used to design the well and select a pump and motor.
2. During the drilling operation,
the contractor shall take the necessary precautions to prevent the
contamination of any aquifer and the exchange of waters between
aquifers.
3. When the drilling of a
pilot hole or a test hole is temporarily suspended and the rig moves away from
the drilling site, the hole shall be considered an abandoned hole unless
drilling operations are resumed within 30 calendar days of the initial date of
suspension of drilling or an extension, in writing, is granted by the
department. During the "shut down" period, a mud column of sufficient weight
and height shall be maintained in the hole at all times to prevent seepage of
surface water and foreign materials into any aquifer and to prevent
interaquifer movement of water. Additionally, the hole shall be capped and the
immediate area shall be conspicuously marked to protect and warn the public.
The cap shall be sufficiently strong and anchored to prevent easy and
unintentional entry.
4. If the
drilled test hole is deeper than the interval to be tested, the contractor
shall use cement-bentonite slurry to set a plug extending from the bottom of
the hole upward to a depth within 20 feet of the bottom of the proposed screen
setting or to the top of clay or shale layer underlying the sand to be tested.
A sufficient period of time shall be allotted for the cement to set before
development begins. If sands were not penetrated below the bottom of the sand
to be screened, heavy drilling mud or bentonite slurry may be used in lieu of
cement-bentonite slurry to plug the bottom of the hole.
5. If another aquifer at a shallower depth is
to be tested, the contractor shall use cement-bentonite slurry to set a plug
extending upward from the top of the plug, previously placed in the bottom of
the hole, to within 20 feet of the depth where the bottom of the test screen is
to be set in the shallower aquifer, or to the top of the clay or shale layer
underlying the shallower sand to be tested.
6. Abandoned pilot holes and test holes shall
be plugged in accordance with requirements of §531, respectively.
K. Drilling of Heat Pump Holes
(Closed Loop-System)
1. Heat pump holes shall
be constructed in accordance with the pertinent provisions of this Chapter in
order to protect freshwater aquifers from surface contamination and to prevent
movement of water of objectionable quality from one aquifer to
another.
2. Piping, casing or
tubing materials shall conform to the applicable ASTM standards for polyvinyl
chloride (PVC), polyethylene (PE), or polybutylene (PB) plastics and shall be
installed and joined according to manufacturer's recommendations.
3. If used, antifreeze compounds shall be
nontoxic and approved for use by the U.S. Environmental Protection
Agency.
4. The entire depth of the
closed loop heat pump holes shall be sealed in accordance with requirements of
§531 within 30 calendar days after
completion of drilling operations.
5. Service manifold should be protected from
external forces as recommended by the manufacturer, designer and/or local
building codes.
L.
Drilling of Monitoring Wells
1. Monitoring
wells shall be constructed in accordance with the pertinent provisions of this
Chapter in order to protect freshwater aquifers from surface contamination and
to prevent movement of water of objectionable quality from one aquifer to
another.
2. To prevent the
introduction of extraneous compounds into the formation water, the use of
drilling mud in the monitoring wells is discouraged.
3. Monitoring wells shall be cased and the
casing shall be strong enough to resist the forces imposed during and after
installation, including reaction upon the casing by natural or foreign
constituents or contamination.
4.
The entire annular space of the monitoring wells shall be sealed with
cement-bentonite slurry, unless specified otherwise by the Department of
Environmental Quality (DEQ). Prior to cementing, flushing of the annular space
with water will be necessary when obstructions are present or suspected. Coarse
ground bentonite or bentonite pellets shall be placed between and the sand pack
and the cement-bentonite slurry. The ground surface around the well shall be
covered with a concrete slab at least 4 inches thick, extending at least 2 1/2
feet from the well in all directions. The surface of the slab shall be sloped
to drain away from the well.
5.
Monitoring wells shall be covered with a protective cover or cap.
6. Abandoned monitoring wells shall be
plugged in accordance with requirements of §531
Note: Construction of Monitoring Wells for facilities
regulated by the department of Environmental Quality (DEQ) require approval
from DEQ prior to construction.
M. Drilling of Geotechnical Boreholes
1. Boreholes shall be drilled in accordance
with pertinent provisions of this Chapter in order to protect the fresh-water
aquifers from surface contamination and to prevent movement of water of
objectionable quality from one aquifer to another.
2. Geotechnical boreholes shall be plugged in
accordance with requirements of
§531 within 30 calendar days after the
termination of drilling and sampling operations.
NOTE: Drilling of geotechnical boreholes for facilities
regulated by the Department of Environmental Quality (DEQ) require special
consideration by that department.
N. Reworking of Water Wells
1. Rehabilitation or modification of water
wells shall be accomplished in accordance with the provisions of this Chapter
of the rules, regulations and standards for water well drilling in order to
protect the fresh-water aquifers from contamination.
O. The following operations shall be
considered as reworking water wells and shall require a water well contractor's
license.
1. removing and replacing
screen;
2. replacing gravel pack
around screen;
3. placing a new
screen within the old screen;
4.
placing a liner pipe within the old casing;
5. redeveloping a well by surging, adicizing,
jetting, etc.
P. When a
well is reworked or the sanitary seal is removed, the drop pipe, jet line or
column pipe, pump/motor, etc., shall be cleaned and the well shall be
disinfected in accordance with Chapter XII of the State Sanitary
Code.
AUTHORITY NOTE:
Promulgated in accordance with R.S.
38:3091-38:309.8.
