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10 CSR 23-3.100 Sensitive
Areas
PURPOSE: This rule
sets specific additional standards for sensitive areas shown on the map
that have been designated on the basis of either naturally occurring problems
caused by unique groundwater chemistry or because they are located in
a fragile groundwater environment which is experiencing rapid population
growth or urbanization.
Editor's
Note: Area maps mentioned in this rule may be found following 10
CSR 23-3.110 on the MO-DNR Web site or
by clicking on the hyperlinks that are located within this Web page to
view specific Figures for the applicable area.
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(1) Sensitive Area A.
All persons engaged in drilling wells in this area (Figure
8) and encounter Pennsylvanian shales and/or sandstones shall-
(A) Set no less than eighty
feet (80') of casing extending not less than thirty feet (30') into bedrock
where Pennsylvanian shale and sandstone are not present and no less than one
hundred fifty feet (150') of casing extending not less than thirty feet (30')
into bedrock where the Pennsylvanian shale and sandstone are present;
(B) Construct the drillhole
a minimum of eight and five-eighths inches (8 5/8") in diameter to the surface
casing point;
(C) Install new steel
or plastic casing as specified in 10
CSR 23-3.030 (steel) or 10
CSR 23-3.070 (plastic);
(D) Install and seal casing
as follows:
1. Full-length grout
is preferred and will ensure a better annular seal but sealing the lowermost
thirty feet (30') of casing using approved grout materials and procedures
set out in 10
CSR 23-3.030 is required. Drill cuttings and a drive shoe or drill cuttings
used by themselves are not approved grout materials. Drill cuttings may
be placed above grouted interval to fill in the annular space-
A. If steel casing
is used, a drive shoe is required except on wells where the grout is allowed
to cure before drilling resumes; and
B. If plastic casing
is used, a packer, coupling or inverted bell is required to be secured
near the bottom of the casing and must hold the grout in place while drilling
continues. No packer, coupling or inverted bell is required if grout is
allowed to cure before drilling resumes; and
2. The following times
must be followed for curing grout when no packer is used:
A. Hi-early cement-minimum
set time of twelve (12) hours;
B. Portland
Type I cement-minimum set time of seventy-two (72) hours;
C. Chipped bentonite-minimum
hydration time of four (4) hours; and
D. High solids
bentonite slurry- varies based on additives and manufacturer's specifications.
(2) Sensitive Area B.
Wells drilled within one-quarter (1/4) mile of the major lakes in Missouri (Figure
8) (see list of lakes) must be cased so that they do not produce
lake water into their wells. Wells drilled within one-quarter (1/4) mile of
the major lakes that are not drilled below normal pool level of the lake are
not required to meet sensitive Area B requirements. These wells must be constructed
to Area 1 requirements stated in 10
CSR 23-3.090(1). The following specifications shall be followed:
(A) List of Lakes-
1. Truman;
2. Stockton;
3. Table Rock;
4. Bull Shoals;
5. Lake of the Ozarks;
6. Wappappello;
7. Pomme de Terre;
8. Norfolk; and
9. Clearwater.
(B) If the well is to
be drilled closer than one-quarter (1/4) mile to the shoreline of the lake,
casing must be set to a point fifty feet (50') below the bottom of the lake.
The deepest part of the lake within one-quarter (1/4) mile radius from the
well location shall be used in this determination. Example: If the drill site
is located one thousand feet (1,000') from the lake, is located fifty feet
(50') higher in elevation than the shoreline and the deepest estimated bottom
of the lake within one-quarter (1/4) mile from the well is thirty feet (30')
deep, then one hundred and thirty feet (130') of casing must be set. Fifty
feet (50') (elevation above lake) + thirty feet (30') (depth of water) + fifty
feet (50') (below lake bottom) = one hundred thirty feet (130') casing;
(C) It is highly recommended
that before a well is drilled that is located closer than one-quarter (1/4)
mile to the shoreline of any major lake, a casing point request form (supplied
by the division) be submitted to the division. The casing point request form
will be used to establish the required amount of casing and will supply information
on requested water yield amounts and corresponding total depth of well. To
ensure the location of the proposed drill site a copy of the landowner's property
deed showing detailed location information and a copy of the landowner's plat
(if available) showing proposed drilling site location, must be attached to
completed casing point request form. The casing point request form will be
processed quickly and returned to the landowner or driller, or both. After
the well is drilled the casing point request form must be submitted with the
certification form. If a well is drilled within one-quarter (1/4) mile of
one (1) of the lakes contained in section (2) and less than the required amount
of casing is set, the well installation contractor must bring the well up
to the standards set in this rule and will be subject to disciplinary action
deemed necessary by the division;
(D) A minimum of eighty
feet (80') of casing must be set;
(E) The drill hole shall
be constructed a minimum of eight and five-eighths inches (8 5/8") in diameter
to the surface casing point;
(F) The new steel or plastic
casing shall be installed as specified in 10
CSR 23-3.030 (steel) or 10
CSR 23-3.070 (plastic);
(G) The casing shall be
installed and scaled as follows:
1. Full-length grout
is preferred and will ensure a better annular seal but sealing the lowermost
thirty feet (30') of casing using approved grout materials and procedures
set out in 10
CSR 23-3.030 is required. Drill cuttings and a drive shoe or drill cuttings
used by themselves are not approved grout materials. Drill cuttings may
be placed above grouted interval to fill in the annular space;
A. If steel casing
is used, a drive shoe is required except on wells where the grout is allowed
to cure before drilling resumes;
B. If plastic casing
is used, a packer, coupling or inverted bell is required near the bottom
of the casing and must hold the grout in place while drilling continues.
No packer, coupling or inverted bell is required if grout is allowed to
cure before drilling resumes;
C. The following time
must be followed for curing grout when no packer is used:
(I) Hi-early cement-minimum
set time of twelve (12) hours;
(II) Portland Type I cement-minimum set time of seventy-two (72) hours;
(III) Chipped bentonite-minimum hydration time of four (4) hours; and
(IV) High solids bentonite slurry- varies based on additives and manufacturer's
specifications; and
(H) In areas that have
water quality problems that would be aggravated by the use of steel casing,
plastic casing is recommended. If it is necessary to set steel casing due
to geologic reasons, the following may substitute for casing:
1. Set no less than
eighty feet (80') of casing; and
2. Liner must be set
through the casing to point as determined in subsection (1)(C). Example:
If the casing point was determined to be one hundred and eighty feet (180'),
one hundred and eighty feet (180') of liner must be set. The liner must
meet all requirements as stated in 10
CSR 23-3.080, including grouting.
(3) Sensitive Area C.
The Springfield area is one in which urbanization is occurring at a rapid rate
in an extremely sensitive and fragile geologic and hydrologic setting. The area
is underlain by fractured, and cavernous limestone and pollutants are able to
migrate quickly, both vertically and horizontally. Because of these factors,
it is necessary to treat this area differently than surrounding areas and have
stricter well construction standards. All persons engaged in drilling of wells
in the sensitive area C (Figure
8) shall-
(A) The casing shall be
set as determined by Area C casing depth map. When drilling in Sensitive Area
C, it is strongly recommended that a casing point request be submitted so
that the exact amount of casing can be set, limiting the amount of grout required.
Approval must be obtained before drilling begins. Area C casing depth map
sets the minimum amount of required casing that will extend at least ten feet
(10') below the Northview Shale. Due to surface elevation changes within the
quarter (1/4) section (one-quarter (1/4) mile), the amount of casing stated
on the casing depth map may extend more than ten feet (10') below the bottom
of the Northview Shale. In those instances, where the casing extends more
than ten feet (10') below the bottom of the Northview Shale, more than thirty
feet (30') of grout is required to seal off the Northview Shale. See 10 CSR
23-3.100(3)(D);
(B) The drillhole shall
be constructed a minimum of eight and five-eighths inches (8 5/8") in diameter
to the surface casing point;
(C) New steel or plastic
casing shall be installed as specified in 10
CSR 23-3.030 (steel) or 10
CSR 23-3.070 (plastic);
(D) Full-length grout
is preferred and will ensure a better annular seal but sealing the lowermost
thirty feet (30') of casing using approved grout materials and procedures
set out in 10
CSR 23-3.030 is required if the casing does not go more than ten feet
(10') below the bottom of the Northview Shale. Due to surface elevation changes
within the quarter (1/4) section (one-quarter (1/4) mile), the amount of casing
required is calculated at the highest elevation. Therefore, if a well is drilled
in a lower elevation area, the required casing will go more than ten feet
(10') below the bottom of the Northview Shale. In many cases, thirty feet
(30') of grout will not seal off the Northview Shale since the bottom of the
casing is much deeper. The Northview Shale interval must be grouted from ten
feet (10') below to the top of the shale regardless of the amount of casing
set. A minimum of thirty feet (30') of grout is required. Drill cuttings and
a drive shoe or drill cuttings used by themselves are not approved grout materials.
Drill cuttings may be placed above grouted interval to fill in the annular
space. Install and seal casing as follows:
1. If steel casing is
used, a drive shoe is required except on wells where the grout is allowed
to cure before drilling resumes;
2. If plastic casing
is used, a packer, coupling or inverted bell is required to be secured near
the bottom of the casing and must hold the grout in place while drilling
continues. No packer, coupling or inverted bell is required if grout is
allowed to cure before drilling resumes; and
3. The following times
must be followed for curing grout when no packer is used:
A. Hi-early cement-minimum
set time of twelve (12) hours;
B. Portland Type I cement-minimum set time of seventy-two (72) hours;
C. Chipped bentonite-minimum hydration time of four (4) hours; and
D. High solids bentonite slurry- varies based on additives and manufacturer's
specifications; and
(E) In areas that have
water quality problems that would be aggravated by the use of steel casing,
plastic casing is recommended. If it is necessary to set steel casing due
to geologic reasons, the following may substitute for casing:
1. No less than one
hundred feet (100') of casing shall be set. The drill hole shall be constructed
a minimum of eight and five-eighths inches (8 5/8") in diameter and new
six-inch (6") inside diameter steel casing shall be installed as specified
in 10
CSR 23-3.030. A six-inch (6") hole is then drilled to total depth and
a plastic liner having an outside diameter no greater than four and one-half
inches (4 1/2") shall be secured into place. No variances will be issued
for this requirement; and
2. Liner must be set
through the casing to the required casing point. The liner must be set to
the casing depth as determined by Area C casing depth map. The liner must
meet all requirements as stated in 10
CSR 23-3.080 concerning liners, including grouting. More than sixty
feet (60') of grout may be required as stated in 10 CSR 23-3.100(3)(D).
(4) Special Area.
Due to the unique and varied geological conditions present because the bedrock
is deeply weathered and often highly fractured, openings filled with mud may
extend deep into the bedrock. Caving-in of the hole during drilling and after
well construction is a problem. The following rules are the minimum that are
required but in many cases much more steel casing may be necessary to secure
the well bore. Also, in some cases plastic liner is not strong enough to hold
the well bore open and steel should be used. All persons engaged in the drilling
of a domestic well in special area 1 (see Figure
1 and Figure
7 included herein) shall-
(A) Set no less than
eighty feet (80') of casing. The hole shall be cased fifteen feet (15')
below residuum, broken rock, or mud pockets into solid bedrock or if rock
is not encountered within one hundred and fifty feet (150') consult the
division for further instructions concerning a variance, unless casing will
be set into deeper bedrock;
(B) Construct the drill
hole a minimum of eight and five-eighths inches (8 5/8") in diameter to
the surface casing point;
(C) Install new steel
casing as specified in 10
CSR 23-3.030. Plastic casing of any type will not be allowed in this
area; and
(D) Install and seal
casing as follows:
1. Full-length grout
is highly recommended and will ensure a better annular seal but sealing
the lowermost thirty feet (30') of casing using approved grout materials
and procedures set out in 10
CSR 23-3.030 is required. Drill cuttings with a drive shoe or drill
cuttings used by themselves are not approved grout materials. Drill cuttings
may be placed above grouted interval to fill in the annular space;
2. A drive shoe is
required except on wells where the grout is allowed to cure before drilling
resumes. A. The following times must be followed for curing grout when
no packer is used:
(I) Hi-early cement-minimum
set time of twelve (12) hours;
(II) Portland Type I cement-minimum set time of seventy-two (72) hours;
(III) Chipped bentonite-minimum hydration time of four (4) hours;
(IV) High
solids bentonite slurry- varies based on additives and manufacturer's
specifications; and
3. If drilling conditions
do not permit a bottom seal, then the casing must be driven and grouting
material introduced around the outside casing while the casing is being
driven. If the casing cannot be sealed to prevent surface contamination
from entering the well, a liner must be set and sealed according to 10
CSR 23-3.080.
(E) In areas where poor
drilling conditions exist and it is necessary to drive multiple strings
of smaller diameter casing through the surface casing, each succeeding liner
should extend into the preceding liner or casing at least twenty feet (20')
and the annulus created between the casing and liner must be grouted.
(F) In wells where it
is necessary to set casing below static water levels, it may be advisable
to set plastic liner as stated in 10
CSR 23-3.080 from the surface to a point below the pumping water level
to avoid excessive iron in the produced well water.
(5) Special Area 2
Definitions.
(A) "Lower aquifer"
means that portion of transmissive, water-bearing geologic material extending
from the Cotter Dolomite to igneous bedrock. The lower aquifer includes
all formations constituting the Ozark Aquifer and the St. Francois Aquifer
in the southwestern portion of the state.
(B) "Low-permeability
bedrock" means that portion of geologic material between the lower aquifer
and upper aquifer that does not readily transmit water in sufficient quantities
to supply a well. The Northview Formation, the Chattanooga Shale, and the
upper thirty feet (30') of the Cotter Dolomite shall constitute the low-permeability
bedrock. The low permeability bedrock serves as a natural barrier to groundwater
mixing between the upper aquifer and lower aquifer. See Figure
7A included herein for an illustration of geology in Special
Area 2.
(C) "Upper aquifer"
means that portion of the transmissive, water-bearing geologic material
above the top of the low-permeability bedrock. The upper aquifer includes
all formations constituting the Springfield Plateau Aquifer in the southwestern
portion of the state.
(D) "Maximum contaminant
level (MCL)" is the maximum permissible concentration of a contaminant in
drinking water as listed by the National Primary Drinking Water Regulations
(NPDWR).
(E) "Action level (AL)"
is the maximum permissible concentration of lead in drinking water as specified
in the Code of Federal Regulations. ALs are levels used for contaminants
that do not have established MCLs.
(F) "TCE" shall mean
the organic chemical trichloroethylene (a common solvent) and its known
degradation products, including but not limited to dichloroethylene and
vinyl chloride.
(G) "Impact area" is
defined as that land surface area that is underlain or surrounded by water-bearing
units that contain groundwater above the MCL or AL for at least one (1)
contaminant of concern (lead, cadmium, TCE or TCE degradation products,
or other contaminants of the NPDWR). Standard contouring methodology shall
be used to delineate the MCL and AL isoconcentration line, which will define
the geographic limit of an impact area.
(6) Special Area 2.
All of Newton County and Jasper County shall be listed as Special Area 2 (Figure
7B included herein) due to the contamination of portions of the
upper aquifer by one (1) or more of the following: lead, cadmium, TCE, TCE degradation
products or other contaminants of the NPDWR. The upper aquifer and lower aquifer
are separated by a thickness of low-permeability bedrock (Figure
7A). This low-permeability bedrock limits migration of groundwater
and any associated contamination from the upper aquifer to the lower aquifer.
Wells that penetrate the low-permeability bedrock without an adequate length
of surface casing which has had the annulus sealed by approved methods through
the low-permeability bedrock may place the lower aquifer at risk to future contamination.
Due to chemical and metal contamination present in the upper aquifer in portions
of this area, it is necessary to require more stringent well construction standards
for new wells that are drilled into the lower aquifer, to cease construction
of additional upper aquifer wells in impact areas, and to limit deepening of
existing upper aquifer wells in impact areas. New wells constructed outside
of the impact area shall be constructed to standards that are no less stringent
than the minimum well construction requirements for Area 1. All persons engaged
in drilling wells in Special Area 2 shall-
(A) Before beginning construction
of the well, determine if the well to be drilled is located within the impact
area as shown on maps provided by the division or as determined by division
staff. If data indicate change in impact area status, the impact area map
may be modified by the division during January of the calendar year and that
map will be maintained and available at: Department of Natural Resources,
PO Box 250, Rolla, MO 65402-0250.
(B) Drill new wells within
the impact area to a depth required to produce water from the lower aquifer.
All new wells drilled in the impact area shall have steel or plastic casing
properly installed and grouted to the depth determined by the Special Area
2 casing depth map.
1. The drill hole shall
be a minimum of eight and five-eighths inches (8 5/8") in diameter to the
surface casing point;
2. New steel casing
shall be installed as specified in 10
CSR 23-3.030 (steel);
3. The well must be
sealed by positive displacement grouting with high-solids bentonite slurry.
The annulus between the casing and the borehole wall shall be grouted from
the base of the borehole. The volume of grout shall be no less than the
calculated volume necessary to accomplish full-length grouting of the annulus.
Alternatively, full-length pressure grouting (10
CSR 23-3.030(3)(A)4.) with high-solids bentonite slurry or neat cement
meets the requirements of this rule. In addition, casing must be sealed
as follows:
A. When steel casing
is used, a drive shoe is required except on wells where the grout is allowed
to cure as specified in subparagraph (6)(B)3.C. of this rule before drilling
resumes;
B. If plastic casing
is used, a drill hole shall be constructed a minimum of ten inches (10")
in diameter to the casing point. Plastic casing shall be installed as
specified in 10
CSR 23-3.070 (plastic) and, a packer, coupling, or inverted bell is
required to be secured near the bottom of the casing and must hold the
grout in place while drilling continues. PVC and ABS plastic casing shall
not be used when known gasoline or solvent contamination exists within
the impact area. The annular space shall be sealed as specified in paragraph
(6)(B)3. of this rule. No packer, coupling, or inverted bell is required
on wells where the grout is allowed to cure as specified in subparagraph
(6)(B)3.C. of this rule before drilling resumes; and C. The following
times must be allowed for curing grout when no packer is used:
(I) High-solids
bentonite slurry- varies based on additives and manufacturer's specifications.
At least one hour of curing after initial slurry placement is suggested.
This amount of curing time should elapse during casing placement.
(C) Uncontaminated upper
aquifer wells in impact areas of Special Area 2 existing before the date of
this rule may be deepened to the top of the low-permeability bedrock.
(D) Water from all new
wells and deepened old wells throughout Special Area 2 shall be sampled and
analyzed for lead and cadmium, plus TCE and its degradation products within
TCE impact areas. Where indicated by objective factors, the division may require
sampling and analysis for other contaminants listed in the NPDWR. Qualified
and properly trained persons must complete sample collection. The laboratory
that analyzes the sample must be approved by the EPA for such analysis. A
copy of the chain of custody form shall be submitted to the division with
the well certification report form to document sampling has occurred. An appropriate
chain of custody form will be available from the division.
1. In order to ensure
proper well development, the well pump must run continuously for five (5)
hours or until the water clears, whichever occurs first, but in no case
shall the well be pumped less than two (2) continuous hours.
2. After proper well
development, water samples shall be collected from the tap nearest the well.
3. All new and deepened
old wells in Special Area 2 shall be constructed with a sampling port or
tap within ten feet (10') of the wellhead. Water must be purged from the
sampling port prior to collection of a sample.
4. Water from all new
wells in Special Area 2 with less than three (3) times the applicable maximum
contaminant level (MCL) or action level (AL) may be retested over a one
(1)-month period following pump installation and development to assess water
quality changes that may have resulted from drilling and/or well construction.
The well cannot be used for human consumption until contaminant levels are
below MCLs or ALs. Qualified and properly trained persons must complete
sample collection. The laboratory that analyzes the sample must be approved
by the EPA for such analysis. A copy of the chain of custody form shall
be submitted to the division with the well certification report form to
document sampling has occurred. An appropriate chain of custody form will
be available from the division. The division may require any new well, whose
contaminant levels do not fall below MCLs or Als after the retest period,
to be plugged.
5. Properly constructed
new lower aquifer wells that are determined to be contaminated may be allowed
to use water treatment systems on a variance basis, if other domestic water
sources are not available at the time of well construction. Otherwise, the
well must be plugged by using full-length, high-solids bentonite grout emplaced
by tremie pipe which extends to within twenty-five feet (25') of the bottom
of the borehole. Grout, extending from the bottom of the borehole to within
two feet (2') of land surface and finished per 10
CSR 23-3.110 (2)(A)3.G., is preferred; in any case, the minimum volume
of grout shall be no less than the volume calculated as necessary to accomplish
full length plugging of the well.
6. Existing wells that
extend uncased and/or unsealed through the low-permeability bedrock and
that are found to be contaminated with lead, or cadmium, or TCE, TCE degradation
products, or other contaminants of the NPDWR may be required to be plugged
full-length with high-solids bentonite grout, emplaced by tremie pipe, which
extends to within twenty-five feet (25') of the bottom of the borehole.
Grout, extending from the bottom of the borehole to within two feet (2')
of land surface and finished per 10 CSR
23-3.110(2)(A)3.G., is preferred; in any case, the minimum volume of
grout shall be no less than the volume calculated as necessary to accomplish
full-length plugging of the well.
AUTHORITY: sections 256.606 and 256.626, RSMo Supp. 1991.* Original rule filed April 2, 1987, effective July 27, 1987. Emergency amendment filed Nov. 16, 1993, effective Dec. 11, 1993, expired April 9, 1994.
Amended: Filed Aug. 17, 1993, effective March 10, 1994.
*Original authority: 256.606, RSMo 1991 and 256.626, RSMo 1985, amended 1991
MO
Dept. of Natural Resources: CODE OF STATE REGULATIONS - Matt Blunt (11/30/01)
Secretary of State
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