Current through Vol. 41, No. 13, March 15, 2024
(a) Soil liners
shall be constructed to meet the following minimum requirements:
(1) Constructed in lifts or layers no more
than six (6) inches thick when compacted.
(A)
Soils used in the liner shall be free of foreign material, including trash,
brush, and fallen trees.
(B) All
side slopes and the floor of the retention structures shall be checked after
each lift to ensure proper compaction and moisture content. All readings shall
be recorded and properly documented. Minimum information required for
documentation shall include:
(i) Project
name.
(ii) Date.
(iii) Test method used per ASTM
specification.
(iv) Site name.
(v) Technician name.
(vi) Location of reading, include sketch.
(vii) Percent compaction
(viii) Wet density in pounds per
cubic foot (pcf).
(ix) Dry density
in pounds per cubic foot (pcf).
(x)
Moisture content, percent.
(xi)
Lift number.
(xii) Soils lab name,
report number, and Proctor Test results used to obtain field
measurements.
(2) Compaction to a minimum of ninety-five
percent (95%) of Standard Proctor (ASTM D 698) at optimum or wetter moisture
content.
(3) Hydraulic
conductivities of no greater than 1 x 10
-7 cm/sec. The field permeability of the
liner shall be verified by using one of the following methods:
(A) If a sealed Double Ring Infiltrometer is
used to determine the field permeability of the liner, at least one
representative location on each corner and one location in the center of the
waste retention structure bottom shall be selected for Double Ring
Infiltrometer determination.
(B) At
least four (4) representative undisturbed core samples, one from each corner of
the waste retention structure bottom shall be retrieved for permeability
determination in the laboratory. The permeability shall be determined using a
Flexible Wall Permeameter (ASTM D 5084).
(4) Minimum thickness of one and one half
(1.5) feet.
(5) Maximum hydrostatic
head of ten and one half (10.5) feet.
(6) Hydrostatic head or water depth may be
increased above ten and one half (10.5) feet in one of the following
circumstances:
(A) Liner thickness above the
minimum shall be increased by an amount needed to maintain the allowable
seepage rate, which shall not exceed eighty three one hundredths (0.83) feet
per year pursuant to Darcy's Velocity.
(B) Soils with permeabilities less than 1 x
10
-7 cm/sec are used to maintain the
allowable seepage rate, which shall not exceed eighty three one hundredths
(0.83) feet per year pursuant to Darcy's Velocity. Soils which do not meet the
maximum criteria of 1 x 10
-7 cm/sec can be mixed with a sufficient
amount of bentonite clay to achieve the desired standard.
(C) Any combination of (A) or (B). In no case
shall hydraulic conductivity be used to reduce the minimum thickness of one and
one half (1.5) feet or shall thickness be used to increase the maximum
hydraulic conductivity of 1 x 10
-7 cm/sec.
(b) The owner
shall maintain the liner to inhibit infiltration of wastewaters. Liners shall
be protected from burrowing and other animals by fences or other protective
devices. Liners shall also be protected from the potential root zone of all
trees.
(c) Any mechanical or
structural damage to the liner shall be evaluated by an environmental,
agricultural, or other Department approved professional engineer registered in
the state of Oklahoma within thirty (30) calendar days of the damage.
Documentation of liner maintenance shall be kept with the Pollution Prevention
Plan.
(d) Flexible membrane or
synthetic liners may be used in connection with a soil liner or as a substitute
for a soil liner. Geosynthetic liners and flexible membrane liners shall be
installed so as to protect waters of the State from contamination.
(1) The subgrade soil shall be prepared
according to the design standards. A subgrade verification form shall be
submitted with liner documentation.
(2) The surface to be lined shall be rolled
and compacted and free of irregularities, undulations, protrusions, vegetation,
excessive moisture, loose soil, or abrupt changes in slope.
(3) The subgrade surface shall be free of
foreign material including stones, cobbles, broken pieces of wood, plastic, or
glass.
(4) The owner shall provide
a copy of a completed Surface Acceptance Form indicating acceptable locations.
In no case shall the installer deploy any geomembrane or flexible membrane
liner in areas not acceptable within these rules.
(5) If at any time during the installation
the subgrade surface deteriorates or is damaged, or in any way deemed
unacceptable by the regulatory authority, all work shall stop until proper
repair is performed.
(6) The anchor
trench shall be constructed according to the standard industry practices. The
trench shall be adequately drained to prevent ponding or softening of the side
walls. After installation of the liner, the trench shall be back filled,
compacted, and anchored according to the standards.
(7) The liner placement plan shall take into
consideration the site drainage, low lying areas, temperature, and prevailing
wind velocity and direction. Field panels shall be deployed one at a time and
seamed as soon as possible to minimize the risk of wind or water damage.
(8) Field panel deployment shall
not proceed at an ambient temperature below forty degrees (40°) F, unless
Low Temperature Welding Procedures are used. All deployed panels should be
amply ballasted or sand bagged at all times to avoid wind damage.
(9) Personnel responsible for placement of
the liner shall not smoke, wear damaging shoes, or engage in other activities
which may cause damage to the liner. The method of deployment shall not cause
scratches, crimps, or tear the liner or damage the subgrade. Adequate sand bags
shall be placed on the edges of the liner to avoid wind uplifting.
(10) The installer shall visually inspect the
panels as soon as possible after deployment for damage or distressed surfaces.
(11) A seam is considered a
separate entity if it joins two panels. Repairs are not considered seams in
this context. Seams shall be generally oriented parallel to the line of maximum
slope, or along instead of across the slope. In corners and odd shaped
geometric locations the number of seams should be minimized.
(12) The Extrusion Process shall be used only
for repairs and patching and shall not be used for the overall operation. The
Fusion Process shall be used for seaming panels together using hot-wedge type
or solid wedge type automated self-propelled apparatus equipped with
temperature gauges.
(13) The
nondestructive seam continuity test shall be performed during daylight hours
and certified by the owner.
Added at 25 Ok Reg 1795,
eff 7-1-08; Amended at 29 Ok Reg 912, eff
7-1-12