Sec. 7.
(a) The
owner, operator, or permittee of an MSWLF containing existing MSWLF units
constructed without a composite bottom liner shall install a final cover system
as appropriate to subsection (b) or (c) within one hundred eighty (180) days on
any area in the MSWLF units as approved in the closure plan that:
(1) has received the final waste volume;
or
(2) is filled to the approved
final waste elevation; or as approved under section 5(b) of this
rule.
(b) Unless
otherwise approved by the commissioner based on a final cover system providing
equivalent environmental protection, final cover systems for existing MSWLF
units constructed with a soil bottom liner and a leachate collection system
that were permitted under 329 IAC 2, which was repealed in 1996, and closing
after January 1, 1998, must consist of the following:
(1) On slopes equal to or less than fifteen
percent (15%) or eight and fifty-three hundredths (8.53) degrees, the final
cover must be constructed as follows:
(A) A
twenty-four (24) inch barrier layer of soil of the Unified Soil Classification
ML, CL, MH, CH, or OH directly over the waste. Other suitable material approved
by the commissioner may be used if it provides an adequate level of protection
to human health and the environment. The soil must be compacted to achieve a
hydraulic conductivity equal to 1 × 10-7 centimeters
per second or less. Grain size, Atterberg limits, and hydraulic conductivity
tests as approved by the commissioner or as required by this article must be
performed to confirm the quality of the final cover.
(B) A vegetative layer must overlay the top
protective layer. This layer must consist of at least six (6) inches of earthen
material capable of sustaining vegetation.
(2) On slopes greater than fifteen percent
(15%) or eight and fifty-three hundredths (8.53) degrees, the final cover must
be constructed as follows:
(A) A twenty-four
(24) inch barrier layer of soil of the Unified Soil Classification ML, CL, MH,
CH, or OH directly over the waste. Other suitable material approved by the
commissioner may be used if it provides an adequate level of protection to
human health and the environment. The soil must be compacted to achieve a
hydraulic conductivity equal to 1 × 10-6 centimeters
per second or less. Grain size, Atterberg limits, and hydraulic conductivity
tests as approved by the commissioner or as required by this article must be
performed to confirm the quality of the final cover.
(B) A vegetative layer consisting of at least
six (6) inches of earthen material capable of sustaining vegetation must
overlay the barrier layer.
(C) An
increase in the thickness of the layers required in this subdivision may be
required by the facility permit or the commissioner.
(3) The maximum projected erosion rate of the
final cover must be no more than five (5) tons per acre per year.
(4) The final cover must have a slope:
(A) no less than four percent (4%) or two and
twenty-nine hundredths (2.29) degrees; and
(B) no greater than thirty-three percent
(33%) or eighteen and twenty-six hundredths (18.26) degrees.
(c) Unless otherwise
approved by the commissioner based on a final cover system providing equivalent
environmental protection, final cover systems for existing MSWLF units
constructed without a soil bottom liner or a leachate collection system that
were permitted under 329 IAC 1.5, which was repealed in 1989, or 329 IAC 2,
which was repealed in 1996, and closing after January 1, 1998, must consist of
the following:
(1) On slopes equal to or less
than fifteen percent (15%) or eight and fifty-three hundredths (8.53) degrees,
the final cover not including benches, swales, and drainage features, must be
constructed as specified in section 6(b)(1) through 6(b)(7) of this
rule.
(2) On slopes greater than
fifteen percent (15%) or eight and fifty-three hundredths (8.53) degrees, the
final cover must be constructed as specified in subsection (b)(2).
(3) The maximum projected erosion rate of the
final cover must be no more than five (5) tons per acre per year.
(4) The final cover must have a slope:
(A) not less than four percent (4%) or two
and twenty-nine hundredths (2.29) degrees; and
(B) not greater than thirty-three percent
(33%) or eighteen and twenty-six hundredths (18.26) degrees.
