Ill. Admin. Code tit. 62, § 1816.46 - Hydrologic Balance: Siltation Structures
a) Definitions. For the purpose of this
Section only:
1) Siltation structure means a
sedimentation pond, a series of sedimentation ponds, or other treatment
facility.
2) Disturbed area shall
not include those areas:
A) In which the only
surface mining activities include diversion ditches, siltation structures, or
roads that are designed, constructed, and maintained in accordance with this
Part; and
B) For which the upstream
area is not otherwise disturbed by the permittee.
3) Other treatment facilities means any
chemical treatments, such as flocculation, or mechanical structures, such as
clarifiers, that have a point-source discharge and that are utilized to prevent
additional contributions of suspended solids to stream flow or runoff outside
the permit area, or to comply with all applicable State and federal water
quality laws and regulations.
b) General Requirements
1) Additional contributions of suspended
solids sediment to stream flow or runoff outside the permit area shall be
prevented to the extent possible using the best technology currently
available.
2) All surface drainage
from the disturbed area shall be passed through a siltation structure before
leaving the permit area, except as provided in subsection (b)(5) or
(e).
3) Siltation structures for an
area shall be constructed before beginning any surface mining activities in
that area and, upon construction, shall be sealed by a qualified registered
professional engineer to be constructed as designed and as approved in the
reclamation plan.
4) Any siltation
structure which impounds water shall be designed, constructed, and maintained
in accordance with Section
1816.49.
5) Siltation structures shall be maintained
until removal is authorized by the Department and the disturbed area has been
stabilized and revegetated. In no case shall the structure be removed sooner
than two years after the last augmented seeding.
6) When a siltation structure is removed, the
land on which the siltation structure was located shall be regraded and
revegetated in accordance with the reclamation plan and Sections
1816.111
through
1816.117.
Sedimentation ponds approved by the Department for retention as permanent
impoundments shall be exempted from this requirement.
7) The Department encourages the retention of
sedimentation ponds which will receive drainage from agricultural areas in the
post-mining land use plan.
c) Sedimentation ponds
1) When used, sedimentation ponds shall:
A) Be used individually or in
series;
B) Be located as near as
possible to the disturbed area and out of perennial streams unless approved by
the Department in accordance with Section
1816.57;
and
C) Be designed, constructed,
and maintained to:
i) Provide adequate
sediment storage volume;
ii)
Provide adequate detention time to allow the effluent from the ponds to meet
effluent limitations specified in Section
1816.42;
iii) Contain or treat the ten year, 24 hour
precipitation event ("design event") unless a lesser design event is approved
by the Department based on terrain, climate, other site specific conditions,
and on a demonstration by the permittee that the effluent limitations of
Section
1816.42
will be met;
iv) Provide a
nonclogging dewatering device adequate to maintain the detention time required
under subsection (c)(1)(C)(ii);
v)
Minimize, to the extent possible, short circuiting;
vi) Provide periodic sediment removal
sufficient to maintain adequate volume for the design event;
vii) Ensure against excessive
settlement;
viii) Be free of sod,
large roots, frozen soil, and acid- or toxic-forming coal processing waste;
and
ix) Be compacted
properly.
2)
Spillways. A sedimentation pond shall include either a combination of principal
and emergency spillways or a single spillway configured as specified in Section
1816.49(a)(9)
of this Part.
d) Other
treatment facilities
1) Other treatment
facilities shall be designed to treat the ten year, 24 hour precipitation event
unless a lesser design event is approved by the Department based on terrain,
climate, other site specific conditions, and a demonstration by the permittee
that the effluent limitations of Section
1816.42
will be met.
2) Other treatment
facilities shall be designed in accordance with the applicable requirements of
subsection (c).
e)
Exemptions. Exemptions to the requirements to pass all drainage from disturbed
areas through a siltation structure may be granted if the disturbed drainage
area within the total disturbed area is small; and
1) Alternate sediment control measures as
described in Section
1816.45(b)
are used in lieu of a siltation structure, and the permittee demonstrates that
siltation structures are not necessary for drainage from the disturbed area to
meet the effluent limitations and water quality standards for the receiving
waters set forth in Section 1816.42; or
2) The permittee demonstrates that siltation
structures and alternate sediment control measures are not necessary for
drainage from the disturbed area to meet the effluent limitations and water
quality standards for the receiving waters set forth in Section
1816.42.
Notes
Amended at 24 Ill. Reg. 5967, effective March 21, 2000
State regulations are updated quarterly; we currently have two versions available. Below is a comparison between our most recent version and the prior quarterly release. More comparison features will be added as we have more versions to compare.
No prior version found.