Current through Register Vol. 48, No. 38, September 20, 2024
a)
Performance Standard. The owner or operator of a CCR surface impoundment must
install a groundwater monitoring system that consists of a sufficient number of
wells, installed at appropriate locations and depths, to yield groundwater
samples that:
1) Accurately represent the
quality of background groundwater that has not been affected by leakage from a
CCR surface impoundment. A determination of background quality may include
sampling of wells that are not hydraulically upgradient of the CCR management
area where:
A) Hydrogeologic conditions do
not allow the owner or operator of the CCR surface impoundment to determine
what wells are hydraulically upgradient; or
B) Sampling at other wells will provide an
indication of background groundwater quality that is demonstratively as
representative or more representative than that provided by the upgradient
wells; and
2) Accurately
represent the quality of groundwater passing the waste boundary of the CCR
surface impoundment. The downgradient monitoring system must be installed at
the waste boundary that ensures detection of groundwater contamination. All
potential contaminant pathways must be monitored.
b) The number, spacing, and depths of
monitoring system wells must be determined based upon site-specific technical
information identified in the hydrogeologic site characterization conducted
under Section 845.620.
c) The
groundwater monitoring system must include a sufficient number of monitoring
wells necessary to meet the performance standards specified in subsection (a)
based on the site-specific information specified in subsection (b). The
groundwater monitoring system must contain:
1)
A minimum of one upgradient and three downgradient monitoring wells;
and
2) Additional monitoring wells
as necessary to accurately represent the quality of background groundwater that
has not been affected by leakage from the CCR surface impoundment and the
quality of groundwater passing the waste boundary of the CCR surface
impoundment.
d)
Multiunit Groundwater Monitoring System
1) The
owner or operator of multiple CCR surface impoundments may install a multiunit
groundwater monitoring system instead of separate groundwater monitoring
systems for each CCR surface impoundment.
2) The multiunit groundwater monitoring
system must be equally as capable of detecting monitored constituents at the
waste boundary of the CCR surface impoundment as the individual groundwater
monitoring system specified in subsections (a) through (c) for each CCR surface
impoundment, based on the following factors:
A) Number, spacing, and orientation of each
CCR surface impoundment;
B)
Hydrogeologic setting;
C) Site
history; and
D) Engineering design
of the CCR surface impoundment.
e) Monitoring wells must be properly
constructed in a manner consistent with the standards of 77 Ill. Adm. Code
920.170.
1) The owner or operator must document and
include in the facility's operating record the design, installation,
development, and decommissioning of any monitoring wells, piezometers and other
measurement, sampling, and analytical devices. The qualified professional
engineer must be given access to this documentation when completing the
groundwater monitoring system certification required by subsection
(g).
2) The monitoring wells,
piezometers, and other measurement, sampling, and analytical devices must be
operated and maintained so that they perform to the design specifications
throughout the life of the monitoring program.
f) The owner or operator of a new CCR surface
impoundment must submit a construction permit application containing
documentation showing that the groundwater monitoring system is designed to
meet the requirements of this Section. The owner or operator of all CCR surface
impoundments must submit an operating permit application containing
documentation showing that the groundwater monitoring system has been
constructed to meet the requirements of this Section.
g) The owner or operator must obtain a
certification from a qualified professional engineer stating that the
groundwater monitoring system has been designed and constructed to meet the
requirements of this Section. If the groundwater monitoring system includes the
minimum number of monitoring wells specified in subsection (c)(1), the
certification must document the basis supporting this determination. The
certification must be submitted to the Agency with the appropriate permit
application.
