Current through Register Vol. 48, No. 9, September 27, 2024
a.
Class Three landfills shall be located in areas that can be demonstrated to
have the characteristics listed below (258.17.a. (1), a. (2), a. (3), and a.
(4)). The inability of a site to meet full compliance with these criteria may
not necessarily make the site unsuitable, but the applicant has the burden to
demonstrate to the satisfaction of the Department why variance from the
criteria will not compromise protection to human health and the environment. If
Department review finds the demonstration to be inadequate, the application may
be denied. Upon notification from the Department that the site meets the
requirements of this section, the applicant may submit a complete application
to the Department. This approval shall not be valid after a period of twelve
(12) months of the date of issuance if the complete application has not been
submitted, unless granted a variance by the Department.
(1) The site shall not be located in an area
where the hydrogeologic conditions allow the groundwater to migrate from
shallow geologic units that have little potential as an underground source of
drinking water, into deeper units. At the disposal area, any release to the
uppermost aquifer would remain in the uppermost aquifer until discharge into
the perennial stream nearest to the disposal area. The potentiometric head in
the shallow portion of the uppermost aquifer shall be equal to or lower than
the potentiometric head in the deeper portion of the uppermost aquifer (i.e., a
lateral or an upward hydraulic gradient shall exist).
(2) The estimated deflected (or settled)
bottom elevation of the landfill base grade shall be a minimum of three feet
above the seasonal high water table elevation as it exists prior to the
construction of the disposal area. The seasonal high water table shall be
determined by interpretation of a minimum of 12 months data obtained from a
representative number of monitoring wells approved by the Department. In cases
where there is insufficient information to support the seasonal high water
table elevation determination, additional separation may be required by the
Department.
(3) A minimum 10 foot
vertical separation of naturally occurring or engineered material shall be
maintained between the base of the constructed liner and bedrock; provided,
however, the nature of the material and sufficient separation exists to provide
for installation and operation of an effective groundwater monitoring system.
The nature of the material comprising this interval is subject to Department
approval.
(4) The landfill shall
not be located over an area where a stratum of limestone exhibiting secondary
permeability with an average thickness of greater than five feet lies within 50
feet of the base of the landfill.
b. Class Three landfills are prohibited in
areas where the permittee cannot demonstrate to the satisfaction of the
Department that:
(1) The Class Three landfill
is not located in a manner that would result in the destruction of a perennial
stream, within 200 feet of a perennial stream, within that portion of a
drainage basin included in a 2500 foot radius on the upstream side of a public
drinking water supply intake, and within that portion of a drainage basin which
is within 1000 feet of a lake, pond, or reservoir used as a source of public
drinking water supply; and,
(2) The
hydrogeologic properties of the site can be adequately characterized. The
characterization shall include, but not be limited to, a detailed description
of the geologic units below the site (including mineralogy, sedimentary
structures, thickness, continuity, and structure), the hydraulic properties of
each geologic unit (including secondary porosity and a discussion of variations
noted across the site), hydraulic gradient, hydraulic conductivity, and
direction and rate of groundwater flow within the uppermost aquifer system and
all interconnected aquifers and confining units using a groundwater flow net.
In addition, the relationship between the units below the site to locally and
regionally recognized geologic and hydrogeologic units shall be
described.
c. Class
Three landfills shall not be located over Class GA groundwater or over the
recharge area for Class GA groundwater as designated by the Department, over a
sole source aquifer, or over the recharge area for a sole source aquifer as
designated by the Department.
d.
All Class Three landfills shall demonstrate compliance with the groundwater
monitoring requirements pursuant to Subpart E.
