Current through Register Vol. 47, No. 17, September 10, 2024
(1) Tanks at CAFOs
shall be operated and maintained so as not to discharge wastewater to ground
water.
(2) Impoundment liners
(a) An impoundment at a CAFO shall be
constructed and maintained to comply with one of the following standards, as
applicable:
(i) The seepage rate from an
impoundment shall not exceed 1 x 10-6 cm/sec;
or
(ii) Where approved by the
Division for an impoundment with an earthen liner that collects only open-lot
runoff, the seepage rate from the impoundment shall not exceed 7.35 x
10-6 cm/sec. The operator of the impoundment shall
submit to the Division a request that the impoundment be approved to meet this
seepage standard. Such a request shall include, but not be limited to,
information documenting that only open-lot wastewater will be diverted to the
impoundment, that the impoundment is not designed as an evaporation
impoundment, and that the ten foot soil depth zone immediately beneath the
impoundment has a cation exchange capacity of at least 15 meq/100 g of soil.
Demonstration of compliance with the cation exchange capacity criteria requires
the following:
(A) At least seven soil
samples shall be acquired from below the entire surface area of the impoundment
and analyzed for cation exchange capacity.
(B) The soil samples shall be reasonably
equidistant from each other, with five locations being within ten feet of, and
downslope of, the two-foot freeboard elevation of the impoundment, and two
locations from the middle of the impoundment.
(C) The operator shall have available a map
of the impoundment and soil sampling locations.
(D) Where soil samples were taken below
existing impoundments, the operator shall have available documentation from a
professional engineer registered in the State of Colorado of how the core
locations were sealed to meet a 1 x 10-6 cm/sec
maximum seepage rate.
(b) CAFO operators shall have available
documentation, including the supporting information required by section 81.7 ,
prepared by a professional engineer registered in Colorado certifying that the
provisions of section 81.7 have been met, and stating what constitutes each
constructed liner (e.g., synthetic, clay).
The liner certification and, where applicable (i.e., for
impoundments constructed after February 27, 2009), the seepage rate
calculations using Darcy's Law shall be available prior to wastewater entering
the impoundment.
(i) Copies of the
liner certification and supporting information shall be made available to the
Division or its designee, upon request.
For a newly constructed impoundment, submit the documents to
the Division by no later than 30 days after construction of the impoundment is
complete.
(c) A
CAFO operator shall visually inspect the exposed liner of an impoundment weekly
to identify physical changes or deficiencies that may affect the integrity of
the liner. Such deficiencies and physical changes shall be corrected 30 days of
having been identified.
(i) The operator
shall record the date of the inspection, deficiencies identified, corrective
actions taken, and dates that corrective action was completed.
(ii) Deficiencies not corrected within 30
days shall be accompanied by an explanation of the factors preventing
completion of corrective actions within this time period.
(iii) The records shall be maintained on-site
for five years from the date of creation and shall be made available to the
Division upon request.
(3) Removal of manure or wastewater from an
impoundment shall be accomplished in a manner that does not damage the
integrity of the liner. The operator shall submit to the Division for approval
a Standard Operating Procedure (SOP) that demonstrates how manure, including
sludge, will be removed such that the liner integrity of impoundments is not
damaged. The SOP also shall indicate the expected frequency with which manure
will be removed from impoundments.
(a) The
approved SOP must be available on-site and be submitted to the Division upon
request.
(b) The operator shall
follow the approved SOP whenever manure, including sludge, is removed. Where
the SOP was not followed, the Division may require that the operator make the
liner available for inspection. Where the Division has just cause as a result
of the inspection, the Division may require re-certification of the liner by a
professional engineer registered in Colorado.
(c) A CAFO shall submit the SOP no later than
120 days after animals are placed on the production area.
(i) The operator shall submit a revised SOP
for approval within 30 days of a change having been made to the impoundment(s)
at the facility that requires a revision of the SOP, such as a new impoundment
or different liner having been constructed.
(d) The operator shall certify after each
manure, or sludge removal event that the manure or sludge was removed in
accordance with the approved SOP.
(i) The
certifications must be available on-site and be submitted to the Division upon
request.
(ii) For a concrete-lined
impoundment, where a certification for each removal event is not completed, at
least once every five years the operator shall:
(A) Drain and clean the impoundment. The
operator shall use best professional judgment to determine whether the liner
integrity is capable of having a maximum seepage rate of 1 x
10-6 cm/sec.
(B) Where the operator determines that the
impoundment remains capable of having a maximum seepage rate of 1 x
10-6 cm/sec, the operator shall document the
determination within five days of the liner inspection. The documentation shall
include photographs supporting the determination.
(C) Where the operator determines the liner
integrity is damaged such that the impoundment is no longer capable of having a
maximum seepage rate of 1 x 10-6 cm/sec, the
operator shall:
(I) Repair the impoundment
within 30 days of the liner inspection so that the impoundment is capable of
having a maximum seepage rate of 1 x 10-6
cm/sec.
(II) Within 14 days of
repairing the impoundment, submit evidence of the properly completed repair to
the Division. The evidence shall consist either of photographs with
accompanying written documentation or of other evidence approved by the
Division.
(e) Where the SOP is not followed, the
operator shall provide notice to the Division within 30 days of the date of
manure removal.
(4) Any
depth marker in an impoundment shall be installed in a manner that maintains
the integrity of the liner and maintains the required seepage rate
standard.
(5) Wastewater Conveyance
Structures - Conveyance structures shall be designed and maintained to convey
but not store any manure or wastewater.
(a)
Conveyance structures that carry process-generated wastewater continuously (48
hours or less between conveyance events) shall be constructed and maintained to
have a maximum seepage rate of 1 x 10-6
cm/sec.
(b) Where upon inspection
the Division has just cause to determine that the required liner is not in
place, the Division may require that the operator submit to the Division a
certification that the conveyance structure meets the requirements of section
81.7 . The certification shall be made by a professional engineer registered in
the State of Colorado.
(6) Setbacks for New and Expanded
Impoundments - A new impoundment constructed after June 30, 2008, or an
existing impoundment that is expanded by 50 percent or more of existing storage
capacity after June 30, 2008, shall not be located:
(a) Except as provided below, where the
seasonally high ground water level is located within four feet of the bottom of
the impoundment liner; and
(i) Where the
seasonally high ground water level is located within four feet of the bottom of
the impoundment liner, the impoundment shall be constructed and maintained in
accordance with the design by a professional engineer registered in the state
of Colorado that accounts for hydrostatic pressure adversely affecting the
integrity of the impoundment's liner.
(b) Within 150 feet of a private domestic
water supply well or within 300 feet of a community domestic water supply
well.
(7) Ground Water
Monitoring - Where an impoundment is not in compliance with section 81.7 , or
where the Division determines that an impoundment liner is not being properly
maintained, the Division may require the operator to conduct site-specific
ground water quality monitoring of, but not limited to, total nitrogen,
ammonia-nitrogen, nitrate-nitrogen, and fecal coliform. In making a
determination of whether ground water monitoring is required, the Division
shall consider all pertinent factors, including but not limited to: whether the
impoundment poses a significant potential risk to beneficial uses of ground
water, whether there is suspected contamination of ground water attributable to
the facility, whether early detection of ground water contamination is
essential to protect valuable drinking water sources, and whether there has
been a significant failure on the part of the operator to comply with sections
81.7 , or (7).
(8) Ground Water
Remediation - When the Division determines that non-compliance with sections
81.7(2), (3), (4), (6), or (7) has caused, or contributed to, the exceedance of
established ground water quality standards, the operator shall:
(a) Submit, in consultation with the
Division, an approvable investigation plan within 60 days of being notified by
the Division of the exceedance, unless an extension of time is granted by the
Division based on good faith efforts made by the operator.
(i) The investigation plan must indicate how
the nature and extent of the contamination will be delineated and shall include
the following, at minimum:
(A) A plan to
determine the full vertical and horizontal extent of ground water
contamination.
(B) All potential
human and environmental receptors, including:
1) all surface water features including
springs, streams, and lakes that could be impacted; and
2) all municipal, agricultural, and domestic
ground water users.
(C)
A plan to obtain other site-specific hydrogeologic data necessary to fully
determine the nature and extent of the contamination. These shall include, as
appropriate, but not be limited to, the hydraulic conductivity of all
hydrogeologic units, associated porosity values, ground water flow directions,
regional and local hydraulic gradients, and pumping rates associated with all
wells. The Division may require that the operator install additional monitoring
wells for the purpose of fully determining the nature and extent of the
contamination.
(D) A reasonable
timeline for completing the investigation.
(ii) The operator shall implement the
investigation plan within 30 days of it being approved by the
Division.
(b) The
operator shall submit the following information by no later than 60 days after
completion of the approved investigation plan, unless an extension of time is
granted by the Division based on good faith efforts made by the operator:
(i) A summary report of the findings of the
investigation conducted pursuant to section 81.7(8)(a).
(ii) A comparison of all appropriate and
applicable remediation alternatives, including innovative technologies, the
associated performance and costs of each alternative, the estimated timelines
to achieve the required remediation goals and the monitoring that will be done
until the remediation goal(s) is reached. The Division shall review remediation
alternatives based on technological, economic and environmental risk factors.
In determining economic reasonableness, the Division shall take into account
such factors as costs of the various alternatives, the potential impact of the
alternatives on a project's profitability or competitive position and any
long-term energy impacts. In determining environmental risk factors the
Division will include potential exposures of sensitive human and environmental
receptors. In cases where sensitive human and environmental impacts could
occur, the Division may require interim, or emergency, remedial
activities.
(c) The
operator shall submit an approvable remediation plan by no later than 60 days
of being notified of the Division's preferred remediation alternative, unless
an extension of time is granted by the Division based on good faith efforts
made by the operator. The remediation plan shall contain designs and plans for
implementation of the preferred alternative.
(i) The operator shall implement the
remediation plan within 30 days of it being approved by the Division.
(9) Impoundment Closure
- The operator of a facility shall remove manure and wastewater from a closed
impoundment, to the fullest extent practicable within 60 days of the
impoundment being closed, unless an alternative timeline is approved by the
Division. Within 120 days of an impoundment being closed, an impoundment shall
be backfilled with soil that is graded to blend with surface topography and
prevent ponding, unless an alternative procedure and timeline is approved by
the Division.
