5 Colo. Code Regs. § 1002-81.7
Current through Register Vol. 47, No. 11, June 10, 2024
Section 5 CCR 1002-81.7 - GROUND WATER PROTECTION REQUIREMENTS - CAFO OPERATIONS (PERMITTED AND NON-PERMITTED)(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.40 CR 13, July 10, 2017, effective 7/31/2017