(a) Owners or operators of all MSWLF units must install a final cover system that is designed to minimize infiltration and erosion. The final cover system must be designed and constructed to:

(1) Have a permeability less than or equal to the permeability of any bottom liner system or natural subsoils present, or a permeability no greater than 1 × 10−5 cm/sec, whichever is less, and

(2) Minimize infiltration through the closed MSWLF by the use of an infiltration layer that contains a minimum 18-inches of earthen material, and

(3) Minimize erosion of the final cover by the use of an erosion layer that contains a minimum 6-inches of earthen material that is capable of sustaining native plant growth.

(b) The Director of an approved State may approve an alternative final cover design that includes:

(1) An infiltration layer that achieves an equivalent reduction in infiltration as the infiltration layer specified in paragraphs (a)(1) and (a)(2) of this section, and

(2) An erosion layer that provides equivalent protection from wind and water erosion as the erosion layer specified in paragraph (a)(3) of this section.

(3) The Director of an approved State may establish alternative requirements for the infiltration barrier in a paragraph (b)(1) of this section, after public review and comment, for any owners or operators of MSWLFs that dispose of 20 tons of municipal solid waste per day or less, based on an annual average. Any alternative requirements established under this paragraph must:

(i) Consider the unique characteristics of small communities;

(ii) Take into account climatic and hydrogeologic conditions; and

(iii) Be protective of human health and the environment.

(c) The owner or operator must prepare a written closure plan that describes the steps necessary to close all MSWLF units at any point during their active life in accordance with the cover design requirements in § 258.60(a) or (b), as applicable. The closure plan, at a minimum, must include the following information:

(1) A description of the final cover, designed in accordance with § 258.60(a) and the methods and procedures to be used to install the cover;

(2) An estimate of the largest area of the MSWLF unit ever requiring a final cover as required under § 258.60(a) at any time during the active life;

(3) An estimate of the maximum inventory of wastes ever on-site over the active life of the landfill facility; and

(4) A schedule for completing all activities necessary to satisfy the closure criteria in § 258.60.

(d) The owner or operator must notify the State Director that a closure plan has been prepared and placed in the operating record no later than the effective date of this part, or by the initial receipt of waste, whichever is later.

(e) Prior to beginning closure of each MSWLF unit as specified in § 258.60(f), an owner or operator must notify the State Director that a notice of the intent to close the unit has been placed in the operating record.

(f) The owner or operator must begin closure activities of each MSWLF unit no later than 30 days after the date on which the MSWLF unit receives the known final receipt of wastes or, if the MSWLF unit has remaining capacity and there is a reasonable likelihood that the MSWLF unit will receive additional wastes, no later than one year after the most recent receipt of wastes. Extensions beyond the one-year deadline for beginning closure may be granted by the Director of an approved State if the owner or operator demonstrates that the MSWLF unit has the capacity to receive additional wastes and the owner or operator has taken and will continue to take all steps necessary to prevent threats to human health and the environmental from the unclosed MSWLF unit.

(g) The owner or operator of all MSWLF units must complete closure activities of each MSWLF unit in accordance with the closure plan within 180 days following the beginning of closure as specified in paragraph (f) of this section. Extensions of the closure period may be granted by the Director of an approved State if the owner or operator demonstrates that closure will, of necessity, take longer than 180 days and he has taken and will continue to take all steps to prevent threats to human health and the environment from the unclosed MSWLF unit.

(h) Following closure of each MSWLF unit, the owner or operator must notify the State Director that a certification, signed by an independent registered professional engineer or approved by Director of an approved State, verifying that closure has been completed in accordance with the closure plan, has been placed in the operating record.

(i)(1) Following closure of all MSWLF units, the owner or operator must record a notation on the deed to the landfill facility property, or some other instrument that is normally examined during title search, and notify the State Director that the notation has been recorded and a copy has been placed in the operating record.

(2) The notation on the deed must in perpetuity notify any potential purchaser of the property that:

(i) The land has been used as a landfill facility; and

(ii) Its use is restricted under § 258.61(c)(3).

(j) The owner or operator may request permission from the Director of an approved State to remove the notation from the deed if all wastes are removed from the facility.

[56 FR 51016, Oct. 9, 1991; 57 FR 28628, June 26, 1992, as amended at 62 FR 40713, July 29, 1997]

(a) Following closure of each MSWLF unit, the owner or operator must conduct post-closure care. Post-closure care must be conducted for 30 years, except as provided under paragraph (b) of this section, and consist of at least the following:

(1) Maintaining the integrity and effectiveness of any final cover, including making repairs to the cover as necessary to correct the effects of settlement, subsidence, erosion, or other events, and preventing run-on and run-off from eroding or otherwise damaging the final cover;

(2) Maintaining and operating the leachate collection system in accordance with the requirements in § 258.40, if applicable. The Director of an approved State may allow the owner or operator to stop managing leachate if the owner or operator demonstrates that leachate no longer poses a threat to human health and the environment;

(3) Monitoring the ground water in accordance with the requirements of subpart E of this part and maintaining the ground-water monitoring system, if applicable; and

(4) Maintaining and operating the gas monitoring system in accordance with the requirements of § 258.23.

(b) The length of the post-closure care period may be:

(1) Decreased by the Director of an approved State if the owner or operator demonstrates that the reduced period is sufficient to protect human health and the environment and this demonstration is approved by the Director of an approved State; or

(2) Increased by the Director of an approved State if the Director of an approved State determines that the lengthened period is necessary to protect human health and the environment.

(c) The owner or operator of all MSWLF units must prepare a written post-closure plan that includes, at a minimum, the following information:

(1) A description of the monitoring and maintenance activities required in § 258.61(a) for each MSWLF unit, and the frequency at which these activities will be performed;

(2) Name, address, and telephone number of the person or office to contact about the facility during the post-closure period; and

(3) A description of the planned uses of the property during the post-closure period. Post-closure use of the property shall not disturb the integrity of the final cover, liner(s), or any other components of the containment system, or the function of the monitoring systems unless necessary to comply with the requirements in this part 258. The Director of an approved State may approve any other disturbance if the owner or operator demonstrates that disturbance of the final cover, liner or other component of the containment system, including any removal of waste, will not increase the potential threat to human health or the environment.

(d) The owner or operator must notify the State Director that a post-closure plan has been prepared and placed in the operating record no later than the effective date of this part, October 9, 1993, or by the initial receipt of waste, whichever is later.

(e) Following completion of the post-closure care period for each MSWLF unit, the owner or operator must notify the State Director that a certification, signed by an independent registered professional engineer or approved by the Director of an approved State, verifying that post-closure care has been completed in accordance with the post-closure plan, has been placed in the operating record.

[56 FR 51016, Oct. 9, 1991; 57 FR 28628, June 26, 1992]

(a) Lake County Municipal Landfill final cover requirements. Paragraph (a) of this section applies to the Lake County Landfill, a municipal solid waste landfill owned and operated by Lake County on the Confederated Salish and Kootenai Tribes' Flathead Reservation in Montana. The alternative final cover request submitted by Lake County, Montana, consisting of the “Lake County Landfill Alternative Cover,” dated May 2007, the “Construction Quality Assurance & Control Plan for the Lake County Class II Landfill Unit Landfill Closure Project” and the “Lake County Landfill Plans for Final Closure January 2009,” dated January 2009, is hereby incorporated by reference. The Director of the Federal Register approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 Cspan part 51. You may inspect or obtain a copy at the Environmental Protection Agency, Region VIII, Montana Office, 10 West 15th St., Suite 3200, Helena, MT or by calling 406-457-5000. You may also inspect a copy at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. The facility owner and/or operator may close the facility in accordance with this application, including the following activities more generally described as follows:

(1) The owner and operator may install an evapotranspiration system as an alternative final cover for the 15.4 acre active area.

(2) The final cover system shall consist of a 5.5-feet-thick multi-layer cover system comprised, from bottom to top, of an 18-inch intermediate and gas vent layer, a 24-inch native sand layer, an 18-inch imported silt layer and a 6-inch topsoil layer, as well as seeding and erosion control.

(3) The final cover system shall be constructed to achieve an equivalent reduction in infiltration as the infiltration layer specified in § 258.60(a)(1) and (a)(2), and provide an equivalent protection from wind and water erosion as the erosion layer specified in paragraph (a)(3) of this section.

(4) In addition to meeting the specifications of the “Lake County Landfill Alternative Cover” dated May 2007, and the “Construction Quality Assurance & Control Plan for the Lake County Class II Landfill Unit Landfill Closure Project” dated January 2009, the owner and operator shall:

(i) At 50% final design, submit to EPA for approval an Operations and Maintenance Plan that includes an inspection schedule (at least quarterly) and remediation plan to address any potential rodent damage to the final cover; and

(ii) Achieve re-vegetation rates greater than 50% by the end of the first season and a complete stand of native grasses by the end of the third season.

(5) The owner and operator shall place documentation demonstrating compliance with the provisions of this Section in the operating record.

(6) All other applicable provisions of 40 Cspan part 258 remain in effect.

(b) Picacho Municipal Solid Waste Landfill—alternative list of detection monitoring parameters and alternative final cover. This paragraph (b) applies to the Picacho Landfill, a Municipal Solid Waste Landfill operated by Imperial County on the Quechan Indian Tribe of the Fort Yuma Indian Reservation in California.

(1) In accordance with § 258.54(a), the owner and operator may modify the list of heavy metal detection monitoring parameters specified in appendix I of this part, as required during Post-Closure Care by § 258.61(a)(3), by replacing monitoring of the inorganic constituents, with the exception of arsenic, with the inorganic indicator parameters chloride, nitrate as nitrogen, sulfate, and total dissolved solids.

(2) In accordance with § 258.60(b), the owner and operator may replace the prescriptive final cover set forth in § 258.60(a), with an alternative final cover as follows:

(i) The owner and operator may install an evapotranspiration cover system as an alternative final cover for the 12.5 acre site.

(ii) The alternative final cover system shall be constructed to achieve an equivalent reduction in infiltration as the infiltration layer specified in § 258.60(a)(1) and (2), and provide an equivalent protection from wind and water erosion as the erosion layer specified in § 258.60(a)(3).

(iii) The final cover system shall consist of a minimum three-foot-thick multi-layer cover system comprised, from bottom to top, of:

(A) A minimum 30-inch thick infiltration layer consisting of:

(1) Existing intermediate cover; and

(2) Additional cover soil which, prior to placement, shall be wetted to optimal moisture and thoroughly mixed to near uniform condition, and the material shall then be placed in lifts with an uncompacted thickness of six to eight inches, spread evenly and compacted to 90 percent of the maximum dry density, and shall:

(i) Exhibit a grain size distribution that excludes particles in excess of three inches in diameter;

(ii) Have a minimum fines content (percent by weight passing U.S. No. 200 Sieve) of seven percent for an individual test and eight percent for the average of ten consecutive tests;

(iii) Have a grain size distribution with a minimum of five percent smaller than five microns for an individual test and six percent for the average of ten consecutive tests; and

(iv) Exhibit a maximum saturated hydraulic conductivity on the order of 1.0E-03 cm/sec.; and

(3) A minimum six-inch surface erosion layer comprised of a rock/soil admixture. The surface erosion layer admixture and gradations for 3% slopes and 3:1 slopes are detailed below:

(i) 3% slopes: For the 3% slopes the surface admixture shall be composed of pea gravel ( 3/8-inch to 1/2-inch diameter) mixed with cover soil at the ratio of 25% rock to soil by volume with a minimum six-inch erosion layer.

(ii) For the 3:1 side slopes the surface admixture shall be composed of either: gravel/rock ( 3/4-inch to one-inch diameter) mixed with additional cover soil as described in paragraph (b)(2)(iii)(A)(2) of this section at the ratio of 50% rock to soil by volume and result in a minimum six-inch erosion layer, or gravel/rock ( 3/4-inch to two-inch diameter) mixed with additional cover soil as described in paragraph (b)(2)(iii)(A)(2) of this section at the ratio of 50% rock to soil by volume and result in a minimum 12-inch erosion layer.

(iii) The owner and operator shall place documentation demonstrating compliance with the provisions of this section in the operating record.

(iv) All other applicable provisions of this part remain in effect.

(B) [Reserved]

(c) City of Wolf Point Municipal Landfill final cover requirements. Paragraph (c) of this section applies to the City of Wolf Point Landfill Phase 2, a municipal solid waste landfill owned and operated by the City of Wolf Point on the Assiniboine and Sioux Tribes' Fort Peck Reservation in Montana. The facility owner and/or operator may close the facility in accordance with this application, including the following activities more generally described as follows:

(1) The owner and operator may install an evapotranspiration system as an alternative final cover for the 3.5-acre Phase 2 area.

(2) The final cover system shall consist of a 4-foot-thick multi-layer cover system comprised of the following from bottom to top: A 12-inch intermediate layer, a 24-inch native silty-clay till layer, and a 12-inch native topsoil layer, as well as seeding and erosion control.

(3) The final cover system shall be constructed to achieve an equivalent reduction in infiltration as the infiltration layer specified in § 258.60(a)(1) and (a)(2), and provide an equivalent protection from wind and water erosion as the erosion layer specified in paragraph (a)(3) of this section.

(4) In addition to meeting the specifications of “The City of Wolf Point Landfill License #3—Phase 2 Alternative Final Cover Demonstration (Revised)” application of February 9, 2016, the owner and operator shall:

(i) At finalization, submit to the EPA for approval final cover plans and specifications, including the final Construction Quality Assurance/Quality Control Plan and final Closure/Post-Closure Plan; and

(ii) Achieve re-vegetation rates greater than 75% by the end of the third year after revegetation.

(5) The owner and operator shall place documentation demonstrating compliance with the provisions of this section in the operating record.

(6) All other applicable provisions of 40 Cspan part 258 remain in effect.

(d) Cocopah Municipal Solid Waste Landfill—Alternative final cover and alternative location for the storage of facility records. This paragraph (d) applies to the Cocopah Landfill, a Municipal Solid Waste landfill operated by Republic on the Cocopah Indian Reservation near Somerton, Arizona.

(1) In accordance with § 258.60(b), the owner or operator may replace the prescriptive final cover set forth in § 258.60(a), with an alternative final cover as follows:

(i) The owner or operator may install an evapotranspiration cover system as an alternative final cover for the 135-acre site.

(ii) The alternative final cover system shall be constructed to achieve an equivalent reduction in infiltration as the infiltration layer specified in § 258.60(a)(1) and (2) and provide an equivalent protection from wind and water erosion as the erosion layer specified in § 258.60(a)(3). Top-deck cover slopes shall have a minimum slope of 2%. All side slopes in the South Fill Area shall be regraded to a maximum 3 horizontal to 1 vertical (3H:1V). The existing side slope of 2.5H:1V in the North Fill Area will remain; however, drainage benches shall be installed on portions of the slope where the vertical height exceeds 50 feet.

(iii) The final cover system shall consist of a minimum three-feet-thick multi-layer cover system comprised, from bottom to top, of:

(A) A minimum 30-inch thick infiltration layer consisting of:

(1) Existing intermediate cover; and

(2) Additional cover soil from on-site sources, which, prior to placement, shall be wetted to optimal moisture and thoroughly mixed to near uniform condition, and the material shall then be placed in lifts with an uncompacted thickness of six to eight inches, spread evenly and compacted to 90 percent of the maximum dry density, and shall:

(i) Exhibit a grain size distribution that excludes particles in excess of three inches in diameter;

(ii) Have a minimum fines content (percent by weight passing U.S. No. 200 Sieve) of 12 percent for the average of ten consecutive tests; and

(iii) Have a grain size distribution with a minimum of six percent finer than five microns for the average of ten consecutive tests; and

(B) A surface erosion layer comprised of a rock/soil admixture for top deck slopes and rock armoring for side slopes. The surface erosion layer requirements for top-deck slopes and side slopes are detailed below:

(1) Top deck slope surface erosion layer requirements: The top deck slope surface erosion layer shall be a minimum six-inch surface erosion layer comprised of a rock/soil admixture. The top deck surface erosion layer shall achieve the following gradation specification:

(i) Exclude particles in excess of three inches in diameter;

(ii) 40% to 75% passing No. 4 sieve

(iii) 10% to 50% passing No. 40 sieve

(iv) Less than or equal to 15% passing No. 200 sieve

(2) Side slope surface erosion layer: The side slope surfaces erosion layer shall consist of a 4-inch thick rock armor underlain by an 8 ounce per square yard (oz/sy) non-woven geotextile filter fabric. The side slope surface erosion rock armor layer shall achieve the following gradation specification:

(i) Exclude particles in excess of three inches in diameter;

(ii) 10% to 40% passing No. 4 sieve

(iii) 0% to 10% passing No. 40 sieve

(2) In accordance with 40 Cspan 258.29(a), the owner operator may retain all required documentation relating to the operating record of the Cocopah Landfill at the administrative offices of Copper Mountain Landfill. The address of Copper Mountain Landfill is 34853 East County 12th Street, Wellton, Arizona 85356.

(3) The owner or operator shall place documentation demonstrating compliance with the provisions of this Section in the operating record.

(4) All other applicable provisions of 40 Cspan part 258 remain in effect.

[75 span 50932, Aug. 18, 2010, as amended at 81 span 69409, Oct. 6, 2016; 82 span 25535, June 2, 2017; 85 span 53178, Aug. 28, 2020]