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conductivity layer described in&(a)(2).For any proposed vegetative cover,the discharger shall propose a species
<br /> mix which harmonizes with the proposed post-closure land use,and which requires as little long-term maintenance as
<br /> feasible by virtue of its tolerance of the vegetative layer's soil conditions(e.g., the presence of landfill gas),its
<br /> resistant to foreseeable adverse environmental factors(e.g., climate, disease, and pests),its rapidity of germination
<br /> and growth,its persistence and ease of self-propagation,its high percentage of surface coverage(sufficient to prevent
<br /> surface erosion),and its minimal need for irrigation and maintenance;and
<br /> e. by virtue of its composition,its maintained vegetation density,and its finished-and-maintained grade,will
<br /> be resistant to foreseeable erosion effects by wind-scour,raindrop impact,and runoff;or
<br /> 2. Mechanically Erosion-Resistant Layer—an erosion-and ultraviolet light-resistant layer which,by virtue
<br /> of its composition and finished-and-maintained grade,resists foreseeable erosion effects by wind-scour,raindrop
<br /> impact,and runoff(e.g., a ]-foot thick layer ofcobbles, the interstices ofwhich arefilled with gravel).
<br /> (B) The discharger shall maintain all components of the erosion-resistant layer throughout the post-closure
<br /> maintenance period,and,if closed after July 18, 1997,shall implement such maintenance in accordance with an
<br /> approved Cover-Integrity Monitoring and Maintenance Program,pursuant to&(a)(4).
<br /> (4) Cover Maintenance Plan&Annual Cost Estimate—The final cover shall be designed and constructed to
<br /> function with the minimum maintenance possible.For landfills and for other Units closed as landfills,if the closure
<br /> occurs after July 18, 1997,the preliminary and final closure and post-closure maintenance plan shall incorporate a
<br /> cover-integrity monitoring and maintenance program which includes at least the following components.The
<br /> annualized post-closure maintenance plan cost analysis[of[21769(c)]shall include an itemized estimate of the
<br /> annual cost of each component:
<br /> (A) Periodic Leak Search—a schedule for carrying out periodic monitoring of the integrity of the low-
<br /> hydraulic-conductivity layer,including a method for effectively identifying and repairing breaches in that layer(for
<br /> example and where allowed, by temporarily discontinuing active gas extraction and using surface gas probes or
<br /> inserted soil gas probes to identify locations where landfill gas is emergin,-J;
<br /> (B) Periodic Identification of Other Problem Areas—a schedule for periodically identifying and addressing
<br /> other cover problems,including at least:
<br /> 1. areas of the vegetative cover,if any,requiring replanting;
<br /> 2. eroded portions of the erosion-resistant layer requiring regrading,repair,or(for areas where the problem
<br /> persistently reoccurs)increased erosion resistance;
<br /> 3. eroded portions of the low-hydraulic-conductivity layer needing repair or replacement;
<br /> 4. areas lacking free drainage;
<br /> 5. areas damaged by equipment operation;
<br /> 6. [Reserved];and
<br /> 7. localized areas identified in the iso-settlement survey[of&(e)(2)]as having sustained repeated or severe
<br /> differential settlement.
<br /> (C) Prompt Cover Repair—a plan for repairing,in a timely manner,any breach or other cover problem
<br /> discovered pursuant to&(a)(4)(A or B).For any repairs of the low-hydraulic-conductivity layer,this plan shall either
<br /> contain a Construction Quality Assurance(CQA)plan[under]21710(a)(5)],or shall accomplish this goal through
<br /> the incorporation-by-reference of appropriate portions of an approved CQA plan;and
<br /> (D) Vegetation Maintenance—for a final cover utilizing a vegetated erosion resistant layer[under
<br /> &(a)(3)(A)1.],a plan for maintaining this vegetative cover,including fertilization,irrigation,elimination of species
<br /> that violate the rooting depth limit[of&(a)(3)(A)l.d.],replanting,and irrigation system maintenance.
<br /> (5) Discharges of Liquids to Covers.
<br /> (A) Leachate and Gas Condensate—The discharge of leachate,gas condensate,or other waste liquids to any
<br /> final-covered portion of an MSW landfill is subject to the restrictions under 420200(d).[Note:see also 1)definitions
<br /> of"leachate"and "landfill gas condensate"in /20164, and 2) 120705(8,re:daily and intermediate cover.]
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