SITE INFORMATION AND CORRESPONDENCE

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(B)Other Liquids—The discharger shall moderate the application rate of liquids discharged to the cover for dust control,irrigation of the vegetative layer,or other non-disposal purpose in a manner that minimizes the potential for throughflow to the underlying waste.The RWQCB can establish cover throughflow monitoring requirements (e.g., via intermittent tensiometer measurements of the cover)to ensure compliance with this requirement. (6) Stability Analysis—For any portions of the final cover installed after July 18, 1997,for which the RWQCB has not approved a slope and foundation stability report on or before that date,the discharger shall meet the requirements of 421750(f)(5). (b) Grading Requirements. (1) Prevent Ponding,Erosion,and Run-On. (A) General—The final drainage plan shall be included as part of the approved final closure plan for the Unit. In spite of differential settlement,the final cover of closed landfills(including waste piles and surface impoundments closed as landfills)shall be designed,graded, and maintained to prevent ponding and to prevent soil erosion due to high ran-off velocities.Except as provided in&(b)(1)(B), all portions of the final cover shall have a slope of at least three percent.[Note: for additional requirements concerningfinal grading, see[21142.1 (B) Flatter Areas—The RWQCB can allow portions of the final cover to be built with slopes of less than three percent if the discharger proposes an effective system for diverting surface drainage from laterally-adjacent areas and preventing ponding in the allowed flatter portion.Analyses submitted in support of such a proposal shall take into account the design storm intensity for the Unit[under 420365]. (C) Qualified Professional—The final grading design shall be designed and approved by a registered civil engineer or certified engineering geologist to meet the performance standards of&(b)(1)(A and B),taking into consideration pertinent natural and constructed topographic features(including any related to the proposed post- closure land use),and climate. (D) Prompt Incremental Closure—'Kris paragraph applies unless the RWQCB has approved,as part of the final closure plan,a waiting period(for installation of the final cover)not to exceed five years after the date a portion of the landfill reaches final elevation,in order to avoid subjecting the final cover to potential damage from the high rate of differential settlement that so often occurs during the first few years following the final receipt of waste.To the extent feasible,based on site-specific factors,the complete closure,including final grading and installation of the final cover,for each portion of the landfill shall be implemented as soon as possible after that portion reaches final elevation.[For additional related requirements,see&(d), f21110, 121120.1 (E) CQA—After July 18, 1997,both the initial construction of the final cover and any later repair work that involves the cover's low-hydraulic-conductivity layer[of&(a)(2)]shall be carried out in accordance with an approved CQA plan[see 420323&420324]. (2) Steeper-Sloped Portions—Areas with slopes greater than ten percent,areas having surface drainage courses,and areas subject to erosion by water or wind shall be protected from erosion or shall be designed and constructed to prevent erosion. (3) Precipitation&Drainage Plan—The final closure plan for the Unit shall incorporate a precipitation and drainage control plan for the closed landfill,and shall meet the requirements of 520365. (c) General Post-Closure Duties—Throughout the post closure maintenance period,the discharger shall: (1) maintain the structural integrity and effectiveness of all containment structures,and maintain the final cover as necessary to correct the effects of settlement or other adverse factors; (2) continue to operate the leachate collection and removal system as long as leachate is generated and detected; (3) maintain monitoring systems and monitor the ground water, surface water,and the unsaturated zone in accordance with applicable requirements of Article 1,Subchapter 3,Chapter 3, Subdivision 1 (f20380 et seq.); (4) prevent erosion and related damage of the final cover due to drainage; and (5) protect and maintain surveyed monuments [installed under 120950(d)].