NR 514.05(10)(a)10.
10. Access roads and ramps on the perimeter of the disposal area and within the active fill area.
NR 514.05(10)(a)11.
11. The filling sequence or phasing interfaces and other facility features.
NR 514.05(10)(b)
(b) Cross-sections shall be included to illustrate all important construction features of the liner, final cover, lysimeters, leachate collection trenches and sumps, liner penetrations, sideslope risers, piping systems for gas and gas condensate and drainage systems for storm water.
NR 514.05(10)(c)
(c) Detailed plan view sheets shall be included for piping outside the limits of filling for leachate header and drain lines, gas and condensate lines, and leachate forcemains, with notations of pipe slope and intersection elevations with appurtenances such as manholes, lift stations, collection tanks and gas blower stations.
NR 514.05(11)
(11)
Details. Drawings showing details and typical sections shall be included for storm water control structures; access roads; fencing; final cover and base liner systems; leachate and gas control systems such as pipe bedding, manholes, transfer lines, force mains and storage tanks; leachate transfer lines which extend through the liner; groundwater and unsaturated zone monitoring devices; and buildings. This plan sheet shall include all other construction details such as leachate and refuse containment berms between subsequent phases of development.
NR 514.05 History
History:
Cr.
Register, January, 1988, No. 385, eff. 2-6-88; correction in (2) (k) made under s. 13.93 (2m) (b) 5., Stats.,
Register, May, 1994, No. 461; am. (intro.), (2) (intro.), (b), (5), (9), (11), r. and recr. (2) (c) to (k), (3), (4), (6) to (8),
Register, June, 1996, No. 486, eff. 7-1-96;
CR 05-020: am. (7)
Register January 2006 No. 601, eff. 2-1-06;
correction in (intro) made under s. 13.92 (4) (b) 7., Stats., Register July 2022 No. 799. NR 514.06
NR 514.06 Operations manual and design report. The plan of operation for all new landfills and expansions of existing landfills shall contain an operations manual and design report which shall comply with ss.
NR 500.05,
504.05 to
504.12 and, at a minimum, shall contain the following information:
NR 514.06(1)
(1)
Table of contents. The report shall include a table of contents which outlines by section title and page number the discussion required in this section.
NR 514.06(2)
(2)
General information. The report shall identify the name of the landfill; the registered professional engineer who prepared the plans; landfill owner, licensee and operator; location by quarter-quarter section; the proposed limits of filling; the anticipated life and closure date; disposal capacity; waste tonnages and corresponding volumes, percent municipal waste versus industrial waste, anticipated geographic service area, and anticipated industrial waste types; waste types and quantities to be disposed; any exemptions requested from the department; and a list of the conditions of facility development as stated in the feasibility determination and the measures incorporated in the plan of operation to address those conditions.
NR 514.06(3)
(3)
DESIGN RATIONALE. The report shall include a discussion of the considerations and rationale behind design of the discretionary aspects of major engineering features which are not explicitly required by state or federal regulations or the conditions of the department's feasibility approval for the landfill. This shall include base grade configuration and relationship to subsurface conditions, liner design, phases of landfill development and closure, traffic routing, storm water management, erosion, and sediment control measures, gas extraction and treatment systems, final cover systems, and monitoring systems. Specific attention shall be given to sidewall penetrations, sideslope riser and sump area volumes and construction, and piping located outside of the limits of filling. In addressing each of the above design items, the report shall indicate how the anticipated waste types and characteristics influenced the chosen design.
NR 514.06(4)
(4)
Initial construction. The report shall discuss initial preparations and construction methods relating to clearing and grubbing, topsoil stripping and other excavations; soil storage and visual screening development; storm water control features; base liner and granular drainage layers; leachate collection and gas venting systems; access roads and entrance area screening and fencing; environmental monitoring device installation and other special design features. This discussion shall propose a schedule of field measurements, photographs to be taken, and sampling and testing procedures to be utilized to verify that the infield conditions encountered were the same as those defined in the feasibility report.
NR 514.06(5)
(5)
Storm water management. The report shall describe storm water management at the time of initial construction, during phased development, and after closure of the landfill. The report shall include:
NR 514.06(5)(b)
(b) Detailed description of temporary and permanent erosion and sediment control measures to be used to accomplish the concepts in s.
NR 504.09 (1) (b).
NR 514.06(5)(c)
(c) Specifications for design of sediment basins, culverts, drainage ditches, auxiliary sediment traps, and the anticipated extent of cleared ground and stockpiles during each major phase of landfill development.
NR 514.06(5)(d)
(d) A list of anticipated actions and materials needed for sediment and erosion control.
NR 514.06(5)(f)
(f) Schedules for the following activities: cleaning sediment basins and ditches; seeding and stabilization of stockpiles and drainage channels; and topsoiling, seeding and stabilization of disturbed areas and areas affected by erosion.
NR 514.06(6)(a)(a) The report shall include a proposed testing schedule to document the placement of all general soil fill and backfill, base liner, final cover layers and all venting or drainage layers used in any phase of development or closure. The report shall contain an explicit statement and description of testing methods if construction and documentation are proposed to be performed other than in accordance with the requirements of ch.
NR 516. The report shall include justification for any proposed changes to the testing requirements of ch.
NR 516.
NR 514.06(6)(b)
(b) The report shall specify the proposed gradations of soil materials and the proposed size of the perforations used in the leachate collection system piping and the drainage layer in the final cover system. The report shall include an analysis of the pipe and soil materials to demonstrate whether the gradation of sand and gravel and the pipe opening sizes are stable and self-filtering. The report shall describe the use of filter layers or other mechanisms used to maintain the porosity in the leachate collection blanket, collection trenches and sumps.
NR 514.06(6)(c)
(c) The report shall include the documentation required by s.
NR 504.075 for any soil borrow source that was not included in the approved feasibility report for the landfill.
NR 514.06(7)(a)(a) The report shall include a proposed monitoring program for groundwater, surface water, volumes and quality of gas and gas condensate, unsaturated zone, leachate volume and quality, and surface settlement developed in accordance with ch.
NR 507 and the specific requirements of the feasibility approval. The proposed monitoring program shall include a table listing frequencies of sampling, parameters to be analyzed, and a schedule for the anticipated installation or abandonment of sampling points. The table shall indicate existing and proposed sampling points and devices and the anticipated periods during which the points and devices will be monitored before landfill development, during each major phase of landfill development, and during the period of long-term care.
NR 514.06(7)(b)
(b) The report shall include a listing of all groundwater elevation data collected from all groundwater sampling points subsequent to preparation of the feasibility report.
NR 514.06(8)
(8)
Operations. The report shall describe the daily operations including a discussion of the timetable for the construction of each phase of liner or final cover; waste types accepted or excluded; typical waste handling techniques and methods for handling unusual waste types; hours of operation; traffic routing; storm water management; sediment and erosion control; windy, wet and cold weather disposal operations; fire protection equipment; anticipated staffing requirements; methods for vector, dust and odor control; daily cleanup; leachate removal during hours of operation as well as nights, weekends, and holidays; direction of filling; salvaging; record keeping; and parking for visitors, users and employees. The report shall describe any limitations or operational practices necessary due to the presence of other open or closed landfills, demolition landfills, processing facilities, storage facilities, composting facilities or any other solid waste facilities located on the same property.
NR 514.06(9)
(9)
Phased development. The report shall describe landfill operations and the development of subsequent phases. This discussion shall define the critical stage of refuse disposal for each phase as it relates to the start of construction of subsequent phases. The purpose of this planning is to ensure that the scheduling of future construction takes into account the length of the construction season, limitations imposed by weather and season, and the capacity remaining in existing phases such that an orderly transition is maintained. The report shall describe the anticipated construction in each phase for storm water management, monitoring, abandonment of fill areas, and the installation and maintenance of gas and leachate control structures.
NR 514.06(10)
(10)
Phased closure. The report shall describe landfill operations, actions taken when phases of the landfill reach waste final grades and closure of phases at waste final grades. The report shall include a discussion of the anticipated sequence of the required events for closure of the landfill and a discussion of those actions necessary to prepare the landfill for long-term care and final use.
NR 514.06(11)
(11)
Long-term care. The report shall include a proposed long-term care schedule describing the procedures to be utilized for the inspection and maintenance of cover vegetation, storm water control structures, refuse or ground surface settlement or siltation, erosion damage, gas and leachate control features, gas, leachate and groundwater monitoring, and other long-term care needs. The report shall include a final use plan for the landfill.
NR 514.06(12)
(12)
Written agreements. The appendix of the report shall include the following written agreements:
NR 514.06(12)(b)
(b) A signed clay procurement agreement or option for acquisition of the borrow source property for the volumes necessary to construct and close the first major phase of the facility.
NR 514.06(13)
(13)
Specifications. The report shall include specifications for construction, operation and closure of the landfill. These specifications shall include detailed instructions to the operator and any contractors for all aspects of construction and operation. References to specifications on the plan sheets shall be described. This may include information such as geosynthetic material installation instructions, tank manufacturer installation instructions and pump performance criteria, materials and construction methods for sideslope risers, sidewall penetrations, sump areas, and all piping located outside the limits of filling.
NR 514.06(14)
(14)
Design calculations. The report shall include and explain all design calculations to facilitate department review and provide the necessary information on financial responsibility for closure and long-term care of the landfill as required by subch.
IV of ch. 289, Stats. The report shall include a discussion of all calculations, such as refuse to cover balance computations, base liner and final covering soils materials needs related to available borrow soil volumes, stockpile sizing estimates, required interface shear strength and shear strength of the soil materials where the interfaces evaluated include the upper and lower interfaces for all geosynthetics such as geomembranes, geotextiles, and geosynthetic clay liners, design of the storm water management system, infiltration and leachate collection and leakage volumes. All calculations shall be summarized with the detailed equations presented in the appendix of the report. References to the appropriate plan sheets, from which variables are obtained for these calculations, shall be included in these summaries.
NR 514.06(14m)
(14m)
Assessment. The report shall include an assessment of the shear strength and slope stability of soils and wastes in the following scenarios:
NR 514.06(14m)(a)
(a) Interim and final waste slopes, incorporating in-field waste densities, settlement, leachate recirculation, precipitation and any other factors that affect strength of waste or final cover. The analyses shall include interior slopes between filling phases and exterior slopes after attainment of waste final grades.
NR 514.06(14m)(b)
(b) Haul roads and access ramps on interim slopes at waste final grades and on final cover, including passive load of cover soils and dynamic loads due to construction, hauling and maintenance vehicles.
NR 514.06(15)
(15)
Financial responsibility analysis. A detailed analysis in accordance with ch.
NR 520 shall be made of the costs associated with closure of the landfill and of performing each year of long-term care. All assumptions used in developing the cost estimates shall be listed, including sources of the cost estimates and rationale for the selected cost factors. The anticipated operating life and replacement schedule of all engineering design features shall be addressed and reflected in the cost estimates. The proposed methods of establishing proof of financial responsibility for closure as well as long-term care shall also be specified.
NR 514.06(16)
(16)
Appendix. An appendix shall be included which lists the references used and includes any additional data not previously presented, supplemental design calculations, material specifications, operating agreements such as draft leachate treatment agreements or signed soil borrow agreements, documents related to long-term care funding, documents related to placing a notification on the deed of properties with wells within the 1200-foot setback and other appropriate information.
NR 514.06 History
History:
Cr.
Register, January, 1988, No. 385, eff. 2-6-88; am. (intro.), (2), (4), renum. (3) to be (13), (5) to (11), (12) and (15) to be (6) to (12), (14) and (16) and am. (6) (a), (b), (7) (a), (b), (8), (9), (10), (11), (13) and (14), cr. (3), (5), (15), r. (13), (14),
Register, June, 1996, No. 486, eff. 7-1-96;
CR 04-077: cr. (14m)
Register November 2005 No. 599, eff. 12-1-05;
CR 05-020: cr. (6) (c), am. (16)
Register January 2006 No. 601, eff. 2-1-06;
correction in (intro) made under s. 13.92 (4) (b) 7., Stats., Register July 2022 No. 799. NR 514.07
NR 514.07 Miscellaneous requirements for plans of operation. The plan of operation for all new landfills and expansions of existing landfills shall include the following information where applicable:
NR 514.07(1)
(1)
Geosynthetics requirements. The plan of operation for any landfill which includes a composite liner, composite capping layer or utilizes a geomembrane for a liner or utilizes a geomembrane or geomembrane-GCL for a capping layer shall provide the following design details and specifications for the geosynthetic components. The department may specify additional requirements for other geosynthetic materials used in significant structural features of the landfill.
NR 514.07(1)(a)
(a) A description of the proposed geomembranes, GCLs and other geosynthetics to be used in construction of the landfill, including resins and additives, physical properties, bentonite characteristics, chemical resistance properties and potential suppliers. For GCLs, this shall include identification of the geotextile properties and reinforcement.
NR 514.07(1)(b)
(b) Design calculations that demonstrate the stability of the landfill and its components against failure along potential failure surfaces, such as the leachate collection system and final cover, during operations as well as after closure. Potential failure surfaces considered shall include the interfaces both below and above the geomembrane in the liner and final cover. Potential failure scenarios considered shall include both saturated and unsaturated conditions for the cover. The design calculations may use typical data or specifications from technical literature rather than values from testing of site specific materials if the sources of the typical data or specifications and the test methods used to generate them are cited with the calculations and a safety factor of at least 1.3 is used to assess stability.
NR 514.07(1)(c)
(c) Construction methods and supervisory controls for preparing the surface of the topmost lift of compacted clay prior to the installation of a geomembrane or soil barrier layer prior to installation of a GCL. The plan of operation shall propose inspection methods and removal of coarse gravel or cobbles after rolling the topmost lift of compacted clay or soil barrier layer to achieve a smooth surface.
NR 514.07(1)(d)
(d) A description of measures to be taken to store and protect all geomembranes, GCLs and geocomposite drains, transport geomembrane, GCL and geocomposite drain panels from storage to the working area, and construction methods to be used to place geomembrane, GCL and geocomposite drain panels.
NR 514.07(1)(e)
(e) The proposed orientation of all geomembrane and GCL panels for the landfill liner and capping layer in relation to slope, collection trenches, penetrations, anchor trench and phase boundaries, seaming methods and phased construction.
NR 514.07(1)(f)
(f) Typical design details of geomembrane and GCL seams and seaming methods, anchor trenches, patches, collars for all penetrations, installation in corners and leachate collection trenches. The plan of operation shall describe acceptable working conditions for geomembrane, GCL and geocomposite drain installation, installation instructions for working under weather variations and extremes, and criteria for halting or limiting GCL and geomembrane installation.
NR 514.07(1)(g)
(g) Proposed methods for testing welds or other joining methods for geomembranes and other components or penetrations if geomembranes used in previously constructed phases are obtained from different manufacturers or are made from different resins. The plan of operation shall also include measures to preserve the edges of geomembranes and GCLs to be joined to future phases and describe measures to repair all geomembrane, GCL and geocomposite drain defects, unacceptable wrinkling, and unacceptable seams.
NR 514.07(1)(h)
(h) Construction methods for placing the leachate collection system, sump backfill, and sideslope riser over the composite liner; the first 10 feet of wastes over the leachate collection system; and subsurface drain layer and rooting zone soils over the composite cap. The measures shall assure that the geomembrane and GCLs are not damaged by construction of soil layers, placement or compaction of wastes, waste consolidation or mass movements or puncturing of the geomembrane.
NR 514.07(1)(i)
(i) A construction quality control plan that will be followed by all contractors preparing the surface of the compacted clay liner or soil barrier layer, constructing the geomembrane liner and placing drainage blanket. The construction quality control plan shall include means for determining and documenting: receipt of the proper geomembrane, GCL and geocomposite drain material; acceptable subgrade and weather conditions for work to occur; seamer qualifications and procedures for trial seams; acceptability of test welds and machine settings; acceptable seaming practices; achieved seam quality and procedures for dealing with failing tests; patching; and sealing of geomembrane penetrations. The construction quality control plan shall also describe how progress in construction, as well as any variations from the approved plans, will be recorded and reported.
NR 514.07(1)(j)
(j) A construction quality assurance plan that will be followed by the registered professional engineer and qualified technician responsible for evaluating the construction and ensuring that the fabrication and installation meet design specifications. The construction quality assurance plan shall include continuous observation of all aspects of geomembrane, GCL and geocomposite drain installation activities by qualified engineers or technicians. The construction quality assurance plan shall include use of nondestructive and destructive testing of seams and samples and shall propose a schedule of tests and associated frequencies in accordance with those specified in ch.
NR 516. The construction quality assurance plan shall include proposed methods of verifying the acceptability of the prepared subgrade, repairs, patches, penetrations, seams, and adaptations by the owner and contractors to unforeseen conditions.
NR 514.07(1)(k)
(k) An outline of the contents of the anticipated preconstruction submittal which complies with the requirements of s.
NR 516.04 (5) concerning geomembrane and GCL construction and which will be prepared and submitted prior to each construction event.
NR 514.07(1)(L)
(L) A construction quality assurance plan for conducting a leak location survey on the installed geomembrane. The leak location survey shall be conducted after placement of the leachate collection layer for a composite liner. The quality assurance plan shall include continuous observation of all aspects of the leak location survey testing by qualified professional engineers or technicians. The quality assurance plan shall include use of nondestructive methods to detect, locate and verify repairs of defects in geomembrane. The quality assurance plan may include electrical resistivity testing or other testing methods acceptable to the department.
NR 514.07(2)
(2)
Codisposal of industrial solid wastes. The plan of operation for any landfill which accepts municipal solid wastes shall describe measures to be taken for the disposal of solid wastes from industrial sources, cleanups of spills and contaminated sites, or other commercial activities. The plan of operation shall propose lists of waste categories, testing protocols and schedules, and disposal protocols. The plan of operation shall describe the format for transmitting summary information to the department.
NR 514.07(3)
(3)
CLOSURE OF LANDFILLS WITH COMPOSITE LINERS AND COMPOSITE CAPS. The plan of operation for any landfill which accepts municipal solid wastes may propose to delay final cover placement for one or more years after attaining final waste grades in each phase of closure provided the following requirements are followed:
NR 514.07(3)(a)
(a) Intermediate cover consisting of a minimum of one foot of soil shall be placed and the area shall be seeded as portions of a phase reach waste final grades.
NR 514.07(3)(b)
(b) No additional waste placement shall occur in areas which have reached waste final grades and received intermediate cover.
NR 514.07(3)(c)
(c) For landfills designed with active gas extraction systems, the components of the active gas extraction system within each phase shall be installed and made operational following attainment of waste final grades within that phase. The blower, flare, driplegs, controls, condensate handling, and appurtenances of the gas extraction system shall be installed prior to or as part of the attainment of waste final grades within the first phase of waste filling.
NR 514.07(4)
(4)
Closure of papermill sludge landfills. The plan of operation for a landfill designed to accept pulp and papermill sludges or other low-strength wastes may propose that final cover placement be delayed after completing placement of the support layer in each phase of closure. The time period of the delay shall be limited to 2 years unless otherwise approved by the department. The proposal shall also justify why the delay in final cover placement is warranted.
NR 514.07(5)
(5)
Municipal solid waste combustor residue management plans. The plan of operation for any landfill which proposes to accept municipal solid waste combustor residue shall include a residue management plan. The department may approve residue management plans for facilities which have approved plans which are substantially equivalent to the requirements of ss.
NR 514.04 to
514.08.
NR 514.07(5)(a)
(a) All residue management plans shall contain the name and location of the proposed sources and the expected volume from each source of municipal solid waste combustor residue to be accepted.
NR 514.07(5)(b)
(b) All residue management plans shall establish a timetable for evaluating the results of the testing requirements of s.
NR 502.13 (8) and any trends in the results from previous testing periods to determine the need for any changes to the proposed landfill design or operation.
NR 514.07(5)(c)
(c) The residue management plan shall include plan sheets which address the design requirements of s.
NR 504.11 and include plan views, cross-sections and details as necessary to illustrate the applicable design features of the portion of the landfill which will be utilized for disposal of municipal solid waste combustor residue. Phasing plan sheets shall also be included to show development of that portion of the landfill through time.
NR 514.07(5)(d)
(d) The residue management plan shall contain an operations manual and design report which describes the daily operation of the portion of the landfill to be utilized for disposal of municipal solid waste combustor residue, including a discussion of the timetable for the phases of development; waste types accepted or excluded; typical waste handling techniques and methods for handling unusual waste types; hours of operation; traffic routing; drainage and erosion control; windy, wet and cold weather disposal operations; methods for dust control; and direction of filling. Methods to maintain compliance with the requirements of s.
NR 506.15 shall also be described.
NR 514.07(5)(e)
(e) The residue management plan shall propose any modifications to the groundwater, unsaturated zone and leachate monitoring program necessary to comply with the requirements of ch.
NR 507.
NR 514.07(6)
(6)
Other requirements. The plan of operation shall provide the following details and specifications, where applicable. The department may specify additional requirements.
NR 514.07(6)(a)
(a) Descriptions of alternative cover materials to be used for daily or intermediate cover.
NR 514.07(6)(b)
(b) Description of a 24 hour leak test for the geomembrane component of lysimeters and sumps for sideslope risers. Alternative leak detection methods, such as electrical resistivity may be proposed.
NR 514.07(6)(c)
(c) Documentation of the strength of the selected resin, diameter and wall thickness of the sideslope riser pipe, with regard to maximum overburden weight over the sumps of municipal solid waste or industrial waste at field capacity. The plan of operation shall include a description of physical and hydraulic specifications of commercially available pumps that are able to traverse any bend or elbow in the riser pipe to reach design pump intake position, for both placement and removal. The description shall include cross-sections of the riser pipe bends and the pumps when wheels, connectors, hoses, electrical leads and head level controls are attached. Pump selection shall be based on the maximum pumping capacity needed for the highest calculated leachate flow rates, including potential leachate recirculation.
NR 514.07(6m)
(6m)
Contiguous landfill expansions. The plan of operation for any proposed landfill which is either a vertical or horizontal overlay to an existing approved facility shall include a summary of all applicable conditions of department issued, chs.
NR 500 to
538, approvals or orders that are active and subject to compliance at the time of the plan of operation report submittal. The summary shall be submitted on forms provided by the department and at a minimum shall contain all of the following:
NR 514.07(6m)(a)
(a) A chronological listing of all department issued chs.
NR 500 to
538 approvals, orders and expedited plan modifications deemed as acceptable by the department under s.
NR 514.09 for the existing landfill.
NR 514.07(6m)(b)
(b) A listing of all approval conditions or order conditions that are active and subject to compliance at the time of the plan of operation report submittal.
NR 514.07(6m)(c)1.
1. “Remain active": The applicant intends to continue to meet the requirement of the condition in the proposed expansion.
NR 514.07(6m)(c)3.
3. “Alternative proposed": The applicant believes the condition is no longer required due to changes in the proposed plan of operation report.
NR 514.07(6m)(d)
(d) Identification of specific applicable codes, plan of operation report sections or further justification to support the applicant's recommended status category in par.
(c).
NR 514.07(6m)(e)
(e) The department shall provide a summary of the facility's active approval conditions or order conditions as an informational attachment to the plan of operation determination. This summary shall consider the applicant's recommended status in par.
(c) and any applicable department issued conditions in the plan of operation determination. A department summary under this paragraph does not relieve the applicant of the compliance requirement of any condition prior to the issuance of the summary.
NR 514.07(7)
(7)
Leachate recirculation plans. The plan of operation for any landfill that proposes to recirculate leachate shall include a leachate recirculation plan. The leachate recirculation plan shall include, at a minimum, the following elements:
NR 514.07(7)(a)
(a) A narrative which explains the design rationale for the proposed system. The design rationale shall address the leachate loading rate; distribution frequency; leachate distribution system including well or pipe spacing and placement, well or pipe length, screened interval, sealing material and bedding material; anticipated flow characteristics; and restricted areas where leachate will not be recirculated. The design shall incorporate, as appropriate, the requirements of s.
NR 504.095.
NR 514.07(7)(b)
(b) Plan sheets to show the conceptual layout of the leachate recirculation distribution system and design details.
NR 514.07(7)(c)
(c) Proposed loading rates for leachate recirculation shall be calculated for each leachate drainage basin. Calculation methods shall be defined so that supplemental calculations can be performed to accommodate changes due to field observations, waste characteristics, weather and other factors. Factors to be addressed shall include recirculated volumes of leachate, precipitation based on local records and on-site data, field capacities and absorptive capacities of the landfilled waste, waste filling rates, separation distances and elevations of distribution piping or wells, and loss of water by waste decomposition processes and water vapor in landfill gas.
NR 514.07(7)(d)
(d) Calculation of effects on flow rates in the leachate collection system and maximum leachate head on the liner. The location of leachate head level monitoring devices relative to the collection pipes and base grade slope lengths shall be used to determine the maximum leachate head in the facility. Proposed loading rates for leachate recirculation shall be determined which limit maximum leachate head on the liner to 12 inches.
