NR 504.07(4)(b)(b) For industrial solid waste landfills that predominantly accept compressible wastes or wastes with high water contents and low strength, the clay layer may be replaced by a GCL overlying a minimum of a one foot sand layer. The gradation of the sand layer shall be a uniform sand selected to vent gas, drain leachate and provide hydration water to the GCL.

NR 504.07(4)(c)(c) For industrial solid waste landfills that predominantly accept ash, the clay layer may be replaced by a GCL overlying a minimum of 2 feet of soil barrier layer. The soil barrier layer shall meet the requirements of par. (a) 13. to 17. The upper foot of soil barrier layer shall also meet the requirements of par. (a) 12. The lower foot shall be designed to provide a capillary break between the ash and the upper one foot of soil barrier layer.

NR 504.07(4)(d)(d) The lower one foot of the clay layer may be replaced with a minimum of one foot of foundry green sand system sand with a bentonite content of greater than 6%, a liquid limit of greater than 20, a plasticity index of greater than 6, and a hydraulic conductivity of less than 1x10-7 cm/sec. The green sand system sand shall be compacted to 90% modified or 95% standard Proctor density or greater at a moisture content at or wet of optimum.

NR 504.07(5)(5) Geomembrane layer. A geomembrane layer shall be designed to provide a low hydraulic conductivity barrier to percolation. The design and construction of the geomembrane component of the final cover system shall meet the requirements of s. NR 504.06 (3) (c) to (j) and the following:

NR 504.07(5)(a)(a) The nominal geomembrane thickness shall be 40 mils or greater, with no thickness measurements falling below industry accepted manufacturing tolerances.

NR 504.07(5)(c)(c) Penetrations of the geomembrane, such as gas extraction wells, shall be fitted with prefabricated collars of pipe and membrane or plate and welded at the same angles which the penetrations make with the final cover slope. Methods of fixing membrane boots to vertical pipes extending above the geomembrane shall allow for differential settlement of the waste with respect to the piping without damage to the membrane seal.

NR 504.07(6)(6) Drainage and rooting zone layer. A minimum 2.5 foot thick drainage and rooting zone layer shall be designed above the geomembrane layer or clay capping layer. This layer shall include a rooting zone to provide additional rooting depth for vegetation and to protect the geomembrane layer or the clay capping layer from freeze-thaw damage and other environmental effects. It shall also include a drainage layer to allow for the drainage of liquid infiltrating through the cap. Soils available on or near the proposed landfill property may be proposed for the rooting zone portion of this layer. This layer may not be densely compacted.

NR 504.07(6)(a)(a) For all landfills, a drainage layer shall be designed immediately above the capping layer. The drainage layer shall consist of a minimum of one foot of sand with a minimum hydraulic conductivity of 1x10-3 cm/sec or a geosynthetic drain layer of equivalent or greater flow capacity. The design shall include an analysis which demonstrates whether the maximum head in the drain layer will be confined within the thickness of the drain. Drain calculations shall include infiltration rates based on saturated characteristics of the topsoil and rooting zone and a hydraulic gradient of one through the topsoil and rooting zone.

NR 504.07(6)(b)(b) A perimeter drain pipe shall be placed at the low end of all final cover sideslopes. The drain pipe shall be surrounded by a minimum of 6 inches of gravel or sand with a minimum hydraulic conductivity of 1x10-2 cm/sec. The drain pipe shall be sloped to a series of outlets at spacings no further than every 200 feet. Modeling may be submitted to the department which supports the proposal of a different spacing.

NR 504.07(7)(7) Topsoil. A minimum of 6 inches of topsoil shall be designed over the cover layer to support the proposed vegetation. Fertilizer and lime shall be added in accordance with section 630, Wisconsin department of transportation standard specifications for road and bridge construction or other appropriate specifications in order to establish a thick vegetative growth.

NR 504.07(8)(8) Revegetation. The seed type and amount of fertilizer applied shall be proposed depending on the type and quality of topsoil and compatibility with both native vegetation and the final use. Unless otherwise approved by the department in writing, seed mixtures and sowing rates shall be those specified for right–of–ways according to section 630, 2003 edition of the Wisconsin department of transportation standard specifications for highway and structure construction and the 2004 supplemental specifications. Application rates for fertilizer and mulch shall also be specified.

NR 504.07 NoteNote: The 2003 edition of the Wisconsin department of transportation standard specifications for highway and structure construction and any annual supplemental specifications are available at http://www.dot.wisconsin.gov/business/engrserv/procedures.htm or can be obtained from the department of natural resources, bureau of waste management, 101 S. Webster Street, P.O. Box 7921, Madison, WI 53707-7921, (608) 266-2111, waste.management@dnr.state.wi.us. Copies are also available for inspection at the offices of the legislative reference bureau and the secretary of state.

NR 504.07(9)(9) Final use. The proposed final use shall be compatible with the final cover system. The following activities are prohibited at solid waste disposal landfills which are no longer in operation unless specifically approved by the department in writing.

NR 504.07 HistoryHistory: Cr. Register, January, 1988, No. 385, eff. 2-6-88; am. (1) (a), (b), (2), cr. (1) (c), (d), (5), (6) (a), (b), r. and recr. (3), (4), r. (5) (a) to (c), renum. (5) to (8) to be (6) to (9) and am. (6) (intro.), (7), (9) (intro.), (a), (b), Register, June, 1996, No. 486, eff. 7-1-96; CR 04-077: am. (6) (a) Register November 2005 No. 599, eff. 12-1-05; CR 05-020: r. and recr. (4), am. (8) Register January 2006 No. 601, eff. 2-1-06.

NR 504.075(1)(1) General. This section applies to all soil borrow sources developed for the purpose of constructing, operating or closing landfills. Written approval from the department shall be obtained prior to initiating soil borrow activities at any borrow source subject to these requirements.

NR 504.075(2)(2) Exemptions.

NR 504.075(2)(a)2.2. Excavation of soils from construction projects off of the landfill property, provided the soils will be used for purposes other than a compacted clay liner or capping layer, soil barrier layer, leachate collection layer or final cover drain layer.

NR 504.075(2)(b)(b) Soil borrow sources which are exclusively within the proposed or approved limits of filling for a landfill or areas where soils are obtained from excavation projects developed primarily for purposes other than construction, operation or closure of a landfill are not subject to the requirements of subs. (3) and (4) (b).

NR 504.075(3)(3) Initial site inspection. An initial site inspection shall be conducted in accordance with s. NR 509.04 for each proposed soil borrow source.

NR 504.075(4)(4) Locational information.

NR 504.075(4)(a)(a) Submittals for soil borrow sources shall include a description of total acreage, ownership, location by quarter – quarter section and by parcel corner using a coordinate system and datum acceptable to the department, present land uses, transportation routes, any access restrictions and travel distance to and from the landfill.

NR 504.075(4)(b)(b) Submittals for soil borrow sources shall include site–specific surface water drainage patterns and significant hydrologic features such as surface waters, springs, drainage divides and wetlands; areas of special natural resource interest; and historical or archaeological areas within and adjacent to the proposed limits of excavation.