1. (1) Primary composite liner. The primary composite liner must be constructed using a GCL which restricts flow through the GCL equal to or better than a compacted soil liner with a hydraulic conductivity of 1x10^-7 centimeters per second or less and which is constructed with bentonite demonstrating chemical and physical stability. The GCL must be placed below and in direct and uniform contact with the primary geomembrane liner. The carrier geotextile of the GCL must be a material that will inhibit the migration of bentonite into the secondary leachate collection and removal system.

2. (2) Secondary composite liner. The secondary composite liner must be constructed using a minimum two-foot-thick soil liner placed below and in direct and uniform contact with the secondary geomembrane liner. The soil component of the secondary composite liner must:

   1. (i) be free from stones greater than one inch in diameter and stones having an angular surface;
   2. (ii) be a total of at least 24 inches in compacted thickness;
   3. (iii) have a remolded hydraulic conductivity of 1x10^-7 centimeters per second or less throughout its thickness;
   4. (iv) be constructed and maintained to minimize the presence of cracks and granular material as long as it is exposed, as specified in a department-approved CQA/CQC plan; and

   5. (v) be overlain by and in direct and uniform contact with a geomembrane.

      (b) Construction requirements.

      The project engineer must ensure that the installation of the soil and/or GCL components of the liner system conforms to the following minimum requirements:

3. (1) GCL liner components.

   1. (i) All GCLs must be placed in accordance with requirements specified in section 363-6.8(b)(2)-(4) of this Subpart and without damaging any component of the secondary leachate collection and removal system. The GCL must be placed at a slope of no less than two percent except for along the leachate collection pipes which must have slopes of no less than one percent. The GCL must be placed at a slope of no greater than 33 percent in any direction.
   2. (ii) GCL field seams must be primarily oriented parallel to the line of maximum slope (i.e., oriented along, not across the slope).
   3. (iii) All GCL field seams must be made using bentonite and a minimum 12-inch overlap, and must be made in accordance with the manufacturer’s specifications as approved by the design engineer.
   4. (iv) The GCL must not be installed during a precipitation event. Installed GCLs must be covered by the approved geomembrane by the end of the day they are installed and must be loaded with at least 1 foot of soil within 60 days of installation. Any GCL that becomes hydrated after it is installed and before it is covered with an approved geomembrane must be removed, unless the project engineer determines, and certifies in construction certification report, that the degree of hydration will allow the overlying geomembrane and soil material to be placed without affecting the performance of the installed GCL and that its properties are compliant with the approved specifications.

4. (2) Soil liner components.

   1. (i) The soil component of the liner system must be placed at a slope of no less than two percent in directions perpendicular to leachate collection pipes, and no less than one percent in directions parallel to the leachate collection pipes. The soil component of the liner system must be placed at a slope of no greater than 33 percent in any direction.
   2. (ii) During compaction, proper control of the moisture content, lift thickness, compactive energy/kneading action, placement operations and other details necessary to effectively destroy soil clods, eliminate lift interfaces and avoid mixing with subgrade soils must be maintained. The final compacted thickness of each lift must not exceed eight inches. Placement of the first lift of the soil component of the liner system must prevent mixing of the soil liner system materials and subgrade.

   3. (iii) The moisture content and compacted density of the soil component of the liner system must be maintained at all times within the range identified in the moisture-density-permeability relation developed in accordance with subparagraph (c)(2)(v) of this section to ensure that the remolded lift hydraulic conductivity is less than or equal to 1x10^-7 centimeters per second.

      (c) Certification requirements.

5. (1) For GCLs, the project engineer must certify that:

   1. (i) all GCL sheets used in liner system construction have been inspected by the manufacturer and at the job site for needles and sheet defects; and
   2. (ii) all construction meets the requirements of (b)(1) of this section.

6. (2) For soil barrier components, the project engineer must certify the quality control testing of any soil liner materials, document that the specified material meets the approved engineering drawings, engineering report, CQA and CQC plan, and project specifications. The hydraulic conductivity requirement for the soil liner material must be less than or equal to 1x10^-7 centimeters per second. Before and during construction of the soil component of the liner system, the results of the following testing at a minimum must be reviewed and accepted by the project engineer prior to placement:

   1. (i) one analysis of soil particle size for every 2,500 cubic yards of material placed;
   2. (ii) one Atterberg limits analysis of plastic and liquid limits and plasticity index for every 1,000 cubic yards of material placed;
   3. (iii) one laboratory permeability test using a triaxial cell with back pressure for every 5,000 cubic yards of material placed;
   4. (iv) one moisture content test for every 1,000 cubic yards of material placed; and
   5. (v) a minimum of one comparison of the moisture-density-permeability relation for every 5,000 cubic yards of material placed.

7. (3) Quality assurance testing of soil components required under this paragraph must be compared to and evaluated against the quality control testing of paragraph (2) of this subdivision where applicable.

   1. (i) Quality assurance testing locations must be evenly distributed across the side slopes and bottom area of the landfill and must include density and moisture content tests to be performed at a minimum of nine locations per acre per lift of soil material placed.
   2. (ii) For each location, the density and moisture content must be compared to the appropriate moisture-density-permeability relation to determine the permeability at that location.
   3. (iii) One shelby tube sample for laboratory permeability testing must be taken per acre per lift.
   4. (iv) Any tests resulting in penetration of the soil liner must be repaired using bentonite or other means or material acceptable to the department.
8. (4) The certification report must address all measures taken to remedy GCL or soil liner damage that occurred during and after construction and any measures taken to prevent damage.

(a) Primary and secondary composite liners.