74:27:12:21.  Final cover. A minimum of 18 inches of compacted soil material and 6 inches of topsoil must be placed over MSWLF units that have reached design capacity. The compacted soil layer for existing MSWLFs or for MSWLFs meeting the small-town exemption criteria specified in § 74:27:12:25 must have a permeability of 1 x 10^-5 cm/sec or less.

          The compacted soil layer for new MSWLFs or lateral expansion of existing MSWLFs must have a permeability of 1 x 10^-5 cm/sec or less. The final surface gradient of the unit must be at least 2 percent to prevent ponding. The vegetative cover must be seeded and established in accordance with the South Dakota Field Office Technical Guide, Section IV-A, Plant Sciences, (September 26, 1984), Critical Area Planting, and in consultation with the local soil conservation district office personnel. Other facilities must install a minimum of two feet of earthen material capable of maintaining perennial vegetation.

          Source: 17 SDR 8, effective July 26, 1990; 19 SDR 186, effective June 10, 1993.

          General Authority: SDCL 34A-6-1.6.

          Law Implemented: SDCL 34A-6-1.6.