Section 329IAC10-17-11. Protective cover component of the liner; design requirements

   (a) Unless the alternative design described in subsection (b) is used, a protective cover must be placed directly over the uppermost drainage layer of the liner system and must comply with the following requirements:

(1) Consist of one (1) of the following:

(A) A soil material of sufficient quantity to bring the final depth of the combined drainage layer and protective cover to thirty (30) inches.

(B) Eighteen (18) inches of bottom ash or foundry sand if the drainage layer consists of a soil material.

(C) Thirty (30) inches of bottom ash or foundry sand if the drainage layer consists of a geosynthetic material.

(2) Satisfy the following standards:

(A) Meet the Unified Soil Classification System of SC, SM, SP, SW, GC, GM, GP, or GW.

(B) Contain less than fifty percent (50%) (by weight) material that can pass through the number 200 sieve.

(C) Be free of any organic material except that organic material naturally occurring in the soil.

(D) If placed over a drainage layer that consists of any soil materials or soil-like materials specified in subdivision (1), meet the following criteria or an equivalent criteria:

Where:	D15	=	the grain diameter in millimeters at which 15% (by weight) of the grains are finer.
	D85	=	the grain diameter in millimeters at which 85% (by weight) of the grains are finer.

  (b) An alternative design to the option described in subsection (a) uses a puncture-resistant geotextile that meets the following requirements:

(1) The geotextile must be placed directly over the geomembrane.

(2) The geotextile must have a minimum weight of sixteen (16) ounces per square yard.

(3) The geotextile must be covered with twelve (12) inches of clean gravel that:

(A) is classified as GW or GP by the Unified Soil Classification System; and

(B) has no more than five percent (5%) (by weight) of grains passing the number 200 sieve.

(Solid Waste Management Division; 329 IAC 10-17-11; filed Mar 14, 1996, 5:00 p.m.: 19 IR 1838; filed Mar 19, 1998, 11:07 a.m.: 21 IR 2779)