8 CAR § 60-431 – Landfill configuration

(a) Applicability. This section applies to the design and operation of all landfills.
(b) Slopes.
1. (1) Finished grades of the landfill cap shall be selected to minimize standing water and erosion.
2. (2) The design shall at a minimum consider the:
  1. (A) Potential ultimate settlement of the waste mass;
  2. (B) Erodibility of the soil cover; and
  3. (C) Slope stability.
3. (3) Slopes shall not be less than four percent (4%) or more than twenty-five percent (25%).
4. (4) For sites having greater natural slopes, a thirty-three-percent slope may be considered if terracing is incorporated into the design.
(c) Ground water. A minimum of five feet (5’) of separation shall be maintained between the top of the landfill liner system and the seasonally high ground water elevation unless approval is obtained from the Director of the Division of Environmental Quality for a landfill that is designed to maintain a positive inward ground water flow gradient.
(d) Bedrock. A minimum of two feet (2’) of separation shall be maintained between bedrock and the top of the landfill liner system including the liner thickness.