(a) Applicability.

1. (1) Owners or operators of new units, existing units, and lateral expansions located in an unstable area must demonstrate that engineering measures have been incorporated into the unit's design to ensure that the integrity of the structural components of the unit will not be disrupted.

2. (2) The owner or operator must:

   1. (A) Place the demonstration in the operating record;
   2. (B) Notify the Director of the Division of Environmental Quality that it has been placed in the operating record; and
   3. (C) Provide the demonstration to the director for approval.

3. (3) The owner or operator must consider the following factors, at a minimum, when determining whether an area is unstable:

   1. (A) On-site or local soil conditions that may result in significant differential settling;
   2. (B) On-site or local geologic or geomorphologic features; and
   3. (C) On-site or local human-made features or events, both surface and subsurface.

(b) Definitions. For purposes of this section:

1. (1)

   1. (A) “Areas susceptible to mass movement” means those areas of influence, i.e., areas characterized as having an active or substantial possibility of mass movement, where the movement of earth material at, beneath, or adjacent to the municipal solid waste landfill unit, because of natural or human-induced events, results in the down slope transport of soil and rock material by means of gravitational influence.
   2. (B) Areas of mass movement include, but are not limited to:

(i) Landslides;

1. (ii) Avalanches;

   1. (iii) Debris slides and flows;

      1. (iv) Soil fluction;
      2. (v) Block sliding; and
      3. (vi) Rock fall;

2. (2)

   1. (A) “Karst terrain” means areas where karst topography, with its characteristic surface and subterranean features, is developed as the result of dissolution of:

      1. (i) Limestone;
      2. (ii) Dolomite; or
      3. (iii) Other soluble rock.

   2. (B) Characteristic physiographic features present in karst terrain include, but are not limited to:

      1. (i) Sinkholes;
      2. (ii) Sinking streams;
      3. (iii) Caves;
      4. (iv) Large springs; and
      5. (v) Blind valleys;
3. (3) “Poor foundation conditions” means those areas where features exist which indicate that a natural or human-induced event may result in inadequate foundation support for the structural components of a solid waste unit;
4. (4) “Structural components” means liners, leachate collection systems, final covers, run-on/run-off systems, and any other component used in the construction and operation of the facility that is necessary for protection of human health and the environment; and

5. (5)

   1. (A) “Unstable area” means a location that is susceptible to natural or human-induced events or forces capable of impairing the integrity of some or all of the landfill structural components responsible for preventing releases from a landfill.

   2. (B) Unstable areas can include:

      1. (i) Poor foundation conditions;
      2. (ii) Areas susceptible to mass movements; and
      3. (iii) Karst terrain.