(1) An applicant for a license for a new Class II landfill unit, or a lateral expansion of an existing Class II landfill unit, located in an unstable area shall submit to the department for approval, with the application, a report prepared by a Montana licensed professional engineer demonstrating that the unit is designed to ensure that the integrity of the structural components of the unit will not be disrupted. The owner or operator shall place the approved report in the operating record and notify the department that it has been placed in the operating record. When determining whether an area is unstable, the owner or operator shall consider the following factors, and any other factor determined by the department to be necessary to protect human health or the environment:

(a) on-site or local soil conditions that may result in significant differential settling;

(b) on-site or local geologic or geomorphologic features; and

(c) on-site or local artificial features or events, both surface and subsurface.