(1) The requirements in this subchapter apply to Class II and Class IV landfill units, except as provided in (2).

(2) Ground water monitoring requirements under ARM 17.50.1304 through 17.50.1307 for a Class II or Class IV landfill unit may be suspended by the department if the owner or operator submits, and obtains department approval for, a demonstration that there is no potential for migration of a constituent in Appendix I or II to 40 CFR Part 258 (July 1, 2008) from that Class II or Class IV landfill unit to the uppermost aquifer or underground drinking water source, as required in ARM 17.50.1204, during the active life of the unit and the post-closure care period. This demonstration must be certified by a qualified ground water scientist, and must be based upon:

(a) site-specific field collected measurements, sampling, and analysis of physical, chemical, and biological processes affecting contaminant fate and transport; and

(b) contaminant fate and transport predictions that maximize contaminant migration and consider impacts on human health and environment.

(3) The owner or operator of an existing Class II or Class IV landfill unit, or a lateral expansion of an existing Class II or Class IV landfill unit, except one meeting the conditions of ARM 17.50.1203, shall comply with the ground water monitoring requirements of ARM Title 17, chapter 50, subchapters 5 through 14.

(4) A new Class II or Class IV landfill unit must be in compliance with the ground water monitoring requirements specified in ARM 17.50.1304 through 17.50.1307 before waste may be placed in the unit.

(5) Once ground water monitoring has begun at a Class II or Class IV landfill unit, the owner or operator shall continue to conduct ground water monitoring throughout the active life and post-closure care period of that unit, as specified in ARM 17.50.1404.

(6) The department may establish, and the owner or operator shall comply with, alternative schedules for demonstrating compliance with ARM 17.50.1304(6)(b), pertaining to notification of placement of certification in operating record; ARM 17.50.1306(5)(a), pertaining to notification that statistically significant increase (SSI) notice is in operating record; ARM 17.50.1306(5)(b) and (7), pertaining to an assessment monitoring program; ARM 17.50.1307(2), pertaining to sampling and analyzing constituents in Appendix II to 40 CFR Part 258 (July 1, 2008); ARM 17.50.1307(4)(a), pertaining to placement of notice (Appendix II constituents detected) in record and notification of notice in record; ARM 17.50.1307(7), pertaining to sampling for Appendix I and II; ARM 17.50.1307(7), pertaining to notification (and placement of notice in record) of SSI above ground water protection standard; ARM 17.50.1307(7)(a)(iv) and ARM 17.50.1308(1), pertaining to assessment of corrective measures; ARM 17.50.1309(1), pertaining to selection of remedy and notification of placement in record; ARM 17.50.1310(3)(e), pertaining to notification of placement in record (alternative corrective action measures); and ARM 17.50.1310(7), pertaining to notification of placement in record (certification of remedy completed).