20.9.9.8

GROUND WATER MONITORING APPLICABILITY.

1. A. The owner or operator of a municipal or special waste landfill, unless it is a category 1 landfill, is waived under 20.9.2.14 NMAC, or is suspended under Subsection C of this section, shall submit, obtain approval of, and implement a ground water monitoring system plan and a ground water monitoring plan in accordance with the following:

   (1) owners or operators of category 4 landfills and landfills seeking approval of lateral expansions shall obtain approval of a ground water monitoring system plan and ground water monitoring plan in compliance with 20.9.9 NMAC prior to placement of waste in the landfill or lateral expansion, as part of their permit or permit modification; owners or operators of category 4 landfills and landfills making lateral expansions shall implement and comply with their ground water monitoring system plan and ground water monitoring plan as approved;

   (2) owners or operators of category 3 landfills or landfills that closed on or after October 9, 1993 shall submit and obtain approval of a ground water monitoring system plan and ground water monitoring plan in compliance with 20.9.9 NMAC as part of their permit or closure or post closure care plan, and shall implement and comply with the approved ground water monitoring system plan and ground water monitoring plan; and

   (3) owners or operators of category 2 landfills shall comply with 20.9.9 NMAC, with the exception that the ground water sampling parameters may be limited to those approved in the closure and post-closure care plan;

   (4) the secretary may require monitoring for additional parameters as necessary to protect the public health, welfare and the environment.

2. B. Construction and demolition landfills, scrap tire monofills, and asbestos monofills are not required to comply with the ground water monitoring requirements of 20.9.9 NMAC unless required in the permit, or if the secretary orders groundwater monitoring, based on a finding that there is a potential for constituents to migrate from the facility to the uppermost aquifer. If contamination is detected at a construction and demolition landfill, scrap tire monofill or asbestos monofill, the requirements of 20.9.9 NMAC shall thereafter apply.

3. C. The secretary may suspend part or all of the ground water monitoring requirements of 20.9.9.9 - 20.9.9.13 NMAC if the owner or operator demonstrates that there is no potential for migration of constituents referenced in 20.9.9.20 NMAC from the landfill to the uppermost aquifer during the active life or post-closure care period of the landfill. This demonstration shall be certified by a qualified ground water scientist and presented in the permit application or a permit modification or petition (from non-permitted landfills) for approval by the secretary. For category 2 landfills that closed prior to receiving a solid waste facility permit, the demonstration shall be presented in an application for a closure and post closure care plan or an application to modify the approved closure and post closure care plan. The demonstration shall include:

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

   (2) contaminant fate and transport predictions that maximize contaminant migration and consider impacts on public health, welfare and environment; and

   (3) a plan for periodic leak detection or vadose zone monitoring or ground water monitoring in compliance with Subsection N of 20.9.9.9 NMAC may be implemented as a secondary monitoring approach to support approval of a monitoring suspension.

4. D. If a suspension is granted, the secretary may require the owner or operator to conduct periodic ground water or vadose zone monitoring and leak detection at any landfill during the active life or post-closure care period as necessary to protect the public health, welfare or environment.
5. E. If ground water contamination is detected after a suspension has been granted pursuant to Subsection C of this section, the suspension is revoked and the requirements of 20.9.9 NMAC shall apply, unless the owner or operator can demonstrate that ground water cannot be adversely affected and there is no risk to human health or the environment. If contaminants are detected in vadose zone monitoring instruments or a leak is detected after a suspension has been granted pursuant to Subsection C of this section, actions specified in the vadose zone monitoring or leak detection plan must be undertaken to respond.
6. F. The secretary may require the owner or operator to conduct periodic ground water or vadose zone monitoring at any landfill for which ground water monitoring has been waived under 20.9.2.14 NMAC during the active life or post-closure care period to demonstrate the landfill is not contaminating ground water.

[20.9.9.8 NMAC - Rp, 20 NMAC 9.1.VIII.801, 8/2/2007]