(a) Applicability. As provided in 8 CAR § 60-1201(a), a ground water monitoring system must be installed that consists of a sufficient number of wells installed at appropriate locations and depths to yield ground water samples from the uppermost aquifer (as defined in R8 CAR § 60-106) that:

1. (1)

   1. (A) Represent the quality of background ground water that has not been affected by leakage from a unit.
   2. (B) A determination of background quality may include sampling of wells that are not hydraulically up gradient of the waste management area where:

(i) Hydrogeologic conditions do not allow the owner or operator to determine what wells are hydraulically up gradient; or

1. (ii) Sampling at other wells will provide an indication of background ground water quality that is as representative or more representative than that provided by the up gradient wells; and

2. (2)

   1. (A) Represent the quality of ground water passing the relevant point of compliance specified by the Director of the Division of Environmental Quality under 8 CAR § 60-424(d).
   2. (B) The downgradient monitoring system must be installed at the relevant point of compliance specified by the director under 8 CAR § 60-424(d) that ensures detection of ground water contamination in the uppermost aquifer.
   3. (C) When physical obstacles preclude installation of ground water monitoring wells at the relevant point of compliance at existing units, the downgradient monitoring system may be installed at the closest practicable distance hydraulically downgradient from the relevant point of compliance specified by the director under 8 CAR § 60-424(d) that ensures detection of ground water contamination in the uppermost aquifer.

(b) Multi-unit monitoring. The director may approve a multi-unit ground water monitoring system instead of separate ground water monitoring systems for each landfill when the facility has several units, provided the multi-unit ground water monitoring system meets the requirement of 8 CAR § 60-1201 and will be as protective of human health and the environment as individual monitoring systems for each landfill, based on the following factors:

1. (1) Number, spacing, and orientation of the landfill units;
2. (2) Hydrogeologic setting;
3. (3) Site history;
4. (4) Engineering design of the landfills; and

5. (5) Type of waste accepted at the landfills.

   1. (c) Well construction and decommissioning requirements:
6. (1) Monitoring wells must be constructed in accordance with 8 CAR § 60-1103;
7. (2) The owner or operator must notify the director that the design, installation, development, and decommission of any monitoring wells, piezometers, and other measurement, sampling, and analytical devices documentation has been placed in the operating record; and

8. (3) The monitoring wells, piezometers, and other measurement, sampling, and analytical devices must be operated and maintained so that they perform to design specifications throughout the life of the monitoring program.

   1. (d) Site-specific design. The number, spacing, and depths of monitoring systems shall be determined based upon site-specific technical information developed in accordance with the requirements of Subpart 11 of this part that must include thorough characterization of:
9. (1) Aquifer thickness, ground water flow rate, ground water flow direction, including seasonal and temporal fluctuations in ground water flow; and

10. (2) Saturated and unsaturated geologic units and fill materials overlying the uppermost aquifer, materials comprising the uppermost aquifer, and materials comprising the confining unit defining the lower boundary of the uppermost aquifer, including, but not limited to:

    1. (A) Thickness;
    2. (B) Stratigraphy;
    3. (C) Lithology;
    4. (D) Hydraulic conductivities;
    5. (E) Porosities; and
    6. (F) Effective porosities.

(e) Certification.

1. (1) The ground water monitoring system must be certified by a qualified ground water scientist or approved by the director.
2. (2) Within fourteen (14) days of this certification, the owner or operator must notify the director that the certification has been placed in the operating record.