Section 616.205  Groundwater Monitoring Program

The owner or operator must develop a groundwater monitoring program that consists of:

a)         Consistent sampling and analysis procedures that are designed to ensure monitoring results that provide a reliable indication of groundwater quality below the unit.  At a minimum, the program must include procedures and techniques for:

1)         Sample collection;

2)         Sample preservation and shipment;

3)         Analytical procedures; and

4)         Chain of custody control.

b)         Sampling and analytical methods that are appropriate for groundwater monitoring and that allow for detection and quantification of contaminants specified in this Subpart, and that are consistent with the sampling and analytical methods specified in 35 Ill. Adm. Code 620.

c)         Determining the groundwater head elevation each time groundwater is sampled.

d)         Determining at least annually the groundwater flow rate and direction.

e)         If the owner or operator determines that the groundwater monitoring program no longer satisfies the requirements of this Section, the owner or operator must, within 90 days, make appropriate changes to the program. Conditions under which a groundwater monitoring program no longer satisfies the requirements of this Section include:

1)         A Maximum Allowable Result (MAR) is exceeded in any monitoring well that is being used as a background monitoring well or that the owner or operator has previously determined to be hydraulically upgradient from the facility; or

2)         A redetermination of groundwater flow rate and direction conducted under subsection (d) shows that the existing monitoring system is not capable of assessing groundwater quality at the compliance points or points.

(Source:  Amended at 47 Ill. Reg. 7631, effective May 16, 2023)