R315-319-95. Groundwater Monitoring and Corrective Action - Assessment Monitoring Program

  (a) Assessment monitoring is required whenever a statistically significant increase over background levels has been detected for one or more of the constituents listed in appendix III to Rule R315-319.

  (b) Within 90 days of triggering an assessment monitoring program, and annually thereafter, the owner or operator of the CCR unit shall sample and analyze the groundwater for all constituents listed in appendix IV to Rule R315-319. The number of samples collected and analyzed for each well during each sampling event shall be consistent with Subsection R315-319-93(e), and shall account for any unique characteristics of the site, but shall be at least one sample from each well.

  (c) The owner or operator of a CCR unit may demonstrate the need for an alternative monitoring frequency for repeated sampling and analysis for constituents listed in appendix IV to Rule R315-319 during the active life and the post-closure care period based on the availability of groundwater. If there is not adequate groundwater flow to sample wells semiannually, the alternative frequency shall be no less than annual. The need to vary monitoring frequency shall be evaluated on a site-specific basis. The demonstration shall be supported by, at a minimum, the information specified in Subsections R315-319-95(c)(1) and (2).

  (1) Information documenting that the need for less frequent sampling. The alternative frequency shall be based on consideration of the following factors:

  (i) Lithology of the aquifer and unsaturated zone;

  (ii) Hydraulic conductivity of the aquifer and unsaturated zone; and

  (iii) Groundwater flow rates.

  (2) Information documenting that the alternative frequency will be no less effective in ensuring that any leakage from the CCR unit will be discovered within a timeframe that will not materially delay the initiation of any necessary remediation measures.

  (3) The owner or operator shall obtain a certification from a qualified professional engineer stating that the demonstration for an alternative groundwater sampling and analysis frequency meets the requirements of Section R315-319-95. The owner or operator shall include the demonstration providing the basis for the alternative monitoring frequency and the certification by a qualified professional engineer in the annual groundwater monitoring and corrective action report required by Subsection R315-319-90(e).

  (d) After obtaining the results from the initial and subsequent sampling events required in Subsection R315-319-95(b), the owner or operator shall:

  (1) Within 90 days of obtaining the results, and on at least a semiannual basis thereafter, resample all wells that were installed pursuant to the requirements of Section R315-319-91, conduct analyses for all parameters in appendix III to Rule R315-319 and for those constituents in appendix IV to Rule R315-319 that are detected in response to Subsection R315-319-95(b), and record their concentrations in the facility operating record. The number of samples collected and analyzed for each background well and downgradient well during subsequent semiannual sampling events shall be consistent with Subsection R315-319-93(e), and shall account for any unique characteristics of the site, but shall be at least one sample from each background and downgradient well;

  (2) Establish groundwater protection standards for all constituents detected pursuant to Subsection R315-319-95(b) or (d). The groundwater protection standards shall be established in accordance with Subsection R315-319-95(h); and

  (3) Include the recorded concentrations required by Subsection R315-319-95(d)(1), identify the background concentrations established under Subsection R315-319-94(b), and identify the groundwater protection standards established under Subsection R315-319-95(d)(2) in the annual groundwater monitoring and corrective action report required by Subsection R315-319-90(e).

  (e) If the concentrations of all constituents listed in appendices III and IV of Rule R315-319 are shown to be at or below background values, using the statistical procedures in Subsection R315-319-93(g), for two consecutive sampling events, the owner or operator may return to detection monitoring of the CCR unit. The owner or operator shall prepare a notification stating that detection monitoring is resuming for the CCR unit and submit the notification to the Director for approval. The owner or operator has completed the notification when the notification is placed in the facility's operating record as required by Subsection R315-319-105(h)(7).

  (f) If the concentrations of any constituent in appendices III and IV to Rule R315-319 are above background values, but all concentrations are below the groundwater protection standard established under Subsection R315-319-95(h), using the statistical procedures in Subsection R315-319-93(g), the owner or operator shall continue assessment monitoring in accordance with Section R315-319-95.

  (g) If one or more constituents in appendix IV to Rule R315-319 are detected at statistically significant levels above the groundwater protection standard established under Subsection R315-319-95(h) in any sampling event, the owner or operator shall prepare a notification identifying the constituents in appendix IV to Rule R315-319 that have exceeded the groundwater protection standard. The owner or operator has completed the notification when the notification is placed in the facility's operating record as required by Subsection R315-319-105(h)(8). The owner or operator of the CCR unit also shall:

  (1) Characterize the nature and extent of the release and any relevant site conditions that may affect the remedy ultimately selected. The characterization shall be sufficient to support a complete and accurate assessment of the corrective measures necessary to effectively clean up all releases from the CCR unit pursuant to Subsection R315-319-96. Characterization of the release includes the following minimum measures:

  (i) Install additional monitoring wells necessary to define the contaminant plume(s);

  (ii) Collect data on the nature and estimated quantity of material released including specific information on the constituents listed in appendix IV of Rule R315-319 and the levels at which they are present in the material released;

  (iii) Install at least one additional monitoring well at the facility boundary in the direction of contaminant migration and sample this well in accordance with Subsection R315-319-95(d)(1); and

  (iv) Sample all wells in accordance with Subsection R315-319-95(d)(1) to characterize the nature and extent of the release.

  (2) Notify all persons who own the land or reside on the land that directly overlies any part of the plume of contamination if contaminants have migrated off-site if indicated by sampling of wells in accordance with Subsection R315-319-95(g)(1). The owner or operator has completed the notifications when they are placed in the facility's operating record as required by Subsection R315-319-105(h)(8).

  (3) Within 90 days of finding that any of the constituents listed in appendix IV to Rule R315-319 have been detected at a statistically significant level exceeding the groundwater protection standards the owner or operator shall either:

  (i) Initiate an assessment of corrective measures as approved by the Director and as required by Subsection R315-319-96; or

  (ii) Demonstrate that a source other than the CCR unit caused the contamination, or that the statistically significant increase resulted from error in sampling, analysis, statistical evaluation, or natural variation in groundwater quality. Any such demonstration shall be submitted to and has received approval from the Director and supported by a report that includes the factual or evidentiary basis for any conclusions and shall be certified to be accurate by a qualified professional engineer. If a successful demonstration is made, the owner or operator shall continue monitoring in accordance with the assessment monitoring program pursuant to Section R315-319-95, and may return to detection monitoring if the constituents in appendices III and IV to Rule R315-319 are at or below background as specified in Subsection R315-319-95(e). The owner or operator shall also include the demonstration in the annual groundwater monitoring and corrective action report required by Subsection R315-319-90(e), in addition to the certification by a qualified professional engineer.

  (4) If a successful demonstration has not been made at the end of the 90 day period provided by Subsection R315-319-95(g)(3)(ii), the owner or operator of the CCR unit shall initiate the assessment of corrective measures requirements under Subsection R315-319-96.

  (5) If an assessment of corrective measures is required under Subsection R315-319-96 by either Subsection R315-319-95(g)(3)(i) or (g)(4), and if the CCR unit is an existing unlined CCR surface impoundment as determined by Subsection R315-319-71(a), then the CCR unit is subject to the closure requirements under Subsection R315-319-101(a) to retrofit or close. In addition, the owner or operator shall prepare a notification stating that an assessment of corrective measures has been initiated.

  (h) The owner or operator of the CCR unit shall establish a groundwater protection standard for each constituent in appendix IV to Rule R315-319 detected in the groundwater. The groundwater protection standard shall be:

  (1) For constituents for which a ground water protection standard has been estaliblished in rule R315-308, the ground water protection standard in Rule R315-308;

  (2) For constituents for which a ground water protection standard has not been established in Rule R315-308, the background concentration for the constituent established from wells in accordance with Section R315-319-91; or

  (3) For constituents for which the background level is higher than the ground water protection standard identified under Subsection R315-319-95(h)(1), the background concentration.

  (i) The owner or operator of the CCR unit shall comply with the recordkeeping requirements specified in Subsection R315-319-105(h), the notification requirements specified in Subsection R315-319-106(h), and the Internet requirements specified in Subsection R315-319-107(h).