a) Within 90 days after the Agency's approval of the corrective action plan submitted under Section 845.670, the owner or operator must initiate corrective action. Based on the schedule approved by the Agency for implementation and completion of corrective action, the owner or operator must:

1. 1) Establish and implement a corrective action groundwater monitoring program that:

   1. A) At a minimum, meets the requirements of the monitoring program under Section 845.650;

B) Documents the effectiveness of the corrective action remedy; and

1. C) Demonstrates compliance with the groundwater protection standard under subsection (c).
2. 2) Implement the corrective action remedy approved by the Agency under Section 845.670; and
3. 3) Take any interim measures necessary to reduce the contaminants leaching from the CCR surface impoundment, and/or potential exposures to human or ecological receptors. Interim measures must, to the greatest extent feasible, be consistent with the objectives of, and contribute to the performance of, any remedy that may be required by Section 845.670. The following factors must be considered by an owner or operator in determining whether interim measures are necessary:

A) Time required to develop and implement a final remedy;

1. B) Actual or potential exposure of nearby populations or environmental receptors to any of the constituents listed in Section 845.600;
2. C) Actual or potential contamination of sensitive ecosystems or current or potential drinking water supplies;
3. D) Further degradation of the groundwater that may occur if remedial action is not initiated expeditiously;
4. E) Weather conditions that may cause any of the constituents listed in Section 845.600 to migrate or be released;
5. F) Potential for exposure to any of the constituents listed in Section 845.600 as a result of an accident or failure of a container or handling system; and
6. G) Other situations that may pose threats to human health and the environment.

c) Corrective action must be considered complete when:

1. 1) The owner or operator of the CCR surface impoundment demonstrates compliance with the groundwater protection standards established by Section 845.600 has been achieved at all points within the plume of contamination that lies beyond the waste boundary;
2. 2) Compliance with the groundwater protection standards has been achieved by demonstrating that concentrations of constituents listed in Section 845.600 have not exceeded the groundwater protection standards for a period of three consecutive years, using the statistical procedures and performance standards in Section 845.640(f) and (g); and

3) All actions required to complete the remedy have been satisfied.

1. d) All CCR managed under a remedy approved by the Agency under Section 845.670, or an interim measure required under subsection (a)(3), must be managed in a manner that complies with this Part.

2. e) Upon completion of the corrective action plan, the owner or operator must submit to the Agency a corrective action completion report and certification.

   1. 1) The corrective action completion report must contain supporting documentation, including:

      1. A) Any engineering and hydrogeology reports, including monitoring well completion reports and boring logs, all CQA reports, certifications, and designations of CQA officers-in-absentia required by Section 845.290;
      2. B) A written summary of the implementation of the corrective action plan as stated in the construction permit and this Part;
      3. C) Groundwater monitoring data demonstrating compliance with subsection (c);
      4. D) Any remedial actions completed under subsection (d);
      5. E) Documentation showing compliance with the selected remedy requirements of Section 845.670(b); and
      6. F) Any other information relied upon by the qualified professional engineer in making the closure certification.
   2. 2) The corrective action completion certification must include a statement from a qualified professional engineer attesting that the corrective action plan has been completed in compliance with the requirements of subsection (c).
   3. 3) The owner or operator must place the corrective action completion report and certification in the facility's operating record as required by Section 845.800(d)(18).