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HomeMy WebLinkAboutHercules CAP Response Letter 02-02-21ROY COOPER Governor MICHAEL S. REGAN Secretary S. DANIEL SMITH Director NORTH CAROLINA Environmental Quality February 2, 2021 Chrissy Piechoski, Remediation Project Manager Ashland Hercules Research Center 500 Hercules Road Wilmington, DE 19808 Re Corrective Action Plan Report (CAP) Former Cape Industries Waste Injection Facility (Hercules) Wilmington, New Hanover County, North Carolina Sent via Email as Attachment Dear Ms. Piechoski: The Division of Water Resources (DWR) received the Corrective Action Plan (CAP) for the Former Cape Industries Waste Injection Facility (Hercules). Thank you. Staff has reviewed the CAP and have the following few comments/requests. Section 6 Numerical Model (MODFLOW, MT31)) It appears that there are incorrect references to sections in the CAP. In some cases, these references pertain to sections in the previously submitted 2018 Site Assessment Report (SAR). For example, in Section 6.3 of the CAP is the following: In order to model the vertical transport, the MODFLOW domain included layers individually representing the aquifers and aquicludes described in Section 3.3 and shown in Figure 31. Section 3.3 in the CAP concerns analytical parameters. Section 3.3 in the SAR includes the hydrogeologic layers. Please double check all references to sections and figures in the CAP and correct where needed. Section 8 Proposed Correction Actions Section 8.3.4(9) states the following: (9) that public notice of the request has been provided in accordance with Rule. 0114(b) of this Section; and • Public notice of this CAP submittal to the NCDEQ will be published for public notice per Rule .0114(b) of this Section. Please provide documentation that the requirements of 15A NCAC 02L .0114(b) have been met. DNorth Carolina Department of Environmental Quality Division of Water Resources E Q�� _ 512 North Salisbury Street 1 1636 Mail Service Center I Raleigh, North Carolina 27699-1636 NORTH CAROLINA Department of Emimnmental Quality /`� 919.707.9000 NCDEQ Division of Water Resources Groundwater Resources Section 3/22/2021 Page 2 of 2 Section 9 Corrective Action Performance Monitoring The proposed 5-year monitoring frequency is inappropriate. The next sampling event should be in 2022, which would be the scheduled time under the current 2-year monitoring cycle for this site. After review of laboratory analytical results in 2022, staff may recommend a modification to a 3- year monitoring frequency. Therefore, please provide a Monitoring Plan Table listing the wells, parameters, and proposed frequency with the next sampling event occurring in 2022, and then every 3 years thereafter. Section 10 Summary The third check mark item states the following: Abandon wells once gas generation is negligible allowing for safe abandonment of the wells (or sooner if a well is in imminent risk of failure). Please include a Well Inspection Plan on how and when the wells will be inspected (i.e., visually inspect, remotely or visually monitor pressure, how often, etc.). In addition to inspection methods, the plan should also have in place contingency steps to take in the event a well is determined to be in imminent risk of failure. Conclusion Please submit a revised CAP titled Corrective Action Plan (Revised) reflecting changes to the items above. For the ease of the reviewer/reader, somewhere in the CAP please list those pages that have been modified or sections where new pages have been inserted. This could be in the cover or transmittal letter. If you have any questions regarding this letter please contact me at Michael.Rogers(kncdenr.gov or Rick Bolich at rick.bolich(kncdenr.gov Sincerely, Michael Rogers, PG (NC & FL) UIC Program Manager - Hydrogeologist NC Division of Water Resources cc Morella Sanchez King, Wilmington Regional Office Scott Andresini, GESOnline