2015 AOC Investigation and Remediation: Groundwater Flow Patterns

Understanding the flow patterns of groundwater in the subsurface is important to assess the environment in the Red Hill area and investigate contamination around and underneath the facility.

The Navy has modeled groundwater flow in the past, but additional work is needed to ensure that models developed for the area reflect actual groundwater flow conditions. The results of the modeling efforts, both for groundwater flow and contaminant fate and transport, will inform decisions on the feasibility and necessity of recovering any leaked fuel.

Groundwater Modeling Workgroup

Beginning in June 2017, the Navy and the U.S. Geological Survey convened regular monthly meetings of a Red Hill Groundwater Modeling Workgroup. Members of the workgroup include representatives from the U.S. Navy, EPA, the Hawai'i Department of Health, the U.S. Geological Survey, the Hawai'i Department of Land and Natural Resources’ Commission of Water Resource Management, the University of Hawai'i , and the Honolulu Board of Water Supply. The workgroup meetings allow the Navy to demonstrate their progress in updating the groundwater flow and fate and transport modeling for the Red Hill area.

EPA and the Hawai'i Department of Health are reviewing the Navy’s environmental work as it continues to proceed. Our most recent written comments are available below.

Key Documents

• EPA and Hawai'i DOH Letter: Limited Utility of the 2023 Best Available (Groundwater Flow) Model (pdf) (243.97 KB, September 29, 2023)
  EPA and Hawai'i Department of Health Letter responding to Navy's June 28, 2023, Groundwater Flow Model Technical Memorandum.
• EPA and Hawai'i DOH Letter: Red Hill Groundwater Flow Model Deliverable Deadlines (pdf) (283.85 KB, February 6, 2023)
  EPA and Hawai'i Department of Health letter to U.S. Navy concerning Red Hill Groundwater Flow Model deliverable deadlines.
• EPA and Hawai'i DOH Letter: Response to Navy's May 20, 2022 and June 15, 2022 Submittals (pdf) (541.43 KB, August 30, 2022)
  EPA and Hawai'i Department of Health Letter responding to Navy's May 20, 2022 and June 15, 2022 Submittals
• Groundwater Model Progress Report 01, Red Hill Bulk Fuel Storage Facility (Redacted) (pdf) (92.13 MB, July 1, 2022)
  Report from Navy in response to the EPA and DOH March 17, 2022 Groundwater Flow Model Disapproval Letter. This Progress Report describes some the Navy’s progress and the next steps that the Navy recommends for developing a new model or models.
• Groundwater Flow Model Disapproval Letter with Attachments (pdf) (6.03 MB, March 17, 2022)
  Letter from EPA and HDOH to the Navy disapproving their March 2020 submittal of the Groundwater Flow Model Report. The Navy’s flow modeling effort is being conducted in support of the Investigation and Remediation of Petroleum Product Releases and Groundwater Protection and Evaluation project at the Red Hill Bulk Fuel Storage Facility, Joint Base Pearl Harbor-Hickam, O‘ahu, Hawai‘i as a part of the Administrative Order on Consent sections 6 and 7.
• Groundwater Flow Model Report (redacted) (pdf) (103.65 MB, March 25, 2020)
  Report from the Navy on groundwater flow at and near the Red Hill Bulk Fuel Storage Facility. The Navy’s flow modeling effort is being conducted in support of the Investigation and Remediation of Petroleum Product Releases and Groundwater Protection and Evaluation project at the Red Hill Bulk Fuel Storage Facility, Joint Base Pearl Harbor-Hickam, O‘ahu, Hawai‘i as a part of the Administrative Order on Consent sections 6 and 7.
• Navy Response to Regulators Approval for an Extension for Groundwater Flow Model (pdf) (2.1 MB, January 20, 2020)
  This letter is the Navy’s acknowledgement of the conditions and considerations laid out by the regulators in their approval of the Navy’s extension request. The Navy was granted an extension on the Groundwater Flow Model Deliverable as well and the Investigation of Remediation of Releases (IRR) report as a part of the Red Hill AOC.
• Navy Response to Regulator Letter on Contaminant Fate and Transport (pdf) (17.93 MB, January 13, 2020)
  This letter is the Navy’s response to a comment letter sent by the regulators on April 22nd titled “Comments on Environmental Work and Development of the Contaminant Fate and Transport Model for the Red Hill Administrative Order on Consent ("AOC") Statement of Work ("SOW")”. Response to letter by EPA/DOH found here: www.epa.gov/sites/production/files/2019-05/documents/red_hill_aoc_6and7_comments_20190422.pdf
• Navy Response to Regulator Letter on Vadose Zone Model Comments (pdf) (3.08 MB, January 13, 2020)
  This letter is the Navy’s response to a comment letter sent by the Regulators on July 1st titled “Comments on Vadose Zone Modeling for the Red Hill AOC SOW. Response to letter by EPA/DOH found here: www.epa.gov/sites/production/files/2019-09/documents/comments_vadose_zone_modeling-2019-07-01.pdf
• Comments on Red Hill Environmental Work (pdf) (433.48 KB, July 1, 2019)
  EPA and Hawai'i DOH comments on Vadose Zone Modeling for the Red Hill Administrative Order on Consent ("AOC") Statement of Work ("SOW").
• Regulatory Agency Comments on Environmental Work: Red Hill AOC 6 and 7 (pdf) (5.71 MB, April 22, 2019)
  Comments on Environmental Work and Development of the Contaminant Fate and Transport Model for the Red Hill Administrative Order on Consent ("AOC") Statement of Work ("SOW").
• Additional Documents