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Navy Reduces Water Pumping Operations at Red Hill Shaft

by Navy Closure Task Force-Red Hill Public Affairs
30 April 2024

Navy reduces granular activated carbon water pumping system rates from 4.2 to 1.8 million gallons per day 

The Navy began reducing water pumping operations at the Red Hill Shaft from 4.2 million gallons a day (MGD) to 1.8 MGD, April 29, after working with state regulators for months on a plan to allow the Navy to reduce the amount of water discharged into the Halawa Stream.  

Since January 2022, and at the direction of state regulators, the Navy has continuously pumped approximately 4.2 MGD to create a capture zone within the shaft to reduce the potential spread of groundwater contamination.  

The pumped water is treated through a granular activated carbon (GAC) filtration system, then discharged under a National Pollution Discharge Elimination System permit into the stream. 

The shaft is located under the Red Hill Bulk Fuel Storage Facility (RHBFSF), which Navy Closure Task Force-Red Hill (NCTF-RH) is currently working to decommission.  

The reduction will save 72 million gallons of water per month, or 864 million gallons per year.  

The reduction of water pumping rates at the Red Hill Shaft marks a major milestone in the Navy’s efforts to conserve one of Hawaii’s most important resources,” said Rear Adm. Steve Barnett, commander, NCTF-RH. 

The Navy has been working with the DOH to reduce the flow of discharge by conducting several detailed studies to evaluate the impacts of such a reduction on the environment.   

To evaluate the aquifer conditions at various pumping rates, the Navy conducted a GAC Flow Optimization survey from April 2023 to June 2023, in accordance with DOH and Environmental Protection Agency (EPA)-approved work plans. The survey included weekly groundwater sampling and water level monitoring events from 51 monitoring well locations, including the entry and exit points of the GAC, to ensure discharged water is free of contaminants.  

In May 2023, the Navy submitted the initial Consolidation and Optimization of the Groundwater Sampling Programs memorandum to EPA and DOH and received comments on July 31, 2023.  

  In August 2023 the Navy made its initial request to reduce the amount of water being pumped from the shaft, and in September 2023 the Navy submitted a final report of its findings to DOH. This report presented data to evaluate the feasibility of reducing the flow from the Red Hill Shaft to meet the objective of long-term sustainability of the drinking water resource. 

  On Nov. 15, 2023, after reviewing the Final Report of Findings, the DOH submitted a letter to the Navy indicating the study did not provide sufficient evidence that a reduction in pumping at the shaft would not result in harm to human health or the environment. DOH recognized the importance of conserving the island’s natural resources and outlined a path forward to reduce pumping rates through an increase in monitoring and evaluation of the Navy’s plans and processes. 

The Navy since acknowledged DOH’s letter and resubmitted its plan, receiving direction to implement the water flow reduction on April 22, 2024.  

During the time, the Navy installed a truck fill station at the facility to allow some of the excess water to be used to clean the inside of the tanks in the coming months. The Navy continues to evaluate other potential beneficial reuses of the water but must consider the physical site constraints and available infrastructure. 

NCTF-RH is committed to working with all government agencies and community stakeholders to safely and deliberately close the Red Hill Bulk Fuel Storage Facility underground storage tanks and associated piping system, conduct long-term environmental remediation, and ensure continued access to safe drinking water in compliance with all Federal, State, and local laws, policies and regulations. 

For more information about NCTF-RH, visit  or download the mobile app by searching for “NCTF-Red Hill” in the Apple App store or Google Play store.