Navy reports no detected groundwater migration from Red Hill but expands monitoring, plans well reactivations

HONOLULU — The Navy Closure Task Force gave the Commission on Water Resource Management a detailed update May 20 on groundwater monitoring, well recovery and site assessment work at the Red Hill bulk fuel storage facility, saying the Navy’s monitoring to date has not shown contaminant migration beyond the facility. The presentation described expanded well drilling, more frequent sampling and plans to pilot treatment systems before any reactivation of the two offline production shafts.

The Navy’s director of engagement for the Red Hill task force, Megan Ostrom, and Commander Ben Dunn, the task force deputy for environment and remediation, told commissioners the Navy has installed dozens of monitoring wells and continues to plan off‑site “sentinel” wells to better cover the area between the tanks and nearby drinking‑water sources. “The data we’ve collected over the last three years, which is an extensive amount of groundwater monitoring data, does not show any contaminant migration off of Red Hill,” Commander Dunn said.

Why it matters: the Navy’s joint base drinking‑water system for Pearl Harbor‑Hickam relies on three production shafts. Two — the Red Hill Shaft and the Navy IEA Halawa Shaft — have been offline since the November 2021 contamination event. The Navy says it intends to recover both with interim and eventual permanent treatment systems, but stressed reactivation requires Department of Health approval after pilot testing and other prerequisites.

What the Navy presented and the context - Monitoring network: the Navy said it now has about 46 monitoring wells in and around the Red Hill property — roughly two‑thirds on‑site and about a third off‑site — and is targeting additional off‑site sentinel locations in the west and northwest corridor near H‑3 where fewer wells exist. Wells are sampled on a rotating schedule; higher‑priority wells are sampled more frequently. - Sampling and lab turnaround: the Navy samples many wells twice a month; most laboratory analyses are shipped to EPA‑certified mainland labs and take roughly one to two weeks for results and data validation. - Monitoring results: Dunn noted the extensive dataset does not show a trend of chemicals migrating off site or even across Red Hill, but he cautioned that groundwater moves slowly and that more wells are needed to increase confidence. The Navy’s groundwater flow model estimates groundwater velocities on the order of a quarter‑mile to a third‑mile per year in the study area. - Drinking‑water sources: the Navy described its three production shafts (Wai‘awa, Red Hill and Navy IEA Halawa), noting Wai‘awa is the largest capacity well and the other two are smaller. Navy IEA Halawa has low PFAS detections historically; the Navy installed a temporary granular activated carbon (GAC) system…