As officials respond to the fallout of a water contamination crisis tied to the Navy’s Red Hill fuel tanks, they are concerned that pollution from the facility could migrate toward civilian wells but say there is a lack of critical information to assess how and when that could happen.

Scientists are struggling to pin down vital details, including exactly how much fuel contamination is under the World War II-era facility, how much already has spread, how quickly it’s moving and what direction it may be going, according to academics, regulators and other stakeholders.

Despite the yearslong threat the Navy facility posed to Honolulu’s water supply, the aquifer that lies beneath it has not been thoroughly studied and therefore is not well understood, experts said.

Now that Pearl Harbor area communities were sickened by fuel contamination, the work of groundwater modeling has taken on new urgency.

The Navy continues to pump water out of the Red Hill shaft, filter it and discharge it into the Halawa Stream, but contamination remains. Courtesy: U.S. Navy/2022

Complex Aquifer

The issue has critical implications for environmental remediation in Oahu’s primary aquifer and tracking additional threats to the island’s drinking water supply after fuel that leaked from the Red Hill facility late last year affected the tap water used by some 93,000 people in the Pearl Harbor area.

The Board of Water Supply closed three of its wells as a protective measure since it gets water from the same aquifer, which stores water in the porous lava rock beneath the ground.

“Where are those contaminants in the groundwater? Are they just under Red Hill, or are they somewhere else?” asked Clifford Voss, a hydrologist with the University of Hawaii Water Resources Research Center. “Without having that information, we’re working blind. We don’t really know what to do about it.”

The Navy, the Hawaii Department of Health, the U.S. Geological Survey, the Honolulu Board of Water Supply and the Hawaii State Commission on Water Resource Management are all actively working to gain a better understanding of the groundwater flow in this area.

The University of Hawaii is seeking $5 million in grants from the Office of Naval Research to fund multiple studies on the geophysics and groundwater around Red Hill.

A major challenge is that the geology of Oahu’s aquifer is unique and complex. The underground landscape can be drastically different just tens of feet apart, according to Fenix Grange, a supervisor in the health department’s Hazard Evaluation and Emergency Response Office.

Illustration of Hawaii's aquifer system where rainfall moves through the ground and collects in underground freshwater aquifers.
An illustration of Hawaii’s aquifer system. View full size. April Estrellon/Civil Beat/2022

Don Thomas, a geochemist at the University of Hawaii, compared it to a paint-by-numbers canvas with only 20% of the cells filled in with color.

“It’s still pretty hard to understand what it is you’re looking at,” he said.

Fuel from last year’s leaks — totaling an estimated 19,000 gallons — is likely combined with fuel from earlier releases, including a 27,000-gallon leak in 2014, in Oahu’s groundwater, the Board of Water Supply said.

The Navy has worked to clean up the latest release, but fuel is still in the Red Hill well and underneath a nearby tunnel, according to Grange. The Navy did not respond to multiple requests for interviews.

Military Model Rejected

Where that contaminated groundwater is headed is a matter of debate.

The Navy has maintained for years that the water under its facility moves from the mountain to the ocean and would not threaten the civilian water source as long as its own Red Hill well was pumping water.

But earlier this month, the Environmental Protection Agency and the state Department of Health officially rejected the military’s groundwater flow model that had been submitted in 2020 and ordered the Navy and the Defense Logistics Agency to make corrections.

“The Navy’s model is not what is being observed in the field,” said Erwin Kawata, a program administrator for the Honolulu Board of Water Supply.

Red Hill groundwater flow model #51e
One of the groundwater flow scenarios submitted by the Navy shows water flowing toward Pearl Harbor. It’s not necessarily the flow of contamination, which will be addressed in a future study. April Estrellon/Civil Beat/2022

Understanding Red Hill’s groundwater flow will be a critical factor in the Honolulu Board of Water Supply’s decision on whether to reopen the three wells near the Navy’s Red Hill shaft, BWS officials said. That includes the Halawa Shaft, which provided 20% of the supply for the region spanning Moanalua to Hawaii Kai.

BWS, unable to make up the difference with its remaining wells, has called on residents to conserve water and warned of impending shortages that could impact daily life and the island’s economy. New wells could take five to seven years to get online, and BWS Chief Engineer Ernie Lau has said he will not reopen the closed wells until he is certain the water pumped from them will be clean.

‘There Ain’t An Easy Way’

Scientists have been trying to learn about Oahu’s groundwater flow since at least the 1940s, according to Bob Whittier, a health department geologist. Whittier said he himself has been exploring the subject for more than 20 years.

“It has been ongoing for some time,” he said.

The conventional thinking has been that groundwater in the Red Hill area flows from the mountains toward Pearl Harbor. But there are many potential complicating factors, including valley fills, geological barriers that water can’t easily permeate and other impacts of volcanic eruptions thousands of years ago that can steer water a certain way.

It’s possible that a geological barrier could block Red Hill contamination from reaching the Halawa shaft, Thomas said, but that question needs to be studied.

Red Hill groundwater flow model #53
The Navy’s groundwater flow models acknowledge that groundwater could move from under the Red Hill tanks to the Halawa shaft. The flow of contamination will be examined in a future study. April Estrellon/Civil Beat/2022

Focus on Red Hill’s groundwater flow intensified after the 2014 leak at the fuel facility, Grange said. As part of a regulatory agreement, called the Administrative Order on Consent, the Navy was ordered to study the subject and report back to regulators.

The Navy submitted its 700-page Groundwater Flow Model Report in March 2020. Regulators tested the model for a year and later spent “considerable time” in technical meetings with the Navy talking about how to improve it, according to EPA Red Hill Project Coordinator Gabriela Carvalho.

In the end though, regulators said the military got it wrong.

According to a letter DOH and the EPA sent to the Navy, the military’s model is “geologically implausible” and included so many deficiencies that the results can’t be trusted to keep the aquifer safe. Regulators outlined eight major problems with the Navy’s model, any of which would be grounds for plan rejection on its own, regulators said.

Regulators had warned the Navy about problems in its groundwater modeling approach for years, they said, but the Navy apparently disregarded that feedback.

It will be expensive and difficult to clean up the fuel contamination, experts say. Courtesy: U.S. Navy/2022

DOH wrote in its response that the Navy’s model needs to be verifiable and advised doing field studies to support its predictions.

One major problem with the Navy’s model was its suggestion that in the case of a contamination event, the Red Hill shaft — the well that provided drinking water to Joint Base Pearl Harbor-Hickam — could act as a “vacuum” for the aquifer, Kawata said.

The military model indicated the well could be pumped such that it would suck up the pollution, containing the damage, according to Kawata. The Navy has referred to it as a “capture zone.”

But now that contamination has occurred, that contention has been disproven, Kawata said. Monitoring wells around the Red Hill facility show levels of contamination that are stagnant or elevated, he said.

If the BWS’ Halawa Shaft were still pumping, the water utility believes it would pull the Red Hill groundwater contamination toward it. But with Halawa pumping turned off, it’s unclear how long it would take for the polluted water to reach the well, Kawata said.

Fuel does degrade in the environment over time, Kawata said. But experts don’t know the extent to which that would happen in Oahu’s aquifer, nor how quickly.

“There’s a lot of debate about that too,” Kawata said.

After regulators approve the Navy’s groundwater modeling regime, the Navy will have six months to submit a report on how it believes fuel will move in the aquifer. Grange said DOH is encouraging the Navy to complete that report, called a “fate and transport” study, sooner rather than later.

To get answers, scientists will need to drill “observation wells” into the water table, collect data and map the contamination — an expensive and difficult process, UH’s Voss said.

“There ain’t an easy way,” he said.

While some geophysical techniques allow scientists to detect substances underground, Voss said he’s not aware of one for petroleum products. In theory, one could track the contamination’s movement by testing petroleum byproducts in Pearl Harbor to see if they match Red Hill’s fuel. But the water there is already so polluted that likely wouldn’t be helpful, Voss said.

If the contamination is only located directly beneath the tanks, Voss said it could be possible to inject cement to try to contain it. If it has spread, water treatment will be a must, Voss said. It’s likely the fuel isn’t just floating on top of the water but has also dissolved into it, he said.

Overall, Kawata said groundwater modeling will be useful, but it won’t solve Oahu’s immediate water needs.

“It tells you the nature and extent of the damage or contamination itself and will help us make informed decisions about our next steps,” he said.

“In the meantime, we need to move forward in an expeditious way to look for new wells and new water supplies to try to make up the capacity lost from the wells that are shut down.”

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