New scientific research has added more evidence about the risks of mining near the Okefenokee Swamp, with potential implications for future permitting applications.
Philanthropists neutralized the latest attempt to withdraw minerals near the ancient wetland by purchasing property on Trail Ridge.
Twin Pines Minerals was engaged in a years-long petition to mine titanium dioxide when the Conservation Fund announced the purchase agreement in June.
The company had argued that its plans to draw an average of 1.4 million gallons of water a day from an aquifer deep underground would not harm the swamp.
Environmentalists and scientists asserted that water withdrawal of that magnitude would lower the swamp’s water level. That in turn, they argued, would wreak havoc on a rich ecosystem that is among the best preserved blackwater wetlands in the world and home to endangered and threatened species
Now, researchers have found more evidence that the Okefenokee is linked to the aquifer and that drawing water from the aquifer would effectively draw water from the swamp.
In an article published last week in Environmental Research: Water, University of Georgia scientists report that water in the Okefenokee has the same “fingerprint” as water in nearby parts of the much larger aquifer deep underground, which means the Okefenokee is likely draining into the aquifer.
Water samples can have different atomic mass, or isotopes, depending upon the number of neutrons present. Water that has undergone significant evaporation can be a heavier isotope, and scientists used this characteristic to document similarities between what is in the Okefenokee and what they extracted from the Upper Floridian Aquifer beneath it. Water in the aquifer that was farther from the swamp was lighter.
They also found another connection: they examined decades of records and found that the swamp and aquifer water levels tracked each other. When the swamp level rose after a rainstorm, the aquifer would rise a month later.
For years, a thick intervening layer of clay known as the Hawthorne Formation was assumed by some to create an impermeable barrier between the two bodies of water.
The UGA researchers’ finding of similar isotopes in both the swamp and nearby parts of the aquifer “overturns long-held assumptions in the region’s hydrogeologic conceptual model and has implications for water budgets, ecological dynamics, and groundwater management,” they wrote.
Todd Rasmussen, emeritus professor of hydrology at UGA, was one of the three authors.
He said the evidence is strong enough to suggest at least a temporary policy against mining in Charleton, Clinch and Ware counties, where most of the swamp is located.
“There should be a moratorium on groundwater pumping in those counties until further evaluations have been conducted,” Rasmussen said.
He said the state Environmental Protection Division, which was considering the Twin Pines’ permit application, saw the Hawthorne Formation as a solid barrier despite what he considered to be inadequate data about its effectiveness as a water seal.
The agency had no comment. Spokeswoman Sara Lips said Monday that Division staff had a copy of the study but had not had sufficient time to review it.
Although Rasmussen and other scientists had already hypothesized a connection between the swamp and the aquifer, this new finding provides more solid evidence.
Jordan Clark, a University of California at Santa Barbara hydrology professor, used isotopes to trace water in the Upper Floridian Aquifer in the 1990s. He was not involved in the new study, but it cites his work.
He rated the research approach in the new study as “pretty strong” and “very valid.”
Clark said, however, that further testing to confirm that the water in the aquifer isn’t ancient would provide more solid confirmation of a connection, since some theorize that the aquifer was filled by glaciers over 10,000 years ago.
He said evidence of human influence, such as traces of atomic testing from the 1950s and 1960s that would have been present in groundwater, would be more convincing. But he also said he doubts the aquifer is still holding water from 10,000 years ago and that water recharge from the surface in the past half century is probably the easiest explanation for the aquifer’s water source.
Activist Josh Marks, a lawyer who wants to protect the Okefenokee and who fought the mining permit, heralded the findings as a “game changer” that proves a mine would harm the swamp. He said the Environmental Protection Division’s position on the issue is “yet another reminder” that the agency “is simply incapable of regulating mining at the Okefenokee” and that lawmakers should step in and ban mining there.
Megan Huynh, a senior attorney over the Southern Environmental Law Center’s wetlands and coastal protection program, said the new research will be useful if another landowner seeks permission to mine near the swamp.
“The science was out there already to say that mining next to the Okefenokee couldn’t be done safely and was a bad idea,” she said. “This is more evidence to support that.”
The device that Jaivime Evaristo, co-author of new research about water “fingerprints” linking the Okefenokee Swamp to an aquifer below, used to measure water isotopes. Evaristo is a University of Georgia assistant professor of hydrology and water resources. (Courtesy of Jaivime Evaristo)
This article is available through a partnership with Capitol Beat News Service, a project of the Georgia Press Association’s nonprofit, tax-exempt Educational Foundation.
