Hydrologists ask EPD officials to change mining assessment
Feb. 21—A group of hydrologists from seven different universities in five states are asking state regulators to reconsider which gage they plan to use when assessing the potential impacts from mining near the Okefenokee National Wildlife Refuge.
Officials with the Georgia Environmental Protection Division plan to use a gage in Macclenny, Florida, to monitor the effects of the swamp's hydrology if mining is permitted. The professors said that gage is "inappropriate for such analysis" because it is too far away, and there is one that would provide more accurate information.
C. Rhett Jackson, a professor at the University of Georgia, sent a letter to state EPD officials that was signed by 10 other hydrology professors, urging them to use a gage at the north prong of the St. Marys River near Moniac. The professors come from Duke University, Virginia Tech, Mississippi State University, Georgia State University, University of Florida, University of Virginia and University of Georgia.
"Until now, EPD has treated this gage selection issue as simply a disagreement between one academic hydrologist (me) and their technical staff," Jackson said. "This letter shows that there is no real question about which gage is appropriate. EPD's rationale for using the Macclenny, Florida, gage is unsupportable."
He said the gage in Macclenny would provide data that is "irrelevant to the pertinent questions" needed to evaluate any impacts from mining.
"To have relevance and value, EPD's water withdrawal analyses must be redone using data from the USGS gage at Moniac, Georgia," he said.
He said a "very different conclusion" will be reached using data from the Moniac gage.
"The Macclenny gage drains a basin that is 4.4 times larger than the Moniac gage," Jackson said. "Three-quarters of the area draining to this gage is in relative highlands of north central Florida. The hydrologic inputs to this basin and the hydrologic behavior of this basin are in no way similar to that of the southeastern portion of the Okefenokee Swamp. Furthermore, the sheer size of the basin and its flows at this gage will mask the effects a fixed withdrawal would have where the river exits the swamp."
The gage in Moniac is "ideal for analyzing potential impacts to swamp hydrology of consumptive ground water withdrawals beneath Trail Ridge," he said.
Conclusions drawn from the Macclenny gate "cannot be applied to the question of how Trail Ridge groundwater withdrawals will affect the swamp."
"To assess this question, it is necessary to use flow data from the Moniac gage," he said. "I know you agree that it is important to get this right. We all want to make the best-informed decision for the State of Georgia."
