A leak in the shaft for a natural gas pipeline beneath a Georgia river has reinforced environmental worries at Florida’s Suwannee River and other waterways in the pipeline’s path.

The leak into the Withlacoochee River near Valdosta, Ga. underscored earlier concerns about twin hazards from the Sabal Trail pipeline: that pipeline shafts could leak contaminants into rivers, and let river water escape through cracks in the area’s sinkhole-riddled bedrock.

"What they said couldn’t happen did happen," said John Quarterman, president of the WWALS Watershed Coalition Inc., a group fighting work on the 515-mile pipeline planned to cross three states.

The aquifer feeding North Central Florida’s signature rivers and springs already faces long-term supply strains, and pipeline critics argue that underground drilling could compound those if it accidentally opened routes for water to drain into underground voids and caverns.

The leak last month didn’t cause any harm, but the pipeline was already controversial.

Fourteen people – five from the Jacksonville area – were jailed over the weekend in Gilchrist County, west of Gainesville, after a demonstration protesting the project’s use of water from the Santa Fe River.

Another demonstration, opposing both Sabal Trail and the Dakota Access pipeline in North Dakota, is planned Tuesday outside the U.S. Army Corps of Engineers office on Jacksonville’s Southbank.

A contractor for Sabal Trail Transmission, the company building the pipeline, told Georgia’s Environmental Protection Division last month that material it described as "drilling mud" appeared in the Withlacoochee west of Valdosta, Ga., while workers were drilling a pilot hole under the river, a first step toward installing the pipeline.

Drilling mud is made with bentonite, a clay containing aluminum that reduces friction and is used in some construction for waterproofing.

But it wasn’t waterproof enough last month.

As a crew drilled Oct. 20 under the Withlacoochee, near U.S. 84 between Valdosta and Quitman, Ga., an environmental contractor emailed regulators that "some kind of substance" floated to the river’s surface, and workers put up a barrier to keep it from moving downstream. The next day, the same contractor told the state drilling mud was found on the riverbed in about 2 feet of water.

Georgia officials didn’t return messages left by phone and email Monday.

A Sabal Trail Transmission spokeswoman, Andrea Grover, said the state and the Federal Energy Regulatory Commission "have reviewed and are satisfied that the work and containment is appropriate."

Quarterman said he learned of the contractor’s emails Friday, when a state employee working through the Veteran’s Day holiday forwarded them to him as part of a public records request.

Quarterman said he didn’t know how the state reacted to the leak last month, but that two members of his organization checked the river Saturday and found a barrier still looping around a section of the waterway that was discolored.

The contractor’s emails to the state said drilling for the pilot hole was about 400 feet short of being complete on Oct. 21, but a construction progress report filed with the Federal Energy Regulatory Commission said that by Oct. 30 the pilot hole had been completed.

The report to the commission, which regulates gas pipelines, didn’t mention a leak.

"There was never any danger to human health or safety, and no harm to the environment," Grover said.

But pipeline opponents had warned about risks before and said the leak shouldn’t have happened.

"I am so angry because this is what we said would happen and we were assured the rivers wouldn’t be affected because they were drilling under them," Deanna Mericle, a member of WWALS, said in a release from the group describing the river Saturday.

"… We told them it was likely because of our karst geology and we got patronized and patted on the head. You can guarantee they will downplay it and just drill another hole," Mericle said in the weekend statement.

Karst geology is the pattern of limestone bedrock and unpredictable voids that happens in a lot of Florida where water has gradually washed away porous rock.

That process leads to sinkholes, and water management officials questioned whether underground drilling for the pipeline could create problems.

"We were considering the crossings of the rivers. … The porosity in the area is pretty high," Carlos Herd, director of the Suwannee River Water Management District’s water supply division, said during a videotaped hearing last year about a challenge WWALS brought last year to fight approval of the pipeline by Florida’s Department of Environmental Protection.

An administrative law judge concluded the group, which advocates for several watersheds near the Florida-Georgia border, didn’t show it had legal standing for the challenge. The judge said concerns the group’s members couldn’t enjoy rivers like the Suwannee or Santa Fe if they were damaged was "speculative."

A spokeswoman for Florida’s Department of Environmental Protection said the federal commission will regulate the pipeline, but state regulators inspected work as it progressed, the most recent time being last week. No problems were found, said the spokeswoman, Dee Ann Miller.

State officials will examine the Santa Fe by boat this week for water-quality violations or problems with construction runoff or other debris making the river too cloudy, Miller said.

Demonstrators arrested over the weekend were protesting the fact that water from the Santa Fe was being loaded into trucks for work on the pipeline project.

Protesters blocked a truck as it tried to move into a work area, with some climbing onto the trailer truck or getting under it, said Gilchrist County chief deputy Jeff Manning. He said one person used a bicycle lock around his neck to attach himself to the truck.

Steve Patterson: (904) 359-4263