Months Later, Oklahoma’s Salt Fork River Fish Kill is Still a Mystery

• Joe Wertz
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  Joe Wertz was a reporter and managing editor for StateImpact Oklahoma from 2011-2019. He reported on energy and environment issues for national NPR audiences and other national outlets. He previously worked as a managing editor, assistant editor and staff reporter at several major Oklahoma newspapers and studied journalism at the University of Central Oklahoma.

A summer fish kill in north-central Oklahoma is worrying anglers, river-goers and nearby water users.

The Salt Fork River die-off was massive and, still months after it was reported, mysterious. Researchers and state authorities say they still don’t know who or what the killer is.

Bob Sands / OETA

The scene of the Salt Fork fish kill in June 2013.

Two fish kills were reported to the Oklahoma Department of Environmental Quality, records show. The first one on June 3, upstream near Lamont; the second on June 17, near Tonkawa. The two fish kills are likely related, so state authorities are investigating them as one event, officials from the DEQ, state Department of Wildlife Conservation and Corporation Commission tell StateImpact.

“In the areas that overlapped during the kills, there is absolutely zero aquatic life other than turtles,” says Spencer Grace, a state game warden stationed in Kay County.

Most of the Salt Fork’s large fish — including catfish like flatheads and spoonbills — died in the two fish kills, Grace says. The demise of these hardy fish is worrying and puzzling.

Local angler Baron Owens says he watched a parade of 60-pound dead catfish float down the river.

“They were all running up on the bank and dying, but the buzzards wouldn’t even eat them,” he says. “Buzzards will eat anything. I mean, it doesn’t matter. It’s the first time I’ve ever seen something like that. It’s crazy.”

DEQ investigators took water samples from the river and sent dead fish specimens to a lab for analysis. The agency’s final report is pending, but preliminary results showed astronomically high levels of salt, says environmental programs manager Jay Wright.

“When you compare them to data the Water Resource Board has collected over the last 12-15 years, these were some of the highest readings that had been recorded there,” Wright says.

Pass the Salt

Fish kills are common in Oklahoma lakes, rivers and streams — especially in the summer. Most are caused by golden algae, like the June outbreak at Altus-Lugert Lake, which rendered the southwestern Oklahoma reservoir “dead as a fishery.”

Most Oklahoma fish kills are caused by low levels of dissolved oxygen, but preliminary tests of the Salt Fork water showed plenty of dissolved oxygen.

Drought makes fish kills more likely, says Buck Ray, an environmental biologist at the Oklahoma Department of Wildlife Conservation who’s helped with the Salt Fork investigation.

Bob Sands / OETA

Thousands of large fish, including flatheads and spoonbills, died in the June fish kill on the Salt Fork River.

“There’s no rain bringing freshwater in, so what’s in the lake or river just stagnates and concentrates,” Ray says.

But Ray says drought alone doesn’t explain the record-high salt content recorded in the Salt Fork River. Strangely, each of the two Salt Fork fish kills followed rainstorms.

“We had fresh water coming in,” says game warden Grace. “Also something else coming with it, either from on the surface or from below.”

Not Well

So where could the salt come from?

One clue might be in the name of the river itself. The Salt Fork is fed by the Great Salt Plains Reservoir, which is flanked by a great salt flat filled with salty crystals and deposits. It’s possible that the rainstorms washed a natural salty deposit into the river.

Officials at the state agencies investigation the fish kill have no record of this happening in the past, but say it’s conceivable.

There’s another source of saltwater in north-central Oklahoma: Oil and natural gas drilling.

The Salt Fork snakes through the Mississippi Lime, a promising oil play that’s one of the state’s most active. Saltwater is a byproduct of many oilfield operations, including drilling. Briny fluid is also used in extraction operations like hydraulic fracturing, the extraction process known as “fracking.” Oilfield saltwater is stored in tanks, transported in trucks and pipelines and injected deep underground into disposal wells designed to trap the toxic water in layers of rock.

But the chemical composition of the salt contamination in the river doesn’t match the brine from a nearby disposal well, says Tim Baker, the Corporation Commission’s pollution abatement manager. The commission is currently testing other disposal wells, he says.

Game warden Grace is advising people to stay out of the river, but drinking water is also a concern. Oklahomans who have wells near the river are have reported problems, Grace says.

It’s unclear if the unknown fish kill contaminant is also responsible for bad well water, but Davy Brown, who lives on the river, says something is definitely wrong with his water.

“I got a water well here and it’s no good,” he says. “They tell me it’s fine to bathe in, but not to drink, so we’re using bottled water.”