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Which was worse for water quality: Gold King Mine spill or 416 Fire floods?

Study compared metal loading in both events; results surprised researchers
The left photo shows the Animas River on July 17 after a deluge of mud, rock, ash and other debris polluted the river. The right photo shows the river on Aug. 6, 2015, after 3 million gallons of wastewater from the Gold King Mine spill turned the river orange.

A new report shows that runoff from the 416 Fire burn scar this summer dumped higher concentrations of potentially toxic metals into the Animas River than the Gold King Mine spill three years ago.

“It was surprising,” said Scott Roberts, an aquatic biologist with Mountain Studies Institute, who led the research.

“The fact is, we’ve seen actual ecological impacts from the 416 Fire runoff and still haven’t detected any impacts from the Gold King Mine spill. That is noteworthy.”

It has been a rough couple of years for the Animas River.

In August 2015, the Environmental Protection Agency accidentally caused the Gold King Mine, near Silverton, to blow out, sending 3 million gallons of toxic waste down the Animas River, turning it orange.

Then, this July, heavy rain fell over the 416 Fire burn scar in the Hermosa Creek drainage, just north of Durango, and sent a torrent of black mud, rocks and other debris down the Animas River.

After both events, Mountain Studies Institute, an environmental research and education nonprofit, extensively monitored and researched the impacts on aquatic life and water quality in the Animas River.

The Animas River just north of Durango turned orange Aug. 6, 2015, after a blowout at the Gold King Mine in Silverton. The metal-laden water tested above federal standards, but it paled in comparison to runoff from the 416 Fire.

Though only a few months removed from the July floods, the preliminary data show the impacts of the Gold King Mine spill pale in comparison to the mudslides and debris flows from the 416 Fire burn scar.

Peter Butler with the Animas River Stakeholders Group said that point was made clear when the 416 Fire runoff caused nearly all the fish in the Animas River to die.

By comparison, there has never been any evidence that the tainted Gold King Mine water caused any die-off of aquatic life.

Roberts’ study backs this with data.

The study took samples at the height of the 416 Fire debris flows on July 17 and July 24 on the Animas River, near Rotary Park, and compared it to samples taken during the mine spill as it passed through the same spot Aug. 6 to Aug. 9, 2015.

During the 416 Fire runoff, heavy metal concentrations of aluminum were 50 times higher than when the river was tainted with mine wastewater. Iron was six times higher, manganese 20 times higher, and levels of mercury were 3 times higher.

All of the metal concentrations on the water samples from 416 Fire runoff tested above EPA and state health standards.

Unlike the landscape around Silverton where the Gold King Mine is located, the Hermosa Creek drainage has no mines and is not known as a highly mineralized area, which raises the question: Where are the metals coming from?

Roberts said it is likely the disturbance on the land from the 416 Fire, which burned an estimated 54,000 acres, caused the combustion and release of metals stored in vegetation and soils.

Then, those metals were taken into the water during those big rainstorms.

Roberts said the study confirms the city of Durango’s decision to close off its water intake from the Animas River during the storms.

“Without having these numbers, the city was proactive – and for good reason,” he said.

While the metal concentrations for the 416 Fire runoff did exceed safe levels for aquatic life, it’s likely the fish die-off was more likely a result of suffocation from heavy sediment and ash in the river, Roberts said.

The Animas River just north of Durango turned black July 17 after a rain storm above the 416 Fire burn scar. The runoff sent ash, dirt, debris and metals into the river, causing a significant fish die-off.

Calls to Colorado Parks and Wildlife aquatic biologist Jim White were not returned this week.

Butler said some of the concentrations were shocking.

The levels of aluminum and iron in the runoff after the fire do not come close to levels found in the mines around Silverton, he said. And, the levels of lead exceeded the safety standards for water supplies.

Going forward, efforts are afoot to help lessen the impacts of future runoff in the 416 Fire burn area.

La Plata County budgeted $150,000 and is trying to secure grants to meet a 25 percent match with the Natural Resource Conservation Service to fund a project to help protect homes and property from future flooding.

If local funding is secured – about $1.8 million – the Natural Resource Conservation Service will cover the other 75 percent of the estimated $7 million project.

“The landowners up there have already been hit hard and used a lot of their own money to mitigate what’s already happened,” said La Plata County Commissioner Gwen Lachelt.

Local officials are also trying to nudge the U.S. Forest Service to take on some projects to help offset the impacts of the 416 Fire on public land. Nearly all the acreage burned during the fire was in the San Juan National Forest.

Jonina Vanderbilt, Forest Service spokeswoman for the San Juan National Forest, said the agency conducts mitigation projects on areas damaged by wildfire. Those projects tend to focus on emergency situations, such as threat to life or property.

As for the 416 Fire, Vanderbilt said a final Burned Area Emergency Response study is close to completion, and that will identify areas and projects the Forest Service can take on to repair damaged areas.

The state of Colorado generally says it takes five years for a watershed to recover after a wildfire, Roberts said. MSI will continue to monitor the Animas.

“I’m hopeful the worst events are behind us,” he said. “But it’s of course dependent on where rainstorms fall in coming years.”


Mountain Studies Report (PDF)

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