The first data from a 2018 research project is now published.
The 2015 Durango Herald photograph was instantly recognized as the scene of an environmental disaster: three kayakers paddling the Animas River in southwest Colorado, the water below them as orange and radiant as a Creamsicle.
A containment pond near Silverton, Colo., Was accidentally drilled at the Gold King mine and 3 million gallons of metal-laden sludge was released into the Animas, flowing downstream into the San Juan River.
The river cleared again within days, but much of the heavy metals and other pollutants released from the spill made their way downstream until they hit Lake Powell, along with all of the other sediments that had been transported downstream by the Colorado River and its tributaries since the completion of the Glen Canyon Dam in 1963.
âLake Powell is the integrator of the entire upper Colorado River basin,â said Scott Hynek, a hydrologist for the United States Geological Survey (USGS) at the Utah Water Science Center. âOnce they closed that dam, whatever went through there that was sediment stayed. “
[Related: As Lake Powell shrinks, the Colorado River is coming back to life]
The federal government, which oversaw the cleanup of the Gold King mine when the accident occurred, then paid hundreds of millions of dollars in settlements to affected areas of Utah, New Mexico and the Navajo Nation. . He also earmarked funding for the USGS to study sediment samples in Lake Powell, a project led by Hynek in late 2018.
A rotating crew of 20 to 30 people spent more than a month on the reservoir in what Hynek describes as a âkind of floating cityâ consisting of two to three barges, a barge pusher, a platform. form of a well, a working laboratory and an office. 24 hours a day. The USGS team partnered with the Utah Department of Environmental Quality, the United States Bureau of Reclamation, and the United States National Park Service to extract 30 cores from the beds of the San Juan and Colorado rivers.
The objective was to understand not only the potential impacts of the Gold King mine disaster, but also to analyze the record of sediment trapped in the upper part of Lake Powell and 50 feet thick in places.
Initial data collected on the project has just been released and Hynek made a public presentation on the preliminary results earlier this month. He hopes the project will be useful to scientists working across the river basin on a variety of projects. The sediment recording, he explained, “is like the ultimate ground truth about what happened in the upper Colorado River basin on a massive scale over 70 years.”
Core samples taken from the San Juan arm of the reservoir show spikes of lead and zinc that may have been deposited by the Gold King mine spill in 2015, but there are much larger – and more concerning – spikes in the metals. which were likely deposited in the 1970s, when larger mine waste disasters occurred in the watershed.
âMore important things happened in the ’70s in San Juan than the Gold King,â Hynek said.
The San Juan and its tributaries have a long history of hard rock mining, and copper and lead concentrations are higher in sediment cores from the San Juan River than those collected from the Colorado River arm. The Colorado side had a more active history of uranium mining and processing, including near Moab, and the core showed higher concentrations of uranium in the Colorado River Arm.
But some of the metal peaks found in the silt from the reservoir aren’t necessarily related to historic mining. The San Juan River, for example, has seen an increase in lead concentrations after monsoon rains fell on burn scars from wildfires.
Hynek pointed out that the project’s data is only being analyzed now and that much more detailed reports are expected to be released over the next 18 months with more raw data, which he hopes will be used by university professors for a number of research projects. .
âWe have a chance to provide a better view of history now than first-hand recordings [from the time]”Hynek said.
Zak Podmore is a Report for America corps member and writes about conflict and change in San Juan County for the Salt Lake Tribune. Your matching donation to our RFA grant helps her continue to write stories like this; please consider making a tax deductible donation of any amount today by clicking here.