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Aspen Journalism: Lincoln Creek workgroup has decisions to make

Heather Sackett
Aspen Journalism
Water quality monitoring equipment can be seen in the mineralized tributary just before its confluence with Lincoln Creek. A consultant hired by the Lincoln Creek workgroup presented several options for improving the water quality.
Lincoln Creek1

A workgroup dedicated to improving the water quality of Lincoln Creek should develop a vision, goals, and objectives, which will guide any future projects on the contaminated waterway. 

That is one of the high-priority recommendations from a consultant hired by the Lincoln Creek workgroup. A memo from LRE Water says the group should also analyze several options for projects designed to address high levels of copper, aluminum, iron, and other metals in the waterway. Engineers with LRE presented the memo at a workgroup meeting on Tuesday.

“I think the most critical path item now would be for the workgroup to really put their heads together to design and figure out what the objectives and goals are of the group,” said Brent Johnson, a geochemist with LRE Water. “It would be my recommendation to get those done as soon as possible, maybe before the end of the year, and that could help propel into designing the next phases of technical work.”



The Lincoln Creek workgroup is an ad hoc group composed of officials from Pitkin County, Colorado Parks and Wildlife, the U.S. Forest Service, Colorado Department of Public Health and Environment, Independence Pass Foundation, other organizations, and interested citizens. The group’s draft vision statement says its goal is to “better characterize the Lincoln Creek drainage to understand how contaminants (i.e., copper, iron, aluminum, and possibly other materials as they are identified) are impacting or could impact both Lincoln Creek and the Roaring Fork River using data from continued sampling efforts to assess current conditions and predict future conditions, including impacts from climate change, to influence decision-making, and possible mitigation efforts.”

Pitkin County Environmental Health Manager Kurt Dahl said honing a strategy and making sure that group members are in agreement on a way forward will be the next step.




“I think being more focused and deliberate on what we want to pursue, that will help us in the future, and then what’s that going to cost and where are we getting the funding,” Dahl said.

Local officials, residents, and environmental groups have long been concerned about water quality in Lincoln Creek. The tributary to the Roaring Fork has been under increased scrutiny in recent years as fish kills and discoloration of the water downstream of Grizzly Reservoir have become more frequent. 

In July, reservoir owners and operators Twin Lakes Reservoir & Canal Co. drained it for a planned dam-rehabilitation project. A slug of sediment-laden water from the bottom of the reservoir was released downstream, turning the Roaring Fork through Aspen bright orange and alarming residents. Testing showed that the water had high levels of iron and aluminum but not copper, which is toxic to fish.

An Environmental Protection Agency report in 2023 determined that a “mineralized tributary,” which feeds into Lincoln Creek above the reservoir near the ghost town of Ruby, is the source of the high concentrations of metals downstream. 

The process that causes metals leaching into streams can be both naturally occurring and caused by mining activities. In both cases, sulfide minerals in rock come into contact with oxygen and water, producing sulfuric acid. The acid can then leach the metals out of the rock and into a stream, a process known as acid rock drainage. The contamination from acid rock drainage seems to be increasing at other locations around Colorado and may be exacerbated by climate change as temperatures rise. 

Treatment options

LRE’s memo, which is based on a Sept. 6 site visit, listed eight potential options for addressing the metals contamination. 

“What I really wanted to get out there was that there are options, and some of these are not full-on active water treatment,” Johnson said. “In fact, I would hope to avoid that if at all possible. It’s expensive, it’s invasive, and there would be structures up there. I think there a lot of other good options that would result in achieving the goals the group is thinking about.”

One of those options could be sulfate-reducing bioreactors, which use microbes to strip the metals from the mineralized tributary. The drawback of this method is that it is less effective in cold temperatures. 

Another option could be an upstream chemical amendment. This option would add an alkaline element to the mineralized tributary, such as lining the channel with limestone, to counteract the acidity. 

A third option could be toxicity management, which entails increasing the “hardness” of the water with calcium and magnesium to cancel out the toxicity of the aluminum and copper. 

Johnson said controlling the metals contamination at the source where it is in the highest concentrations could also be an effective treatment. 

“We’d get a big bang for the buck up there if we could do something modest at the source that has a really big impact downstream,” he said. “That would be a really cost-effective way to start improving and controlling and managing the whole system.”

The memo encouraged the workgroup to look into either acquiring the Ruby Mine, which is located just upstream from the mineralized tributary, or developing a working relationship with the current owner, so that the mine could be used to improve water quality. 

LRE agreed with the EPA report that the naturally occuring mineralized tributary — and not the mine — is the primary source of contamination. But the mine property could be used as part of the solution by installing water-treatment equipment in the underground mine workings. Flows from the mineralized tributary could then be directed into the mine to be treated before flowing into Lincoln Creek.

“There’s an opportunity to utilize those mine pools as part of a passive treatment system,” Johnson said. “Maybe there’s some way to design a system that would result in a lower metals load to Lincoln Creek by including those facilities in the mix.”

The memo also recommends developing a hydrological and geochemical conceptual model of the Lincoln Creek watershed to better understand the big picture of water flows and chemical loading in various stream reaches. At Tuesday’s meeting, local resident Sallie Bernard pointed out that mine adits upstream from the Ruby may be additional sources of contamination.

“I just think it needs more looking at again to see what the contribution is of that,” Bernard told the group.

LRE also recommends creating a high-level guidance document that outlines a five- to 10-year plan for addressing the contamination. 

The memo was the first half of the scope of work that the workgroup hired LRE to do. The second half, which Johnson said should be completed by the end of the year, entails reviewing the water quality sampling of the watershed. Five entities have been taking water quality samples this year: Roaring Fork Conservancy, Pitkin County Environmental Health, the U.S. Forest Service, Colorado Parks and Wildlife, and the Institute of Arctic and Alpine Research at the University of Colorado Boulder.

LRE’s work was funded by Pitkin County Healthy Rivers and the Independence Pass Foundation. 

“I know the Independence Pass Foundation’s goals are to determine what, if anything, can be done and what our options are to help clean up Lincoln Creek and protect the Roaring Fork River,” said Karin Teague, executive director of the Independence Pass Foundation. “I think everyone would be in agreement on that overarching goal. As for how we get there, how quickly and where the funding comes from, those are all questions that need to be answered.”

This story is provided by Aspen Journalism, a nonprofit, investigative news organization covering water, environment, social justice, and more. Visit aspenjournalism.org.

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