Presenters at a public meeting Thursday about contamination on Lincoln Creek hosted by agencies that oversee water quality offered a lot of information, but few solutions yet to the problem.
The meeting, held at the Rocky Mountain Institute in Basalt, featured the results of water quality sampling and presentations from a panel of experts from agencies including Environmental Protection Agency, Colorado Parks and Wildlife, U.S. Fish and Wildlife Service, Colorado Department of Public Health and Environment, the U.S. Forest Service, Colorado Division of Reclamation, Mining and Safety, the U.S. Geological Survey, environmental group Trout Unlimited and Pitkin County Environmental Health.
“We have a lot of questions,” said Kurt Dahl, Pitkin County environmental health manager. “Is (the contamination) going to continue to increase? What does it mean for the Roaring Fork? For my office? For human health? … There’s also this question around mitigation. I think we want to get our arms around, is this a possibility? What does this look like? What are the costs? Can we afford it?”
A report released in November by the EPA based on water-quality samples from 2022 found that Lincoln Creek in the four miles between the Ruby Mine and Grizzly Reservoir exceeds state water quality standards for aquatic life for aluminum, cadmium, copper, iron, lead, manganese and zinc. Aluminum and copper concentrations were especially high.
Water quality issues on Lincoln Creek have been a concern for years, with the creek above the reservoir often running a yellowish color, and Grizzly Reservoir often a bright turquoise. In September 2022, Lincoln Creek below the reservoir turned a milky-green color, and white and yellow sediment settled on the streambed, prompting water quality testing in the fall of 2022 and the EPA report. These conditions in 2022 could be seen downstream at the confluence with the Roaring Fork River, sparking concern for local residents and organizations.
And the problem has gotten worse in recent years. The high concentrations of aluminum and copper are toxic to fish, and Lincoln Creek and Grizzly Reservoir experienced a fish die-off in 2021. In fall of 2023, there was a fish kill downstream in the Roaring Fork in the North Star Nature Preserve, which experts say was probably due to a combination of high metals concentrations and too-warm water.
The EPA report also found that the main source of contamination is not drainage from the Ruby Mine, but is naturally occurring from a “mineralized tributary” just downstream from the mine.
During the Q&A portion of the meeting, attendees asked whether the Ruby Mine, where turn-of-the-20th-century prospectors dug for gold and silver, could really be the source of contamination. Mindi May, water quality program director with CPW, said she initially shared the audience’s skepticism that the mine wasn’t the main source of contamination, but after visiting the site she agrees with geologists’ findings that it’s naturally occurring.
“You could just see the water from the mineralized trib just seeping out of the ground,” she said. “So at this point I am convinced … that the mineralized trib and the Ruby are separate and that the mineralized trib is natural and that it really is the problem.”
The fact that the contamination of the creek is naturally occurring creates a question about who’s responsible for cleaning it up. The EPA is authorized to address elevated metals concentrations only from human-caused sources, not contamination from natural sources.
Primarily an ecological problem
Panelists addressed the potential human health impacts from the contaminated water in the creek and at Grizzly Reservoir, a popular spot for summer camping, hiking and fishing. The U.S. Forest Service manages the seven-site Portal Campground near the reservoir.
Mike Carney, a toxicologist with U.S. Fish and Wildlife Service, said his agency is primarily concerned with arsenic and lead, which have health risks but aren’t the main contaminants in Lincoln Creek. He said there’s not much risk associated with someone’s skin coming into contact with the copper and aluminum-laden water. As for drinking the water, backpacking filters are unlikely to filter out all the contamination and gastrointestinal distress could result. But would-be guzzlers of the orange-tinted water would probably be turned off by the taste.
“At those concentrations, that water would likely not be palatable because it would taste very bad,” Carney said. “This is primarily an ecological problem here.”
Carney said they did not find worrisome concentrations of metals accumulating in the tissue of fish sampled from Grizzly Reservoir. CPW restocks the fish every summer so they may not spend enough time living in the reservoir to build up metals concentrations before they die or are caught and eaten by anglers.
Lincoln Creek feeds into the Twin Lakes Reservoir and Canal Company’s transmountain diversion system, in which Grizzly Reservoir is used as a collection pool before sending water through the Twin Lakes Tunnel to the Arkansas River basin, where it is used primarily in Front Range cities, including for drinking water. Colorado Springs Utilities owns the majority of the water in the Twin Lakes system.
The November EPA report said the substantial mixing, the distance that the water travels to the Front Range and the water-treatment process limit the impacts to Colorado Springs’ drinking water.
Twin Lakes is planning to drain Grizzly Reservoir this summer so it can do a rehabilitation project, including installing a membrane over the steel face of the dam, replacing the gates that control the flow of water into the Twin Lakes Tunnel and repairing the outlet works that release water down Lincoln Creek.
Repairs to fix damage after a log got caught in the outlet works in 2015 resulted in the release of a slug of contaminated water and sediment from the reservoir that quickly boosted flows in the Roaring Fork near Aspen and turned it yellow, alarming residents. Twin Lakes board president Alan Ward said that wouldn’t happen with this summer’s planned draw-down.
“The company was very embarrassed by that, we do not want that to happen again,” he said. “We talked with our contractor about a drawdown plan and we need to make sure that as we get to those sediments, that we’re moving slowly and have a lot of sediment control in place so that we’re not putting that in the creek.”
Leaching metals and climate change
When water and oxygen come into contact with pyrite-rich rock, it reacts to form sulfuric acid and causes the leaching of metals from the rock. One take-away from Thursday’s presentations is that this type of metals contamination of Colorado waterways is increasing with climate change.
Thomas Chapin, a research chemist with USGS, said drought and climate change have reduced the volume of streamflows, meaning metals concentrations will be higher even if the overall amount of metal leaching stays the same. But melting ice and ground that was once frozen also allow water and oxygen to come into contact with rock that used to be inaccessible to the leaching process.
“The combination of the decrease in flow coming down, so less dilution, and the lowering of the water table and exposing more material to acid rock drainage, it’s a double whammy,” Chapin said.
Pitkin County isn’t the only place in Colorado where increasing metals concentrations is negatively impacting water quality. Chapin said a recent study looking at the Snake River, a tributary of the Blue River in Summit County, found a 100% to 400% increase in the amount of zinc concentrations over 30 years.
“We saw similar data with Lincoln Creek,” he said. “Those September values have gone up quite a bit.”
The recently released Climate Change in Colorado report found that temperatures have warmed more in fall than other seasons.
Dahl wrapped up the meeting, which ran 30 minutes past its scheduled time of 6 to 7:30 p.m., by saying that local water quality experts are talking about next steps and plan to hold another public meeting this spring.
“We recognize that there was a lot of information here without a lot of opportunity to ask questions,” he said. “We’ve already agreed that we need to have another public meeting.”
This story ran in the Feb. 3 edition of The Aspen Times.
