For the first time in as many as a hundred years, fish have been found in the upper parts of Mineral Creek, a tributary of the Animas River historically plagued by acid mine drainage just outside Silverton.
“This is the first time in recorded history of a report of fish existing in the headwaters of Mineral Creek,” said Bill Simon, a retired coordinator of the Animas River Stakeholders Group. “We are a bit surprised by the great results so soon after remediation.”
Over the past few weeks, U.S. Geological Survey crews were out in the streams and tributaries within the Animas River watershed around Silverton collecting fish for the Environmental Protection Agency.
Andrew Todd, research biologist with USGS, said about five rainbow trout and five brook trout were collected from select stretches of the creek, and will be used for the EPA’s “ecological and human health risk assessment,” as the agency seeks to better understand the region in its Superfund efforts.
“We’re also looking at what’s likely fish habitat, and what’s not,” Todd said. “It’s about setting realistic expectations for what could be gained in the Superfund process, from a perspective of trout habitat in the headwater reaches.”
Upstream of Burro Bridge – which crosses Mineral Creek going up to Ophir Pass – USGS crews found brook trout in multiple age classes in a stretch not known to support fish populations.
“Brook are not stocked, so those fish are there on their own volition,” Todd said.
Peter Butler, a coordinator of the Animas River Stakeholders Group, said when the group started addressing the negative impacts of mining around Silverton more than 20 years ago, Mineral Creek was devoid of aquatic life.
Since that time, he said 12 mine remediation projects affecting upper Mineral Creek have been completed: eight by ARSG, two by Sunnyside Gold Corp., which also provided funding for one other project, and one by the Forest Service.
“We knew that water quality in the upper part of Mineral Creek had dramatically improved, but we didn’t expect it to support trout,” Butler said. “We’re thrilled with the result. This may be the first time in one hundred years that fish have been seen in this stretch.”
Butler and Simon speculated the trout came from Mill Creek and its headwaters at Columbine Lake, which is upstream of the Burro Bridge and has good water quality. Because the fish spanned various ages, the men said it’s likely the population is resident to Mineral Creek.
Mineral Creek has been a success story. Since remediation began, there’s been a 70 percent reduction in zinc and copper, and a 50 percent reduction in cadmium. Because of natural circumstances, Butler said, there hasn’t been a reduction in levels of iron and aluminum.
The EPA has listed seven mining-related sites within the Mineral Creek drainage basin out of its total 48 sites that make up the Bonita Peak Mining District Superfund listing.
During the summer, the agency embarked on an “early action” task at the Brooklyn Mine that diverted a pipeline discharging 15 gallons a minute of acid mine drainage away from a mine waste pile, reducing the amount of added contaminates it was picking up along the way.
Rebecca Thomas, project manager for the Superfund site, said over the winter the agency will identify other early actions it can take, as well as draft an overall plan for each source of pollution in the basin.
All in all, the summer was filled with good news for trout in the Animas: The state health department found no bioaccumulation in fish tissue after last year’s Gold King Mine spill; Colorado Parks and Wildlife found encouraging signs in fish populations around Durango; and anglers around the area noted the better-than-usual fishing year.
The USGS also found brook trout for the first time in a short stretch of the upper Animas River between Denver Lake and Burrows Gulch, below the Lucky Jack mine, which the ARSG remediated about 10 years ago.
However, there’s much room for improvement, officials agree, as fish populations are impaired below the Burro Bridge, and on a large stretch of the Animas River below Silverton to above Bakers Bridge, among other areas.
As the EPA increases its focus on the basin, it’s likely researchers as well as the public will learn much more about the Animas River.
“Understanding is the point of this exercise,” Todd said. “By exploring and understanding, we can get a sense of where we might head.”
This story has been updates to clarify the work the EPA did at the Brooklyn Mine this summer.