Case Studies

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Remediation at Leadville Superfund Sites
helps restore upper Arkansas River habitat

Led by Project Manager John DeAngelis, PWT successfully completed management
and oversight of remediation activities at the California Gulch Operable Unit
(OU) 11 Superfund Site near Leadville, Colorado. Work on this project contributed
to the recent addition of the upper Arkansas River to the list of Gold Medal
Trout Waters.

At OU 11, PWT provided project management and oversight of first-of-its-kind
in-situ remediation of large areas impacted by historical flooding of mine tailings,
and acquisition and management of construction subcontractors. PWT conducted
remediation and revegetation of 150 acres of irrigated meadows pastureland and
18 acres of fluvial deposits that bordered 3,000 feet of the Arkansas River
south of Leadville. Remediation of the fluvial deposits included streambank

Excerpt from the Herald Democrat, Leadville, Colorado, January 31, 2014:

The Colorado Parks and Wildlife Commission has announced the upper Arkansas
River as the newest addition to the statewide list of Gold Medal Trout Waters.
The Gold Medal reach is 102 miles long from the confluence with the Lake Fork
of the Arkansas River, near Leadville, downstream to Parkdale at the U.S. 50
bridge crossing above the Royal Gorge.

In the last 20 years, the upper Arkansas River has undergone a habitat transformation.
Fish populations in the area were impacted by heavy metal pollution from mining
in the Leadville area. Because of the pollution, trout could not live in the
area, and they did not live beyond three years old further downstream. Today,
trout are living up to 10 years old due to habitat restoration, improved water
quality and creative fishery management.

With the addition of the Arkansas River, total Gold Medal stream miles in Colorado
increases by 50 percent to 322 total miles. It will also be the longest reach
of Gold Medal water in the state.

OU 11 before and after.
OU 11 before and after


  • August 2011
  • June 2011
  • April 2011