In 2002, Shattuck Chemical agreed to pay $1.25 million for restoration of South Platte River following years of chemical release. 10 years later, the river was restored for migratory birds and native species

Hazardous substances discovered in soil and groundwater beneath and adjacent to the Shattuck Chemical Company site raised concerns that contaminants had reached the South Platte River and affected its natural resources.

In 2002, Shattuck Chemical Company entered into a settlement to address injuries caused by the release of hazardous substances. The company agreed to pay $250,000 to the Department of the Interior and $1.25 million to the State of Colorado.

The settlement funded restoration efforts in two areas: Denver, near the former Shattuck Chemical Company site, and Colorado's Eastern Plains, as per a report. By 2012, restoration projects in the Eastern Plains had been successfully implemented.

Chemical releases raised concerns for the South Platte

The Shattuck Chemical Company site was one of several locations in Colorado where minerals and other materials, including radioactive substances, were processed.

The facility operated for most of the 20th century before closing in 1984. After it shut down, uranium, arsenic, other metals and some organic chemicals were discovered in soil and groundwater beneath and adjacent to the site, as per the StoryMaps report.

The contaminants were shown to have infiltrated a storm sewer next to the property, raising concerns that they had likely reached and impacted the South Platte River and its natural resources.

Settlement funds were used for restoration

The chemical release led to a Natural Resource Damage Assessment and Restoration settlement involving the Department of the Interior, represented by the U.S. Fish and Wildlife Service, and the State of Colorado.

The funds could be used to restore, rehabilitate, replace or acquire the equivalent of injured natural resources, including migratory birds and their supporting habitat.

In the Eastern Plains, restoration focused on habitats traditionally created by flooding along the South Platte River. Working with landowners and other partners, projects were designed to provide spring and fall foraging sites for wetland-dependent migratory birds.

The work included low-level contour levees, impoundments and infrastructure to move water, creating enhanced floodplain, shallow open-water and wetland habitat.

Projects restored wetland and wildlife habitat

Several restoration projects were carried out in the Eastern Plains.

The Jankovsky Restoration, implemented in March 2010, aimed to restore 31 acres of saltgrass wet meadow and shallow-water wetland habitat. Around 16 acres of cropland were also seeded with an upland grassland mix.

At Drakeland Restoration, work began in January 2012 to improve shallow-water wetland habitat for migrating waterfowl. The project was expected to increase wetland area from 25 to 52 acres and positively impact more than 7,000 feet of the South Platte River.

The Winterhaven Restoration, implemented in January 2011, included seasonal riparian and permanent wetland habitat across an 850-acre project area. It involved restoring 125 acres of shallow-water wetlands and enhancing 725 adjacent upland acres.

At the Schiller Restoration in June 2010, shallow-water impoundments were added to improve foraging conditions for waterfowl and other species.

Restoration also took place in Denver

The trustees and stakeholders also considered restoration near the site of the natural resource injury important.

At Overland Pond Park, invasive trees and shrubs were removed and native plant species were introduced. Park amenities and facilities were upgraded, with community volunteers playing an important role in the restoration work.

Changes to the riverbank and surrounding area were also made to improve conditions for wildlife and recreation. A large drop-off in the river was removed, making the South Platte safer for humans and wildlife and more accessible for fish moving upstream and downstream.

Improvements at Pasquinel's Landing reconnected the South Platte River to the floodplain, restored the natural connection between surface and groundwater, and improved riparian and avian habitat.

At Grant Frontier, a drop structure promoted fish movement and developed foraging and spawning areas.

Bird populations and species diversity increased

Community volunteers surveyed local bird populations for more than 20 years between 1994 and 2013.

Over time, the number of birds and the diversity of species using Overland Pond Park were observed to increase as new habitats and native species were established.

Citizen-led surveys also found that more birds were returning to Overland Pond Park and Eastern Plains sites during spring and winter migrations.

Across 345 community-led surveys, more than 173 bird species were observed using the park and its surrounding habitat. These included double-crested cormorants, spotted sandpipers, marsh wrens and mallards.

Monitoring continued after the Eastern Plains projects were implemented to ensure that objectives for enhancing habitat for waterfowl and native plant species were being met. The State of Colorado also carried out additional restoration projects along the South Platte in the Denver area.