Stewardship Action: Rocky Flats Ecologist Reflects on Site’s Environmental Transformation

This year marks the 50th anniversary of Earth Day on April 22, a celebration launched in 1970 encouraging people to advocate for the environmental preservation of the planet. As steward of the nation’s nuclear legacy sites, the U.S. Department of Energy Office (DOE) of Legacy Management (LM) demonstrates this mindset daily, committed to ensuring its 100 sites remain protective of human health and the environment.

The Rocky Flats Site exemplifies the LM mission. In just 15 years since the site transferred to LM, this Colorado property, once a host to nuclear weapons production, has seen significant changes.

“The site basically started as an industrial city,” said Jody Nelson, senior ecologist for the LM Support contractor at the Rocky Flats Site. Nelson began working on the project in 1994, before it was managed by LM.

“After cleanup, the previous 400-acre industrial area was just bare ground — if you stood in the middle of the site and spun around 360 degrees, there was mostly freshly seeded soil surface. But if you do the same thing today, you’ll see plants growing, a herd of elk gathered here, a coyote running there, hawks flying overhead, and birds nesting in the grass. It’s been a complete transformation of a large industrialized area back to nature.”

Cleanup of the site’s past nuclear activity impacted approximately 650 acres that needed revegetating. Nelson was charged with helping identify important environmental elements to protect throughout the cleanup and closure process.

One such consideration was the habitat of Preble's meadow jumping mouse, a threatened species unique to Colorado and Wyoming. Many of the site’s structures stood in the mouse’s habitat and required special approvals from the U.S. Fish and Wildlife Service for cleanup and closure activities in these areas. After cleanup, LM ecologists monitored the habitat of the Preble’s mouse until it was deemed properly restored and met mitigation success criteria.

While preservation efforts dominated much of the first half of Nelson’s career at the site, most of the work he conducts with LM today focuses on revegetation and natural resources management.

“We always tried to limit any damage that we would have on a habitat,” Nelson said of the site’s cleanup, “but sometimes, it was inevitable. And any time you disturb a habitat, you have to recreate it. So, LM has reestablished certain areas, monitoring them for several years until we meet success criteria.”

A key plant community that Nelson and his colleagues have attempted to reestablish is the rare xeric tallgrass prairie, a remnant of the last Ice Age along the Colorado Front Range. The site’s ecologists made it a top priority to reseed the dominant native species present in the community, and Nelson reports that they are establishing very well.

Wildflowers were another important focus of the Rocky Flats Site revegetation work because of their ability to attract and sustain pollinators such as bees and monarch butterflies, which are experiencing an alarming decline worldwide. In the late 2000s, Nelson designed a special nursery system for replanting wildflowers. He created nearly 20 wildflower seed plots, strategically placed so that the wind could spread the seeds from established plants to other areas of the site. Ten years later, many of the nursery plots have reached full bloom, many different pollinators are enjoying their newfound resources, and the site team has identified wildflowers sprouting up across the property.

“I always say if you can grow it, they will come,” Nelson said. “That’s always been my thinking. I knew that if we could grow what the animals want, they would come back — and they have.”

For the past 26 years, Nelson has shepherded the site’s metamorphosis. As one of the few individuals to witness its transformation over that time, he considers the experience to be the highlight of his career. While he knows the journey to full revitalization of the Rocky Flats Site will take many more decades, the ecologist recognizes that in today’s age of sprawling suburbia, simply starting the recovery project is a success.

“I think it’s really important for our planet to have these green areas, whether it’s a remote grassland or a city park. But in most places, it’s going in the wrong direction — you’ve got this great, open area, and then it’s turned into a shopping center or a housing development,” he said. “It’s very rare that you get to see something going in the direction of the Rocky Flats Site, where we’ve taken an industrialized area and recreated what it used to be — or at least tried to recreate it as best we can, letting nature take its course. That’s true environmental stewardship.”