Noxious weeds overtake Flats
DOE considers prescribed burns to combat risk of grasslands fire

Colorado Daily Staff Writer


To most people, the name "Rocky Flats" probably doesnít conjure up visions of wild plants and animals in a pristine, natural setting. Yet in reality, more than 90 percent of the Rocky Flats site consists of grasslands, shrublands, wetlands and riparian areas.

The 5,800-acre "buffer zone" that surrounds the 400-acre former nuclear weapons plant has been relatively undisturbed by development for almost half a century, since Rocky Flats was built in 1952. As a result, the buffer zone is home to grassland habitats that have nearly disappeared elsewhere along the Front Range. The zoneís unit of xeric grassland prairie, for example, is thought to be the largest of its kind in North America.

But the buffer zone hasnít just been untouched by development. For the last 25 years it has also been nearly untouched by a natural force that ecologists consider vital to healthy grasslands: fire. Now, the Department of Energy wants to reintroduce fire as a way to manage the vegetation in the area, a proposal that has some observers concerned but has drawn support from others.

Prescribed burns are identified as one of several preferred approaches in a draft vegetation management plan developed by the DOE. Additional approaches ó most of which are already being used on the site ó include herbicide application, biological controls, mowing and manual removal.

According to Patricia Powell, a physical chemist at Rocky Flats, the prescribed burns would be used to remove 25 years of buildup of dead vegetation in the buffer zone. Not only would this reduce the danger of an accidental fire raging out of control; it would also help native plants that are being choked by noxious weeds, she said. "It allows the moisture to get to the ground and allows sunlight to reach the seedlings," Powell said.

Since 1990, the vegetation management plan states, the buffer zone has been invaded by several types of noxious weeds that threaten the native plants, including diffuse knapweed, Canada thistle, muck thistle and Dalmatian toadflax.

"The Department of Energy is required to take action to control the spread of these weeds and reduce their populations on-site in order to maintain habitat quality and comply with several state and federal weed control statutes," the vegetation management plan states.

But Paula Elofson-Gardine of the Environmental Information Network, a Rocky Flats watchdog organization, called the burning proposal "a really bad idea." As the DOEís own draft plan points out, plants have been shown to absorb plutonium from soil. Elofson-Gardine said burning plants in the buffer zone would release plutonium into the air as particulate matter, which could then be inhaled by people downwind. "This is a hazard for local residents," Elofson-Gardine said. "This stuff is really bad when itís inhaled. Thatís the worst pathway of exposure."

In 1991, tests by the state health department showed elevated levels of plutonium in the ashes from a haystack fire that took place just off the site, across from the plantís east entrance, Elofson-Gardine said. Rather than burning, the DOE should consider letting livestock eat the vegetation, or removing it manually, she said.

But Powell said removing dead vegetation from a 5,800-acre area by hand would be a "daunting" task. And using livestock simply wouldnít work because animals prefer to eat fresh plants, she said. "Livestock wouldnít eat dead and downed vegetation," Powell said.

Moreover, Susan Jones-Hard of the state health departmentís laboratory and radiation services department said the 1991 tests were actually conducted to measure radiation from dirt that firefighters used to put out the haystack fire. While the dirt was found to be contaminated, the health department concluded that "there was no significant increased risk to the firefighters," Jones-Hard said.

Powell also said the DOE had conducted a radiation assessment of a hypothetical prescribed burn in one of the buffer zoneís most contaminated areas, and found that it would not cause significant releases of radionuclides. Burns would not be conducted in certain parts of the buffer zone that are known to be highly contaminated, and burns would only take place under "favorable weather conditions," including low wind speeds, according to the plan.

Elofson-Gardine, however, said she didnít believe the DOE knows where all the contaminated areas are. She cited documents which she said indicated that Rocky Flats workers used to secretly dump radioactive waste in the buffer zone.

Rocky Flats spokesman Pat Etchart responded that contamination in the buffer zone has been thoroughly mapped through sampling. Before conducting any burns, the DOE would obtain a burn permit from Jefferson County and notify neighbors. Crews would also monitor the air during burns and have outside officials participating and observing.

The DOE has discussed the plan with neighboring landowners, including the city of Boulder and Boulder County, whose open-space areas abut the site.

Cindy Owsley, an ecologist with the Boulder County open space department, said she supported using prescribed burns at Rocky Flats. "I can understand why there is a concern to have burning on that site," Owsley said. However, fires will occur one way or another, and itís better to do it in a prescribed fashion than to wait for an accidental, out-of-control fire, she said. "Itís not if a burn would happen," Owsley said. "Itís when a burn would happen. ... Itís going to happen eventually."

The DOE is seeking public comments on its draft vegetation management plan through April 19. If the plan receives final approval, burns could take place late this spring or in the fall. The plan can be viewed at Copies can also be ordered by calling Mariane Anderson at (303) 966-6088.