Los Alamos digs in to prevent toxic runoff

To prevent soil erosion, aerial hydroseeding is being carried out in and around Los Alamos, New Mexico, where 48,000 acres of land burned in May

July 19, 2000
Web posted at: 11:48 a.m. EDT (1548 GMT)

By Environmental News Network staff

Putting out the fire that burned 48,000 acres of land in and around Los Alamos, New Mexico, in May was only half of the battle.

Now, work crews at Los Alamos National Laboratory are in a race against nature to build structures that will contain erosion before heavy rains, common during the state's summer monsoon season, bring flash floods to the area, washing contaminants from lab property to the Rio Grande River valley.

LANL officials and the New Mexico Environment Department found no evidence of radioactive or hazardous contaminants in the air during or after the fire. Lab representatives say the risk of contaminants washing from LANL property into nearby waterways is slight.

"Our belief it that even if the contaminants don't stay on site, it won't have an impact on anyone because the concentrations are so low," said Mike Baker, project leader of the lab's Emergency Rehabilitation Team. "All risk assessments indicate no significant impact to people and animals. Nevertheless, if you're downstream, you don't want (contaminants) coming down into your property."

The Cerro Grande fire burned off vegetation from the hills surrounding the laboratory, leaving a landscape of hard, black soil and matchstick trees. The loss of vegetation has increased the potential for surface runoff and soil erosion.

In the event of heavy rains, ash and other fire byproducts could wash into drainages, arroyos and streams near the lab, and even 10 miles downstream into the Rio Grande River.

"The watersheds above the lab and upstream from the lab were severely burned in the fire," said Baker. "This caused, besides a loss of a lot of vegetation, damage to the soil so it won't absorb water nearly as well as it used to. There's a large effort to mitigate damage."

The damage is expected to come from flash floods and ash that could wash off the burned hillsides, making its way into waterways and killing fish.

"We're not terribly concerned about radioactive and hazardous contaminants from the lab getting off lab property," said Paul Ritzman, deputy secretary of the New Mexico Environment Department. "The lab has really made an extensive effort to make sure nothing leaves their property of hazardous or radioactive nature. They are taking it to an extreme to prevent that."

Satellite photos show the area around Los Alamos, New Mexico, before the fire, top, and after, bottom

"The biggest struggle we face is that there's going to be a lot of ash and soot in the Rio Grande if we get the right rain event, and we're probably going to have fish kills," said Ritzman. "The ash chokes the fish by taking oxygen out of water.

"When it rains, it's going to affect mostly the upper watershed. That's going to bring ash from the upper watershed down into the Rio Grande."

The NMED is planning to take samples of watersheds in and around the lab when the rains come. "We'll be testing for everything when we get a major event that takes things to the Rio Grande. Our hope is that we don't come up with anything but ash," said Ritzman.

Airplanes have spread 750,000 pounds of grass seed over 21,000 acres of land at the lab and dropped hydromulch — a combination of fertilizer, seed, shredded wood, water and tackifier to aid seed germination — onto steep hillsides.

Workers raked the glassy top layers of burned soil to increase water absorption, and contaminated soil is being removed from sites identified as threats.

In addition, the U.S. Army Corp of Engineers is helping LANL crews build weirs and rock walls to prevent runoff from flowing into sites containing radioactive or chemical contaminants. Lab officials are most concerned about flooding in Pajarito, Pueblo and Los Alamos canyons.

In Pajarito Canyon, crews built a retention wall around LANL facilities at site TA-18. The wall is designed to prevent debris from hitting Kiva One, one of the nuclear facilities at TA-18. Crews are also working on a water diversion channel at TA-18 and have moved containers of uranium solutions from Kiva One out of the canyon.