Wildfires near Santa Fe are classified in official reports as an "immediate threat" to part of the city's water supply, but managers say that so far, neither the Las Conchas Fire nor the Pacheco Fire has damaged water resources.

A blaze that broke out in the Santa Fe National Forest on June 18 was about 15 percent contained Tuesday and had torched just more than 10,000 acres. The Pacheco Fire remains at least a mile and a half from the boundaries of the Santa Fe Municipal Watershed and is headed in the opposite direction.

"Fire has not entered the watershed and is actually moving away from it, and has been for a few days," said Denise Ottaviano, a public information officer with the U.S. Forest Service.

The watershed is a forested area that contains the headwaters of the Santa Fe River and two large reservoirs. Fire there could lead to increased soil erosion and a buildup of soot and debris in stored water.

Two fire lines are in place to prevent the unlikely movement of the fire toward the watershed, according to Ottaviano, who said there's also not much heat on the side of the fire closest to the edge of the watershed.

Meanwhile, the larger, more-distant fire that has consumed more than 60,000 acres in the Jemez Mountains between Cochiti Lake and Los Alamos has the potential to affect the region's newest water-supply project — the Buckman Direct Diversion.

The structure that pulls water out of the Rio Grande and sends it to taps in the city and in Santa Fe County is downstream from where Los Alamos Canyon and Pueblo Canyon drain into the river, but upstream from areas that the Las Conchas Fire has already torn through, such as Frijoles Canyon.

Rick Carpenter, water resources and conservation manager for the city of Santa Fe, said he's monitoring reports from firefighters on both fronts, and so far there's no reason for alarm.

Even if fire does reach canyons upstream of the diversion, unless there is a hard rain, sediment will not create additional challenges in the near future, he said. Treatment systems are designed to filter very small particles to aid in the removal of any nuclear contamination that is suspended in sediment moving off of Los Alamos National Laboratory land.

"It would have to be a summer monsoonal-type storm or a really significant snow or rain event to become an issue for us," Carpenter said.

Early-warning systems are in place to allow diversion workers to turn off the river intake when storms occur or at any other time there is an immediate threat.

Los Alamos Fire Chief Doug Tucker said at a Tuesday news conference that southern and southwestern wind patterns did not appear likely to send the fire toward Los Alamos Canyon, but if winds shifted, flames would reach that area.

The City Council plans to discuss tonight whether to ask for federal money through the U.S. Department of Agriculture for restoration of any watershed or river-diversion structures damaged by the fires.

Even though she agrees that it appears the watershed isn't in imminent danger, Felicity Breonnen, director of the Santa Fe Watershed Association, said it's not safe to assume threats are absent.

"The erratic winds present us with absolutely no ability to predict anything," she said. "We always have to be prepared to deal with wherever the fire goes. I hope it will continue to move north and away from the watershed. I would never say I am confident that the Santa Fe watershed is perfectly safe."

The Cerro Grande Fire in 2000 caused more than $17 million in damage to Los Alamos water systems. Erosion and heat damage caused the collapse of several key pieces of infrastructure. A reservoir used for irrigating town parks also filled with ash following the fire.

Contact Julie Ann Grimm at 986-3017 or jgrimm@sfnewmexican.com.