Monitoring the mud

LA CRESCENTA — As a pile of dirt excavated from foothill debris basins has grown into a massive dumping site, Glendale and Burbank police helicopters have been regularly monitoring the area.

Officers make daily flyovers of the Dunsmuir Sediment Placement site, which is adjacent to Deukmejian Wilderness Park. Los Angeles County Public Works crews began dumping loads of material from area debris basins after the Feb. 6 mudflows in La Cañada Flintridge.

Concerns that the pile could give way during a heavy rainstorm have prompted the need to keep an eye on the growing dirt pile, which sits above a row of Markridge Road homes, said Sgt. Steve Robertson of the Glendale and Burbank Joint Air Support Unit.

“What happens if the hill comes down and hits the site?” he asked.

Before crews began dumping dirt at the site, two helicopter landing pads were the highest point on the mountain, Robertson said. The mountain has since overtaken that mark.

“This is one of the key areas that we watch,” he said.

And while the dirt pile has quickly grown into a mountain, county officials have assured city officials that the site is safe, City Engineer Roubik Golanian said.

The Air Support Unit has also been tracking Glendale and Burbank’s debris basins and the hills of Deukmejian park on a daily basis.

Soon after the Station fire, the flight crew was given a crash course on what to look for in the blackened mountains, Robertson said. The crew also watches Glenoaks Canyon, the site of the Freeway fire.

“You need to be adaptable with what you can do with a helicopter,” he said.

During major rainstorms, the crew monitors reservoirs, debris basins, fire access roads, overpasses and schools, he said.

Robertson and his crews photograph any new fissures and fractures on the hillsides and turn them over to city engineers.

“You have to do as much as you can with the resources you have,” he said.

Some of the mountain slopes are showing signs of weakening, Robertson said.

Officials with the U.S. Geological Survey could not be reached Tuesday.

In a flight Tuesday above Deukmejian park, Robertson pointed out the deep incisions along the mountains. Small splashes of new vegetation had started to pop up, although officials have said it could be years before root systems are strong enough to shore up the hillsides.

Until then, the potential of mudslides has brought on a new set of responsibilities for the flight crew, which has come to play a critical role in monitoring the weak hillsides, Golanian said.