Empty debris basins wait for Station Fire's winter impact

Three months after the Station Fire ignited in dry brush in the Angeles National Forest, fire officials still consider it active.

But cold weather and the possibility of rain have Los Angeles county public works crews ready for the fire’s winter flood fallout.

The Dunsmuir debris basin above Glendale sits ready to catch mud, boulders and shrubs that rain pound off steep forest hills. The debris basin is a hole dug down to bedrock at the bottom of a watercourse, about a football field in size. Chris Stone’s a civil engineer with the water resources division of the LA County Department of Public Works. He points out a white tower set in the debris basin’s low point. The tower rises 50 feet, marking a full basin. Stone says basin filters the water that flows downhill. "It also reduces the size of the flood control that’s needed downstream because you’re keeping all the sediment up here & just releasing clean water down below," he adds.

Just below the Dunsmuir debris basin, water runs out of the hills in narrow concrete channels. Here in Glendale, it slides between houses where sandbags are stacked and barriers are ready one block below Deukmejian Park. The US Army Corps of Engineers and LA County designed the runoff system more than a half-century ago. It’s kept mud and rocks out of foothill communities – and Chris Stone says because it’s worked well, those communities have expanded upslope. "Now we see most of our debris basins where they have residential development all the way around the debris basins," he says. "We now have to deal with trucking in these neighborhoods, schools in the haul routes, things like that."

Dunsmuir and 28 other debris basins - about a fifth of the county’s total - sit below watershed terrain stripped by the Station Fire. Stone says at all of them, the sound of a coming mudslide is unmistakable. "It’s scary. It really is scary. You will hear a rumbling of rocks and boulders as they’re coming down thru the canyon and spilling into the basin here it’s just incredible it can come as a wall of mud and water People have described it almost as hearing a freight train coming down the canyon."

One thing LA County Public Works did differently this fall is talk more to state and federal agencies to coordinate disaster response and public outreach after the fire. Chris Stone and his colleague Bob Spencer have gone to two-dozen meetings in hillside communities to assure people the county’s ready if the rain comes. Spencer says in these close-knit communities, neighbors tell newcomers how to get their homes ready for mudslide hazards. "There were a lot of old time residents up here who lived through the debris flows and they have really been great mentors up here," Spencer says.

The mudslide hazard the Station Fire presents draws comparisons to the winter of 1975, when debris flowed fast and heavy down these slopes. Spencer admits the size of the Station Fire makes the threat unusually hard to gauge this time. There’s no doubt because of the very nature of this massive fire, 163 k acres, the biggest in the county’s history, that we’re on a heightened state of alert this year," Spencer says. But he says the county's ready.

Public Works crews are cleaning out debris basins in La Canada Flintridge, where a short heavy rain hit last week. Spencer says the risk here could last for five years.

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