Contractors working for the U.S. Forest Service are racing against Mother Nature to spread straw mulch over 1,200 acres of fire-scorched mountainside exposed by the King fire.
As several storms arrive in the next week, forest officials fear a big, wet one will hit. Without the underbrush and plant material that normally cover the forest, massive erosion will wash away roads, fill reservoirs and harm other critical infrastructure.
The September wildfire burned 97,717 acres. While much of the damaged forest survived with the trees’ canopy largely intact, an estimated 30 percent of the damage is severe, said Mary Moore, a key member of the team assessing the damage. Of that area, 1,200 acres were identified as key to protect through an aerial drop of mulch on the steep slopes near roads, waterways and other assets.
“As you can see, there is no duff layer. There is no vegetation. There is no grass growing. Nothing. And the trees are pretty much dead,” said Moore, a Forest Service hydrologist, as she took journalists on a tour Friday through a heavily damaged area. “The rain is going to hit this and start taking off down the hill.”
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The cost of the coverage is about $500 an acre. The project got a financial assist from Sacramento’s public power provider, SMUD.
“This will provide a significant reduction in erosion to the tune of thousands of tons of material that won’t be getting in to the waterways,” said Grant Nelson, the SMUD project manager.
SMUD is funding 250 acres of aerial mulching near Brush Creek and Slab Creek reservoirs, which provide hydroelectric power. SMUD’s goal is to prevent erosion into those reservoirs, protecting its power generation capacity.
“If we lost 10 percent of storage capacity, then that reservoir’s power generation capacity would drop by 10 percent,” Nelson said.
The work of delivering and spreading the mulch went to contractor Bradco Environmental. The straw, which replicates pine needles, arrives by truck in packed bales. As needed, the bales are tossed into a shredder with large construction equipment.
The loose straw is then placed on nets for pickup by helicopter. Once in operation, a copter can cover an acre with a ton of straw in a single load, Moore said. Each round trip takes about 4 minutes.
Elsewhere within the fire damaged area, crews removed dead trees, augmented drainage systems and secured roads.
Moore noted that not all of the damaged acres will be treated. In the bulk of the damaged forest, natural recovery will heal the fire scars, she said.
Call The Bee’s Ed Fletcher, (916) 321-1269. Follow him on Twitter @NewsFletch.