Helicopter mulching aims to protect critical watersheds in East Troublesome burn scar
GRANBY — Far into the East Troublesome burn scar, a semi truck dumped roughly 50,000 pounds of wooden mulch at the staging area near North Supply Creek.
The rainy, overcast Wednesday meant no helicopters were flying in Arapaho National Forest, but there was still plenty of work to do for Kimberly Mihelich, source water protection specialist for Northern Water, and Brad Piehl, a contractor with JW Associates.
Mihelich scooped a sample of the mulch into a gallon bucket and sifted it through chicken wire with 1-inch square openings into a green storage container. She tossed away the pieces too large to make it through and returned the smaller bits to the gallon bucket. The debris stayed below the line in the bucket marking one-third of the sample.
“Good mulch,” Piehl declared.
The mulch the two were inspecting Wednesday, Sept. 29, which came from a private property in Winter Park, has to have a good size distribution in order to be scattered on the burn scar in Arapaho National Forest.
“We want bigger pieces because they resist moving downhill a lot better,” Piehl said.
The work was part of a project to mulch 2,200 acres of the burn scar in the Emergency Watershed Protection Area. Northern Water sponsored the $5 million project, but it wouldn’t have been possible without critical funding from the Natural Resources Conservation Service and matching funds from the Colorado Water Conservation Board along with a number of other partners.
Grand County began a similar project Sunday, Oct. 3, for private properties on the other side of Colorado Highway 125.
For Northern Water’s project, over the course of three weeks, 300 truckloads of mulch were hauled to staging sites around the Supply Creek drainage. That mulch will be scattered via helicopter on specific sites to help preserve the critical watershed.
“If we can stop some of this debris here, it’s not going to go down into there,” Northern Water Public Information Officer Jeff Stahla said, gesturing southeast to Grand Lake and Shadow Mountain Reservoir. “… Anything we can do to keep the debris in place, it’s going to beneficial for the forest but also for everybody downstream.”
On better weather days, helicopters lifted nets filled with up to 3,000 pounds of mulch and released them onto targeted sites within a 2-mile radius, covering about a third of an acre per load. Mulching costs about $2,500 per acre, which means Northern Water has to target what sites to protect.
Of the nearly 200,000-acre burn scar, the water company has identified 23,000 acres worth of mulching needs in the forest that meet the criteria for slope, burn severity and proximity to roads that don’t sit in a wilderness area. The group did work on 2,500 acres of the Willow Creek drainage earlier this summer, totaling about 4,700 critical acres mulched this year.
Piehl explained that natural forests in Colorado tend to have a duff layer of organic material that absorbs most of a rainfall, meaning there’s very little runoff.
“When you have a fire, even if it’s a moderate burn, it burns most of that away,” Piehl said. “Most of the organic layer is gone. Now, you can get water running straight down the hill slope, which creates all kinds of problems.”
Not only does the rain now erode the soil that remained under the duff, the soil can end up deposited downstream and into a reservoir or lake. Northern Water is especially concerned about this because Grand County’s reservoirs and lakes help the company to provide water to more than one million people in northeastern Colorado.
Along with preventing the peak flows that can be 10-50 times higher than pre-burn, the mulch retains moisture to help plants grow back faster.
“You’re basically adding that texture back into the soil so the water can soak in,” Mihelich said.
After the helicopters apply the mulch, Piehl and Mihelich go out to areas where it’s been applied and do ground-based inspections. The mulch needs to cover at least 70% of the targeted area.
According to Water Quality Specialist Katherine Morris, Grand County’s mulch project taking place this week on private lands will be a combination of mulching where seed has already been spread and seeding and mulching in areas that had moderate to high soil burn severity on a 20-60% slope. Northern Water’s most recent project didn’t include a seed mix as that was not part of the Forest Service permit.
Grand County’s seeding and mulching will occur in the Coyote Creek drainage up Highway 125, as well as some sections in the Drowsy Water and Sheriff Creek drainage for a total of about 390 acres.
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