Improving water quality in places like Oak Creek and Lake Mary is the goal of a new Forest Service proposal to block off and restore miles of unofficial and unauthorized dirt roads that crisscross the forest south of Flagstaff.
Forest roads are among the biggest contributors of sediment to stream courses across national forests and are causing declines in water quality locally as well, said Tom Runyon, a hydrologist on the Coconino National Forest. Both Oak Creek and Lake Mary do not meet state water quality standards due to high E. coli and mercury levels linked to sediment delivered from the surrounding watershed.
Under its proposal, the Forest Service would target roads that have been decommissioned or were created by forest users and aren’t part of the agency’s road system. Road entrances would be blocked off, then workers would break up the hard-packed dirt surface, apply mulch and then seed the area to return it to a more natural forest condition, Runyon said.
The goal is to reduce the sources of sediment that gets picked up and carried downstream when water flows through the forest.
The Forest Service is still mapping roads in the five-watershed area that the project will encompass, but on the 20 percent it has surveyed crews found 10 miles of non-system roads, Runyon said.
Those are roads that haven’t been maintained and often haven’t been constructed with adequate drainage and erosion controls to make them sustainable, he said.
Roads in places where sediment could drain directly into a stream will be prioritized first for naturalization, and the first area targeted for work will probably be east of Mountainaire, Runyon said.
He said the Coconino hopes to fund an eight-person crew to begin the work this summer but is also hoping to recruit volunteer groups for tasks like mulching, seeding and using branches to disguise road entrances.
While the Forest Service’s proposal won’t solve the entire problem of road-related sediment washing into places like Oak Creek it will “make a nice dent in the problem,” said Sharon Masek Lopez, executive director with the Oak Creek Watershed Council.
In Oak Creek, sediment contributes to E. coli levels that exceed state standards by acting as a reservoir for the bacteria, Masek Lopez said. The E. coli bacteria persist in streambed soils and sediments and when that material is disturbed by an influx from rain or snowmelt or by people recreating, it stirs the bacteria into the water column, Masek Lopez said.
The watershed council has worked on other erosion control projects in places like Schnebly Hill Road with a similar goal of reducing sediment flow into Oak Creek.
“There is sort of never ending work to do as far as erosion control goes,” Masek Lopez said.
User-created or non-system roads are far from the only source of sediment, she said. Dirt roads that are part of the Forest Service’s system, the Slide Fire burn scar and social trails near Oak Creek also pose erosion problems that affect the creek, Masek Lopez said.
In the broader scope of forest health projects, the Forest Service’s road restoration proposal fits well with the 2.4 million-acre Four Forest Restoration Initiative, Runyon said. In addition to thinning trees and using prescribed fire on the landscape, 4FRI calls for wildlife habitat improvement, spring restoration and road decommissioning.
The more specific proposal would give the Forest Service’s local districts the ability to do more restoration of non-system roads than what has been approved in the 4FRI plan, Runyon said.
“We’re taking it one step further,” he said.