One complaint about off-highway vehicles in the Sedona area is that their use is damaging the Coconino National Forest, but neither the Red Rock Ranger District nor the city of Sedona have an estimate of the number of acres damaged by such uses.
Ranchers Becki and Dustin Ross have documented 347 locations outside Sedona city limits where they feel the Forest Service needs to mitigate OHV damage to the land. On the basis of a tour of these locations that the Rosses gave on Nov. 8, the total area of damage to the forest represented by these locations likely amounts to 78.7 acres, or .004% of the entire forest.
Becki Ross said that drone survey company SkySkopes was expected to conduct an aerial survey of damage to the area on Nov. 16.
Remediation
Dustin Ross defined remediation of the OHV problem as the grass growing back in the damaged areas. He pointed out the current condition of an area along the Diamondback Trail known as the “donut hole,” where OHV drivers may go to spin doughnuts, that was fenced off by the Red Rock OHV Conservation Crew in 2022. Grass and shrubbery have returned to the area. At another site closer to the Ross’ ranch that was similarly eroded in 2017, the vegetation is now largely indistinguishable from that of the surrounding areas.
The Rosses said they would like to see the U.S. Forest Service place boulders not along the current edges of the OHV trails, but rather along the original borders of the roads, shrinking their width. They also discussed a two-month OHV use season that could be similar to a hunting season, as well as the possibility of making some of the trails one-way only to reduce volume and passing.
“It’s incredible what the public is allowed to do on public land,” Dustin Ross said. “It’s totally legal … I just wish they had the courage to say, ‘Oh, this is legal, this is how it’s going to be,’ or, ‘Well, we’re going to do something about that.’ Instead, we just go to meetings and talk.”
City Study
Sedona City Manager Karen Osburn said during the City Council’s budget work sessions in June that the city had completed a new environmental impact assessment of OHV use focused on volume, noise and air quality. The assessment was based on data collected by the consulting firm Kimley-Horn from March 17 to 19 at Soldier Pass, Forest Road 152C, Schnebly Hill Road, Dry Creek Road and Broken Arrow Road.
The average number of OHV vehicles per day was 111 for Broken Arrow, 114 for Dry Creek, 197 for Schnebly Hill, 153 for FR 152C and 25 for Soldier Pass. This included three types of vehicles classified as OHVs: All-terrain vehicles with handlebars and straddled seats, utility terrain vehicles with side-by-side seats and roll cages and SUVs such as Jeeps. ATVs were recorded only on Broken Arrow and Schnebly Hill. The proportions of SUVs to UTVs were 84% to 13% on Broken Arrow, 56% to 44% on Dry Creek, 70% to 28% on Schnebly Hill, 83% to 17% on Soldier Pass and 28% to 53% on FR 152C with an additional 19% that were other vehicles.
“It can neither be confirmed or denied that there has been an increase in OHVs at the trailheads,” the study stated. “Personal OHVs made up most vehicles using Broken Arrow Trail, Dry Creek Road and Schnebly Hill Trail.”
The proportions of personal vehicles to rental vehicles were 53% to 13% at Broken Arrow, 43% to 25% at Dry Creek, 47% to 18% at Schnebly Hill and 57% to 28% at FR 152C. Tours accounted for the remainder of usage. No private usage of Soldier Pass was recorded and tours represented 83% of usage at that location.
Noise
The loudest OHV noise level recorded during the study was 98.7 decibels, “which would be similar to standing next to a gas-powered lawnmower,” Kimley-Horn stated. “Individual UTVs were observed generating an average impulse noise level ranging between 75 decibels and 90 decibels, which would be perceived by the ear as volumes between a loud conversation to a kitchen blender. Typically, this level of noise was generated by UTVs that accelerated to drive over the boulders at the entrances of the trailheads.”
Risk of injury to humans occurs at noise levels above 120 decibels, which would be more than 100 times greater than the maximum level of recorded OHV noise on Sedona’s trails.
Average particulate matter concentrations over the study period ranged from 9 micrograms per cubic meter at Schnebly Hill to 30 micrograms at FR 152C for 2.5-micron particles. For 10-micron particles, the figures ranged from 16 micrograms at Dry Creek to 66 micrograms at FR 152C. Federal air quality standards for each particle size are 35 micrograms and 150 micrograms, respectively. “24-hour averages for both PM10 and PM2.5 were below the federal guidelines for human health impacts,” the study concluded.
Given the results of this study, the city does not plan to move forward with a second phase of the environmental assessment.
“There was nothing that came out of that that indicated that regulatory action was needed,” Osburn told the council in June. “There was really nothing to phase two.”
Osburn told the owners of several OHV rental companies on Sept. 12 that “we’ve invested significant money trying to mitigate the negative externalities associated with your industry.”
