There's a quiet scuffle underway along the trails of the Boise Foothills. On any given day the hills are full of hikers, mountain bikers, walkers and runners who see the easy access to recreational trails as one of the best features of the valley.
But as more and more people discover the popular trail system, there are more chances for abuse.
Managers are seeing an upswing in illegal trail construction this spring that has them worried.
"I haven't seen anything like this," said David Gordon, Ridge to Rivers trails coordinator.
Within the last month, Gordon has found four illegally-built trail alterations. He knows of several more done on private land without the landowner's consent.
"I'm hoping they don't understand you can't do anything you want," Gordon said. "They don't know this is a managed trail system."
Ridge to Rivers is the multi-agency organization that works with the U.S. Forest Service, Bureau of Land Management, Idaho Fish and Game, the City of Boise and Ada County to manage 97 miles of public trails in the foothills.
Gordon, one of three full-time employees, said he started seeing illegal trail modifications last fall on the popular Lower Hull's Gulch Trail. There, mountain bikers had built dirt ramps on the uphill side of rocks along the trail, to create jumps.
Work crews removed the unauthorized work. But this spring, Gordon began finding other places where trail users had taken it upon themselves to change the trails. From paths leading around water bars (wooden poles placed across a trail to help mitigate erosion from water) to the removal of large rocks from trails to make the route easier, an increasing number of users are changing public paths to fit their needs.
"Some are well-intentioned and some individuals are out there for their own self-interest," Gordon said. "There's nothing well-meaning about building jumps on a busy trail."
"These people who are doing this are fully aware," said Dave Thomas, secretary of the Southwest Idaho Mountain Biking Association (SWIMBA). "They're doing it at times when they cannot be seen doing it.
"It threatens the usability of those trails for all cyclists," Thomas said. "They don't understand that they're putting those trails at that much of risk when they do those things."
Some of the more substantial changes Gordon has found this year include a "fairly significant" retaining wall, and a bike jump that would enable riders to clear more than 30 feet of air.
These two instances represent two very different causes of illegal trail alterations.
After removing the retaining wall, Gordon's office was contacted by the group that had built it, wondering why all their hard work had been destroyed. Gordon said the group simply didn't know that there is a formal maintenance plan in place for the trail system, and the group now works with Ridge to Rivers to do sanctioned improvement projects.
The big-air jump represents the other side of the issue.
The jump, not far from a very popular trail, was discovered less than a month ago, and already major damage has been done.
The builders used tools to remove sod to create an access trail to a dirt ramp, which was built up on the edge of a ridge. Riders were able to launch themselves off the ramp, clearing a ledge partway down the hill, before landing at a point lower on the slope. The force of the landings tore out most of the vegetation on the lower hillside, and the path leading back to the main trail is still visible.
Gordon and his crew have since replaced the sod along the access trail, removed the dirt ramp and placed a sign at the top of the trail, asking riders to stop misusing the area. A scar on the hillside will be visible for years to come.
Once illegal trail work is found, crews try to rehabilitate the area with either sod or seed, and post signs. If the misuse continues, workers can install fences to keep people out of sensitive areas.
"We manage for sustainability," Gordon said. "We also have to manage the resource.
"There's a lot of sensitive species," he said. "Take out the vegetation, and you get a lot of erosion. There are very few people who think that's acceptable."
Riders are worried too. Boise has an active group of local freeriders, people who launching themselves off jumps and descending hillsides most hikers would be hesitant to walk down.
"It definitely can hurt the reputation," said Darren Lightfield, a Boise-based freerider and SWIMBA board member. "When people are out there doing whatever they want, it's definitely going to hurt the freeride community. People need to get involved with the programs out there and work within the rules."
The possible damage to reputation worries the larger cycling community as well. "That's a reason SWIMBA is working very hard to keep those features at a minimum," Thomas said. "We're working with the land managers to (help people) understand this is not an acceptable practice."
"Across the country, trails get closed all the time to cyclists," Thomas said. "We need to make sure they're treating people and trails correctly."
Lightfield said there has been a breakdown in communications between land managers and the cycling community in the past, but that both sides now realize the need for cohesive action.
"It seems like people are getting on the same page and really getting together on some of these things," he said. "The riding community is becoming more informed on the procedures."
Gordon said Ridge to Rivers is working closely with the freeride community to identify areas appropriate for creating more challenging routes and features.
Among those projects is Velo Park, a new cycling park to be built in Eagle near Highway 55. When completed, the park will feature tracks for BMX riding, mountain biking and freeriding.
Lightfield expects the first phases of the park will be on the ground this year for riders to use. And Bogus Basin is working with area freeriders to install several features on its property.
Thomas said the issue of stopping illegal trail building has been a common topic of discussion among SWIMBA members, and that its more than 200 members are working with land managers to protect the trails system. SWIMBA is the official adopt-a-trail sponsor of the Lower Hull's Gulch trail, helping keep the trail in shape. Gordon said 12 trails have been matched with sponsors, and another 12 groups are still waiting to be paired with a trail.
Gordon said he invites anyone with concerns or ideas for the trails to come into his office and talk.
"There has to be that dialogue, rather than people just taking it on themselves," he said. "It's taking limited Ridge to Rivers resources to take out what they've done."
Gordon said he supports many types and levels of users being able to take advantage of the trail system, as long as it's within the rules.
"Hats off for being able to ride it, but it's inappropriate," he said. "It's just overall respect."