The downhill gravity trails at Lake Leatherwood are popular with mountain bikers and touted as a way to bring a more diverse group of visitors to Eureka Springs to help the local economy. But the trails on steep hillsides can be subject to a lot of erosion and damage when there is rain like April 28 when the area was pounded by a heavy downpour in a short period of time.
David Renko, grounds and natural resources manager for Parks, said there was damage from the three to four inches of rain received on April 28, but that crews worked quickly to reopen the trails by Saturday.
“Most of these issues as far as effects to trails are pretty standard,” Renko said in a telephone interview. “Just like roads, trails need to have maintenance. Some are more challenging to maintain. Downhill trails, just because of the steep grades, tend to be more of an issue. Many trails cross streams. Any time there is heavy flood water, we have to go in and inspect those stream crossings and improve and maintain them.”
Armored drainage pits help flush water and debris and limit clogs and necessary maintenance. Collection basins below the pits hold back flushed debris and water once it exits the pit, slowing silting and damaging high-water flashing.
Renko said during this recent rain there was a wood pile of debris that clogged one of the tunnels that a trail goes through. They had a foot bridge that shifted slightly in the day use area, and minor road damage within the interior of that facility.
He said they were able to get to the difficult spots for a safety and sustainability check and repair critical points before reopening the trails on Saturday.
Renko said the drainage beds are armored with flag stones where a tributary or a stormwater tributary crosses a trail. But they can’t control the amount of water that falls down the hillsides, which gouges the mountainside.
Occasionally culverts are used where the rainwater can go underneath the trail beds. They did have a couple park culverts that washed out and were damaged during the recent storm, but not on the gravity trails.
Another consideration is downfall from high winds and dead trees.
“That is a big consideration we look at from the safety and sustainability inspections we do,” he said. “Those can be hazards that impede people to continue in what we refer to as the flow in a trail. We make sure to have crews cut trees out of the way so people don’t have to clamor over a down or dead tree. This process happens pretty much every time we have high flood waters. That is pretty standard across the board in all recreational areas.”
Renko said the recent rain didn’t cause any cataclysmic losses where Parks lost the function of any trails or roads. Similar heavy rainfall events happen several times a year.
A lot of water over a long period of time is less violent than a lot of water in a short period of time.
“They both can create inundation, which can have negative effects of sediment build up and mushy soils in the trail tread, which in turn often stimulates pedestrian and bike traffic to search for dryer more stabilized surfaces on the trail edges,” Renko said. “Thus, the standard rule is to avoid using trails when they are wet and inundated.”
At public meetings some people have protested that the gravity hills developed for mountain bikers have reduced the number of trails open to hikers. Hikers who get lost and end up on gravity trails can be in for a frightening experience with near collisions with bike riders. Renko indicated in a recent public meeting that designating a couple more trails for pedestrians only is under consideration.
From the beginning, local environmentalists voiced concerns that the trails were not developed in a way to prevent damage from stormwater runoff carrying sediment and debris, some of which ends up negatively impacting water quality at Lake Leatherwood and other resources.
There was also controversy about what some park supporters saw as inadequate planning to protect important plants and animals in the area, and a failure to use best management practices for preventing damage from stormwater runoff on the steep hillsides. The project was funded by the Walton Family Foundation, which has been active in building extensive hiking and biking trails across Northwest Arkansas.
Pat Costner, director, Save the Ozarks, filed a complaint with the Arkansas Department of Environmental Quality (ADEQ) on the issue in April 2018 against the City of Eureka Springs for having failed to apply for the stormwater permit required for constructing the downhill mountain biking trails and associated access roads.
“ADEQ contacted the City, which turned the matter over to Parks Director Justin Huss, who then submitted the permit application,” Costner said. “ADEQ notified Mr. Huss of various deficiencies in the permit application. He responded by ignoring and/or misrepresenting important potential impacts of the downhill trail project. For example, when ADEQ asked Mr. Huss to identify the receiving waters that might be affected, he replied, ‘Receiving waters would be Leatherwood Creek at a considerable distance away.’ However, the project potentially impacted a chain of receiving waters beginning with West Leatherwood Creek, followed by Lake Leatherwood, then Leatherwood Creek, and finally Table Rock Lake.”
Other concerns Costner pointed out in her complaint to ADEQ included that the network of downhill mountain biking trails impinges on ecologically significant areas and habitats and passes through or in very close proximity to particularly vulnerable karst features – two springs and a cave. She said recommended 300-ft. buffers for the cave and springs have not been followed, and both tricolored bats and cave salamanders were identified in the cave. The U.S. Fish & Wildlife Service has published a proposed rule to list tricolored bats (Perimyotis subflavus) as an endangered species.
There are also rare plant species of concern in the area disturbed by the gravity trails.
Citizens have also pointed to miles of poorly built and maintained trails where the surfaces are impervious and create runoff by the over-use by visitors. Discussions are underway at parks to remedy these situations over time with repairs, reroutes, and reconsiderations for use.