City weighs environmental pros and cons of natural greenways

As greenways grow in popularity, the city of Asheville is looking into natural surface trails as a possible way to develop a greenway system that benefits people, the planet and the city’s pocketbook.

Asheville has four greenways totaling almost 5 miles and four shovel-ready greenway projects that are pending funding: Bacoate Branch, Beaucatcher, French Broad River West Bank and Town Branch.  

The city does not currently have capital allocated for the four new greenway projects, and in November it surveyed the public to help prioritize the greenways in the fiscal year 2018-19 budget. According to Lucy Crown, greenways coordinator for the city, the Bacoate Branch, French Broad River West Bank and Town Branch greenways are all $4 million projects, while the Beaucatcher Greenway could cost closer to $6 million. “When the city put the greenway projects out to bid, the quotes came in about 30 percent higher than our professionally estimated costs,” Crown says. 

Trail to savings

The cost of using a natural surface can be substantially lower than paving, but the city’s consideration of natural surface greenways is not just an economic one. “We’ve been thinking about natural surface trails for a couple of years now,” says Crown. “It hasn’t just been a reactionary decision because of funding.”

Asheville residents have asked the greenway committee to explore unpaved trails for many reasons other than the price tag, Crown says. “Their desire for natural surface trails are numerous: for better places to run (natural surface trails are easier on joints than paved paths); the aesthetics of a more natural experience; and the ability to save more trees and lessen the environmental impacts of greenway development,” she says.

It is not always the case that naturally surfaced trails are cheaper to build than traditionally surfaced paths. If a dirt-and-gravel trail is used in the wrong place, long-term maintenance of the trail can become a burden. “The location of a natural surface trail is very important to consider when we are deciding what type of surface we should use on a greenway,” explains Crown. “If it is in a vulnerable area like a floodplain, or if it is a greenway corridor where a lot of people will be using it, it might make more sense to pave it.”

In November, Asheville City Council approved construction of a natural surface path on the western portion of the Town Branch Greenway. For its first official foray into natural surfaces, the city is partnering with Green Opportunities, a local job-training organization that connects marginalized communities with sustainable employment opportunities, to install a natural surface trail on a flat field behind the Wesley Grant Southside Center. For the city, it’s an interim project. “When we do our bond project of building out the Grant Center to the master plan, we will pave that section,” Crown says.

The city is also considering building out the Beaucatcher Greenway in a modified version different from the fully designed plan as an interim project until it has funds to complete it. “This would entail building the sections of the greenway to increase public safety and access but will leave the logging road in the parkland as it is now with minor improvements to improve water runoff issues,” Crown says.

These temporary avenues to getting trails on the ground are exactly the kind of innovation that makes Marcia Bromberg excited. Bromberg is the outgoing president of Friends of Connect Buncombe, which supports the construction of greenways throughout the county. “My perspective is in the short run if you want a connection, and you can’t afford a paved surface, the natural surface can act as a bridge,” she says.

Path to eco-friendliness

Greenways built with natural elements can have less of an environmental impact than those that are paved, says Mary Weber, chair of the city’s greenway committee. “Overall, natural surfaces are more sustainable for a number of reasons,” she says. “They aren’t as wide as a typical greenway, you aren’t using asphalt, which is petroleum-based, and they fit into the environment more.”

Asheville’s paved greenways are 10 feet wide, but natural surface greenways will likely be narrower — possibly between 3 and 5 feet in width, says Weber. Their smaller size means reduced need for tree removal and, because they are pervious, less groundwater runoff.

The feasibility of a natural surface trail — and the kind of upkeep it requires — depends on the kind of surface used and its location. You’ve got to look at “whether you’re simply building a trail with nothing on it or whether you’re putting gravel on it and where the trail is located,” says Bromberg. She adds that designers need to consider whether the natural surface could wash into nearby waterways.

One downside to natural surface trails is the potential for erosion if they are not designed strategically. “If they aren’t built to support the rain runoff, or if they’re not built for the number of people who are going to be using it, then they can fall apart pretty quickly,” says Crown. “They can have gullies and cracks in them. They can have really muddy sections.”

Crown says the durability of natural surface trails comes down to construction. “If they are built in vulnerable areas or built incorrectly, with no regard to slope or water runoff, they require more maintenance in the long run,” she says.

Gravel requires the correct incline, Weber adds, pointing out that the gravel used on these trails won’t be big, chunky rocks. “It’s basically rock dust. Either it’s a pretty small crushed rock or stone dust that is compacted. It doesn’t wash away as much as gravel would,” she says.

The city does not yet have a maintenance plan for natural surface greenways, but a framework for the natural surface trail program will be considered during an update of the city’s Greenway Master Plan this year. “We will not be rushing into natural trail construction without knowing the best way to build and maintain them,” says Crown.

Road to the future

The idea of natural surface trails is just being introduced, and the city is still determining where natural surface trails might be used, but a Greenway Warmer event the city hosted in mid-December drew a large crowd. “People were really enthusiastic,” says Weber. “Most people love natural surface trails.”

Natural surface greenways have been successfully implemented in other cities. Charlotte has four temporary, natural trails it calls “dirtways,” and the Urban Wilderness in Knoxville, Tenn., a network of 50 miles of natural surface trail, has garnered national attention. The trails are designed to have minimal impact on the natural environment.

“The International Mountain Bike Association established a standard a long time ago for sustainable trails,” explains Carol Evans, executive director of Legacy Parks Foundation, a nonprofit that has played a key role in Knoxville’s trail system success. “We don’t cut trees; we don’t disturb natural features. Sustainable trails have been the practice from the very beginning.”

As Asheville updates its Greenway Master Plan, the process will be open to public participation. “We are hoping to look at natural surface trails seriously in the upcoming year,” says Crown.

Those interested in providing input on the Greenway Master Plan or who would like information on the future of natural surface trails can email Crown at lcrown@ashevillenc.gov and request to be added to the distribution list. In the meantime, greenway committee meetings are open to the public every first Thursday of the month from 3:30-5 p.m. at the Municipal Building.

“We are at a tipping point right now,” says Weber. “A lot is happening and about to happen. I think as more of these greenways are connected, more and more people will support it.”