Work is currently underway to improve the Rocky Run Stream Valley Trail. And the Fairfax County Park Authority recently held a meeting at Greenbriar East Elementary to explain the project and answer residents’ questions.

It’s about 4.8 miles of trail between the Fairfax County Parkway and E.C. Lawrence Park, and only 2.3 miles – between the park and Poplar Tree Elementary – are paved. Some 2.5 miles, mostly east of the school, are gravel; and only about .6 mile of that gravel trail – between the school and Stringfellow Road – is in good condition.

“That’s because that section of trail is at the edge of the floodplain and doesn’t get flooded,” said Project Manager Liz Cronauer, who manages the Park Authority’s Trail Program. “But the portion from Stringfellow to the parkway is closer to the stream and gets inundated with water when it rains — and that’s the part we’re concerned with.”

She said flooding leads to loss of surface material — which goes into the stream and forest. In addition, puddles form on the trail and widen it, adversely impacting the forest. “Recently, we’ve had more intense storms,” said Cronauer. “And when the trail is wet or needs repair, it’s unavailable for people to use.”

This situation, she said, leaves the base material “high and dry, which isn’t good to walk on, or for strollers. And when water can’t get through the culvert, it goes around it and causes intense erosion problems. So we’re going to remove these culverts and replace them with a bridge.”

Explaining why paved trails are preferable to gravel, Cronauer said asphalt trails cost about $130,000 per 100 linear feet. Gravel or stone-dust trails start at $100,000. “But asphalt trails last 20 years,” she said. “Gravel trails only last about 10 years and then have to be completely redone. So gravel trails [ultimately] cost more in maintenance and construction costs.”

Cronauer said gravel trails have 4 inches of compacted stone beneath them. “But they can’t handle water or steep slopes,” she said. “So we have to go to asphalt trails to make them sustainable.” Currently, about 40 percent of the Park Authority trails are natural-surface; 40 percent are hard-paved asphalt; and the other 20 percent are either gravel/stone dust or concrete.

The project will be done in three phases:

• Phase One is between Stringfellow and Middle Ridge Drive. All unpaved sections will be paved to create a 6,600-foot-long, 8-foot-wide trail. And six, concrete, fair-weather crossings with pedestals will be added. Time frame: Now until sometime this fall, possibly October, weather permitting.

• Phase Two is between Middle Ridge and the parkway. The culvert crossing will be removed and the trail, rerouted. A bridge will be built where the stream banks are to make it all more stable. Time frame: Design/permitting between now and October 2019; construction between October 2019 and July 2020.

• Phase Three is also between Middle Ridge and the parkway. It’s presently unfunded, so it has no time frame. It will consist of fixing whatever remains after the bridge is in. All unpaved sections in this stretch will be paved to create a 5,000-foot-long, 8-foot-wide trail, and the culverts will be replaced.