Committee focuses on sediment runoff

By Scott Nicholson

nicholson@wataugademocrat.com

When people think of water quality issues, they often think first of industrial pollution and wastewater spills.

According to Lynn Caldwell, director of the “River Builder” program for the National Committee for the New River, sediment runoff is the biggest threat to local streams and rivers.

One of the largest threats is small development or back-yard “improvements” that are made to look cultivated but are actually not only damaging to the environment, but eventually harm the very property that’s trying to be improved.

Caldwell said many homeowners who own land near a stream will clear all vegetation down to the water’s edge, often planting grass for a continuous lawn.

However, the roots of grass are only an inch to an inch-and-a-half deep and don’t adequately hold soil in place. Not only does it harm river health, it eventually takes away big chunks of the property.

“Most people really care about the river and want to do what’s right, but just have no idea,” Caldwell said. “People want a formal-mode look with mown grass, but wild water, creeks and rivers need to be natural.”

For riverbanks, “natural” means a riparian buffer, a mix of shrubs and small trees that have dense root structures designed to hold soil in place. Silky dogwood and silky willow are two native species that serve this purpose, trees that rarely reach 10 feet in height. They do much of their growing underground, weaving a root system that draws water for the plant’s health while stabilizing its immediate environment. “Nature knows how to repair itself if it’s just left alone,” Caldwell said.

Friday, contractors repaired about 100 feet of stream bank near the Winding Creek development on George Hayes Road in the Aho community. The entrance of the development features an attractive stone bridge, and Glenn Sullivan said the bridge had been well-built, with the addition of a second pipe for overflow, but it altered the course of the creek and it began undercutting the banks on a level, fertile plain downstream from the bridge. Sullivan, a former Soil and Conservation worker, said the changes to the stream would continue causing problems if uncorrected, especially since the stream current cut a straight line instead of following its natural, meandering path.

To disrupt the straight flow out of the pipe, Sullivan and his crew installed a series of rock berms and logs in the creek to restore a semblance of natural habitat. The berms will create sand bars that will smooth out the currents and also create a more varied natural habitat for fish and other aquatic life. Using track hoes and hand labor, the crew raked back the hanging lip of exposed soil to a gradually sloping shore, rolled out an erosion-inhibiting fiber matting and pounded “live stakes” into the creek bank.

Live stakes are two-feet sections of plant material cut from living willows or dogwoods that sprout a root system when placed in the ground. Caldwell said the plants themselves are attractive if people accept that “natural is beautiful.”

The shrubs and trees also provide shade to cool the water and improve fish habitat and also provides habitat for birds that feed on aquatic life. It’s not only development that poses a threat to natural stream banks. Agriculture adds its toll to the rivers as well, both through erosion from gardens and from livestock pastures where animals roam freely through the creeks.

“Once you’re aware of it, any creek you see in a cow pasture is an ‘unhappy creek,’” Caldwell said. “It’s ditched, there’s no flood plain and a lot of erosion.”

Caldwell said once people learn how to improve the health of the creek on their property, they are happy to let nature take its course. The Winding Creek property owners’ association contacted Caldwell about the erosion problem at the development, and expressed surprise that they had inadvertently caused environmental damage in a subdivision that prides itself on its wooded, scenic beauty. Caldwell said the property owners’ association contributed money for the project on a cost-share basis, with a grant from the North Carolina Clean Water Management Trust Fund paying 70 percent of the cost.

“This is very typical of what is happening,” Caldwell said. “Not knowing, they cut all the vegetation away from the banks, but there was not enough root mass left to hold the bank in place.”

Riparian buffers not only help stabilize soil, but they also help absorb flood water and catch sediment and runoff before it enters the creek.

Leaves from the vegetation feed some forms of aquatic life and the barrier helps inhibit algae growth, enhancing the amount of oxygen in the water.

Recommended trees for riparian buffers are basswood, black gum, green ashe, red maple and sycamore. Beneficial smaller trees and shrubs are black willow, downy serviceberry, buckeye, buttonbush, common elderberry, meadowsweet, mountain sweet, pepperbush, mountain holly, great rhododendron, spice bush, sweet shrub and tag alder.

“When these live stakes grow out, the owners can cut them low if they want,” Caldwell said. “It’s the root mass we’re most interested in, and we can use the cuttings for live stakes somewhere else.”

The National Committee for the New River started its River Builder program in 1998. Landowners voluntarily agree to leave the plantings alone for 15 years.

So far, the program has helped stabilize stream banks with riparian buffers along 46 miles of the New River and its tributaries, planting more than 420,000 live stakes and nearly 20,000 trees.