How Do You Heal this Stream without Killing the Trees?
Here’s a stream with problems that aren’t easy to solve.
The stream is on a beautiful farm in Henderson County on the banks of the French Broad River—a farm with lush fields of hay, where deer are plentiful and hawks soar overhead. The landowner has been working for more than a decade to improve the ecological health of this family farm where he grew up. As part of that work, he donated a conservation easement to Conserving Carolina on 45 acres along two streams and the floodplain of the French Broad River.
But the streams weren’t in good shape. They were badly eroded and it kept getting worse. During heavy rains, the water was trapped in V-shaped ditches. It couldn’t overflow and spread out. So, all of that stormwater barreled down the gullies, stripping away more soil. The ditches cut deeper. And muddy water dumped into the French Broad. The estimated erosion rate was more than 20 tons of sediment every year!
The landowner’s property was literally washing away. And all of that erosion was polluting the river. Muddy streams and rivers make our water more expensive, because we need treatment plants to filter out that sediment and other contaminants that latch onto it. On top of that, sediment can clog fish gills, cloud the light needed by aquatic plants, and bury underwater habitat—so plants and animals can’t live in the river.
What would you do?
This landowner was committed to improving his stream health, but a stream restoration can be costly. Fortunately, Conserving Carolina was able to secure a grant from the NC Department of Public Safety to improve flood resilience along the French Broad River. Still, there was the question of how to fix these streams.
For the first stream, you could follow a common restoration playbook. You regrade the banks. You bring in earth-moving equipment, and pull the banks back to create a gentle slope. That allows floodwater to overflow and find a place to soak in. You bring back some meanders, or curves, so the stream isn’t pointing in a straight line downhill. Then, you cover the banks in biodegradable netting to hold the soil while plants grow in. You put in live stakes and you plant trees that will stabilize the stream banks in the future.
Here’s what that looks like:
But on the second stream, which had become a 6-foot-deep gully, the problem was harder to solve. That stream was surrounded by mature trees. To regrade the banks, you’d have to cut those trees down.
Torry Nergart, our Stewardship Manager, says, “Here, you have a mature canopy. Of course, the landowner didn’t want all these trees taken out to make room for all the grading that would be required. Why would you kill all these trees to do that work?”
Trees are a stream’s best friend. They shade and cool the water, which improves wildlife habitat. And they stabilize the banks, preventing erosion. However, in this case, the erosion had started before the trees began to grow. Back then, the land was mowed to the waterline—the same reason we see steep, collapsing banks along so many of our rivers and streams.
So, how do you heal this stream without sacrificing the trees?
Greg Jennings, an engineer with Jennings Environmental, came up with an innovative solution. Since it’s not possible to bring the banks down, he proposed to bring the water level up.
The restoration team installed nine rocky berms along the stream that act like speed bumps for water rushing down during storms. Just completed this spring, the berms are now catching debris and sediment and backing up the stream into a series of pools.
Here’s what that looks like:
As Torry says: “Slow that water down. Spread it out.”
What used to be a chute of fast-moving water is finding a new shape. It’s becoming a series of wide, calm pools that provide ideal habitat for wildlife like frogs, salamanders, and turtles. Both of these streams—nearly a quarter of a mile between them—now offer much cleaner water when they flow into the French Broad River.
And every tributary makes a difference. Building on the success of our Mud Creek restoration, Conserving Carolina has six restoration projects—including this one—underway in the Upper French Broad River corridor. Three will be completed by this summer, with three more scheduled for 2024.
Torry says, “Landowners are starting to see a lot of good examples of restoration projects. Many landowners don’t want to see their soil keep washing away. Some farmers are tired of fighting the river where it wants to flood. And a lot of folks just want to do something positive for nature. They’re seeing that there’s funding for good projects and that we can come up with solutions that work for them.”