Natural floodplain restoration improves flood safety

In the blue light before dawn on September 27, Laura Mouser watched the waters of the French Broad River rise higher and higher, toward her house. The trees shook in the wind as the vast brown river flowed around them.

Laura and her husband live just across the river from land owned by Conserving Carolina in Etowah – the restoration of Pleasant Grove’s natural floodplain. They moved here from Florida a few years ago, looking for somewhere safe from the hurricanes that constantly hit the Florida coast. They enjoyed the view of the river and the protected open space beyond.

Laura’s neighbor had told her that the river never exceeded a certain height, but during Tropical Storm Helen, Laura saw the river easily exceed that point. The water engulfed her husband’s vegetable garden. Then he passed the six-foot fence surrounding the garden. At its peak, the river had filled the large valley in front of their house and flowed up the hill where they live, toward the brown fence that surrounds their yard.

Afterward, Laura and her neighbor wondered: How much higher would it have been without the restoration of Pleasant Grove’s natural floodplain?

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1.25 billion gallons of flood water

Earlier this year, Conserving Carolina completed the restoration of Pleasant Grove on the site of an abandoned golf course. The conservation nonprofit brought back natural features like wetlands and a swamp (which looks like a pond connected to the river). They reshaped the waterways into ditches, restoring their natural, meandering beds. They also breached the berms along the French Broad, so that when it floods, the river can flow into its floodplain instead of carrying all that water downstream during massive floods.

After the storm, engineer Greg Jennings of Jennings Environmental, who designed several of Conserving Carolina’s restoration projects, crunched some numbers. He found that just three restoration projects along the French Broad River — Pleasant Grove, Mouth of Mud Creek and Kings Bridge — contained at least 3,680 acre-feet of water. To get an idea of ​​this, imagine 3,680 acres covered by a foot of water. That’s 1.25 billion gallons of water!

Ultimately, during Tropical Storm Helene, it was just a drop in the ocean – but the already terrible flooding could have been much worse. And for some local residents, it has made a real difference.

Lisa Moffit, who lives near the Mud Creek mouth restoration in Mills River, told Conserving Carolina, “I feel like the hard work you’ve done has kept our house on Mud Creek Road from ‘be even more flooded. »

In Riverstone, the neighborhood that borders this restoration, homes on lower streets were flooded. So every inch of water that could spread over the floodplain and enter wetlands instead of rising relentlessly meant that homeowners on the brink of flooding were spared.

During most floods, restored natural floodplains would also reduce downstream flooding, not just local flooding. Because berms are removed along the banks of the river, during a flood the river can overflow and expand instead of sending as much water downstream. However, under Helen, the river was so high that it exceeded all the berms; the water was going to reach the floodplain anyway. In less epic conditions, during the moderate to heavy flooding that regularly occurs in western North Carolina, natural floodplains can mean much less flooding for downstream farms and communities, especially with a growing network of restaurants.

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Over the past five years, Conserving Carolina has completed seven restoration projects and is currently working on nine more.

“In the future, the cumulative effect of more restoration projects like these can make an even bigger difference,” said David Lee, natural resources director for Conserving Carolina. “And we don’t always need to do large-scale restoration. We improve resilience every time we conserve agricultural land and natural areas that already exist in the river corridor. Each conservation and restoration project contributes to a more resilient flood control network that helps safeguard both natural ecosystems and human communities.

The Last Restoration — Kings Bridge

The most recent restoration project involves the 87-acre Kings Bridge Wildlife Conservation Area in Mills River. At Kings Bridge, work to reshape the land – crossing berms, digging a swamp and forming depressions for wetlands – was completed just a week before Tropical Storm Helene. It turned out to be just in time to mitigate the impacts of this epic flood.

Kings Bridge is public land owned by the NC Wildlife Resources Commission, which has partnered with Conserving Carolina on natural floodplain restoration.

“Reconnecting rivers to their floodplains restores the natural form and function of the land-water interface,” said Scott Loftis, upland aquatic habitat coordinator with the agency. “The ecosystem services achieved through these restoration projects not only promote the resilience of our natural resources but also increase the storage capacity of flood flows during flood events.

John Henry Nelson of Stone and Spade, who planted native species at Kings Bridge, says: “Even though construction has just finished, we are starting to see this site come back to life. »

Kings Bridge is temporarily closed for restoration work, including time for newly planted shrubs, trees and wildflowers to become established. When it reopens, Nelson predicts it will be popular with bird watchers, as there is already an abundance of waterfowl, bald eagles, hawks, ospreys, herons, kingfishers and of songbirds. “Every day we see rare birds here,” Nelson said.

Safer in extreme weather conditions

Lee says the restorations reduce risk from extreme weather on several fronts.

• Floods: When water levels rise, a natural floodplain absorbs and retains water, reducing risks to homes, farms and businesses.

• Water quality: Natural floodplains allow floodwaters to spread and slow, allowing sediment to settle on the ground, instead of carrying it downstream as water pollution.

• Droughts: By absorbing and retaining water, floodplains, wetlands, and swamps retain water in the local landscape. They slowly release it to recharge aquifers, feed rivers, and support plants and animals during dry periods.

• Biodiversity and wildlife: In times of flooding, natural floodplains provide calm waters where fish and wildlife can take refuge from strong currents, where they would not be able to survive. During droughts, floodplains provide essential water and shelter for wildlife when nearby areas dry out.

A natural floodplain provides many benefits, even in the absence of extreme weather conditions. Features such as swamps and wetlands were once common along the French Broad River, but are rare today. Restoring these natural features restores vital wildlife habitat, and almost immediately, conservationists begin seeing more birds, amphibians, fish, and other wildlife.

Natural floodplains also improve water quality by filtering sediment, nutrients and pollutants before they enter rivers and streams.

Additionally, restoration projects enhance outdoor recreation. Kings Bridge will reopen to the public in 2025 for fishing, bird and wildlife watching. At the mouth of Mud Creek, Conserving Carolina is working to create greenway connections that will provide public access. And a walking trail system is planned for Pleasant Grove. Vibrant natural spaces also provide a richer experience for the many people who float or paddle the French Broad River.

“Natural floodplains provide many benefits in terms of wildlife habitat, cleaner water and outdoor recreation,” Lee said. “And when we experience extreme weather events, a network of conserved agricultural lands and restored natural floodplains can make our communities safer and healthier. resilient.”

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Rose Jenkins Lane is the communications director for Conserving Carolina, a land trust based in Hendersonville.

This article originally appeared on Hendersonville Times-News: A place to go for water: Natural floodplain restorations improve flood safety.