Loss of wetlands could increase inland flooding.

Loss of wetlands could increase inland flooding.

By Will Atwater

A few months ago, Jemonde Taylor stood, like a proud shepherd, on a bank and looked down at a section of Walnut Creek that runs through Southeast Raleigh’s Rochester Heights community, where he is the rector at St. Ambrose Episcopal Church.

After years of neglect, including illegal dumping, Taylor and members of the predominantly Black community worked to restore the urban wetland, a part of the Walnut Creek Watershed, through volunteer cleanups and advocacy work.

“The Walnut Creek wetland is considered the kidney of this larger water ecosystem that flows down to the Atlantic Ocean,” Taylor said. “And so the wetland because of its state — from sewage and garbage dumping — was like kidneys that needed to be on dialysis.”

As the chair of Raleigh’s Stormwater Advisory Committee, Taylor values wetlands’ vital role in flood mitigation, air and water purification, and wildlife habitat, among other things. For these reasons, he’s concerned about the potential loss of intermittent wetlands.

Unlike the Walnut Creek Watershed, which flows into the Neuse River and empties into the Atlantic Ocean, intermittent wetlands are not “indistinguishable” or directly connected on the surface to a “navigable” body of water and are losing protection under the Clean Water Act.

A new law passed by the North Carolina legislature — Senate Bill 582 — will potentially strip protections for intermittent or seasonal wetlands, leaving them vulnerable to development. The state law comes on the heels of a U.S. Supreme Court decision and could result in the loss of approximately 2.5 million acres of wetlands across the state.

In May, the high court ruled that for wetlands to receive “Waters of the United States” status, which protects them under the Clean Water Act, they must have a direct connection to navigable waters, such as the Great Lakes, the Mississippi or the Atlantic Ocean.

Given the season, changes to wetland protections come into sharp focus as Hurricanes Idalia and Franklin gather strength in the Gulf of Mexico and the Atlantic Ocean.

Hurricane season

During this time of the year, it’s common for Nick Petro and his colleagues to field questions about storms forming in the Atlantic and Caribbean basins. 

Petro, a meteorologist at the National Oceanic and Atmospheric Administration’s Raleigh Forecast Office, reminds people that the agency can offer no guarantees — only predictions — about the number and severity of storms that will form during the hurricane season, which starts June 1 and ends Nov. 30

NOAA is expecting “above normal activity in the Atlantic.” Part of their rationale comes from  “El Nino and record sea surface temperatures contributing factors,” according to information posted on the agency’s website. The predictions include 14 to 20 named storms, six to 10 hurricanes, and three to five major hurricanes. That prediction was recently revised downward from an earlier estimate of “65 percent chance of an above-normal season” to a 60 percent chance. 

Ultimately, time will reveal how accurate their storm forecasting proves to be. But Petro encourages people to prepare for rough weather and flooding in case a tropical storm or a hurricane hits the state.

“It’s never too late,” he said, “even though we’re entering the peak of the hurricane season, which is around the 10th of September — the climatological peak — that’s the day there’s most likely [a chance for] tropical cyclone activity in the Atlantic basin.” 

Petro recommends that people visit the website ready.gov for preparation tips and information. “The way you mitigate your risk and make yourself more resilient is by preparing.”

Chipping away at nature’s mitigation system

Wetlands are a part of nature’s mitigation toolbox and can offer frontline protection by absorbing water when a storm lands, reducing the potential damage to inland communities.

Changes to wetland protections worry environmentalists and researchers because they could lead to a loss of natural defenses against extreme weather events such as hurricanes Matthew and Florence, which each produced “500 year” floods, even though they occurred only 18 months apart. 

Without wetlands, there’s an increased potential for inland flooding, property damage and human casualties.

Wetlands provide essential services to the environment such as flood mitigation, habitat,water filtration. If intermittent wetlands lose Clean Water Act protections, they will be less habitat for wildlife and flood protection in coastal areas, for instance. Credit: NC Wetlands.org

The problem with putting an impervious surface like a parking lot or an athletic field over a dry creek or an area that only holds water seasonally, is that flooding will likely appear farther inland — in areas that previously didn’t flood.

While major storms pose a significant risk, smaller rainstorms could become more threatening with a loss of wetlands.

“Sometimes [these events] are not even a major tropical storm, but they’re dropping several inches of rain, and without those spongy land features of wetlands, we’re exacerbating flooding,” said Christy Perrin, sustainable waters and communities coordinator, North Carolina Sea Grant.

Plant ecologist JeanMarie Hartman, professor emerita, Rutgers University, provides an example of how wetlands can provide flood  and wildfire mitigation: 

“If you had a 10-acre wetland, and the water was four inches below the surface of the soil,” she said, “it could absorb water into those four inches, plus probably hold some standing water on top. Depending on the topography, maybe four more inches, maybe 40 more inches.” 

That could keep water from inundating developed land, she said. And wet, marshy areas can provide wildlife with refuge from wildfires

One acre of wetland can store one to one and a half million gallons of floodwater, according to NC Wetlands.org, a website developed by a group of wetland scientists in the North Carolina Division of Water Resources.

Taylor said that property developers are starting to realize the value of wetlands as an alternative to retention ponds.

“[With wetlands] the water level is lower, and you don’t have all this dirty water sitting there in the community … and there’s plant life, and birds can nest there.”

Wetlands: a closer look

Wetlands are formed from “special” interactions between soil, plants and water. Wetlands must contain enough water long enough for plants to grow, according to NC Wetlands.org, a website developed by a group of wetland scientists in the North Carolina Division of Water Resources.

According to the site, one acre of wetland can store one to one and a half million gallons of floodwater, according to the site.

In North Carolina, the majority of wetlands are in the Coastal Plain and “stabilize Coastal shorelines and serve as buffers against storms and erosion,” a service valued at more than 25 billion annually, the website states.

Types of intermittent or isolated wetlands found in the Coastal Plain include swamps, marshes and pocosins — bogs with deep, sandy peat soil.

Pocosins are in the upper part of the Coastal Plain landscape and are fed by precipitation. So their water levels rise and fall depending on the time of year, said Marcelo Ardon Sayao, associate professor in the College of Natural Resources at N.C. State University. Pocosins, like other wetlands, provide additional services to the environment.

“One of the things that we want to do is decrease the amount of carbon that’s in the atmosphere,” Sayao said. “And pocosins are very good at taking carbon from the atmosphere and storing it into soil for a long period of time.”

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