Results may vary: Research considers NC’s riparian buffer rules

North Carolina’s fast-growing Wake County is poised to get two things—more rain and more development. And that clash could put pressure on state-mandated 50-foot riparian buffers1, vegetated areas along bodies of water that are designed to protect the region’s Neuse River basin by limiting erosion, providing wildlife habitats and naturally cleaning stormwater runoff.

Researchers at North Carolina State University explored whether these long-mandated buffers, part of a 1997 law designed2 to protect water resources, were keeping up with both the flood of development and stronger storms forecasted for the region.

“We were really interested in assessing what is the efficacy of these buffers in being able to mitigate future conditions and how might they perform into the future,” said Elly Gay, PhD, a graduate research assistant at N.C. State University and the study’s lead author.

Just like for locations across the globe, climate change is triggering more rainfall and serious storms for the county, which includes Raleigh, the state’s capital. According to the National Climate Assessment, compared to the average for the region between 1991 and 2020, the county could experience 6% more rain and 24% more days with extreme rain events if the Earth’s temperature rises 2 degrees Celsius.

And, lured by jobs, the region’s educated workforce and good weather, major employers and new residents are flocking to the region. Wake County, along with its neighboring counties, are among the fastest growing regions3 in the country, spawning new office buildings, shopping centers and neighborhoods to keep up.

But all that development puts pressure on streams and natural areas, which can’t always keep up with the water running off more impervious areas, such as rooftops and roads, especially as climate change triggers more serious storms. Gay explored the efficacy of those state required riparian buffers as conditions change. Her research, which she conducted with co-author Katherine Martin, assistant professor of forestry and environmental resources at N.C. State, considered different buffer scenarios, along with projected stream flows and land use. 

They found that buffers do help, particularly in heavily developed or developing areas. “But in the areas in between, it was kind of iffy. What we found is that these buffers might be useful on these more local levels,” she said. “When we zoom out and look at the entire watershed, their effects might be more minimal.”

Going forward, as the climate and development intensifies, more nuanced buffer rules instead of a one-size-fits-all approach may be more effective, Gay said. “Instead of focusing on standardized buffer width through the entire watershed, [look] at more strategic buffer placement.”