Tag Archives: Green Infrastructure

Wetlands and Climate Change


Climate change is the rise in average surface temperatures on Earth, mostly due to the burning of fossil fuels.  Climate change is causing intensifying storm activity, rising sea levels and creating more
frequent floods and droughts in the Carolinas and worldwide. Recent,
significant storm events in North and South Carolina include Hurricane Florence (2018), Hurricane Matthew (2016) and Hurricane Floyd (1999).

Aerial view of Hurricane Florence (2018) heading for the Carolinas. Photo: NASA

Increased storm activity is having a huge economic and environmental impact on our coastal and inland communities in the Carolinas.  Hurricane Matthew caused an estimated $4.8 billion in damages. Hurricane Floyd caused between $7 and $9.4 billion, and the damage from Hurricane Florence was estimated to be nearly $17 billion – more than Matthew and Floyd combined

 Wetlands play a critical role to help mitigate increased storm activity caused by climate change by retaining floodwater, stormwater and storm surges.  Because of their critical importance during these storm events, wetland protection and conservation is essential to combating the effects of climate change in the Carolinas.

Problem Statement

Climate change is here.  As defined by NASA, climate change refers to long-term changes in the average weather patterns that have come to define Earth’s local, regional and global climate1. Climate change causes increased temperatures and storm activity, contributes to rising sea levels, elevates storm surges and causes more frequent flooding. The economic impact of recent, intense storm activity in the Carolinas has been devastating over the last 10 years.  In 2018, Hurricane Florence produced a record storm surge of 9 to 13 feet and caused catastrophic flooding inland for days2. More than 50 people died across the region; 42 in North Carolina alone. North Carolina’s Governor Roy Cooper estimated Florence’s damage in North Carolina at $17 billion—an amount more than Hurricane Matthew and the previous historic hurricane, Floyd in 1999, combined2.

Flooding not only causes property damage, but also impacts public health and overall well-being in our communities3. Flooding can destroy a home, leaving it uninhabitable. There are also numerous hidden dangers in flood waters that create a public health risk: live wires, broken glass, and sharp metal as well as bacteria and other pathogens4.


There is general agreement amongst the scientific community that climate change is real. Also referred to as global warming, climate change is causing a rise in average surface temperatures on around the globe1. 2019 was the warmest year on record in North Carolina. In the Carolinas, scientists have observed an increase in annual average temperature by 1.0o F since 1895.  In North Carolina, the last 10 years (2009 – 2018) represented the warmest 10-year period on record5.  In Charleston, South Carolina, 2019 was the fourth-warmest year on record, which ended the warmest decade to date6. In addition to rising temperatures, climate change is intensifying storm activity, rising sea levels and causing more frequent floods and droughts worldwide. The Carolinas have experienced several major hurricanes in the last 5 years, including Hurricane Matthew (2016), Florence (2018) and Dorian (2019).  These hurricanes caused widespread flooding in dozens of coastal communities, resulting in billions of dollars in property damage. Extreme flooding events occurred during hurricanes Matthew (2016) and Florence (2018) in North and South Carolina5.  Florence was a historic storm, breaking 28 flood records across North and South Carolina7.  Some of the flooding records are over 75 years old, including the Northeast Cape Fear River near Chinaquapin, NC (78 years) and the Little Pee Dee River at Galivants Ferry, SC (77 years).    


Wetlands play an absolutely critical role in mitigating the impacts of climate change, by retaining floodwater, stormwater and storm surges.  Wetlands also store, or sequester, excess carbon in the atmosphere through photosynthesis8.  Carbon dioxide in the atmosphere is absorbed by wetland plants during photosynthesis and is retained in the plants’ biomass (roots, shoots, tree bark and leaves) and in the soil as soil organic matter.

View of Lily Pond in May of 2015 within the Croatan National Forest in North Carolina. This wetland is well known for its capacity to retain water after storm events, slowly releasing the water back into the environment. Photo: Kristie Gianopulos

When an area floods with water, surrounding wetlands act like a giant sponge; living plants and even the dead plant matter along with porous soils can absorb the extra water. Wetlands also help slow down the movement of floodwater to surrounding areas – which would otherwise impact homes and businesses. In coastal areas, marsh wetlands protect shorelines from erosion by buffering wave action and trapping sediments. They reduce flooding by slowing and absorbing rainwater and protect water quality by filtering runoff.  Coastal marshes can also migrate landward (Figure below). Trapped sediments allow the marshes to rise in elevation, which helps mitigate the effects of sea level rise (SLR).Because of their ability to mitigate sea level rise, absorb rainwater, retain floodwater and store atmospheric carbon dioxide, wetland protection and conservation is essential in the Carolinas.

Landward migration of salt marsh with sea level rise (SRL). (Figure courtesy of DCERP 2 Final Report, 2018.)9

  Wetlands can be protected and conserved in a number of ways:

  • By not developing or impacting wetlands (e.g., filling, ditching),
  • By placing wetlands under protective easement (e.g., conservation easement).
  • If you live on waterfront property, wetlands can be protected by installing a “living shoreline” (see photo below) – a mix of plant roots, sand and stone instead of man-made structures, like retaining walls, to stabilize the soil.
View of a living shoreline along the Carolina coast. Photo: Restoration Systems


Climate change isn’t going away.  Climate change intensifies storm activity, and scientists predict an increase in tropical storm frequencies from 1-10% in coming years10. Wetlands play a critical role to help offset the impacts of climate change by retaining floodwater, stormwater and storm surge.  Wetlands also hold tremendous value as a climate change mitigator through their ability to sequester carbon within the organic content in the soil.

View of a saltwater marsh in Francis Marion National Forest. Photo: Kristie Gianopolus

The impacts of climate change on local communities can be significantly lessened by protecting local wetlands. The can be done by:

  • Avoiding the development or impact of wetlands (e.g., filling, ditching);
  • Avoiding wetlands if planning a home, building, shed or farm field expansion; and
  • By placing wetlands under protective easement (e.g., conservation easement).
  • Wetlands can be protected by installing a “living shoreline” (see photo) to stabilize the soil – a mix of plant roots, sand and stone instead of man-made structures, like retaining walls.

There are a number of existing wetland protection programs in place in the Carolinas, and these programs greatly benefit from volunteer contributions and involvement:


  1. NASA’s Climate Center “Overview: Weather, Global Warming and Climate Change” [Online]. Available: https://climate.nasa.gov/resources/global-warming-vs-climate-change/ [Accessed July 1, 2020].
  2. Economic impact of Florence: https://insideclimatenews.org/news/27122018/hurricane-damage-north-carolina-climate-change-2018-year-review-florence-michael-matthew#:~:text=Hurricane%20Florence%20produced%20a%20record,Carolina%20alone%20at%20%2417%20billion.
  3. Economic impact: https://www.newsobserver.com/news/technology/article215476785.html
  4. Health Impacts of Flooding: https://edmdigest.com/resources/florence-flooding/
  5. Kunkel, K.E., R. Easterling, A. Ballinger, S. Biligin, S.M. Champion, D.R. Corbett, K.D. Dello, J. Dissen, J.M. Lackmann, R.A. Lutteich, Jr., L.B. Perry, W.A. Robinson, L.E. Stevens, B.C. Stewart, and A.J. Terando, 2020: North Carolina Climate Science Report. North Carolina Institute for Climate Studies, 233 pp. https://ncics.org/wp-content/uploads/2020/06/NC_Climate_Science_Report_FullReport_Final_revised_May2020.pdf
  6. https://abcnews4.com/news/local/noaa-2019-was-the-2nd-hottest-year-on-record
  7. https://www.newsobserver.com/news/local/article222615945.html
  8. Association of State Wetland Managers: “Carbon Sequestration” [Online]. Available: https://www.aswm.org/wetland-science/wetlands-and-climate-change/carbon-sequestration
  9. DCERP (2018). Defense Coastal/Estuarine Research Program 2 Final Report. Retrieved from https://dcerp.serdp-estcp.org/Portals/0/FinalReports/RC2245_DCERP2_Final_Report.pdf
  10. https://www.gfdl.noaa.gov/global-warming-and-hurricanes/
  11. Michener, W.K., E.R. Blood, K.L. Bildstein, M.M. Brinson and L.R. Gardner. Climate Change, Hurricanes and Tropical Storms, and Rising Seal Level in Coastal Wetlands. 1997. Ecological Applications, Vol. 7, No. 3, pp. 770-801.
  12. C. Kozak, “Restoration Work – A Test for Carbon Farming,” Coastal Review Online, 01-Aug-2019. [Online]. Available: https://www.coastalreview.org/2019/01/restoration-work-a-test-for-carbon-farming/. [Accessed: 11-Feb-2020].

Written by:

Heather Patti, PWS is a Senior Ecologist and Project Manager at TRC Companies, specializing in wetland and stream delineation, permitting and endangered species assessments for the renewable energy industry.  Heather is a proud mother of 2 boys, Ben and Wyatt, and in her free time enjoys hiking, camping, botanizing and kayaking.  She is a terrible fisherman.


By Amin Davis

The importance of maintaining and enhancing green infrastructure, or GI, has become a primary area of focus within the Carolinas and nationally as communities seek ways to increase their resiliency against changing weather patterns and more frequent, high-intensity storms. Concurrently rapidly urbanizing regions such as the Research Triangle, NC and Horry County, SC have to address increased development which causes significant increases in stormwater runoff.

What is Green Infrastructure?

GI, including wetlands, use vegetation, soils, and other natural landscape features to manage wet weather impacts, reduce and treat stormwater at its source, and create sustainable and healthy communities (EPA, 2017). The beauty of these nature-based practices is that in addition to providing environmental benefits, they support community resiliency by providing multiple ecosystem services, or community benefits, that can be quantified by economic, public health and social metrics (see Community Benefits of GI table below). Conversely traditional gray infrastructure such as gutters, stormwater pipes and sewer systems are considered single purpose and can cause major water pollution and flooding downstream in our watersheds. Additionally GI can be integrated into nearly every type of land use (residential to commercial) and development density (low to high).

In searching for resources about GI one may find a wide variety of overlapping terminology and frameworks. For the purposes of this article GI is separated into two broad categories: engineered and natural. Engineered GI practices include bioretention cells, constructed wetlands, green roofs, permeable pavements, rain gardens, vegetative swales, rainwater harvesting (rain barrels or cisterns) and rooftop (downspout) disconnection. These practices are designed to reduce stormwater volumes and improve water quality. Natural GI, on which engineered GI practices are based, includes vegetated wetlands, stream buffers and other vegetated or forested areas. The conservation of relatively stable areas of natural GI and the restoration of degraded areas of natural GI is a critical component of maintaining environmental resiliency against more frequent storms, rising seas and shoreline erosion along our Carolina coastlines.

How to Use Green Infrastructure

There are success stories of developers who have been willing to integrate GI into their site development once this alternative was brought to their attention. A leading example of this is the Market at Colonnade Innovative Stormwater Management Plan that was integrated into the site design of a shopping center in Raleigh, NC. This project involved a suite of GI and other stormwater control measures being designed and constructed which led to a 98 percent reduction in stormwater volume and significant reductions in stormwater nutrient concentrations (total nitrogen, phosphorus and suspended solids). This project was used as a model for successfully negotiating the integration of GI into the site design of a proposed multi-hotel development within a wooded site in Cary, NC.

Source: https://www.cnt.org/sites/default/files/publications/CNT_Value-of-Green-Infrastructure.pdf

Two key elements for the integration of GI into development plans are: 1.) local stakeholder input advocating for GI at the front end of proposed developments (prior to the completion of preliminary development plans); and 2.) working with local nonprofits and watershed groups to make developers aware of grants and other cost-share funding available to offset the costs of integrating GI into their site plans. Below are some grant programs that provide cost-share funding for engineered GI practice:

Common Sense Approach

GI is a common-sense solution that should be a primary requirement for all development everywhere, especially in light of increasing development coupled with more frequent, higher-intensity rain events. Local governments should be allowed to require low-impact development (LID) principles, such as the preservation of green spaces and the integration multiple GI practices, for all new development. They should also be allowed to require the integration of GI retrofits for re-development and urban infill projects. Why? Because there’s an abundance of peer-reviewed and anecdotal evidence that clearly demonstrates that GI is really Community Resiliency Infrastructure. Hopefully this message can be delivered to our elected officials and community leaders to a degree that will lead to broad scale changes in development policies that promote GI.

Additional Resources:

About the Author

Amin Davis is a volunteer and Outreach Coordinator for the Carolina Wetlands Association. Amin is a Certified Ecologist, Professional Wetland Scientist and is active with several community nonprofit organizations that are based in Southeast Raleigh. He has been employed with the NC Department of Environmental Quality since 2008 and has been employed with the NC Division of Water Resources since 2014. He manages a grant program that provides cost-share funding to local governments and their partners for projects associated with green infrastructure, stream restoration (including dam removals and living shorelines) and water-based recreation.