By Lucas Hernandez, MS, MPA Climate Adaptation and Resilience Specialist Weston & Sampson No. Charleston, South Carolina, M. Lee Bundrick, MS, MPA Senior Ecological Health and Conservation Coordinator Kiawah Conservancy Kiawah Island, South Carolina Photos courtesy Weston & Sampson and/or the Kiawah Conservancy
With the increasing frequency and severity of climate change-induced impacts to our coasts, the need for innovative and resilient infrastructure solutions becomes more critical every day.
Nature-based solutions are becoming a preferred alternative infrastructure design technique used by many coastal public works agencies and other similar departments due to their ability to increase the resilience of both the natural and built environment. In this article, we define nature-based solutions as any action “to protect, sustainably manage, and restore natural and modified ecosystems that address societal challenges effectively and adaptively, simultaneously providing human well-being and biodiversity benefits.”
The benefits of nature-based solutions are that they:
- protect coastal uplands
- stabilize shorelines
- reduce flood impacts
- improve water quality
- restore and protect wetlands
- reduce urban heat island effects and/or
- add recreational space.
As an example of what public works or nonprofit agencies can accomplish, the Kiawah Island Natural Habitat Conservancy, Inc. (Kiawah Conservancy) on Kiawah Island in South Carolina has undertaken significant efforts to engage with stakeholders in their community to address barriers to coastal resilience by building a consensus on nature-based solutions and developing guidance documents. They have also taken advantage of the use of geospatial techniques and collaborative efforts to develop implementation strategies within the Kiawah River Watershed.
In the last 10 years alone, Kiawah Island has been heavily impacted by multiple hurricanes and tropical storms, with up to five feet of flood depth in several locations.
Kiawah Island and its vulnerability
Kiawah Island, governed by a combination of five municipal, private, and nonprofit entities, is an approximately 8,500-acre, drumstick-shaped barrier island about 20 miles south of Charleston. As with many other similar low-lying communities along our coasts, Kiawah is highly vulnerable to a variety of climate-change-induced impacts, including sea level rise, more frequent and severe hurricanes and tropical storm events, and pressures from increased development.
There are seven key habitat types found on Kiawah:
- marshland
- maritime forest
- maritime shrub thicket
- salt shrub thicket
- maritime grassland
- freshwater wetlands
- intertidal beaches.
As sea levels rise, we will see marsh dieback as well as “ghost forests” where trees that aren’t suited to the newer, more saline environment begin to die off.
As sea levels rise, coastal marshes must keep pace, and where there are barriers to marsh migration, we will see marsh dieback. Some salt marshes on Kiawah Island, in fact, are already beginning to migrate upland in areas where they can do so. As tidal flooding repeatedly reaches previously dry locations, we are also seeing “ghost forests” appear where trees that aren’t suited to the newer, more saline environment begin to die off.
Kiawah’s approach
Kiawah Island is focused on managing natural resources and designing with nature and, as such, has a deep interest in bolstering resilience through a multi-pronged effort that includes:
- drainage improvements
- resilience and adaptive management planning
- a flood mitigation and sea level rise report
- a comprehensive marsh management plan
- hiring a resilience specialist
- expansion of monitoring programs
- marsh management planning.
There are, however, some inherent challenges and barriers that the island must navigate, with expanding knowledge of historic and current conditions being one of them. As of late, their approach to solving this challenge has been to drastically increase monitoring efforts on the island and to invest in studies to frame how the island has changed over the years. Each of these studies was tailored to a specific focus area. However, there was a good amount of overlap in terms of topics and recommendations between them. One such recommendation was to investigate alternative management practices to address sea level rise, climate change, and flooding on the island.
Kiawah Island is focused on managing natural resources and designing with nature, and as such, has a deep interest in bolstering resilience through a multi-pronged effort.
Information gathering
The Kiawah Conservancy held a comprehensive stakeholder meeting to both generate consensus on proposed nature-based solutions and identify the future direction of potential resilience projects.
In 2020, the Kiawah Conservancy was awarded $125,924 in funds through the National Fish and Wildlife Foundation’s Emergency Coastal Resilience Fund 2019, with support from the National Oceanic and Atmospheric Administration, to address barriers to improving coastal resilience by building consensus and stakeholder collaboration on viable nature-based solutions, with a combined approach focused on both humans and wildlife. The project involved three phases: stakeholder interviews, research and review, and building consensus.
The primary focus of Phase I was to gather information using semi-structured interviews with key stakeholders to address their environmental concerns, get their thoughts on current mitigation strategies, and ascertain their opinions on nature-based solutions.
Phase II was geared toward researching and identifying novel strategies, continuing discussions from Phase I, and conducting additional reviews with stakeholders, residents, and technical experts.
During Phase III, the Conservancy held a comprehensive stakeholder meeting to both generate consensus on proposed nature-based solutions and identify the future direction of potential resilience projects.
Throughout these stakeholder engagement exercises, the Kiawah Conservancy also initiated several monitoring projects to understand environmental conditions throughout the Kiawah River Watershed, including groundwater levels, changes in marsh shoreline conditions, vegetative productivity, and erosion rates. By the end of 2023, over 3,300 acres of tidal salt marsh surrounding Kiawah Island had been preserved by conservation easements held by the Kiawah Conservancy, encouraging the use of nature-based solutions over hardened structures.
A manual for the use of nature-based solutions
The “Nature-Based Solutions Manual for Kiawah Island” was designed to be accessible to a wide swath of the community, with enough technical detail to be practical, and provides “blueprints” for ideas.
The result of all these efforts is a report entitled “Nature-Based Solutions Manual for Kiawah Island" (joom.ag/KJ9d). The manual provides the community with a comprehensive list of 13 nature-based practices to protect the island’s salt marshes and mitigate the impacts of stormwater. The manual was designed to be accessible to a wide swath of the community, with enough technical detail to be practical, and provides “blueprints” for ideas. Some of the concepts in the manual for managing rising sea level rise and increased stormwater runoff in coastal communities like Kiawah are:
- rain gardens
- vegetated buffers
- oyster shell bags
- double coir log placement
- “Envirolok” bank stabilization.
As the ideas and concepts outlined in the manual are implemented on a wider scale and as the resulting benefits are seen by more residents and the entire Kiawah community, we are confident that it will be seen as a model for other communities up and down the coast.
Sea levels will continue to rise, and hurricanes will increase in frequency and severity. As such, it will become increasingly important for communities facing these threats to have a similar manual in their toolbox to have the best chance possible to face these challenges head-on and continue to thrive.
Lucas Hernandez, MS, MPA, can be reached at 843.790.0589 or hernandez.lucas@wseinc.com. M. Lee Bundrick, MS, MPA, can be reached at 843.768.2029 or lee@kiawahconservancy.org.
Published in APWA Reporter, June 2024.