Identify - Conserving Coastal Wetlands for Sea Level Rise Adaptation

Identifying Coastal Vulnerabilities to Sea Level Rise

Because coastal wetlands help protect communities from sea level rise impacts, wetland conservation is a decisive step that communities can take to increase their resilience. However, coastal wetlands are themselves vulnerable to rising seas and can be affected by erosion, inundation, and saltwater intrusion. It is important to identify not only these vulnerable wetlands, but also current upland areas where coastal wetlands might form as the sea level rises.

The location of wetlands in relation to the coast and to communities helps determine their vulnerability and ability to provide protective functions for communities. Communities can use GIS and spatial techniques to identify vulnerable wetlands in the landscape, as well as future wetland areas that will help maintain ecosystem services important for community resilience.

Map Extent of Projected Sea Level Rise

The first step in identifying appropriate wetlands to conserve for sea level rise adaptation is to map the extent of projected sea level rise. Communities should explore multiple sea level rise scenarios to consider a range of potential future states. Accurate, high-resolution elevation data are necessary for mapping sea level rise and associated impacts on wetland systems. Because coastal wetlands exist within a narrow range of elevation, the best available data for mapping sea level rise is lidar, which is the most precise. View a recorded webinar on mapping and visualizing sea level rise and coastal flooding impacts.

Resources

Coastal Inundation Mapping – Training that teaches spatial techniques for mapping inundation.

Mapping Coastal Inundation Primer – Publication that details a four-step process for mapping inundation.

Coastal Lidar – A collection of lidar data available for all coastal states, ranging from shoreline strips to full county coverage.

United States Interagency Elevation Inventory – Tool that enables users to locate and learn about the best available elevation data sets for their area.

Sea Level Rise and Coastal Flooding Impacts Viewer – Tool that displays maps of potential sea level rise scenarios and impacts along the coast.


Map Extent and Locations of Possible Storm Surge

Storm surge events, such as hurricanes, can have devastating impacts on coastal communities. Rising sea levels result in higher storm surge, which could exacerbate coastal flooding and erosion. Mapping storm surge in conjunction with sea level rise predictions can help communities identify coastal wetlands that provide protective barriers during storm events.

Resources

Coastal Inundation Mapping – Training that teaches spatial techniques for mapping inundation, including storm surge considerations.

Coastal Inundation Mapping Guidebook – Publication that details a four-step process for mapping inundation, including storm surge considerations.

Coastal Resilience project – Approach that examines the social conditions and economic exposure of coastal communities and their relationship with coastal wetlands’ potential to provide flood protection.


Locate Position of Existing and Future Coastal Wetlands

Knowing the location and extent of existing coastal wetlands is important for assessing wetland vulnerability to sea level rise. Coastal land cover data depict the distribution and size of wetlands and surrounding land use. Explore land cover change and trend information to discover how past land use decisions may be contributing to current coastal wetland vulnerability and where future development might occur.

There are several models and methods available to predict how coastal wetlands will react to various sea level rise scenarios. Some wetlands may be lost, some may migrate landward, and others may be unaffected in their current location. It is important to choose a method or model that matches a community’s needs and to communicate the uncertainties of any outputs. Wetland elevation and slope are important information needed to assess a wetland’s ability to migrate as sea level rises. Also important is to identify impediments to wetland migration, such as existing development or hardened shorelines that would block inland migration of wetland vegetation. Compare future development projections with potential future wetlands and wetlands predicted to remain intact to find areas important for conservation.

Resources

C-CAP Land Cover Atlas – Tool that enables users to view land cover data and explore changes and trends without the use of GIS.

C-CAP Regional Land Cover – Nationally standardized land cover and land change data for the coastal regions of the U.S.

Coastal Resilience project – Approach that examines the social conditions and economic exposure of coastal communities and their relationship with potential coastal wetland migration.

Habitat Priority Planner – GIS analysis tool that can help assess the quality and connectivity of coastal wetlands.

Marshes on the Move – Document providing a basic understanding of parameters, uncertainties, and appropriate uses of model results depicting potential future impacts of sea level rise on coastal wetlands. View a recorded webinar on the concepts described in this document.

National Wetlands Inventory – Data that depict the status, extent, characteristics, and functions of coastal wetlands.

Sea Level Affecting Marshes Model (SLAMM) – Tool that simulates the potential impacts of long-term sea level rise on wetlands and shorelines.

Sea Level Rise and Coastal Flooding Impacts Viewer – Tool that displays maps of potential sea level rise impacts on wetlands along the coast.

Shifting Shorelines, Shifting Conservation Strategies: Assessing Wetland Conservation Priorities in Maryland – Document highlighting the State of Maryland’s process to identify wetlands vulnerable to sea level rise, predict wetland response to sea level rise, and determine priority wetland conservation areas for climate adaptation.


These maps show 2005 land cover south of Freeport, Texas, and the potential changes in wetland land cover based on a sea level rise scenario of a half meter by 2050. Detailed images, additional scenarios, and wetland migration mapping methods can be accessed in the Sea Level Rise and Coastal Flooding Impacts Viewer.

Identify Locations of Vulnerable People and Property

Community assets, such as people, natural resources, and businesses, located in vulnerable areas should also be considered when prioritizing conservation efforts. Use demographic and socioeconomic data to identify vulnerable populationssuch as the elderly or those living in poverty―and plan to conserve nearby wetlands that can absorb stormwater and wave energy to help protect these populations from hazard events. Use land cover data to identify developed areas that need the protection wetlands can offer.

Resources

Coastal County Snapshots - Flood Exposure – Tool that provides a quick look at a county’s demographics, infrastructure, and land use patterns within the flood zone using easy-to-understand charts and maps.

Coastal Resilience project – Approach that examines the social conditions and economic exposure of coastal communities and their relationship with coastal wetlands’ potential to provide flood protection.

Roadmap for Adapting to Coastal Risk – Web-based training that helps communities explore their vulnerability to sea level rise and other coastal hazards.

Sea Level Rise and Coastal Flooding Impacts Viewer – Tool that displays maps of potential sea level rise scenarios and vulnerable populations that may be impacted along the coast.

Spatial Trends in Coastal Socioeconomics (STICS) – Website that provides demographic and economic characteristics and trends for a wide variety of coastal regions.


View additional publications and websites to learn more about these concepts.