Flood Inundation Vulnerability
Much of the low-lying land in coastal North Carolina is vulnerable to flooding and inundation due to precipitation from storms, storm surges, wind tides, and the long-term process of sea-level rise, which exacerbates storm flooding and causes permanent inundation of some areas. Areas at risk of inundation and flooding include natural resource areas, agricultural areas, residential areas and public infrastructure, particularly water infrastructure. Municipal water infrastructure such as fresh water intakes, municipal wells, pump and transfer stations, wastewater treatment plants and outfalls are frequently located at low elevation sites to use gravity to move water in the system whenever possible. Supply system infrastructure such as electric utilities, transportation and communication are critically important and also vulnerable to inundation in low elevation areas.
In addition to structural damage to infrastructure due to wave action and inundation, flood waters carry with them the risk of water supply contamination. Flood waters can flow into unprotected wells, pumps and transfer stations. Wastewater treatment plants can become overwhelmed when stormwater is combined with sewage or flood waters infiltrate the sewer system. When too much water enters a waterwater treatment plant, water passes through quickly and may not be fully biologically and chemically treated. If storm surges bring saline water into infrastructure systems that are not designed for it, corrosion and decay can cause considerable damage.
Sea-level rise is likely to increase water level in coastal regions, altering drainage patterns, floodplains and storm surges vulnerability. The rate of relative sea-level rise varies along the North Carolina coast due to different geological features, with higher rates in the north. Long-term projections range from 1.3 ft (40 cm) to 3.3 feet (100 cm) of rise by 2100. Many coastal cities around the United States are developing strategies to prepare for storms and inundation conditions when future sea levels are higher.
North Carolina has a rich hurricane history. Find out more at Storms to Life.
National Flood Hazard layers were provided by the North Carolina Flood Mapping Program, a division of North Carolina Emergency Management.
Infrastructure information was provided by Town of Plymouth and Washington County GIS. Other data were obtained from the North Carolina Department of Transportation.
How Can This Map Be Used?
The potential inundation map provides information about the vulnerability of infrastructure to current and future flooding. Understanding the potential threat can inform decisions about the protection or maintenance of current infrastructure and the placement of future infrastructure.
Where to Find More Information
North Carolina Floodplain Mapping Program
Information about flooding from Federal Emergency Management
Carolinas Integrated Sciences and Assessment
NOAA Coastal Climate Adaptation Resources
Georgetown Climate Center Sea-Level rise Adaptation Toolkit