Ocean & Estuarine Shorelines
North Carolina has an extensive shoreline with about 325 miles of ocean shoreline and over 12,000 miles of shore along the estuary, the transitional zone where salt water and fresh water meet. Estuarine shorelines include those along the state’s many sounds, intertidal marshes, rivers and creeks. The salt marshes and other estuarine wetlands along the shoreline provide a variety of ecosystem services in storm protection, seafood nurseries and improved water quality. Shoreline types include swamp forest, intertidal marsh, sediment bank, and modified shorelines.
Shoreline change is a continuous process, driven by currents, waves, wind and human influences. Shorelines can change dramatically in response to storms, which can cause flooding, overwash of sediments and coastal erosion. While much of North Carolina’s estuarine shoreline is undeveloped, over 600 miles is stabilized with structures such as bulkheads and groins. To protect water quality, a 30 foot buffer from the estuarine shoreline is required for properties in the 20 counties designated by the Coastal Areas Management Act.
Shoreline erosion is a significant problem within the North Carolina’s coastal area. Barrier islands and coastal wetlands protect shorelines and waterfront communities by absorbing the impact of storm surges, wind and waves. Sea level rise and intense storms put our public infrastructure, coastal communities and habitats for fish and other wildlife at risk. The Estuarine Shoreline thematic maps allow users to distinguish between undeveloped and stabilized shorelines, and indicate where docks, piers and other structures are located. In selected areas, shoreline change is also depicted.
Density of shoreline structures was calculated using a kernel density estimation technique, which normalizes and smooths data. This technique allows the visualization of areas with high structure density as "hot" red colors and areas with low structure density as "cool" blue colors with the range of colors between indicating relative density. On the North Carolina shoreline, the natural shorelines that have structures are in the blue zone, while shorelines associated with marinas and waterfront developments with extensive docks and piers appear red.
The Estuarine Shoreline layer is provided the North Carolina Department of Environment and Natural Resources Division of Coastal Management Estuarine Shoreline Mapping Project http://dcm2.enr.state.nc.us/Maps/chdownload.htm
Historic Shorelines were digitized as part of a pilot project by J. P. Walsh and colleagues for select areas in Dare County. Aerial photographs from 1970 and 1949 were used to generate these shorelines.
How Can This Map Be Used?
The Estuarine Shorelines map can be used to assess the patterns of shoreline types and the frequency of shoreline structures. This map provides baseline data that can be used to analyze changes to the shoreline, including erosion and accretion, change in the number or type of shoreline stabilization structures or change in shoreline access structures. Where historical shoreline data is available, localized rates of change can be calculated. The map could be used with the Division of Coastal Management Shoreline Stabilization Decision Support Tool (http://dcm2.enr.state.nc.us/estuarineshoreline/Decision%20tree%20Final%20071409.pdf) to help property owners decide which method of stabilization is best to protect their shoreline from erosion.
Where to Find More Information
North Carolina Division of Coastal Management (DCM) Estuarine Shoreline Mapping Project: http://dcm2.enr.state.nc.us/estuarineshoreline/mapping.html
Research: Analyzing Estuarine Shoreline Change: A Case Study of Cedar Island, North Carolina.
Authors: Lisa Cowart, J. P. Walsh, and D. Reide Corbett
K-12 Education: Estuarine shorelines behind complex barrier islands
Authors: Stanley R. Riggs, Dorothea Ames, and Karen Dawkins