HIGH-RESOLUTION MAPPING OF COMPLEX COASTAL INLETS FOR REGIONAL SEDIMENT MANAGEMENT IN NORTH CAROLINA

The land-sea interface adjacent to tidal inlets are complex zones where significant sediment transport can occur very rapidly to alter landscapes surrounding economic infrastructure, important cultural heritage sites or environmentally sensitive areas. Coastal geologists and engineers recognize that while it is critical to quantify volumetric change within this zone, it is unfortunately one of the hardest regions to map. Shore-normal profiles are typically used to measure change within this zone, but these techniques necessarily assume that a series of two-dimensional (2D) profiles is representative of the actual three-dimensional (3D) morphology. Accurate assessments of the complex spatio-temporal changes observed at tidal inlets require a more robust and repeatable data acquisition and processing method in order to calculate accurate change and for the best possible input for numerical models which aid in regional sediment management goals.

Improved instrumentation and purpose built mapping infrastructure facilitates the collection of high-density data needed for detailed surface elevation modeling and datum-derived shoreline analysis. The methods and survey design by which these data are acquired remain paramount to accurately merging topo/bathy data seamlessly within a tidal inlet compartment. The U.S. Army Corps of Engineers is using these highly dense and accurate data products to not only identify key morphological features but as input into sophisticated numerical models to predict shoaling for navigation, beach / shoreface change, sediment transport and evaluation of potential sediment resources all within a 3D to 4D framework.

This combination of modern instrumentation, unique acquisition platforms and high-density, morphologically derived survey designs allow for maximum efficiency in seamless topo/bathy elevation modeling. Grid-based data products provide coastal scientists and egineers with a complete 3D dataset that spans the entire tidal inlet complex for various geospatial analyses in a multidisciplinary GIS environment.