INTEGRATED MORPHOLOGICAL AND HISTORICAL COASTAL MAPPING - A KEY TO REAL-TIME FORECASTING OF STORM IMPACTS

Coastal scientists and engineers are developing capabilities to predict future storm impacts along a particular coastal region on the basis of field, remote-sensing, and theoretical studies. The types of information that are critical to an adequate storm impact forecast are: (1) a geomorphic model that depicts extant ground conditions, (2) a coastal response model that incorporates the impacts of previous extreme storm events, (3) a compilation of historical storm parameters linked to the coastal response model, and (4) near-real-time surge and wave predictions for storms tracking close to the coast or those that are projected to make landfall.

In preparation for real-time forecasting, the U.S. Geological Survey is producing storm vulnerability maps for beaches and barrier islands along the southeastern Atlantic coast and the northern and eastern Gulf of Mexico. Geomorphic mapping involves integration of beach and dune elevations derived from recent lidar surveys, and morphological attributes (beach width, dune continuity, washover areas) derived from recent low-altitude video surveys and accompanying oblique 35-mm photographs. Implied socio-economic attributes are also mapped including type and density of development and type of shoreline protection structures. The maps emphasize features that will influence inland distances and styles of sediment transport. Field observations and photographs are used to ground truth the maps and to predict post-storm changes. Historical analysis of storm impacts involves mapping the morphological changes caused by extreme storms (for example Hurricanes Carla, Camille, Hugo, Andrew, 1962 northeaster) and cataloging the associated storm parameters that apply to the coastal segment being mapped. Maps of extant morphology and historical storm impacts, and linked data are maintained in a GIS database so that they can be displayed as a storm approaches the coast. Comparing intensity of an active storm with intensities of historical storms will provide a basis for applying wave runup and inundation models and forecasting erosional and depositional responses.