The International Information Center for Geotechnical Engineers

Friday, 01 September 2017 00:00

Texas beaches likely to erode, be overwashed, or inundated by Hurricane Harvey

USGS Coastal Change Forecast model predictions indicate that Hurricane Harvey is likely to cause significant beach erosion along the Texas coastline, with water overtopping dunes and in some cases inundating areas.

Hurricane Harvey made a landfall in Texas on Friday night, August 24, and experts fear it could stay in place for days, causing extensive damage to Texas and possibly other gulf coast states beaches as well. Predictions from the U.S. Geological Survey Coastal Change Forecast model, published on the same day, showed that 94% of Texas's 367 miles of coastline would undergo some level of beach erosion from the storm surge and large waves Hurricane Harvey would produce.

There are many factors and variables to consider when trying to determine what a large storm like Harvey might do to the coast. The USGS Coastal Change Forecast model uses the National Hurricane Center's storm surge predictions and National Oceanic and Atmospheric Administration wave forecast models as key inputs, and adds information about the beach slope and dune height to predict how high waves and surge will move up the beach and whether the protective dunes will be overtopped.

The Coastal Change Forecast model also predicted that 47% of Texas's coastline will experience a more severe level of erosion hazard, known as dune overwash, particularly north of Corpus Christi up to the Galveston area. As waves and surge reach higher than the top of a protective dune, overwash occurs, often transporting large amounts of sand across coastal environments and roadways, depositing sand inland and causing significant changes to the landscape and possibly impeding transportation routes.

Inundation is the most severe level of coastal damage from a storm and occurs when beaches and dunes are completely and continuously submerged by surge. Predictions from USGS Coastal Change Forecast model showed that 14% of Texas's coastline shall experience inundation in areas north of Corpus Christi to the Galveston area.

Joseph Long, USGS Research Oceanographer, stated that Texas is faced with a very hazardous condition and that its beaches will look dramatically different after the storm passes.

Although final projections for Hurricane Harvey are subject to change, the Coastal Change Forecast model may be used by emergency managers to help identify locations where coastal impacts might be the most severe, such as where roads may be damaged or covered by sand and impassable even after the storm is over. Maps of estimates can be viewed on the USGS' Coastal Change Hazards Portal.

Source: USGS

Read 547 times Last modified on Thursday, 01 February 2018 08:41

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