COASTAL FLOODING & SOLUTIONS, Workshop Case Studies

USGS Forecasts of Total Water Level and Coastal Change Hazards along the U.S. Gulf Coast

Location:
Sandy open-ocean coastlines along the Gulf of Mexico
Submitted by:
Kara Doran
U.S. Geological Survey St. Petersburg Coastal and Marine Science Center, Oceanographer
Project URLs:
stal.er.usgs.gov/hurricanes/research/twlviewer/; https://marine.usgs.gov/coastalchangehazardsportal/

Project Description

The USGS provides reliable coastal hazards information to communities and local/State/Federal partners in preparation for and in response to extreme storms. Information are presented through two systems: the Coastal Change Hazards (CCH) Portal and the Total Water Level and Coastal Change Forecast (TWL&CC) viewer. The CCH Portal provides National-scale assessments on multiple coastal change hazards: extreme storms, shoreline change, and sea level rise (SLR). Probabilities of erosion during extreme storm conditions are presented for real-time storm events and scenarios. Beach profiles are compared to water levels (tides, surge, and waves) to determine the probability of collision, overwash, and inundation. Shoreline evolution in response to SLR in the Gulf of Mexico is considered through two metrics: the coastal vulnerability index that provides relative susceptibility to SLR; and a Bayesian assessment of shoreline change that incorporates multiple forcing and historical variables. Both metrics utilize the long-term shoreline change data also available in the CCH Portal. The TWL&CC viewer provides a 6-day forecast of the combined effect of tide, surge, and wave runup along the coast. Water levels and waves are extracted from NOAA models and are combined with empirically estimated wave runup. This time-varying TWL is compared to beach profiles along sandy coasts to evaluate potential coastal change. The TWL&CC viewer is available for Florida, Alabama, and portions of Texas.

Key Successes

Probabilistic forecasts of coastal change hazards are available for the entire sandy open-ocean coastline of the United State for planning purposes and in real-time. Operational total water level coastal change forecasts are available for nearly the entire US open-ocean sandy coastline. The operational forecast is used by the National Weather Service in their forecast dashboard, ensuring that this information gets to the public through their local channels.

Challenges

Lack of validation data
Any question regarding this posting, email edl@gatech.edu