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Total Water Level and Coastal Change Forecast expands to include more than a thousand miles of new coverage

The Total Water Level and Coastal Change Forecasts have been extended across an additional 1,700 km of US coastline to provide coastal change hazards predictions to coastal communities.

This article is part of the Sound Waves Special Issue on Coastal Change Hazards.

Map of the east US coast and Gulf of Mexico with colored lines along the coast color coded for years in yellow, blue, and red
The Total Water Level and Coastal Change Forecast has continually expanded since real-time forecasts began in 2015. In 2020, new regions of the Gulf and South Atlantic coasts were added to the forecast and officially approved for use in National Weather Service Forecasts. The Total Water Levels and Coastal Change (TWL-CC) Forecast Viewer is a web-based tool that visualizes forecasts of extreme water levels and coastal change along sandy shorelines based on local tides, storm surge, waves, and beach characteristics. This information is critical for protecting lives and property along our nation’s coasts, and for conducting for post-storm recovery.

The USGS began producing operational forecasts of Total Water Levels and Coastal Change five years ago. The Total Water Level and Coastal Change (TWL-CC) Forecast Viewer is a tool that estimates water levels and the potential for coastal change along sandy shorelines based on local tides, storm surge, waves, and beach characteristics. These forecasts are used by stakeholders such as local cities, emergency managers, the public, as well as federal partners to determine which areas are most vulnerable to coastal change, and where major impacts could occur – especially in the face of strong storms and hurricanes. The potential impacts include dune erosion (when sand is removed by waves and currents), overwash (waves overtopping the dune and pushing sand inland), and inundation (water submerging the beach and dune). The information provided by the TWL-CC viewer is critical for protecting lives and property along our Nation’s coasts, and for conducting post-storm recovery.

Some critical components of the models that feed the forecasts are the timing, height, and frequency of waves in nearshore environments. This information comes from the Nearshore Wave Prediction System (NWPS) developed by our partners at the National Oceanic and Atmospheric Administration (NOAA). This vital partnership, particularly with the NOAA National Centers for Environmental Prediction (NCEP), is needed to provide reliable predictions to help protect our nation’s coasts.

The partnership, along with the model data it provides, has allowed for recent expansion of the TWL-CC models to an additional 1,700 km (more than a thousand miles) of the Nation’s coastline. This means the model now covers a total of 4,700 km of open, sandy coastline on the Atlantic Ocean and Gulf of Mexico coasts.

The forecasts cover new areas in Texas, the northernmost Gulf coast, and new areas of the South Atlantic US coast. These regions are frequently impacted by tropical storms and hurricanes – most recently Isaias, Laura, Marco, Sally, Delta, and Zeta. USGS continues to work with NOAA NCEP to expand the use of NWPS data in new regions to help provide this critical data to additional coastal communities. Ongoing expansion efforts are focusing on the Pacific Coast and coral reef-lined coasts.

The CMHRP has been conducting scientific investigations at Fire Island in order to protect coastal infrastructure
At Fire Island, estuarine, wetland, coastal, and oceanic processes interact, affecting natural and human communities. The CMHRP has been conducting scientific investigations at Fire Island in order to protect coastal infrastructure.

The TWL-CC forecast is a high-profile component of our Coastal Change Hazards focus, and is a prime example of how state-of-the-art USGS science can provide societally-relevant, actionable information to our stakeholders in a timely manner. The forecast is used by National Weather Service (NWS) in their Advanced Weather Interactive Processing System (AWIPS) dashboard, by local emergency planners (e.g., Dare County, NC), and is available to the general public. Additionally, the model will be used for the Consumer Option for an Alternative System to Allocated Losses (COASTAL) Act, a law designed to reduce costs to the National Flood Insurance Program by delineating between wind and water damage for homes destroyed by a tropical cyclone.

TWL-CC forecasts have been critical for predicting damages along the US coastline for many years, but with this new expansion for the Gulf and Atlantic coasts, we are prepared to provide even more coastal citizens with information when and where they need it.

 

 

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