Presentation: NSF Workshop 2018

Improving Accuracy of Real-Time Storm Surge Inundation Predictions

Emergency managers rely on fast and accurate storm surge predictions from numerical models to make decisions and estimate damages during storm events. One of the challenges for such models is providing a high level of resolution along the coast without significantly increasing the computational time. Models with large domains, such as the ADvanced CIRCulation (ADCIRC) model used in this study, are accurate in predicting water levels and their variation in complex coastal regions, however their spatial resolution may limit their predictions of flooding at the scale of buildings, roadways, and critical infrastructure.

A new tool has been developed that uses Geographic Information System (GIS) scripts to enhance the resolution of maximum water level predictions at the boundary of predicted flooding using a high-resolution Digital Elevation Model (DEM). The water levels predicted by the lower resolution model are extrapolated outward to where the water would intersect with the higher resolution elevation dataset. The result is a highly-refined flooding boundary that represents inundation on scales smaller than the typical ADCIRC mesh resolution. This tool can process a 15-m DEM for all 32 coastal counties of the state of North Carolina in less than 15 minutes during a storm event.

Comparison of results using spatial building datasets showed that for a simulation of Hurricane Matthew, 2,353 buildings were predicted to be flooded in Carteret County, NC, prior to enhancing resolution and 3,298 post-enhancement, an increase of 40 percent. In Dare County, the increase was 22 percent. This dramatic increase in flooded buildings shows the importance of achieving high accuracy in floodplains, as a relatively small change in predicted flooding extent can have a substantial impact on the predicted number of flooded buildings. The validity of these results was tested via comparisons to results of an ADCIRC model with the same 15-m resolution as the DEM in Dare County. Dare County is a coastal region with widely-varying topography and land cover, and preliminary comparisons have shown that the GIS method is accurate in coastal regions with steeper slopes and less accurate in flatter, low-lying areas.

N Tull (2018). “Improving Accuracy of Real-Time Storm Surge Inundation Predictions,North Carolina State University.

Conference: ADCIRC 2018

R Cyriac, JC Dietrich, A Fathi, CN Dawson, KM Dresback, CA Blain, M Bilskie, SC Hagen, H Graber. “Wind Effects on the Choctawhatchee River Plume at Destin Inlet, Florida.” ADCIRC Users Group Meeting, NOAA Center for Weather and Climate Prediction, College Park, Maryland, 13 April 2018.

A Thomas, JC Dietrich, JG Fleming, BO Blanton, T Asher, RA Luettich. “High-Resolution Modeling of Surge during Hurricane Matthew.” ADCIRC Users Group Meeting, NOAA Center for Weather and Climate Prediction, College Park, Maryland, 13 April 2018.

N Tull, JC Dietrich, TE Langan, H Mitasova, BO Blanton, JG Fleming, RA Luettich. “Improving Accuracy of Real-Time Storm Surge Inundation Predictions.” ADCIRC Users Group Meeting, NOAA Center for Weather and Climate Prediction, College Park, Maryland, 13 April 2018.

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CCHT Joins COPRI Field Trip to Wilmington-Area Beaches

CCHT members led the annual field trip by the Coasts, Oceans, Ports, and Rivers Institute (COPRI) student chapter at NC State University. The chapter traveled to Wilmington, NC, over two days to visit beaches from Ocean Isle to Kure through Wrightsville. The students learned about beach management practices from Greg Williams and his team at the Wilmington District of the US Army Corps of Engineers, as well as from NC Sea Grant extension specialist Spencer Rogers.

During the first day of the visit, the students visited an active dredge as it finished a beach nourishment project on Ocean Isle. The tour included a visit onto the dredge to learn how it operates, and also to the beach to see how the pumping is controlled and how the sand is worked to meet the design specifications. During the second day, the students visited several beaches closer to Wilmington to learn about terminal groins, nourishment projects, inlet stabilization, and construction practices.

This was the second annual field trip for the COPRI student chapter. During the 2017-2018 academic year, CCHT members served as President (Nelson Tull), Vice President (Rosemary Cyriac), and Treasurer (Alireza Gharagozlou).

Students preparing to board the dredge near Ocean Isle, during the 2018 COPRI field trip.

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Nelson Tull and Ajimon Thomas win Student Poster Awards

MS student Nelson Tull won First Place in the Student Poster Competition at the EWC Research Symposium. Nelson described his research to enhance resolution of coastal flooding forecasts for decision support.

PhD student Ajimon Thomas won Honorable Mention. Ajimon described his research to quantify interactions between tides and storm surge along the U.S. southeast coast during Hurricane Matthew.

This event is an annual showcase for research in our Environmental, Water Resources, and Coastal (EWC) engineering group, as well as a recruiting event for potential students. Awardees are selected by judges from other academic departments, government agencies, and consulting firms. Students presented their posters to judges and visitors during a poster session, and then finalists presented orally to the entire audience.

Congratulations to Nelson and Ajimon!

Nelson Tull shares his poster with judges at the 2018 EWC Research Symposium.