Behind the Scenes of Coastal Flood Modeling
4-Mar-2019 2:05 PM EST
Newswise — From its lifesaving properties that bind humanity to its geographical connections through tributaries, rivers and waterways eventually flowing into the ocean, water is a connecting force. It can also be a destructive power that connects people through disaster response and recovery.
On September 14, 2018, Hurricane Florence made landfall in North Carolina as a slow-moving Category 1 storm. Although the hurricane had the lowest classification relative to wind speed, the heavy rains and snail-like pace caused catastrophic flooding from surging ocean water and freshwater. The overflows caused more than $13 billion in damage and 55 deaths along the southeast coast. However, thanks to in-depth research and detailed storm modeling conducted by Randall Kolar, director of the School of Civil Engineering and Environmental Science and associate director of the WaTER Center, and an interdisciplinary team of engineers and scientists from across the country, North Carolina was able to better anticipate flood extents – possibly preventing additional damage and deaths.
Building a Better System
Kolar’s work in predicting storm surge began over 30 years ago in graduate school where he connected with professors and fellow students who were developing advanced, high-resolution flood models. Other models at that time used empirical data or coarser-resolutions to predict potential damage during a current or upcoming storm.
Such prediction systems were often inaccurate due to their inability to simulate complex terrain and intricate coastlines. The unreliable predictions made it difficult for emergency responders and cities to use them for planning and warning residents. Kolar’s group recognized additional data, such as shoreline geography, infrastructure locations and other topography, that could influence flooding was critical to better predict rising storm surges.
The team graduated and transitioned to careers in academia, research and technology, but they continued their professional relationships and their work to improve flood and storm surge modeling, knowing that a more updated and reliable system was needed to improve readiness and save lives.
“We shared a vision of how we wanted this new model to perform, but it took many years beyond graduate school to realize,” Kolar said. “Fortunately, we were all willing to collaborate and put in the work needed to create a better system.”
Building the better model didn’t happen overnight. It took many years to realize because the team needed to improve the model’s core to take advantage of high performance computing and to input the different and often changing terrain and bodies of water. The end result was the Advanced Circulation – or ADCIRC – modeling system, which simulates storm surge, tides and coastal circulation and is still used by NOAA. However, ADCIRC alone was only able to predict the totality of near-shore flooding.
Kolar and some of his CEES colleagues, Kendra Dresback, research assistant professor, and Chris Szpilka, research associate, as well as affiliated graduate students, continued work with the larger team, studying Hurricane Katrina to learn more about how the hurricane protection system performed during the storm. They used the data to revise the storm surge model to gain more specificity. The team also gathered additional data from multiple storms, such as Hurricane Earl in 2010, Hurricane Irene in 2011 and Hurricane Sandy in 2012. Each event provided observations to help refine their model and better alert emergency management systems to issue more specific evacuations and direct more people to safety.
One of the major additions in the quest for more accurate predictions was to couple the ADCIRC model to an upland hydrologic model capable of predicting flood flows and inundation depths along rivers that connect to the ocean. This was greatly facilitated by collaborations with colleagues at the National Weather Center who provided atmospheric expertise. Kolar’s team worked diligently to make sure their improved model pulled in additional information from precipitation and current topography in order to produce hi-resolution images and incorporate small-scale details to get more precise information across the entire coastal plain.
The data from the improved model is distributed via the Coastal Emergency Risks Assessment system, an interactive online map (see image) that emergency managers, forecasters and other weather specialists can access during a critical hurricane or tropical storm event. The data comes both from real-time measurements of water level stations and riverine and coastal models that predict the river inundation, tide, wind-wave and storm surge conditions, and it can accurately pinpoint flooding that will occur within 50-100 meters of a structure or landmark.
“The system we developed automatically pulls information continuously from several systems and models, including ADCIRC, so we’re able to work with the most updated data available,” Dresback said. “What Dr. Kolar and the larger team has developed has been instrumental in improving safety during hurricanes and flooding events.”
Humanity as a data point
Recently Dresback, Szpilika, Kolar and the larger team have added another significant variable to the model: the human factor. The advanced model system outlines a more dynamic environment by coupling storm surge models with predicted traffic paths and sheltering possibilities. In addition to tying human activity to physical models, meteorological and hydrology data continue to improve performance of the ADCIRC model.
“By creating a more complete picture of a real-time situation, the new model will help reduce risk and protect more people and infrastructure,” Dresback said.
“Connecting the seemingly different parts to the whole system is one of the best ways to understand and predict the environmental response to a natural hazard,” Kolar says. Through this virtual world is how a researcher in landlocked Oklahoma can better predict flooding in coastal areas and help inform city leaders and protect thousands of people. Though the model has performed successfully in several major hurricanes and storms on the east and Gulf coasts, the team continues to apply the model to other regions as they also refine it by updating changing topography and using the ever-increasing amount of earth science data.
“Storm rains fill upland rivers, and those river flow down into coastal areas, which are often altered by time, storms and development,” Kolar said. “Weather events can remind us that we are all connected, and our team is trying to build a better system that keeps people and infrastructure safe, no matter where they are in the chain.”
About the OU WaTER Center
Water Technologies for Emerging Regions
“Just like the connecting essence of a drop of water traveling around the globe, Randy Kolar’s research in water resources and technologies spans across Oklahoma to the banks of North Carolina an on to developing countries worldwide. He is the co-founder and associate director of the WaTER Center at OU.”
The WaTER Center is comprised of an interdisciplinary team of faculty members who work to advance health, education and economic development in impoverished regions through sustainable water and sanitation solutions. To address these challenges, the center focuses on teaching, research and service innovations, as well as international collaboration with countries such as Cambodia, Ethiopia, Bolivia and Pakistan.
The WaTER Center hosts the WaTER Symposium and the biennial WaTER Conference, two events that bring researchers and advocates from around the world to focus on access to clean water and sanitation research and innovation. At the WaTER Conference, an individual is honored with the OU International Water Prize, one of the first and largest prizes recognizing significant contributions to the field of water supply and sanitation in emerging regions.
2019 OU International WaTER Conference
September 16-19, 2019
International Water Prize Award Ceremony
Tuesday, September 17, 2019
Sam Noble Oklahoma Museum of Natural History