January 2006
Engineering professor had it right - unfortunately
By: William G. Gilroy
Joannes Westerink wishes he had been wrong after all.
A Notre Dame associate professor of civil engineering and geological sciences, Westerink is one of the developers of the Advanced Circulation Model, or ADCIRC, an authoritative computer model for storm surge. The U.S. Army Corps of Engineers, the Federal Emergency Management Agency and the state of Louisiana use the model to determine water levels due to hurricane surge as well as to design appropriate levee heights and alignments.
For years, the ADCRIC model has given Westerink and other scientists insight into what would happen if a major hurricane hit New Orleans. Unlike those of us who were shocked at the devastation Hurricane Katrina wrought when it slammed into New Orleans and the Gulf Coast on Aug. 29, Westerink has long been aware of how New Orleans might flood. In 2004, in an exercise simulating a direct hit by a slow-moving and very large Category 3 hurricane, the ADCIRC model showed that the levees would not prevent the flooding of New Orleans.
As New Orleans and the Gulf region struggle to recover from Katrina, and as hurricane researchers warn that the United States is in the midst of a period that is likely to bring more major hurricane strikes, Westerink is playing a leading role in the effort to understand the causes of the catastrophe and the steps needed to prevent its reoccurrence.
“Ultimately, these models allow the design of safe protection systems with optimal alignments and sufficient heights so that this damage doesn’t happen again,” Westerink said.
On Nov. 4, Westerink and Clint Dawson of the University of Texas, provided a briefing on the mathematical modeling of hurricane storm surge for members of the U.S. House Committee on Science. He also is co-leader of the surge and waves team of the Army’s task force that is evaluating hurricane protection policies for New Orleans and southeastern Louisiana.
The ADCIRC model was developed by Westerink and MIT classmate Rick Luettich, now a University of North Carolina professor. Over the past 16 years, the pair and other ADCIRC researchers have refined the computer program. The model employs computer science, coastal oceanography, mathematics and engineering. Its calculations require 132 computer processors which are housed in Westerink’s Computational Hydraulics Laboratory in Cushing Hall.
ADCIRC also is used to forecast incoming hurricane storm surge by researchers at Louisiana State University who use Westerink’s model together with National Oceanic and Atmospheric Administration weather forecasts.
Although frequent images of television reporters being buffeted by strong winds during hurricane season have firmly established the dangers of wind damage in our minds, storm surge is actually a greater danger and a leading cause of destruction and death. Storm surge is the wall of water pushed onto land as a hurricane comes ashore. New Orleans is especially vulnerable to storm surge because roughly 80 percent of the city lies below sea level. ADCIRC models have long shown that a strong hurricane taking the right track could “overtop” the five-or-more-meter high levees that keep the waters of the Gulf and Lake Pontchartrain from New Orleans.
Westerink points out that Category 4 Katrina’s immense damage underscores just how devastating storm surge from a Category 5 hurricane would be to New Orleans.
“We can design a barrier to withstand a Category 5 storm,” Westerink said. “It is technologically feasible. Holland, for example, which is in an extremely vulnerable position, is protected from North Sea surges by a 40-foot dike system.”
Congress approved a project for Category 3 protection in 1965 following Hurricane Betsy, and the Army Corps of Engineers has been working on these protection projects as funding as been made available. Currently, the Army Corps is looking into what it will take to provide Category 4 and 5 protection for the region.
“It becomes a societal and political question,” Westerink said. “How much do we want to spend on this type of protection? Katrina will cost hundreds of billions of dollars in devastation, economic losses and reconstruction. Do we want to spend that again?”
Contact Joannes Westerink at Joannes.Westerink.1@nd.edu