FLOODS in New Orleans following hurricane Katrina were made worse by a channel dug by a US government agency, according to testimony heard by a federal court. The hearing, in which the government is being sued for allowing the channel to be built, could lead to payouts to hundreds of thousands of flood victims. It may also lead to massive reforms in flood protection.
The evidence comes from the most detailed modelling of Katrina鈥檚 storm surge to date. 鈥淪cience is the most critical factor in this courtroom,鈥� says Pierce O鈥橠onnell, lead attorney for the plaintiffs. 鈥淭o win the day, one side has to provide the judge with a more compelling scientific case than the other.鈥�
鈥淭o win the day, one side has to provide a more compelling scientific case than the other鈥�
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The US government cannot be sued for the failure of flood protection measures. The court case, brought by five New Orleans residents, got the go-ahead because it concerns a channel, called the Mississippi River Gulf Outlet (MRGO, or 鈥淢ister Go鈥�) dug by the US Army Corps of Engineers (USACE). The channel was built in the 1960s to bring shipping into the city.
Shortly after Katrina struck in 2005, a computer model run by coastal ecologist Paul Kemp, then at Louisiana State University, and colleagues indicated that MRGO combined with another waterway to create a V-shaped trap that funnelled Katrina鈥檚 storm surge, causing the levees to be overtopped and breached (see map). Other reports doubted this conclusion. Another factor is that vegetation and marshes that could have acted as a natural barrier against a surge were lost when MRGO was built.
Since then, Kemp and other researchers have created an improved model which accurately simulated the timing of the flooding and levee breaches, as well as the magnitude. They claim it provides the best estimates yet of storm surge, waves and currents during Katrina. 鈥淲e wanted to see what Katrina looked like with a GO and without a GO,鈥� says Robert Bea of the University of California, Berkeley, who was part of the team.
Their modelling showed that without MRGO, the storm surge which battered levees protecting the neighbourhoods concerned in the court case led to fewer breaches and less overtopping. Flooding was reduced by up to 9 feet (2.7 metres). 鈥淲e have shown that MRGO spelled the difference between survivable flooding and catastrophic flooding,鈥� O鈥橠onnell claims.
The team began presenting its evidence on 20 April. 鈥淔inally, we are having our day in court,鈥� says Kemp. If the plaintiffs win, others in their neighbourhoods should be able to claim damages too. O鈥橠onnell says that more than 200,000 people and groups have already filed such claims.
As 快猫短视频 went to press, the USACE had yet to present its defence and did not want to comment. In a brief filed to the court, it maintains that 鈥渢his catastrophe would have occurred regardless of the MRGO鈥�.
Other coastal scientists are reserving judgement about MRGO鈥檚 role. The decision in the case will rest with district judge Stanwood Duval. 鈥淚t is fascinating to see what will happen,鈥� says Denise Reed at the University of New Orleans. 鈥淚n my experience, Duval is a pretty smart guy.鈥�