Storm Risk Reduction System Passes Ida’s Test
At its height, Hurricane Ida was the strongest hurricane to hit the Gulf region since the 1850s. When it made landfall at Port Fourchon as a Category 4 storm, its windspeeds of 150 miles per hour at least rivaled the strongest ever recorded. Storm surges were at least 12 feet—16 feet at the barrier island community of Grand Isle, where damage was so extensive as to make the community “uninhabitable,” according to one report. Ida moved up the Mississippi River Valley, crossing the river northwest of New Orleans before swinging northeast through the Tennessee River valley into New England, weakening to a tropical depression as it lost power but drenching its path with inches of rain.
The most serious damage to infrastructure in the New Orleans area so far has been to the power grid. All eight transmission lines to the New Orleans area were knocked out by the intense winds, according to Louisiana Gov. John Bel Edwards in a press conference. More than a million people were without power. Entergy, the region’s electric utility, had hundreds of personnel and trucks standing by to respond. Restoring power to hospitals and other critical users is a priority, Edwards said. Power restoration had begun at WJ press time, but some households were being advised that they may have to wait weeks.
Storm Protection System Held
The “silver lining,” according to Edwards, is that the Hurricane Storm Damage Risk Reduction System appears to have met and passed Ida’s test. The HSDRRS’s interlocking system of barriers, sector gates, floodwalls, floodgates and levees creates a barrier around East Jefferson, Orleans and St. Bernard parishes.
Most of the damage to New Orleans from Hurricane Katrina came from floods, not winds.
An August 30 tweet from the Southeast Louisiana Flood Protection Authority, which covers St. Bernard parish and most of Orleans and Jefferson parishes, said, “There were no levee breaches or over-toppings within the Hurricane Storm Damage Risk Reduction System. There have been no issues with our pumps.” Edwards qualified that statement slightly in his press conference, saying, “We don’t believe there is a single levee anywhere now that actually breached or failed. There were a few smaller levees that were over-topped to a degree for a certain period of time,” Edwards said.
Not All Areas Covered
However, not all the region’s levees are part of the system. Some suburban communities not covered by the system did experience levee over-toppings and floods. Non-federal levees in the Lafitte, La., area were reportedly over-topped. The town of Braithwaite in Plaquemines Parish was completely flooded. It was not clear whether its levee was breached or over-topped. The Burrito levee that protected Grand Isle was reported to have had several breaches.
More Hurricane Ida Coverage:
Highway 23 in Plaquemines Parish, which runs along the west bank of the Mississippi River as it extends out into the Gulf of Mexico, remains flooded at this writing. The area flooded, between Myrtle Grove and Pointe à la Hache, lies in a gap between federal levee protection. Highway 23 is the only access road to the proposed Plaquemines Port Harbor & Terminal District, which reported little storm damage.
Lock Wall Sinks
Further away, in the Tennessee River valley, the upper approach wall at Wilson Lock, at Mile 259.4 of the Tennessee River, sank, apparently as the result of rains from Hurricane Ida. According to the ACBL newsletter American Currents, Wilson Lock was open as of September 1. Lock operators will lock southbound during the day, and northbound at night.