Parts of New Orleans' $14 billion flood system are sinking faster than designers expected

The Hurricane and Storm Damage Risk Reduction System, more than 70 projects built after Katrina, did its job during Hurricane Ida in 2021, according to The B1M's video report. Its concrete structures were overbuilt to allow for subsidence, including the Lake Borgne Surge Barrier, almost two miles long and 26 feet above sea level. Other parts are settling faster than expected. In 2019, a year after completion, a Corps report warned that some levees could pull the system below its promised protection within four years.

The fix is a levee lift. Crews strip grass and soil from the existing levee, cut it into steps so new fill can't slide off, then truck in clay and compact it with rollers, The B1M explained. The cycle repeats across the system for about 50 years. The B1M says the program was proposed at $3.2 billion and had reached $5.3 billion by the time Congress approved funding in 2023. On the west bank, the Corps, Louisiana's Coastal Protection and Restoration Authority and local levee agencies signed an agreement in May to start design of the West Bank and Vicinity lifts, CPRA said. That work is meant to hold 100-year protection through 2073 for about 257,000 residents in four parishes, with 65% of the cost federal and 35% local. The first construction contract is expected in 2029.

A new study argues that the metro area, home to more than a million people, should start planning to relocate, The B1M reported. The city's mayor said the study was chasing “clickbait headlines,” and CPRA chairman Gordon Dove called it the most ridiculous study he had seen. Co-author Jesse Keenan answered that the reaction was what he expected from politicians. Last year the governor canceled a $3 billion project to rebuild wetlands with river sediment, citing its cost.