
During Katrina, water flowed into the London Avenue canal in New Orleans from Lake Pontchartrain, instead of the other way around, causing the concrete walls on top of the canal's soil levees to slip and fail. Since then, gates have been built in the lake to prevent water escaping. Currently, water in the canal is 1.2 metres deep, but from 17 August, the Army Corps of Engineers will begin raising the water level in an isolated a 46-metre section of the canal up to 1.5 metres, while monitoring the impact on nearby walls and soil. If the levees do not shift, water could be pumped from New Orleans to Lake Pontchartrain faster when a hurricane hits, minimising flooding in the city.
As in the days of Noah...