Engineers are diverting Mississippi river to restore Louisiana’s coast

The Mississippi river flows past New Orleans, Louisiana, at an average rate of about 150,000 cubic metres per second, carrying more than a hundred million tonnes of sediment from the middle of the US into the Gulf of Mexico each year. Standing along its shore on land made of such sediment, I watch the silt spin in brown eddies in the river. That mud might soon be put to use.

A construction team not far…