Published on 20 March 2023
Over the past six years, what was once a small canal on the east bank of the Mississippi River has widened to become a major channel, with a flow five times that of New York’s Hudson River.
The channel, called Neptune Pass, is about 25 miles (40 kilometers) upriver from where the Mississippi empties into the deep waters of the Gulf of Mexico. The channel now delivers freshwater and sediment into the shallower coastal waters of Quarantine Bay and Bay Denesse, much closer to New Orleans.
“This is the biggest branch of the river to open up in almost a century,” said Alex Kolker, a coastal geologist at the Louisiana Universities Marine Consortium.
Neptune Pass can be seen cutting through the wetlands on the east bank of the Mississippi River in the image above (right). The image was acquired by the Operational Land Imager (OLI) on Landsat 8 on February 6, 2023. It shows a plume of sediment fanning out across Quarantine Bay, an inlet between the coast and the Gulf of Mexico. The image on the left shows the same area in 2019, before the canal widened.