Without wetlands, storm surge cannot be slowed and water can directly enter St. Bernard, Plaquemines, Orleans, and Jefferson Parishes, causing massive flooding, property damage, and even death. Tidal action and ship traffic have also caused wetland loss. Large ships create a suction that pulls water out of adjacent marshes. After the ship passes, the wave it has created forces water back into the marshes. This crashing wave puts tremendous force on the banks of wetlands causing them to erode.
Tidal action is another cause of wetland erosion.
Linked to the Gulf of Mexico, the MRGO experiences tidal fluctuations. Due to friction in the wetlands, tidal changes are very severe which causes wetlands to erode. In the past 40 years, erosive forces have caused the MRGO to increase in size from the initial 600 feet across to 2,000 feet across. This has caused the area to erode 5 to 35 feet per year, for an average erosion rate of 15 feet per year. Over the past 18 months, local, state, and federal agencies have participated in a Task Force to phase out the shipping channel.