Wetland Sedimentation from Hurricanes Katrina and Rita

More than 131 × 10 6 metric tons (MT) of inorganic sediments accumulated in coastal wetlands when Hurricanes Katrina and Rita crossed the Louisiana coast in 2005, plus another 281 × 10 6 MT when accumulation was prorated for open water area. The annualized combined amount of inorganic sediments per hurricane equals (i) 12% of the Mississippi River's suspended load, (ii) 5.5 times the inorganic load delivered by overbank flooding before flood protection levees were constructed, and (iii) 227 times the amount introduced by a river diversion built for wetland restoration. The accumulation from hurricanes is sufficient to account for all the inorganic sediments in healthy saltmarsh wetlands.