Over the last 5,000 years the Mississippi River has built a series of deltas, creating new land with the tremendous load of sediment the great river carries as it drains two-thirds of the continental United States. Some 2,500 years ago the river began building a delta in the area that is now New Orleans. Within each delta, the river may occupy several different channels. This delta had at least 3 main channels, and one of them, Bayou des Familles, deposited the sediments that underlay the present-day Preserve. In the delta, a combination of soil-type, elevation, moisture, and salinity, controls what plants grow where.
Hardwood forests grow on the elevated land of the natural levee.
Here majestic Live Oaks take advantage of the dry ground. On the back-slope of the levee the forest changes to one dominated by an understory of palmetto. Swamp covers the lowest portion of the natural levee, where water stands for much of the year. This forested wetland is the home to the stately Baldcypress. Beyond the swamp lies the flat treeless marsh, the eastern end of one of the largest expanses of floating freshwater marsh in the world.