The saline marsh is situated closest to the sea, and the brackish marsh interfaces the fresh and saline waters. In order to understand the effects of canal building in the Louisiana coastal wetlands, a better understanding of land gains and losses is needed. This discussion will help to show the relationship between the wetland systems and the magnitude of loss attributable to canal building. Finally, this paper will discuss alternative approaches to mitigate wetland loss, and how backfilling of canals can reduce further loss and restore previously damaged wetlands. Two ways in which land is added to the Louisiana coastline are deposition and accretion.
Deposition occurs when sediment from the Mississippi River is deposited into the Gulf of Mexico.
Continuous sediment loading will create a delta. As the gradient of the river channel changes, the river will change course and build a new delta lobe. When the Mississippi River floods, overland flow deposits a rich load of sediment and nutrients onto the marsh. The marsh increases in height, stimulating vegetation growth, creating dense peat formation and further trapping the sediment. Major storm events add an even greater amount of nutrient-laden ocean sediment to the marsh.