REGION 



CHENIER PLAIN 



TIME SCALE 

 1000 ■¥ YEARS 



BASIN 



CALCASIEU 

 BASIN 



I -100 YEARS 



HABITAT 



i. 



"^ 



O.OI- 10 YEARS 



OPEN WATER 



~ BRACKISH MARSH 



POPULATION 



O.OI -10 YEARS 



Figure 2. The Chenier Plain conceptual hierarchy. 



Figure 3. A simplified model of the formation of the Chenier Plain system. Geologic processes (a) 

 lead to the Mississippi River switching course and control the supply of riverine sediments (b). 

 These sediments form an offshore mud flat. If sediment supply dwindles, the wave energy causes 

 the offshore mud flat to form a beach (c). The beach gains and loses sediment through littoral 

 drift (d). As the beach grows up, it strands the mud flat and forms a stranded Chenier Plain 

 marsh (e, f). Subsidence or sea-level rise can transform this marsh into open water. 



35 



