Various aspects of marsh creation are currently being studied. 

 The U.S. Army Engineer Waterways Experiment Station, Vicksburg, 

 Mississippi, has made marsh-building tests on dredged material at 

 several widely distributed locations. Garbisch (1977) identified 

 105 sites where experimental or applied marsh plantings had been 

 attempted. Data are available from a limited number of sites pri- 

 marily on the Atlantic, gulf, and central (San Francisco Bay) Cali- 

 fornia coasts. Consequently, the information will require consid- 

 erable extrapolation and many of the resulting recommendations will 

 be speculative. However, marsh creation in suitable situations 

 offers real promise; it cannot become a fully established practice 

 until carried beyond the experimental and demonstrational stage. 



This study provides potential users an analysis and interpreta- 

 tion of the current information on marsh creation along the coasts 

 of the continental United States, including the Great Lakes. 



2. Types of Coastal Marshes . 



There are two major groups of coastal salt marshes in the United 

 States, based on physiographic differences — marshes of the Atlantic 

 and gulf coasts and those characteristic of the Pacific coast. The 

 east coast marshes usually form on a gently sloping coast with a 

 broad continental shelf, under conditions of a sea slowly rising 

 relative to the land. West coast marshes are mostly formed in rela- 

 tively narrow river mouths which drain almost directly onto a steeply 

 sloping continental shelf along a slowly emerging coastline (Cooper, 

 1969). Consequently, the west coast estuaries and their marshes are 

 more limited in development than those of the east coast and tend to 

 mature more rapidly. 



Coastal salt marshes are also divided into regularly flooded low 

 marsh, which is considered to be the most valuable, and irregularly 

 flooded high marsh. 



a. East Coast Marshes . Vegetation of east coast marshes is re- 

 markably uniform. The intertidal zone from New England to Texas is 

 dominated by a single species, smooth cordgrass {Spartina attema- 

 floTo) (Fig. 1). Two grasses, saltmeadow cordgrass (5. -patens) and 

 saltgrass (Distiohlis spiaata) , usually dominate the zone immediately 

 above high tide along these coasts with two rushes on slightly higher 

 sites -- black-grass (Junaus gevardi) north of the Virginia Capes and 

 black needle rush (J. roemevianus) southward (Fig. 2). 



East coast marshes divide into three general types: New England, 

 mid-Atlantic, and South Atlantic and gulf. Typical New England marshes 

 occur on fibrous or silty peat because the shore is predominantly com- 

 posed of hard rock. The intertidal zone of pure stands of smooth 



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