The building process in the Chenier Plain continued until a change in the river's course resulted 

 in a loss of sedimentary material. Once the building process ceased, the new marsh came under 

 attack by wave action. Shoreline retreat then followed, with a corresponding formation of local 

 beach deposits. The beach deposits remained along the point of wave attack until another change 

 in the river's course caused a resumption in the buildup along the shoreline. This process caused 

 marshes to again advance seaward, leaving the beaches stranded (Russell and Howe 1935). 



The stranded beaches (cheniers) extend in an east-west direction and have a strategic role in 

 the drainage patterns of the Chenier Plain. In contrast, topographic features of the Deltaic Plain, 

 such as the natural levees of past and present drainage systems, generally run in a north- south 

 direction. 



The areas of marsh in Louisiana have water tables at or near the soil surface most of the time. 

 Many of the soils are subject to occasional or frequent inundation by tidal action. Until recently, 

 coastal lands were included on soil maps as miscellaneous land types, such as tidal marsh, tidal flats, 

 or included in broadly defined soil series. However, recent interests in wildlife, marine biology, 

 land loss, recreation, and urban development have promoted a more detailed inspection of the 

 coastal region and more detailed mapping. 



METHODS AND PROCEDURES 



The primary objective of the National Cooperative Soil Survey (NCSS) program in the State 

 of Louisiana is to obtain through soil surveys an inventory of the State's soil resources, record 

 the location of soils, predict soil performance under defined use and management, facilitate the 

 transfer of soil information from one location to another, and contribute to the knowledge, 

 understanding, and proper use of our land resources. This is a cooperative effort of the Soil 

 Conservation Service, the Louisiana Agricultural Experiment Station, and the Louisiana State Soil 

 and Water Conservation Committee. 



Soil surveys of coastal areas in Louisiana are designed to meet specified objectives. In most 

 survey areas it is not difficult to identify the potential users of the survey. The refinement in 

 map units, purity of delineations, and map scale are then formulated to meet the needs of the 

 users. When the field work is complete, a soil report is published for the survey area. This report 

 contains soil maps showing the geographic distribution of soils and a text that describes, classifies, 

 and interprets the soils. 



Soil maps are prepared on aerial photographs. A soil map consists of soil lines and soil map 

 unit symbols that delineate and identify areas of the soils. Cultural features are also shown. In 

 Louisiana, soil maps have a scale of 1:20,000. 



Generally, the information provided in a soil report is considered to be adequate for most users' 

 needs for a period of about 20-25 years. However, where there are dramatic changes in land use, 

 land composition, or in the needs of users, the information may need to be updated much sooner. 



As of June 1988, field mapping has been completed in 13 of 15 coastal parishes in the State 

 (U.S. Department of Agriculture, unpubl.). About one-half of the completed survey areas are 

 published (U.S. Department of Agriculture 1973, 1977, 1983, 1984). Field work is scheduled to 

 commence in St. Mary and Terrebonne Parishes in early 1991. 



Access to the marshes is difficult, even by boat. Most of the surveys of marsh lands have 

 utilized helicopters for transportation. The aircraft provided by contract with a privately owned 



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