Appendix 1 — Wetland Data 



Early wetland inventories treated all wetlands the 

 same, describing the object of their investigations 

 with such terms as "swamp and overflowed lands" 

 (57). Scientific inventories by the U.S. Fish and 

 Wildlife Service used two similar but distinct 

 wetland classification systems based on charac- 

 teristics of the land, water, and formation of 

 wetlands. A third definition of wetlands, developed 

 by an interagency committee, is based on the com- 

 bination of soil properties and vegetation. 



Classiflcation 



The classification used in the first Fish and Wildlife 

 survey (1954), commonly called the Circular 39 

 classification, distinguished between coastal and in- 

 land areas of fresh and saline wetlands. Within 

 these four broad categories, 20 wetland types were 

 classified on the basis of water depth and vegeta- 

 tion (25). 



For the National Wetland Status and Trends 

 Analysis (13), a new classification system was 

 designed to rectify problems with the older system. 

 In particular, the Circular 39 system ignored 

 ecologically important differences in wetlands and 

 grouped together dissimilar wildlife habitats that 

 are geographically separated. Also, the system was 

 inadequately defined, leading to inconsistencies in 

 application. The NWSTA classification includes 

 both wetlands and deepwater habitats, grouping 

 them in a hierarchical structure on the basis of 

 hydrologic, geomorphologic, chemical, and 

 biological" factors. Five major systems form the first 

 level in the hierarchy. These are further subdivided 

 into subsystems based on degree of inundation, 

 classes, subclasses, and dominance types (8). 



The National Technical Committee for Hydric Soils, 

 made up of representatives from the Soil Conserva- 

 tion Service, the Fish and Wildlife Service, Army 

 Corps of Engineers, and universities, developed a 

 soils definition f49J. A Ust of soils meeting the 

 hydric soils definition was identified, although 

 some phases of these soils may be excluded. 



Inventories 



Analyses in this report are based on a variety of 

 data available on wetlands and their potential for 

 agricultural conversion. Each source is briefly de- 

 scribed here; for further details, consult the list of 

 references. 



3906 USDA Drainage Inventory (57). Successive at- 

 tempts have been made at the national level to in- 

 ventory the agricultural potential of remaining ^ 

 wetlands and the need for drainage to develop 

 those lands. This first modern attempt surveyed 

 knowledgeable people in each county in the humid 

 eastern part of the country. A total of 79 million 

 acres of swampland were thought to have farm 

 potential. One-third of this acreage was in intermit- 

 tent crop use or wet pasture suited to improved 

 drainage, while the remaining two-thirds was not 

 fit for cultivation unless cleared and drained. 



1919 USDA Drainage Inventory (14). This was a 

 more comprehensive inventory based on drainage 

 investigations and soil surveys. The inventory 

 showed 91.5 million acres of land unfit for crops 

 without drainage, with two-thirds in the South and 

 half of the rest in the Lake States. The study 

 estimated that only 75 million of the 91.5 million 

 acres could ever be developed for agriculture, with 

 the remainder in very deep peat or in coastal 

 marshes unsuitable for crops. Further, 68 percent of 

 these 75 million acres would have also required 

 clearing of brush or trees, and some land would 

 have had unfavorable fertility or texture if drained. 



1946-48 American Society of Agricultural Engineers 

 Drainage Survery (2). This effort identified 97 ^ 



million acres of wet, swampy, and overflow lands, ( 

 20 million acres of which could be drained for 

 farming at a reasonable cost. Of the land adaptable 

 to farming, one-third was in cultivation and needed 

 drainage improvements, and the remaining two- 

 thirds was undeveloped land. A related 1948 

 estimate by the Soil Conservation Service showed 

 20.7 million acres physically feasible to drain and 

 develop for agriculture. 



1954 Wetlands Inventory (Circular 39) (38). The 



Fish and Wildlife Service (FWS) and State fish and 

 game departments cooperated to inventory wetlands 

 used by waterfowl. The inventory counted 74.4 

 million acres of wetlands, classified according to 

 the 20 types of the older FWS classification. 



1958 Conservation Needs Inventory (CNIj (51). This 

 USDA inventory identified land needing drainage 

 and small watershed projects needed for water 

 management through farm drainage. A total of 73.5 

 million acres were judged to need treatment for ex- 

 cess water, more than 80 percent of which was 

 cropland. Pasture and rangeland with excess water 

 that needed treatment totaled 13.6 million acres. 

 Some 172.5 million acres had drainage problems, of /*- 

 which 45.5 million acres needed small watershed 

 projects. 



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