) 



Section 2 - Hydric Soils of the United States 



A. The list of hydric soils of the United States (Table Dl) was de- 

 veloped by the National Technical Committee for Hydric Soils (NTCHS) , a panel 

 consisting of representatives of the Soil Conservation Service (SCS), Fish and 

 Wildlife Service, Environmental Protection Agency, Corps of Engineers, Auburn 

 University, University of Maryland, and Louisiana State University. Keith 

 Young of SCS was committee chairman. 



5. The NTCHS developed the following definition of hydric soils: 



A hydric soil is a soil that is saturated, flooded, or ponded long 

 enough during the growing season to develop anaerobic conditions that 

 favor the growth and regeneration of hydrophytic vegetation" (US Depart- 

 ment of Agriculture (USDA) Soil Conservation Service 1985, as amended by 

 the NTCHS in December 1986). 



Criteria for hydric soils 



6. Based on the above definition, the NTCHS developed the following 

 criteria for hydric soils, and all soils appearing on the list will meet at 

 least one criterion: 



a. "All Histosols* except Folists; 



b. Soils in Aquic suborders, Aquic subgroups, Albolls suborder, 

 Salorthids great group, or Pell great groups of Vertisols 

 that are: 



(1) Somewhat poorly drained and have water table less than 



0.5 ft from the surface for a significant period (usually a 

 week or more) during the growing season, or 



(2) Poorly drained or very poorly drained and have either: 



(a) A water table at less than 1.0 ft from the surface for 

 a significant period (usually a week, or more) during 

 the growing season if permeability is equal to or 

 greater than 6.0 in/hr in all layers within 20 inches; 

 or 



(b) A water table at less than 1.5 ft from the surface for 

 a significant period (usually a week or more) during 

 the growing season if permeability is less than 



6.0 in/hr in any layer within 20 inches; or 



c. Soils that are ponded for long duration or very long duration 

 during part of the growing season; or 



d. Soils that are frequently flooded for long duration or very long 

 duration during the growing season. 



* Soil taxa conform to USDA-SCS (1975). 



D5 



