9. PART II focuses on the technical guideline for wetlands, and 

 stresses the need for considering all three parameters (vegetation, soils, and 

 hydrology) when making wetland determinations. Since wetlands occur in an 

 intermediate position along the hydrologic gradient, comparative technical 

 guidelines are also presented for deepwater aquatic sites and nonwetlands. 



10. PART III contains general information on hydrophytic vegetation, 

 hydric soils, and wetland hydrology. Positive wetland indicators of each 

 parameter are included. 



11. PART IV, which presents methods for applying the technical guide- 

 line for wetlands, is arranged in a format that leads to a logical determina- 

 tion of whether a given area is a wetland. Section A contains general infor- 

 mation related to application of methods. Section B outlines preliminary 

 data-gathering efforts. Section C discusses two approaches (routine and com- 

 prehensive) for making wetland determinations and presents criteria for decid- 

 ing the correct approach to use. Sections D and E describe detailed proce- 

 dures for making routine and comprehensive determinations, respectively. The 

 basic procedures are described in a series of steps that lead to a wetland 

 determination. 



12. The manual also describes (PART IV, Section F) methods for delin- 

 eating wetlands in which the vegetation, soils, and/or hydrology have been 

 altered by recent human activities or natural events, as discussed below: 



a. The definition of wetlands (paragraph 26a) contains the phrase 

 ~ "under normal circumstances," which was included because there 



are instances in which the vegetation in a wetland has been 

 inadvertently or purposely removed or altered as a result of 

 recent natural events or human activities. Other examples of 

 human alterations that may affect wetlands are draining, ditch- 

 ing, levees, deposition of fill, irrigation, and impoundments. 

 When such activities occur, an area may fail to meet the 

 diagnostic criteria for a wetland. Likewise, positive hydric 

 soil indicators may be absent in some recently created wet- 

 lands. In such cases, an alternative method must be employed 

 in making wetland determinations. 



b. Natural events may also result in sufficient modification of an 

 "" area that indicators of one or more wetland parameters are 



absent. For example, changes in river course may significantly 

 alter hydrology, or beaver dams may create new wetland areas 

 that lack hydric soil conditions. Catastrophic events (e.g. 

 fires, avalanches, mudslides, and volcanic activities) may also 

 alter or destroy wetland indicators on a site. 



I > 



( 



