one altered before modification) for field indicators 

 of the three technical criteria for wetland. If a 

 human activity or natural event altered the vegeta- 

 tion, proceed to Step 3; the soils, proceed to Step 

 4; the hydrology, proceed to Step 5. 



Step 3. Determine whether hydrophytic vegeta- 

 tion previously occurred: 



1) Describe the type of alteration. Examine 

 the area and describe the type of alteration that 

 occurred. Look for evidence of selective harvest- 

 ing, clearcutting, bulldozing, recent conversion to 

 agriculture, or other activities (e.g., burning, disc- 

 ing, the presence of buildings, dams, levees, 

 roads, and parking lots). 



2) Determine the approximate date when the 

 alteration occurred if necessary. Check aerial pho- 

 tographs, examine building permits, consult with 

 local individuals, and review other possible sourc- 

 es of information. 



3) Describe the effects on the vegetation. 

 Generally describe how the recent activities and 

 events have affected the plant communities. Con- 

 sider the following: 



A) Has all or a portion of the area been 

 cleared of vegetation? 



B) Has only one layer of the plant com- 

 munity (e.g., trees) been removed? 



C) Has selective harvesting resulted in 

 the removal of some species? 



D) Has the vegetation been burned, 

 mowed, or heavily grazed? 



E) Has the vegetation been covered by 

 fill, dredged material, or structures? 



F) Have increased water levels resulted 

 in the death of all or some of the vegetation? 



4) Determine whether the area had hydro- 

 phytic vegetation communities. Develop a list of 

 species that previously occurred at the site from 

 existing information, if possible, and determine 

 presence of hydrophytic vegetation. If site-specific 

 data do not exist, evaluate a neighboring undis- 

 turbed area (reference site) with characteristics 

 (i.e., vegetation, soils, hydrology, and topogra- 



phy) similar to the area in question prior to its alter- 

 ation. Be sure to record the location and major 

 characteristics (vegetation, soils, hydrology, and 

 topography) of the reference site. Sample the vege- 

 tation in this reference area using an appropriate 

 onsite determination method to determine whether 

 hydrophytic vegetation is present. If hydrophytic 

 vegetation is present at the reference site, then 

 hydrophytic vegetation is presumed to have existed" 

 in the altered area. If no indicators of hydrophytic 

 vegetation are found at the reference site, then the 

 original vegetation at the project area is not consid- 

 ered hydrophytic vegetation. If soils and/or hydrol- 

 ogy also have been disturbed, then continue Steps 

 4, 5, and 6 below, as necessary. Otherwise, return 

 to the applicable step of the onsite determination 

 method being used. - 



Step 4. Determine whether or not hydric soils 

 previously occurred: 



1) Describe the type of alteration. Examine 

 the area and describe the type of alteration that 

 occurred. Look for evidence of: 



A) deposition of dredged or fill material 

 or natural sedimentation - In many cases the pres- 

 ence of fill material will be obvious. If so, it will be 

 necessary to dig a hole to reach the original soil 

 (sometimes several feet deep). Fill material will 

 usually be a different color or texture than the origi- 

 nal soU (except when fill material has been obtained 

 from similar areas onsite). Look for decomposing 

 vegetation between soil layers and the presence of 

 buried organic or hydric mineral soil layers. In 

 accreting or recentiy formed sandbars in riverine 

 situations, the soils may support hydrophytic vege- 

 tation but lack hydric soil indicators. 



B) presence of nonwoody debris at the 

 surface - This can only be applied in areas where 

 the original soils do not contain rocks. Nonwoody 

 debris includes items such as rocks, bricks, and 

 concrete fragments. 



C) subsurface plowing - Has the area 

 recentiy been plowed below the A-horizon or to 

 depths of greater than 10 inches? 



D) removal of surface layers - Has the 

 surface soil layer been removed by scraping or nat- 

 ural landslides? Look for bare soil surfaces with 

 exposed plant roots or scrape scars on the surface. 



51 



