then the entire project area is a wetland. If only a 

 portion of the project area is wetland, then the wet- 

 land-nonwetland boundary must be established. 

 Proceed to Step 11. 



Step 11. Determine the wetland- nonwetland 

 boundary. Where a base map or annotated photo 

 was prepared, mark each plant community type on 

 the map or photo with a "W" if wetland or an "N" 

 if nonwetland Combine all "W" types into a single 

 mapping unit, if possible, and all "N" types into 

 another mapping unit. On the map or photo, the 

 wetland boundary will be represented by the inter- 

 face of these mapping units. If flagging the bound- 

 ary on the ground, the boundary is established by 

 determining the location where hydrophytic vegeta- 

 tion and hydric soils give way to nonhydrophytic 

 vegetation and nonhydric soils. This will often 

 require sampling a few more holes to better define 

 the limits of the hydric soils and thereby establish 

 the limits of hydrophytic vegetation. 



Intermediate-level Onsite Determination 

 Method 



4.12. On occasion, a more rigorous sampling 

 method is required than the routine method to 

 determine whether hydrophytic vegetation is 

 present at a given site, especially where the bound- 

 ary between wetland and nonwetiand is gradual or 

 indistinct. This circumstance requires more inten- 

 sive sampling of vegetation and soils than present- 

 ed in the routine determination method. This meth- 

 od also may be used for areas greater than five 

 acres in size or other areas that are highly diverse in 

 vegetation. 



4.13. The intermediate-level onsite determination 

 method has been developed to provide for more 

 intensive vegetation sampling than the routine 

 method. Two optional approaches are presented: 

 (1) quadrat transect sampling procedure, and (2) 

 vegetation unit sampling procedure. The former 

 procedure involves establishing transects within the 

 project area and sampling plant communities along 

 the transect within sample quadrats, with soils and 

 hydrology also assessed as needed in each sample 

 plot. In contrast, the vegetation unit sampling pro- 

 cedure offers a different approach for analyzing the 

 vegetation. First, vegetation units are designated in 

 the project area and then a meander survey is con- 

 ducted in each unit where visual estimates of per- 

 cent areal coverage by plant species are made. Soil 



and hydrology observations also are made as 

 necessary. Boundaries between wetland and non- 

 wetland are established by examining the transi- 

 tional gradient between them. 



4.14. The following steps should be completed: 



Step 1. Locate the limits of the project area 

 in the field and conduct a general reconnaissance of 

 the area. Previously the project boundary should 

 have been determined on aerial photos or maps. 

 Now appropriate ground reference points need to 

 be located to insure that sampling will be conducted 

 in the proper area. In examining the project area, 

 were any significantiy disturbed areas observed? If 

 YES, identify their limits for they should be evalu- 

 ated separately for wetiand determination purposes 

 (usually after evaluating undisturbed areas). Refer 

 to the section on disturbed areas (p. 50) to evaluate 

 the altered characteristic(s) (i.e., vegetation, soils, 

 or hydrology); then return to this method to contin- 

 ue evaluating the characteristics not altered. Keep 

 in mind that if at any time during this determina- 

 tion, one or more of these three characteristics is 

 found to have been significantiy altered, the dis-. 

 turbed areas procedures should be followed. If the 

 area is not significantiy disturbed, proceed with 

 Step 2. 



Step 2. Decide how to analyze plant commu- 

 nities within the project area: (1) by selecting repre- 

 sentative plant communities (vegetation units), or 

 (2) by sampling along a transect. Discrete vegeta- 

 tion units may be identified on aerial photographs, 

 topographic and other maps, and/or by field 

 inspection. These units will be evaluated for hydro- 

 phytic vegetation and also for hydric soils and wet- 

 land hydrology, as necessary. If the vegetation unit 

 approach is selected, proceed to Step 3. An alterna- 

 tive approach is to establish transects for identify- 

 ing plant communities, sampling vegetation and 

 evaluating other criteria, as appropriate. If the tran- 

 sect approach is chosen, proceed to Step 4. 



Step 3. Identifying vegetation units for sam- 

 pling. Vegetation units are identified by examining 

 aerial photographs, topographic maps, NWl maps, 

 or other materials or, by direct field inspection. All 

 of the different vegetation units present in the pro- 

 ject area should be identified. The subject area 

 should be traversed and different vegetation units 

 specifically located prior to conducting the sam- 

 pling. 



35 



