Federal Register / Vol. 56, No. 157 / Wednesday. August 14. 1991 / Proposed Rules 



40463 



purposes. If an illegal disturbance is 

 suspected, and the pre-disturbance 

 condition must be determined for the 

 purposes of weUand regulatory program 

 enforcement purposes, then a detailed 

 investigation of the prior and current 

 conditions of the disturbed area (i.e.. 

 whether the area was and is wetland or 

 non-wetland] is appropriate. However, if 

 an area has been disturbed by legal 

 human activities that have effected the 

 relatively permanent removal of 

 wetland hydrology, hydric soil, or 

 hydrophytic vegetation, then the area is 

 non-wetland, and a detailed 

 investigation of the prior condition of 

 such areas is generally inappropriate. In 

 addition, determination of regulatory 

 jurisdiction for such areas is subject to 

 agency interpretation. For example. 

 Federal wetland regulatory policy under 

 the Clean Water Act, and agricultural 

 program policy under the Food Security 

 Act of 1985, as amended, interprets the 

 relative permanence of disturbance to 

 vegetation caused by agricultural 

 cropping. Be sure to consult appropriate 

 agency in making Federal wetland 

 jurisdictional determinations in such 

 areas. 



In disturbed wetlands, field indicators 

 for one or more of the three technical 

 criteria for wetland identification are 

 usually absent. Where it is necessary to 

 determine whether the "missing" 

 indicalor{s) (especially wetland 

 hydrology) existed prior to alteration, 

 one should review aerial photographs, 

 existing maps, and other available 

 information about the site. This 

 determination may involve evaluating a 

 nearby reference site (similar to the 

 original character of the one altered) for 

 indicator(s) of the "altered" 

 characteristic. 



When a significanUy disturbed 

 condition is detected during an onsite 

 determination, and the prior condition of 

 the area must be determined or it is 

 suspected that the area may still be a 

 wetland, the following steps should be 

 taken to determine if the "missing" 

 indicator(s) was present before 

 alteration and whether the criterion in 

 question was originally met. Be sure to 

 record findings on the appropriate data 

 form. After completing the necessary 

 steps in appendix 7, return to the 

 applicable step of the onsite 

 determination method being used and 

 continue evaluating the site's 

 characteristics. 



Appendix 1. Offsite Preliminary 

 Determination Method 



The foUowring steps are recommended 

 for conducting an offsite weUand 

 determination: 



Step 1. Locate the area of interest on a 

 U.S. Geological Survey topographic map 

 and delineate the approximate subject 

 area boundary on the map. Note 

 whether marsh or swamp symbols or 

 lakes, ponds, rivers, and other 

 waterbodies are present v«thin the area. 

 If they are, then there is a good 

 likelihood that wetland is present. 

 Proceed to Step 2. 



Step 2. Review appropriate National 

 Wetlands Inventory (NWI) maps. State 

 wetland maps, or local wetland maps, 

 where available. If these maps designate 

 wetlands in the subject area, there is a 

 high probability that wetlands are 

 present unless there is evidence on hand 

 that the wetlands have been effectively 

 drained, filled, excavated, impoimded, 

 or otherwise significantly altered since 

 the effective date of the maps. Proceed 

 to Step 3. 



Step 3. Review SCS soil survey maps 

 were available. In the area of interest, 

 are there any map imits listed on the 

 county list of hydric soil map units or 

 are there any soil map units wi\h 

 significant hydric soil inclusions? If YES, 

 then at least a portion of the project 

 area may be weUand. If this area is also 

 shown as a weUand on NWI or other 

 weUand maps, then there is a very high 

 probability that the area is weUand 

 unless it has been recenUy altered 

 (check recent aerial photos. Step 4). 

 Areas without hydric soils or hydric soil 

 inclusions should in most cases be 

 eliminated from further review, but 

 aerial photos still should be examined 

 for small weUands to be more certain. 

 This is especially true if weUands have 

 been designated on the NaUonal 

 WeUands Inventory or other weUand 

 maps. Proceed to Step 4. 



Step 4. Review recent aerial photos of 

 the project area. Before reviewing aerial 

 photos, evaluate climatological data to 

 determine whether the photo year had 

 normal or abnormal (high or low) 

 precipitation two or three months, for 

 example, prior to the date of the photo. 

 This will help provide a useful 

 perspective or frame-of-reference for 

 doing photo interpretation. In some 

 cases, aerial photos covering a multi- 

 year period (e.g.. 5-7 years) should be 

 reviewed, especially where recent 

 climatic conditions have been abnormal. 



Ehuing photo interpretation, look for 

 one or more signs of wetlands. For 

 example: 



(1) Hydrophytic vegetation; 



(2) Surface waten 



(3) Saturated soils; 



(4) Flooded or drowned out crops; 



(5) Stressed crops due to wetness; 



(6) Greener crops in dry years; 



(7) Differences in vegetation patterns 

 due to different planting dates. 

 If signs of wetlands are observed, 

 proceed to Step 5 when site-specific 

 data are available; if site-specific data 

 are not available, proceed to Slep 8. 



Caution: Accurate photo interpretation of 

 certain wetland types requires considerable 

 expertise. Evergreen forested wetiands, 

 seasonally saturated wetlands, and 

 temporarily flooded wetlands, in general, 

 may present considerable difficulty. If not 

 proficient in wetland photo interpretation, 

 then one can rely more on the findings of 

 other sources, such as NWI maps and soil 

 surveys, or seek help in photo interpretation. 



Step 5. Review available site-specific 

 information. In some cases, information 

 on vegetation, soils, and hydrology for 

 the project area has been coUected 

 during previous visits to the area by 

 agency personnel, environmental 

 consultants or others. Moreover, 

 individuals or experts having firsthand 

 knowledge of the project site should be 

 contacted for information whenever 

 possible. Be sure, however, to know the 

 reliability of these sources. After 

 reviewing this information, proceed to 

 Step 6. 



Step 8. Determine whether weUands 

 exist in the subject area. Based on a 

 review of existing information, a 

 preliminary determination can be made 

 that the area is likely to be a weUand if: 



(1) WeUands are shown on NWI or 

 other weUand maps, and hydric soil 

 map unit or a soil map unit with hydric 

 soil inclusions is shown on the soil 

 survey; or 



(2) Hydric soil map unit or soU map 

 unit with hydric soil inclusions is shown 

 on the soU survey (Note: In the latter 

 case, only the hydric inclusion is being 

 evaluated as weUand.), and 



(A) Site-specific information, if 

 avaUable, confirms hydrophytic 

 vegetation, hydric soils, and wetland 

 hydrology, or 



(B) WeUands are shown in aerial 

 photos. 



If. after examining the available 

 reference material one is still unsure 

 whether the area is likely to be weUand, 

 then a field inspection should be 

 conducted, whenever possible. 

 Alternatively, more detailed information 

 on the site's characteristics may be 

 sought to help make the preliminary 

 determination. 



The validity of offsite preliminary 

 determinations are dependent on the 

 availabUity of information for making a 

 weUand determination, the quality of 

 this information, and one's ability and 

 experience to interpret these data. In 

 most cases, therefore, the offsite 

 procedure yields a preliminary 



