tion produce organic acids that speed podzolization 

 including eastern hemlock {Tsuga canadensis), 

 spruces (Picea spp.), pine {Pinus spp.), larches 

 {Larix spp.), and oaks {Querciis spp.) (Buol, et al. 

 1980). To the untrained observer, the gray leached 

 layer may be mistaken as a field indicator of hydric 

 soil, but if one looks below the spodic horizon the 

 brighter matrix colors often disnnguish nonhydric 

 spodosols from hydric ones. The wet spodosols 

 (formerly called "groundwater podzolic soils") 

 usually have thick dark surface horizons, dull gray 

 E-horizons, and low chroma subsoils. Become 

 familiar with these soils and their diagnosnc prop- 

 enies (see "Soil Taxonomy", U.S.D.A. Soil Sur- 

 vey Staff 1975 and county soil surveys). 



13) Mollisols (prairie and steppe soils) - Molli- 

 sols are dark colored, base-rich soils. They are 

 common in the central part of the conterminous 

 U.S. from eastern Illinois to Montana and south to 

 Texas. Natural vegetation is mainly tall grass prair- 

 ies and short grass steppes. These soils typically 

 have deep, dark topsoil layers (mollic epipedons) 

 and low chroma matrix colors to considerable 

 depths. They are rich in organic matter due largely 

 to the vegetation (deep roots) and reworking of the 

 soil and organic matter by earthworms, ants, 

 moles, and rodents. The low chroma colors of 

 mollisols are not necessarily due to prolonged satu- 

 ration, so be particularly careful in making wetiand 

 determinations in these soils. Become familiar with 

 the characteristics of mollisols with aquic moisture 

 regimes, since they are usually hydric, unless 

 effectively drained, and be able to recognize these 

 from nonhydric mollisols (see "Soil Taxonomy", 

 U.S.D.A. Soil Survey Staff 1975 and county soil 

 surveys). 



4.26. The steps for making wetland determina- 

 tions in problem area wetlands, except FACU- 

 dominated wetlands, are presented below. {Note: 

 Procedures for FACU-dominated communities are 

 on pp. 55-56.) Application of these steps is appro- 



priate only when a decision has been made during 

 an onsite determination that wetland indicators of 

 one or more criteria were lacking. Specific proce- 

 dures to be used will vary according to the nature 

 of the area, site conditions, and affected criterion. 

 A determination must be based on the best available 

 evidence, including: (1) information obtained from 

 such sources as aerial photos, wetiand maps, soil 

 sufvey maps, and hydrologic records; (2) field data 

 collected during an onsite inspection; and (3) basic 

 knowledge of the ecology of the panicular wetland 

 type and associated environmental conditions. 

 (Note: The following procedures should only be 

 applied to situations not adequately characterized 

 by the onsite methods in Part IV. Be sure to record 

 necessary information on appropriate data forms.) 



Step 1. Identify each criterion to be reconsi- 

 dered and determine the reason for further consid- 

 eration. Consider how environmental conditions 

 have affected the criterion in question (hydrophytic 

 vegetation, hydric soil, and/or wetiand hydrology). 

 If hydrophytic vegetation is the criterion in ques- 

 tion and the plant community is FACU-dominated, 

 then foUow special procedures presented earlier in 

 this section (see pp. 55-56). Proceed to Step 2. 



Step 2. Document available information on each 

 criterion in question. Examine the available infor- 

 mation and consider personal experience and 

 knowledge of wetiand ecology and the range of 

 normal environmental conditions of the area. Con- 

 tact local expens (e.g., government agency and 

 university scientists) for additional information, if 

 possible. Proceed to Step 3. 



Step 3. Determine whether each wetland criteri- 

 on in question is met. If no information can be 

 found that demonstrates that the wetiand criterion 

 in question is satisfied, the area is nonwetland. 

 {EXCEPTION: Caprock limestone wetlands do not 

 meet the hydric soil criterion where limestone rock 

 is the predominant substrate; this is an exception to 

 the rule.) 



59 



