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



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FACU and UPL species often invade the 

 pool basins in dry years, as they do in 

 other seasonally variable wetlands. 

 Lack of hydrophytic plant species also 

 may be indicative of recent disturbances 

 such as off-road vehicle activities, 

 fanning, or grazing. In delineating these 

 wetlands, it is important to be aware not 

 only of the "pool" but of the vernal pool 

 complex (pool, basin, swales, 

 tributaries), parts of which may have 

 shorter and more variable periods of 

 inundation. 



Appendix 6. Problem Area Wetlands 



Certain situations encountered in the 

 field can make wetland identification 

 and delineation problematic. These 

 situations are discussed below. 



Newly Created Wetlands 



These wetlands include marunade 

 (artificial) wetlands, beaver-created 

 wetlands, and other weUands that have 

 recently formed due to nat\u-al 

 processes. Artificial wetlands may be 

 purposely or accidentally created (e.g., 

 road impoundments, undersized 

 culverts, irrigation, and seepage from 

 earth-dammed impoundments) by 

 human activities. Many of these areas 

 vnil have evidence of wetland hydrology 

 and hydrophytic vegetation. The area 

 should lack typical morphological 

 properties of hydric soils, since the soils 

 have just recently been inxmdated and/ 

 or saturated. Since all of these wetlands 

 are newly established, evidence of one 

 or more of the wetland identification 

 criteria may not be present. One must 

 always consider the relative 

 permanency of the wetter conditions. 

 For example, if a beaver has recenUy 

 blocked a road culvert that has now 

 caused flooding of nonwetland (e.g., 

 upland forest or field), it is quite 

 possible that the blockage v«ll soon be 

 removed. In this case, the action is 

 considered nonpermanent and the area 

 is not considered wetland. If, however, 

 hydrophytic vegetation has colonized 

 the area, the hydrology is considered 

 more or less permanently altered and 

 the area is considered wetland. 

 Temporary roads may impede the 

 natural flow of water and impound 

 water for some time. Yet, since the road 

 is only temporary, the effect is also 

 temporary, so the area is not considered 

 wetland, unless, of course, it was 

 wetiand prior to the road construction. 



Wetlands on Glacial Till or in Rocky 

 Areas 



Sloping wetiands occur in glaciated 

 areas where soils cover relatively 

 impermeable glacial till or where layers 

 of glacial till have different hydraulic 

 conditions that permit groundwater 



seepage. Such areas are seldom, if ever, 

 flooded, but dowmslope groundwater 

 movement keeps the soils saturated for 

 a sufficient portion of the growing 

 season to produce anaerobic and 

 reducing soil conditions. This promotes 

 the development of hydric soils and 

 hydrophytic vegetation. Evidence of 

 wetland hydrology may be lacking 

 during the drier portion of the grovyring 

 season. Hydric soil properties also may 

 be difficult to observe because certain 

 areas are so rocky that it is difficult to 

 examine soil characteristics wnthin 18 

 inches. 



Wetland-Non wetland Mosaics 



In nimierous areas, including northern 

 glaciated regions and the coastal plain, 

 the local topography may be 

 pockmarked vdth a complex of "pits" 

 (depressions) and "mounds" (knolls). 

 The pits may be wet enough to be 

 classified as wetland, whereas the 

 mounds are usually nonwetland. (Note: 

 In some areas, the shallow mounds are 

 also wetland. When this is true, the 

 entire area is wedand.) The 

 interspersion of wet pits and dry 

 mounds may make the delineation of the 

 wetiand boundary difficult when the 

 pits are too small to separate from the 

 mounds. Of course, any area should be 

 mapped vdthin practical limits. When it 

 is not practicable to separate the wet 

 pits from the dry mounds, it is 

 recommended that the weUand- 

 nonweUand boundary be delineated by 

 assessing the percent of the area 

 covered by the wetiand pits in an area 

 of similar pit-mound relief. At least two 

 random transects should be established 

 to determine the percent of pits vs. 

 mounds. Based on the assessment at 

 two-foot intervals along each transect, 

 the percent of wetiand vs. upland points 

 can be established for the area. Consult 

 the appropriate regulatory agency to 

 learn what ratio they want to consider 

 "wetiand" for regulatory purposes. One 

 should also note in his or her field report 

 that this protocol wasjised and give an 

 estimated size range for the wetiand pits 

 (e.g., 3-5' diameter) as well as a brief 

 narrative description of the site. 



Cyclical wetlands 



While the hydrology of all wetiands 

 varies annually, the hydrology of certain 

 wetiands, may natiu-ally fluctuate in a 

 cyclical patterns of a series of 

 consecutive wet years followed by a 

 series of dry years. During the wet 

 periods, hydrophytic vegetation and 

 wetiand hydrology are present, yet 

 during the dry periods, the hydrology 

 does not appear to meet the wetiand 

 hydrology criterion and FACU and UPL 

 plant species often become established 



and may predominate under these 

 temporal drier conditions. Despite the 

 lack of periodic flooding or sat\irated 

 soils for a multi-year period, these are as 

 should still be considered wetiand, since 

 in the long run, wetiand characteristics 

 prevail. Specific examples of cyclic 

 wetlands include Alaska's black spruce- 

 permafrost wetiands, groundwater 

 wetiands of the Cimmaron Terrace of 

 Oklahoma and Kansas, and wetiands in 

 coastal and West Texas. Other cyclical 

 wetiands are associated with drought- 

 prone areas such as southern California 

 and the arid and semi-arid regions of the 

 country. 



Vegetated Flats. 



Vegetated flats typically are 

 characterized by a marked seasonal 

 periodicity in plant grovvrth. They occur 

 both in coastal and interior parts of the 

 country (e.g., regularly flooded 

 freshwater tidal marshes and exposed 

 shores of lakes or reservoirs during 

 drawdowns due to natural fluctuations 

 or human actions). They are dominated 

 by annual OBL species, such as wild 

 rice [Zizania aquatica), and/ or 

 perennial OBL species, such as 

 spatterdock [Nuphar luteum), that have 

 nonpersistent vegetative parts (i.e.. 

 leaves and stems breakdown rapidly 

 during the venter, providing no evidence 

 of the plant on the wetiand surface at 

 the beginning of the next growing 

 season). During printer and early spring, 

 these areas lack vegetative cover and 

 resemble mud flats; therefore, they do 

 not appear to qualify as wetiands. But 

 diuing the grov/ing season the 

 vegetation becomes increasingly 

 evident, qualifying the area as vegetated 

 wetiand. In evaluating these areas, one 

 must consider the time of year of the 

 field observation and the seasonality of 

 the vegetation. Again, one must become 

 familiar vdth die ecology of these 

 wetiand types. 



Interdunal Swale Wetlands 



Along the U.S. coastiine, seasonally 

 wet swales supporting hydrophytic 

 vegetation are located within sand dune 

 complexes on barrier islands and 

 beaches. Some of these swales are 

 inundated or saturated to the surface for 

 considerable periods during the growing 

 season, while others are wet for only the 

 early part of the season. In some cases, 

 swales may be flooded irregularly by 

 the tides. These wetiands have sandy 

 soils that generally lack evidence of 

 hydric soil properties. In addition, 

 evidence of wetiand hydrology may be 

 absent during the drier part of the 

 growing season. Consequentiy. these 

 wetiands may be harder to identify. 



