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25 <br /> Ch�raat�riaation ot 8paroloqy <br /> The importance of water to the exietence of wetland is <br /> clearly stated in the COE definition of wetlands as: <br /> "those areas that are inundated or saturated by <br /> surface or qround water at a frequency and duration <br /> aufficient to support, and that under normal <br /> circumstancea do support, a pravelenca of veqetation <br /> typically adapted for life in saturated soil <br /> conditions" (Federal Register 1986) . <br /> Watland hydr.oloqy, being the primary daterminant for the <br /> developmant of hydric soils and hydrophytic veqetation, is <br /> the most critical factor necessary for wetland formation. <br /> Without wetland hydrology an area cannot be claseified as <br /> wetland. Thus, in identifying and delineatinq wetlands, the <br /> qoal is to determine the extent of wetland hydroloqy. <br /> "Tha term 'wetland hydroloqy' encompasses all <br /> hydroloqical characteristice of areas that ara <br /> periodically inundated or have soils eaturated to the <br /> surfaca at some time durinq the growinq season. Areas <br /> with evident characteristics of wetland hydrology are <br /> those where the presence of water has an overridinq <br /> influence on characteristics of veqatation and soils <br /> due to anaerobic and reducing conditions, <br /> respectively. . . " (Environmental Laboratory 1987:34) <br /> Indicators of wetland hydroloqy include both recorded and <br /> field data. Recorded data typically include the stream, <br /> lake, and tidal gage records of the COE, US Geoloqical <br /> Survey (USGS) , state, county and/or local governments. <br /> Field data includes visual observation of inundation, soil <br /> saturation, watermarks, driftlines, sediment deposits, and <br /> drainaqe patterns (Federal Interaqency Committee for Wetland <br /> Delineation 1989. <br /> Topography snd soil proparties are the factore controlling <br /> local hydrology. Wetland hydroloqy exists because 1) <br /> topography directs water towar3s or impedes water flow out <br /> of an area, or 2) soil conditions impade drainage, or 3) <br /> � both topographic and soil conditione favor wetland <br /> hydrology. Therefora, obeervations of topoqraphy and soil <br /> properties are a necessary part of any watland <br /> determination. <br /> Inundation or soil saturation are the most direct evidence <br /> of wetland hydrology. Rowever, observations of inundation <br /> or saturation must be considered in the context of the <br /> prevailing weather conditions. Saturation does not <br /> necessarily indicate wetland hydroloqy, for evan a well <br /> drained soil may have ponded or saturated conditions vhen <br /> the rate of precipitation exceeds the infiltration rate, or <br />