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1 <br /> The definition of appropriate hydrology according to fhe 1987 Ivlanual incIudes two important <br /> terLns that must be cl.arified. Eirst, the definition of a growing season is needed. The growing <br /> season is def ned in the 19$7 Manual as: ".,:the portion of the .year when soil temperature <br /> (measured 19.7 inches belaw the:surface)is above biological zero (5`C or 41°F)." According to <br /> . fhe 19871VIanual this period of time can be approXimated by using the"starting and ending dates <br /> for the gLOwing season based. on a 28D.F air temperature threshold at a frequency of 5 years .in <br /> 1Q." Based on this def nition the growing.season ranges approximately 1b0 days to 180 days in <br /> 'the Minneapolis/S.t.Paul metropolitan area (160�in the northern,suburlis and greater to the southj. <br /> Therefore, the reguired inundation .or saturation to the surface for S% of the geowing season <br /> would be 8 or 9 consecutive days:that ground water would need to be at the surface.or saeurated <br /> to_the surface. <br /> The secona term in°the appropriate hydralogy definition from the above paragraph to be clarified' <br /> is "in mosc years". This means ia 5 of 10 years :hydrology must exist within a `ju�isdictional <br /> wetland" far the 8 or 9 consecutive days of the growing season. T.his means that one observation <br /> � date or even �ne whole year worth of deta'iled hydrology data may be deemed insufficient to <br /> determine if appropriate hydrology exists at a given locadon. In the event that grecipitation <br /> events aceumulate to above or below narmal durmg just prior ta a site visit or during a more <br /> intensive hydralogy sfudy, the data may be con�ounded by non=normal circumstances.and may <br /> be consideied outside the bound's of "most years". Ideally, both antecedent soil moisture . <br /> conditions and precipitation would be n�rmal during.all delineafions. However, this .is not a <br /> realistic impression of cIimate. Therefore, primary iridicattocs of hydrology must be reviewed � <br /> with scrutin:y prior to determining if hydrology indeed e�ists. <br /> Wetland hydrologq may 'be observed as standing water (inundation), or may be observed as <br /> freestanding water within a soiI pit or auger hole (saturation) usuaTly within the upper I2 inches. <br /> This is. what would.be considered primary hydrology indicators. Examination of this indieator <br /> requires rligging a soil pit to a depth`of 16 inches and oliservinb,fhe 1eve1 at whicli water stands <br /> after sufficient time has been allowed for water:fo drain into the hole. The :required time will <br /> vary depending on soil texture. �'hiS ].evel represents the depth to fhe water table.; the depth to <br /> saturated soils will always be nearer the surface due to the capillary fringe. According to the <br /> . Hydrology eriteria`'in 'the 1987 Delineation ivlanual, for�soil s�tur.ation to impact vegetat�on, it <br /> must occur within a major portion of the root zone, typically within 12 inches of the surface. <br /> Oniy one primary indicatar is necessary to make the determina�ion that wetland•hydrology is <br /> present. However; since a single observadon is nat-enough evidence, based on the percentage of <br /> �the grawing season this inundation or saturation. is required, these data are only valid: when - <br /> reviewed while also considerin� the abundance of recent precipitation events or the seas�nal <br /> trend of ciimate when the site visit was made (this may be c�one through review of precipitation <br /> records whece available). In:addition to the primarl� indicators of wetland hydrology, there are <br /> secondary indicators (e.g. oxidized root channels, water-stained leaves, local soil survey data, <br /> FAC-Neueral test), of which two must be present to consider the sample point as having wetland <br /> hydrology. � � <br />