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# <br /> I <br /> � <br /> i <br /> � _. <br /> The definition of appropriate hydrology accordin� to the 1987 �[anual includes t�vo important <br /> terms that must be clari�ed. First, the clefinition of a growin� season is needed. The growing <br /> season is defined in the 1987 Manual as: ",..the portion ot the year wlien soil ternperature <br /> (measured L9.7 inches below the surface) is above biological zero (S' C or�4 i' F)." According to <br /> tlte 1937 �(anual tt�is period of time can be appcoYimated by using the "stac�ting aad ending dat�s <br /> for the growing season based on a 28" F air te�nperature tEireshald at a frequency of 5 years in <br /> 10." Based on this cietinition the jro�ving season ran�es appi•o�imately 1 b0 days to 180 days in <br /> tl�e Niinneapolis/St. Paul metropolitan area (160 in tlie northern suburbs and greater to the south). <br /> Therefore, the required inundation or saturation to the stirface for 5% of the gro�ving season <br /> would be 8 or 9 consecutive days that ground �vater would need to be at tl;e surface or saturated <br />� to the sucface. <br /> E The second term in tlie appropriate hydrology detinition from tlle abave para;raph to be clarified <br />� <br />; � is �`in most years". This means in 5 of iQ years hydrology nu�st eYist witl�in a "jurisdictional <br />{ wetland" for the 8 or 9 consecutive days of the gro��ing season. T1�is«ieans that one o6servation <br />� date or even one whole year 4vorth of detailed hydrolo;y data may be deemed insufficient to <br /> i determine if appropriate hydrology eYists at a given location. In the event that precipitation <br />; events accu�nulate to above or be(o�v normai diiring just prior to a site visit or during a more <br />� intensive hydrolo�y study, the daEa may be confounded 6y non-norma! circumstances and may <br /> be considered outside the bounds of "most years". Icieally, both ac�tecedent soil moisture <br />' concfitions and precipitation would 6e normal during all delineations. Ho�vever, this is not a <br /> realistic impc•ession of climate. Therefore, pcimary indicators of hydrology must be revie�ved <br /> �vith scrutiny prior to detei7nining iFhydc�ology indeed e:cists. <br />� Wetland hydrology may be observed as standing �vater (inundation), or may be observed as <br />� freestanding �vater within a soil pit or auger hole (saturation) usuaily�vithin the upper [2 incites. <br />� This is what would be consideeec! primary hydrology indicators. E�camination of this indicator <br />; requires digging a soil pit to a depth of l6 inches and observing the (evel at whict� �vater stands <br /> after stifficient time has been allowed for �vater to drain into the hole. The required time �vill <br /> vary depending on soil textuce. This level represents the depEh to dze �vater table; the deptli to <br />` saturated soils will al�vays be nearer the surface due to the capillary fringe. Accordinb to the <br /> Hydrology criteria in the 1987 Delineation Manual, for soi! saEuration to impact vegetation, it <br /> ' must occur �vithin a majoc poction of the root zone, typically �vithin 12 inches of the surface. <br /> Only oite primary indicator is necessary to make the determination that wetland hydrology is <br />� present. However, since a single observation is not enough evidence, based on the percentage of <br />� tl�e growing seasan tl�is in«ndation or saturation is required, these data are only valid when <br /> revie�ved while also considering the abE�ndance of recent pcecipitation events or the seasonal <br /> trend of climate �vhen the site visit was made {this may be done through review of precipitation <br />; records where �vailable). In addition to the primary indicztors oF wetland hydrology, there are <br />; secondary indicators (e,g, oridized root channels, wAter-stained leaves, local soil survey data, <br /> FAC-Ne�Etra) test), of which hvo must be present to consider the sample point as having wetiand <br /> hydrology. <br /> , A-2 <br /> i <br />