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The definition of appropriate hydrology according to the 1987 Manual includes two important <br /> terms that must be clarified. First, the definition of a growing season is needed. The growing <br /> season is defined in t4�e 1987 Manual as: "...tlle portion of tlie year �vhen soil temperature <br /> {measured l 9J inches below the surface) is above biological zero (5` C or�1° F)." According to <br /> the 1987 Manual this period of time can be approsimated by using the "starting and ending dates <br /> for the growing season based on a 28° F air temperature th►•eshotd at a frequency of 5 years in <br /> 10," Based on this detinition the growing season ranges app��oximately l60 days to 180 days in <br /> the Minneapolis/St. Paul metropofitan area (160 in the nocrthern suburhs and greater to the south). <br /> Thecefore, the required inundation or saturation to the surface for 5% of the growing season <br /> would be 8 or 9 consecutive days that ground water would need to be at tlie surf'ace or saturated <br /> to the surface. <br /> The second term in the appropriate hydrology definition from tlie above paragraph to be clarified <br /> is "in most yeaes". This means in 5 of 10 years hydrology must exist within a "jurisdictiona( <br /> wetland" for the 8 or 9 consecutive days of the growing season. This means that one observation <br /> date or even one whole year worth of detailed hydrology data may be deemed insufficient to <br /> detertnine if appropriate hydrology exists at a given location. In the event tliat precipitation <br /> events accumu(ate to above or below normal during just prior to a site visit or during a more <br /> intensive hydralogy study, the data may be confounded by non-normal circumstances and may <br /> be considered outside the boiinds of "most yeat•s". Ideally, both antecedettt soil t�toisture <br /> conditions and precipitation wot�(d be normal during all delineations. However, this is not a <br /> realistic impression af climate. Therefore, primary indicators of hydrology must be reviewed <br /> with scrutiny prior to detetmining if hydrology indeed exists. ' <br /> Wetland hydrology may be observed as standing water (inundatian), or may be observed as <br /> freestanding water within a soil pit or auger hole (saturation) usually �vithin the upper l2 inches. <br /> This is what would be considered primary hydrology indicators. Examination of this indicator ', <br /> requires digging a soil pit to a deptk� of 16 inches and obsetving the level at which water stands ' <br /> after sufficient time has been allowed for water to drain into the hole. The required time will <br /> vary depending on soil texture. This level represents the depth to the water table; the depth ro <br /> saturated soils �vilt always be nearer the surface due to the capillary fringe. According to the ' <br /> Hydrology criteria in the 1987 Delineation Manual, for soil saturation to impact vegetation, it , <br /> must occ�iE• within a major portion of the root zone, typically within 12 inches of the surface. ' <br /> Only one primary indicator is necessary to make the determination that �vetland hydrology is <br /> present. Howevec, since a single observation is n�t enough evidence, based on the percentage of <br /> the growing season this inundatian oi• saturation is required, these data are on(y valid when <br /> reviewed while also considering the abundance of recent precipitation events or the seasonal ' <br /> trend of climate when the site visit was made (this may be done thro��gh review of precipitation ' <br /> records where availabie}, [n addition to the primary indicators of�vetland hydrology, there ace <br /> secondary indicators (e.g. oxidized i•oot channels, water-stained leaves, Loca! soif survey data, <br /> FAC-Neu[ral test), of which two must be p�•esent to consider the sampfe point as having wetland <br /> hydrology. <br /> � <br /> , <br /> A-2 <br /> � <br /> i <br /> i <br /> I' <br />