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The Wartn Series (72) occurs on a middle terrace between the upper Arvada and lower
<br />Torrifluvents terraces. The sandy loam soil characteristics and vegetation documented in the Soil
<br />Survey aze not consistent with those observed on site. Soils within this portion of the site have a
<br />high clay component and are poorly drained. This area of the site is dominated by planted
<br />pasture grasses, salt grass, and abundant weeds. This area has been used as flood irrigated
<br />pasture for a long period of time.
<br />The Tomfluvent Series {65) is directly correlated with the Colorado River floodplain, the lowest
<br />terrace located along the river. The silty clay and alluvial soil characteristics and vegetation
<br />documented in the Soil Survey are consistent with those observed on site. This area of the site is
<br />dominated by a ripazian-wetland plant community and has been fenced to preclude cattle and
<br />grazing.
<br />All three of these soil types appear on the Colorado List of Hydric Soils (USDA, 2006). These
<br />soils and especially the Wann Series occurring on site are influenced by a relatively high
<br />groundwater table and are used during the growing season to produce forage for cattle.
<br />Representative soil borings in uplands and pasture areas up slope from low-lying or excavated
<br />areas identified within the proposed mine area generally had high soil hue, value, and chroma.
<br />Test pits 1, 4, 7, 11, 14, 15 and 18 as documented in the attached data sheets represent upland
<br />(negative data) sites where upland soil characteristics prevail. Test pit 7 maintains hydric soil
<br />characteristics due to an active water table, but does not meet hydrophytic vegetation
<br />requirements. Representative soil borings in wetlands, along river banks, and in low-lying or
<br />excavated areas generally had low soil hue, value, and chroma with and with out mottling. Test
<br />pits 5, 8, 9, 12, 13, 16, 17, 19 and 20 as documented in the attached data sheets represent wetland
<br />(positive data) sites where hydric soils are prevalent. Test pits 2, 3, 6, and 10 are wetland sites,
<br />and will not be affected by the proposed activity. Therefore, these data sheets are not provided.
<br />Vegetation
<br />Subsequent to a delineation performed in October, 2005, during a site visit with the USACE on
<br />Apri120, 2006, the USACE requested additional information and plant identification to
<br />determine the presence or absence of hydrophytic vegetation in and around Areas 7 and 8 as
<br />these areas were disturbed by heavy cattle grazing, After a minimum thirty to forty-five day
<br />cattle removaUrest period, these areas, the Colorado River banks and one island were reassessed
<br />on May 26, 2006. The following information summarizes the findings from the October, 2005
<br />and May, 2006 delineations.
<br />Dominant vegetation in grazed portions of the site (i.e., middle terrace) where mine operations
<br />are proposed and internal areas of a Colorado River island consist primazily of rangeland and
<br />unpalatable species such as saltgrass, slender wheatgrass, and bottlebrush squirreltail. Please note
<br />that saltgrass is prevalent, but does not function as wetland vegetation on this site. Noxious
<br />weeds and invasive grasses aze prevalent due to overgrazing. Pastures and uplands are in very
<br />poor condition. Attached data sheets for Test Pits 1, 4, 7, 11, 14, 15 and 18 represent upland
<br />sites where upland vegetation is dominant
<br />Dominant herbaceous vegetation in wet ditches, channels, swales, river banks and depression
<br />areas within the proposed mine and conveyor route limits consists primarily of saltgrass, reed
<br />canary grass, Baltic rush, and to a lesser extent, common three-squaze bulrush . Wetland/riparian
<br />
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