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<br />1.2._ Physiography and l;eolcry
<br />The prnj ect areas are located in the Canyonlands section of
<br />the Colorado Plateau physiographic prcvince {Femten:an 1931). General?y,
<br />this sactiorr is ct:aracterized by elevated plateaus, hogbacks, lower
<br />plateaus, laccolithic mountains, and deep canyons (Hunt 1°56:2).
<br />Locally, the project areas are found on the vrestern flank cf the
<br />Uncompahgre Plateau, a black of Precamhrian rocks overlain by tlesozoic
<br />sediwentary layers and twice uplifted (Pennsylvanian and late Tertiary
<br />periods) (Chronic 1980:305). Local topography consists of rarrew,
<br />flat-L'cpped ric!ges that are dissected by southwest flowing intermittent
<br />drain:. res (Figure 2). Clevatinns vary from a low of 5647 ft. (1721 m)
<br />in the scuthvrast corner of Tract Ii, to 5800 ft. (1768 n:) in the
<br />rrartlreast corner of Tract I; thus, local relief is about i50 feet (47
<br />rn). Smaller drainages in the area flaw into larger intermittent
<br />drainayes such as Tuttle Draw and Calamity Draw, which in turn empty
<br />into the °_an liiyvel fiiver, the largest waterway in the area.
<br />. Tyre local area is generel?y. underlain by the Cretaceous ace Dakota
<br />Sandstorm and Burro Canyon Forr..ation (lJillianrs 19f.4). The forcer is a
<br />yellovtish-brottn and gray euartzitic and conglon:oratic sandstone with
<br />interbedded Dray to black carbonacecus non+narine shale, while the latter
<br />is a white, gray, and tight brov:n fluvial sandstone and conglerrerate
<br />that is interbedded with siitstone, shale, rwdstorre, anC limestone.
<br />These fnr•raaticns are overlain in the area by scroll, disccntinuous
<br />• patches or undifferentiated Quaternary alluvium and aeolfan Ceposits,
<br />urostly wind-deposited silts and sands (Williars 1964). These patches
<br />correspond closely to those arias locally referred to as "parks" (e.g.,
<br />First Park, Second ('ark, and Spradlin Park), twhich also happen to be
<br />those areas drat are presently cultivated. Trott II is located on the
<br />ncrther•n edge of First Park, v.~hiie Tract I is more directly unaer•lain by
<br />the Dakcta Sandstone and Duero Canyon Formations.
<br />1.2.3 Biuta
<br />The project areas area covered by one or the otfrer• of the
<br />fo'.lovring plant conmunitics: pinyon-juniper woodland, sagebrush,
<br />reseeded mine areas, and cultivated/grazing. The first three com-
<br />munities are principally found in Tract I, while most of Tract li-is
<br />under cultivation cr used for grazing. The pinyon-juniper woodland
<br />Car+nrunity is composed principally of juniper trees, with an under-story
<br />of big sagebrush, black sagebrush, snakeweed, gall eta, blue grams, and
<br />Indian ricearass; a Few widely scattered pinyon pine trees are also
<br />found. T. he sagebrush community consists of biy sagebrush, black sage-
<br />brush, saltbush, ce.lleta, Indian riceorass, cheatorass, blue grams, and
<br />scattered cacti. The bottma~ of same of the larger drainages rn Tract
<br />arc covered with dense Litickets of cattail. Strip r:rinrd areas red olJ
<br />roads in Tract [ have recently been reclaimed and reseeded with native
<br />species such as Indian ricegrass and blue grams. F?though the majority
<br />of Tract ![ has been cultivated, grazed, or otherwise denud2tl of native
<br />vegetation, there are a few small, scattered areas where the vegetatier.
<br />appears to be rrlariccly pristine. Colleel.ivra y, these. unalt.~rrd areas
<br />eorrpri•.c nn n•-ire than abutet 'LU pureent of Tr:.c.t. [i.
<br />•
<br />(Revised July 2006) Attachment 2.04.4-1-12
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