|
<br />I'
<br />I
<br />
<br />II. STUDY AREA
<br />
<br />A,
<br />
<br />Location
<br />
<br />Precipitation
<br />The a~erage annua 1 prec i pi tat i on for the Montrose ~ici nity is
<br />approximately 9 inches (rain and snow). The hydrologic eovirOMent is
<br />moderated by the Uncompahgre Plateau to the southwest of Montros e. The
<br />effect of the Uncompahgre Plateau on the local weather pattern places
<br />Montrose and the Uncompahgre Valley in a precipitation "shadow" in the
<br />winter. This condition also limits the influx of lI~ist air 1I1asses lnto
<br />the valley during the summer. The ~S1Jlt is d relatively low surrmer
<br />and winter precipitatior1 tiithin the valley. Figure 11-1 shows the
<br />location of the geographic features affecting the weather patter ns;n
<br />the vicinity of ~ontrose.
<br />
<br />The City of Montrose is located on the Colorado west slope within
<br />the UnCOI.lpahgre River Basin, approxilMtely 25 miles upstream of the
<br />confl uence of the U ncor;~lahgre Ri ~er wi th the Gunni son Ri vcr. Mont rose
<br />also lies approxiJllately 60 mile:; south of Grand Jundion dnd the
<br />confluence of the Gunnison and Colorado Rivers. Figure 11-1 shows
<br />~ontrose and vicinity.
<br />
<br />B. Major Basin Characteristics
<br />Study Streams
<br />The three study streams: Cedar Cree~, Montrose Arroyo, and Dry
<br />Cedar Cree~ either flow through or near the City of Montrose, Colorado.
<br />Montrose Arroyo flows through the center of Montrose, and is tributary
<br />to Cedar Cree~. Both Cedar Cree~ and Cry Cedar Creek are tributary to
<br />the Uncornpahgre River. Cedar Creek also flows through the City, while
<br />Dry Cedar Creek circumvents the City near its southern boun<1ary (s ee
<br />Figure 11-2),
<br />
<br />Soils
<br />-
<br />
<br />Four general soil associations predominate in the study watershed.
<br />1nthe lowerba,in, the Billing,-Christianburg association is Inadeup
<br />of deep, nearly level and gently sloping, finetomo<1eratelyfinetex-
<br />tured soils on alluvial fdns, flood plains, and terraces. TheChipeta
<br />Persayoassociation is constituted of snall ow, nearly level tohl1ly
<br />fi ne to rnoderate ly fi ne ly textured soil s deri ~ed from ,na 1 e or .
<br />lTIudstone.
<br />
<br />The headwaters of Cedar Creek originate in the Ci""'<lrronRidge
<br />area at an elevation of approximately 9,400 feet. The creek flow, then
<br />Tllo generally westerly direction, through the northeastern por tionof
<br />the City of Montrose to the Uncompahgre River, the downstrealn 1 imitof
<br />this study (approxir.idtely 3 miles northwest of Mont~ose). The dra inage
<br />a rea encompassed is approx i,~ate ly 56 square ,~i1 es (see Fi gure I I -2 -
<br />"SasinandRainfall IsopluvialMap" "nd Table 11-1 for dralnajJe dred of
<br />suo-basins and ~~jor basins).
<br />The upper reaches nf Montrose Arroyo lie apilroxi,nately 7 miles
<br />",~st "f Montrose ~t an e1 evat ion of approxiblately 7,500 feet. The
<br />stream flows ina northwesterly direction through ttleCity of Mon trose
<br />to its confluence with Cedar Creek, irmledidtelynorthwestofthecity.
<br />The st ream's dra i nage area is approximately 17,8 s<judre ,~i 1 es.
<br />The upper "edches of Dry Cedar Creek lie approximately 10 miles
<br />southeast of Montrose at an elevation of approximately 9,400 fee t. The
<br />streal.l flows in a generally norUiwesterly direction to its confluence
<br />with the Uncompahgre ~i ver one mile south of the City_ The stream
<br />drains an area comprising approximately 21.9 square rniles.
<br />
<br />The Bostwick-Cerra aSsocidtion is found ill the upper baSin areas.
<br />It is composed of deep, gently sloping, moderately fine textured soils
<br />on alluvial fans and valley side slopes. The rock outcrop-
<br />Travessillaassociation is composed of bare rock outcrop and snall ow,
<br />rolling to steep r.:Oderate]y coars~ textured soi 1 s found on hill s,
<br />ridges, and sides of IIlli!sas.
<br />
<br />Vegetation
<br />
<br />Alongr"-ich of the rnaJor draina(jes, the '1egetive cover consists 0 f
<br />eJ(trel"ely dense, cedar, juni per forest and sa~ebrush, WIth acco.npanylng
<br />hedvydebris. The land in the upper basin is covered with moderate to
<br />dense growths of brush with a ndtive \lrass understory. The remaining
<br />areas in the lower baSin are primari1y the "Badlands" areas of steeper
<br />slopes wi th IIIi n fm" 1 ground cover. The vegetat i 0" tha~ does ex i,t is
<br />composed basically of various nathe grasses and forbs, with occa-
<br />sional sage. The vegetation in the urbanized areas is composed mainly
<br />of trees ilnd ldwns, (whichtendtoredw:;erunoffduetotheusuallllini-
<br />Inal slope and the water absorption).
<br />
<br />TABLE 11-1
<br />MAJOR DRAINAGE BASIN CHARACTERISTICS
<br />
<br />Land Use
<br />
<br />Strea,n
<br />
<br /> Basin
<br />Elevation (Ft. MSL) Length r,~erage Area
<br />Headwaters Confluence U'li) Slope (') 12.'-1' Mi.)
<br />9400 5700 24.S 2.H 56.3
<br />7500 575(: 1C.6 3,1 l7.S
<br />'1400 5800 14.3 4.7 21.9
<br /> .10-
<br />
<br />In the non-urbanized areas of the basins, land use is devoted to
<br />either irrigated crop land {i.e., alfalfa,corll,maize, or barley) or
<br />grazing land,orthe land ls not used Jt all.
<br />
<br />Cedar Creek
<br />"1olltroseJl_rrOjo
<br />Dry Cedar Cn!ek
<br />
<br />'. i t h i n the urUdlli zed por~ i on of tile bas i ns, tile non.;e~etated
<br />d r~as dre genera 11;; covered by buil dings or pa~e<: aredS (wh i eh f,fe.
<br />
<br />-11-
<br />
|