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<br />Water Quality is Influenced
<br />by Geologic Factors
<br />
<br />....
<br />""'
<br />o
<br /><P
<br />
<br />The underlying Ix-dnx:~ in thl.'
<br />Stud~ linil i<, madl.' up of cf)'<;.tJl-
<br />hne and ,eJimcntary rock... (fig. 51.
<br />.--\J!u\'Jum (,(l!l~hllOg of ...m:am.
<br />L.mJ,JiJe. terrace. and gladal
<br />dl..'Plhih i,~ rre~ent in \alley,
<br />throughout lh...' ha~ln. Weatherillg
<br />nf the differl."tll g('\)!llgll: unih
<br />aJlt"c!~ \\<.J!cr-4u<llity comliuun, III
<br />the na...ill. The 'eJilllL'nlary. ign.....
<br />lIU'. ,md melanhlrphic fll..:k" con-
<br />tribute lllah:nal slIdl as ...alt.. and
<br />In\<..'t' l..'!L'lllt'lIh 10 the ,tn:am". HIgh
<br />cun...'L'lltriJti\ln... of ...Ollll.' material....
<br />pankularly salls. art' Jeri\l.'d lrom
<br />thl.' 'l.'Jiml'THary rod...., whkh arc
<br />llHlrt" common in till' Wl'.,tern pari
<br />(If the tw.in. Abn. highly mineral-
<br />i/....d are;h In the upper ha..in con-
<br />In butI.' tract:' 1lll'lal, to ...urfacl' anLl
<br />gn1urll.l \\;ltt'r. Sekllllllll occur... n:l1-
<br />urall~ in the ....hale hl."drp...')... Ilf Ihl."
<br />middle and lu\\er rl."ach('.... Ilf thl."
<br />h"....m and i.... prc"~l'nt in "urfa...'...' and
<br />grtlllllJ \\att"r.ln addition. milll'ral
<br />hot "prings lo...'a1l."d primanly in
<br />.:arhullall' rock unit.... ill lhl' llllrth-
<br />
<br />centra] p~U1 of th...' ba....1Il contrihute
<br />ahout 13 pt'rcent of the tota] ....alt
<br />load at the outlet of tht" LTOL
<br />(U.S. Department of tht" IllIerior.
<br />1995: Butler. 1t,ll}6J.
<br />
<br />Water Quality is Influenced
<br />by Land Use
<br />
<br />The L'COL ....(udy \\'a.... de.....glll'd
<br />tll im e'\tigatt" I,md-lhe intlut"Il....e:....
<br />on water qualit~ i ....I:'l' .'SllIdy CnJl
<br />D..:....ign:. pagt" 21. fllrd("tail....l,
<br />l :rhal1...k,\,t"lopml."llt. mlllmg. and
<br />agricuhllf~t1 \\'t're Ih...' thn.'...' pnmary
<br />land u....e~ lIl\'e:""llgmed in the
<br />L.COL.
<br />Urtlan de\doprnc-nt ha:.... th!.'
<br />pI)!!.'nti..] 10 afk~'llhe quallly of
<br />~urf;.lCe and ground \l ater by add-
<br />m!; nutrient:..... ha....taja. Pl''\th.'ide.....
<br />hyJnk.:arholl..... tr;to.:e ek'lllenh. and
<br />,,;Ills Imlll ruiOl and nonroint
<br />....oun.:........ and by chang-t'" to Ihe nant.
<br />ral Jand"cape. Urhan land u.......~
<br />al"l"oullh for 11111~ I pl'rCellllll till'
<br />L'COL. v. hich ha.... a populaliollllf
<br />;lboUI .~08.000 people (Bureau of
<br />the Cen....u". 19991. B~ Ih...' y....~1r
<br />2020. the populalillll i.... pmjcdt"d tu
<br />innea~e III more than 500.000
<br />
<br />':'1\
<br />~~NATION k,..,......,...,
<br />t:::;:;::J '9.-...ou.....a<r...'ArT"oJflI~1C lot -I '\ \
<br />_ 1Iol<..~~.n.:I"'tnJ""'" 4(fd~ '. )'
<br />D U'>j,,"""'~ ,,,..~/<~'if::.
<br />=~~~ ('''''.,..r---..~'..''IIIl..,_: ~'o-,.-;-<-~,,,
<br />_ ~a"''''-o,''' ,. ...
<br />... 't<t Lt
<br />.,\- '\'< ~
<br />..., "' /
<br />'.< ..". \
<br />.
<br />
<br />
<br />o ~ _:
<br />~
<br />o 1iJ _0 5(' ~,Ll.O'>'E'ERS
<br />
<br />.'j-
<br />~ ~fJ
<br />f
<br />~~.....J
<br />
<br />Figure 5. The bedrock geology Within the UCOL
<br />changes Irom predominately Igneous. metamorphIC.
<br />and volcanic rock types In the eastern and central
<br />areas to predomlnanfly sedlmental)' rock types In the
<br />western areas (Tweto. 1979: Green, 1992)
<br />
<br />I '
<br />...
<br />
<br />...
<br />
<br />
<br />rOPOg'apny 'ep'''se''laU~'' oftt>1I SOulI1em Roc:~y
<br />Mouma"'.s IPnoIOQraptlbyJef1reyOe&COI1.
<br />U,S GeoIogClI Su~~ey I
<br />
<br />(Colorado DI.'partlllcIlt (If Local
<br />Affair~. ~O(~)l. RI.'....idt"nt populafion
<br />innea.,e.... dOllot n:tle..:t Jevclop-
<br />melH and '(:[\I..:e.... for vacation
<br />ProlX'rtlc". Tht"re are large~ea~onal
<br />t1u.:luaIHlIh 111 llonn:.,id...'nt popula.
<br />lion.... wilhin till' b~l....in due 10 r!.'crc-
<br />atinnal ;Il'II\'ilil's. During thc 1996-
<br />In ....J...i ....ea.,on. IIll)rC than 9 million
<br />.,kler., \'j..itt'd ....ki area.. within the
<br />UCOL (Co]{lrado Ski Country
<br />USA. 20()(1/. Elfe...'I., on v.'alt"r qual,
<br />ll~ from urban dcvelopment are
<br />e\'id""n! in :-'OI11C comlllullltie:-. in thc
<br />SI'uthl'm R{l~.:)...y .\Iounlaim.
<br />
<br />L(I\J...' and pl;tccr mining. a his-
<br />lori....al]y .,ig-lIIlil.alH land u:-.e in thl."
<br />l 'COL. Wi!.... COlllllllln throughoul
<br />th.... SI)ulhem Ro.:ky MOlllllaln'\.
<br />Stream., ;HlJ grounJ watl:r have
<br />bl'l'll afft'':fl'd by point-sour...,C' mine
<br />Ji....charg~ and nl\Jlpoillt-~our....C' run.
<br />Illl fmlllmined ar....a~.
<br />
<br />Ar!.'a... (If irHen"i\'t' agriculture arc
<br />lo....ated primarily IIllhe Colorado
<br />Plaleau. Salinity. "edimt"1l1. nutri-
<br />t"nts. pcqjcide". and ~e1enium and
<br />olher trae!.' element.... arc common
<br />con....tltuent.. in agricultural runoff.
<br />The~e ....l)J]....tllU~nl.... ~..all ha\'C' an
<br />advt"r"l." erred on the "urCI.:e waler.
<br />ground watl."r. and aquatic life.
<br />
<br />IntmJudion 10 the L~p{k'r C"loradl) Ri\ef BaslIl 5
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