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<br />,>i,,~.. ..' BIOLOGICAL MEASURES INDICATE THAT URBAN SITES IN <br />THE UCOL ARE LESS DEGRADED WHEN COMPARED TO <br />OTHER URBAN SITES NATIONALLY <br /> <br />\\-'ithin the UCOL. there are changes in the algal and invertebrate communities in areas of urban develop. <br />ment. Algal biovolume (amount of algae) and rnidge'i (in~ecls considered more tolerant of degraded conditions.) <br />were gre;.l.ter al siles with urban development than siles with little urnan development. However. with the exccp. <br />lion of algal statu.. althe Gore Creek site. biological indices for lieOL urban sites are in the lowt.'~t 25 percent <br />of urban sites from other NAWQA Study Units. The Gore Creek watershed is more urbanized than the East <br />River watershed. and the changes in the algal community reflect increased nutnelll (.'oncclllrations at this site. <br />making il more typical of other urban ..iles nationally. The invertebrate and fish communities .Ire rankeu among <br />lhe least degraded nationally al both UeOL urb.:m sites. <br /> <br />.... <br />. <br />.... <br />N <br /> <br />Site name <br /> <br />---~ <br /> <br />Colorado River be/ow Baker Gulch <br />(referencesne) <br />East River <br />(area of urban development) <br />Gore Creek <br />(area of urban development) <br />EXPLANATION <br /> <br />'J <br />,:=]. <br /> <br />Biological indicators <br />Algal Invertebrate Fish <br />status status status <br /> <br />:J <br />W1 <br />L1 <br /> <br />as <br />o <br />~ <br /> <br />IJ <br />D <br />~ <br /> <br />Lowest 25 percent nationally, least degraded siles <br /> <br />Middle 50 percent nationally <br /> <br />Gmunu w:ner \\ ao; ~alllpleu fnlOl <br />,halh,\\ 1l1llnilOring well... in tht' <br />Cfl'''iCJ Butte. (;unni...(lll, ST!n'r- <br />Ihllrnc. Vail. <lnJ Winter P:lrll <br />Fnhcr arc;!,'" (lig:. 61. D'lmc"'lic <br />Ihl1U_"chll]U ,IIlJ pri\;J.lc) and public <br />,uppl~ JrinKing-\\ah:r \\1,.'11... ,If \ar- <br />IOU' depth... werc ab" ~Jmpkd III <br />urb;ln arl'i1~ throughoul lht' SOlHh- <br />em Rod.~ .\lollntaill~. <br /> <br />'smUt' ~rullnd-\\att'r ~ample... <br />l'ul!l'l'h.d iUllrhan arpa~ t'on. <br />(:tined dl'\all'd le\t'l.; or nitnJle, <br />:\"utricnt~ in ground waler can (Irig, <br />in.!.l!;' fWIll \:irillU, natural ,nun:!;''- <br />('Udl J'- allll(l...phcrie uej:l(hllil1n or <br /> <br />Explanation of Biological Aankings <br />The three selected biological indic'ltors R'~pond 10 <br />,'hangc~ in stream de~r'ldati\ln, [~gradation can <br />resull from a variet) of factors thaI modif)' habitat or <br />orner en\'imnmemal fe'ltures stich as land U&e. waler <br />chemisEl). and Iln...... Algalslatus ftX.useson the <br />changl:'s in Ihe percenlage of cl.naln algae in <br />rt'sponse to incre;lsing siltation and often is positi\"e1y <br />correlaTed with higher nutriem conCentrations in <br />many rej,';ion.s of the Nalion. Invenebrato: slatus is tbe <br />average of II invenebrate melrics that summarize <br />changes in richness. tolerance, trophic cnnditions. <br />and dominan..:-e associated wilh w3tl"r-(juality degra- <br />dation, Fish SlaWs foc-usei on changes in the percent- <br />age;' ofll11crant fish spede~ that make up the total <br />number of fish, 'Toleram" fish are reponed 10 thnve <br />in degraded .....ater quality. For all indicators. higher <br />values jndic'lle degraded W'ller quality. <br /> <br />Ji",-"lulinn of gl'{llll,gi.... rnatcri,tbJ. <br />hu" l'\"cr. dt"\aleJ concentratlon'- In <br />ground \\'3lt'r are IlfIen rclatt'u In <br />human actlvitiC',. ,uc!l a, eftlul'nl <br />(film "'t'ptlC ~y...tem.' or Ihl.' applica- <br />tl{ln 111' fenilizcr'-. :\ilralc l"lllll"L'n- <br />[rat](ll1'\ greall'r than the USEr:\. <br />\l:t\.imum Cllntammam LL'\cl <br />I :-'lCLl drinking-water ~lanuarJ (If <br />10 mglL lU.S, EIl\.iwnml'ntal Pro- <br />IcetlOn Agency. 19961 were <br />Jete...ted in onc ,ample collected <br />from a ,ha]I\)\\ 1l1llnilonng wcll in <br />;lll urb;1Il arca but In n{lne of the <br />urinking-"':lIer welk :\"utnt'1l( l:on- <br />('I,.'ntratlOlh in undc\eJopeu arca, <br /> <br />S Wall'r QualH~ III the Cppt'r Coloradll Rin'r Ba..in <br /> <br />hklermilll'd from d;lIa frum lhl' <br />2n ~..\\\"Q:\ StuJy Unit.. that <br />!:tl'gan III I t)l.j II indkatl' a natlOllal <br />hat:!.;ground nmcentra[illn fnr <br />mlratt' of 2,0 mglL (U.S. Geolngi+ <br />,:al Sun'ey. 19lNl. 'DIe unucwl- <br />{'I'leU art'a.. art' l.OIl..ld..'reu 10 he <br />lllinill1JII~ affected hy agncuhllrt~. <br />urban ue\'eh1pmelll. or a.....neiated <br />bnu u'e,. T\\'elll~ pt'rceIH of the <br />'-ample" wlkt:led from lllonilOring <br />\\.ell~ (and nont' nf the .;ample.. c,,]- <br />k''::!l..J from dnn!.;mgow:uer \\'ell~j <br />,:ontaineJ nitrale eonl'cntrJtion~ <br />greatt'r thall 2.0 mg/L, The...e tind- <br />ing' Illdi..-;lle thai p..mlOll~ llf'the <br />