WSP06433

• File Number: 8273.300
• Description: Colorado River Basin Salinity Control - Federal Agency Reports - USGS
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/2000
• Author: USGS
• Title: Water Quality in the Upper Colorado River Basin - Colorado 1996-98
• Water Supply Pro - Doc Type: Report/Study

Colorado Plateau and the igneou,~
m~t;lmorphic geology uf the South-
(.'rn Rody .\ 1001ll1:llm. Agncul-
tural return I\em ~ abo ,:ontrihu(c 10
lhl.' greater ...edimenl ('t'nCl'nlration,
mea..ured al the agricultural ..ite,

The rderence "itc In Ihe Cull 1-
radl) Plaleau a)..,o had elevated ...edi-
menl cnnC('lllr:llion" .-\ny rain or
../lImn1l'1t t'\('nt in lhe...e area... tend...
lu "'llb~lantially inCfe;l,e lhe ,l'di-
llll'lH cnfh.:l'nlratiUlh Ill' ,tream, .:md
mer... hl'l.:au...e 01 till' high erodlhil.
ity oflhe "'01)..,

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Figure 15, Suspended-sediment
concentrations were greatest In the
agricultural areas of tt1e Colorado
Plateau.

Sed,m-ent and...'a1e'-quality sampling at l'leoo
WaSh ,Photograph b)' ~'~'r'\an Spah. US GeoIog'
oca1S"rveyl

BIOLOGICAL MEASURES INDICATE
THAT UCOl AGRICULTURAL AND
COLORADO PLATEAU MIXED LAND-
USE SITES RANK AMONG THE MORE
DEGRADED SITES NATIONAllY

The ck\':lled nutrient and sediment concentr.llions found in the agricul-
tural and surrounding areas of the Colorado Plateau help to explain the
prevalence of more tolerant biological species. Algal. invertebrate, and fish
communities in the Colorado Plateau generally consis.t of species more tol~
erant 10 nutrients and sediment... The..c result III hight'r degradation rank.
ing~ for all three biological measures. The biological measures in lhe
Colorado Plateau indicate that agricultural and mixed land-use siles in the
VCOL are abow the national average in teml.. of degradation, These rank~
ings compare VCOL agricultur.tl Sill''' lO mher Nt\\VQA agriL'ultural sites
and UCOL mixed land-use sites to other NA WQA mixed land-use sites
narionally.

Biological indicator
Site name Algal Invertebrate Fish
status status status
-
Dry Creek ::::J . .
(agriculluralsite)
Reed Wash . . .
(agricultural site)
Colorado River near Cameo . ....J 0
(Colorado Plateau mixed land use)
Gunnison River near Grand Junction . . .
(Colorado Plateau mi~ed land use)
Colorado River at State line . . 0
(CoIOJado Plateau mixed land use)
EXPlANATION
r~ Middle 50 percenl nationally
. Highesl25 percent nationally, most degraded sites

Explanation of Biological Rankings
llIc th~ 5Clected biological indicalors re~pond to changes in stream deg.ra-
dation. Degradation can resull from a \'ariet}' of faeton; truJt IlR-.dify habitat or
other environmental feature'S such as land use. watl"r chemi~lr)', and flow. Algal
status focuses on the changes in the percentage of eenam algae in respon$C 10
iocreasing sillation and often is positivcl}' corrclalL>d with higher nutrient
con.:cnlration~ 1n man)' regions ofthc Nation. In\'cncDrate status is the a\'erage
of II in\ertd:lrate memcs that summarize changes in richnl"ss, IOleran~,
trophic cl;'nJitions. and dominance associated WIth ~aler-<!ualit)' degradation.
Fisb ~talUS focuses on changes in the percentage of tolerant fi~h s~cics thai
make up the 10lal numl>erof fi~h.. "Tolcralll"' fish are reponl"d to thrhe in
,kg:raded waterquah~. For all indicator<o. higher \ialuc~ indicale degraded ~ atef"
quality.

.\Iajor Finding.. 19