National Water-Quality Assessment U.S. Department of the Interior - U.S. Geologi

Upper Colorado River Basin NAWQA

 

FACTSHEET

Introduction

The sampling design of the National Water-Quality Assessment

(NAWQA) program emphasizes a multidisciplinary approach using

physical, chemical, and biological information to provide multiple

lines of evidence to describe water-quality conditions. The composition of fish communities at stream sites representing selected environmental settings is one characteristic assessed as part of the NAWQA

program (Meador and others, 1993a). The presence and abundance of

fish species can be related to water chemistry, physical habitat, and

land-use activities to provide a more complete picture of water quality

across a river basin.

Although fish communities may have a high degree of natural

variability, they can be useful indicators of ecosystem health (Moyle,

1994). Berkman and others (1986) recommended fish be given consideration in biological water-quality monitoring of streams because they

generally are perceived by the public to be ecologically relevant, and

they are directly related to legislative mandates because of human

health and endangered species concerns. This fact sheet summarizes

the results of an August 1996 fish survey and relates these results

to natural and human factors that affect water quality and physical

habitat in the Upper Colorado River Basin (UCOL) study unit in

Colorado.

Description of Study Unit

The UCOL study unit includes about 17,800 square 

(fig. 1), which varies greatly in climate, geology, topogra

hydrology. The primary river, the Colorado River, origin

mountains of central Colorado and flows 230 miles south

Utah, dropping about 10,000 feet in elevation. The majo

include the Blue, Eagle, Roaring Fork, and Gunnison Riv

1994).

The UCOL study unit is divided almost equally into 

graphic provinces: the Southern Rocky Mountains in the 

high-elevation part and the Colorado Plateau in the west

elevation part (Apodaca and others, 1996). Stream habita

from cool, clear, and forested headwater streams that hav

bedrock with high gradients and coarse substrates in the 

Rocky Mountains, to warm, sluggish, less vegetated, and 

streams that have low gradients and fine substrates in the 

Plateau. Stream habitat and water quality reflect the extr

ences in elevation, climate, vegetation, and geology acro

study unit, which have an associated effect on fish comm

composition.

Effects of Water Quality and Habitat on Composition of Fish Commu

in the Upper Colorado River Basin

—Jeffrey R. Deacon and Scott V. Mize

Natural and human factors in the Upper Colorado River Basin result in differences in water quality an

habitat. Fish community composition is associated with differences in water temperature, concentratio

dissolved solids and suspended sediment, elevation, habitat, and land use.

Brown trout (typical invertivore species present in the Southern

Rocky Mountains province).

Typical stream setting in the Southern Rocky Mountain
Fish Communities in the

Upper Colorado River Basin

A fish community is a group of fish that inhabit the same area of a

stream and interact with each other. The structure of a fish community

is determined by the species present, their relative abundances, their

life stages and size distributions, and their distributions in space and

time (Meador and others, 1993a). Fish communities were assessed at

15 sites throughout the UCOL in August 1996 (fig. 1; table 1). Seven

sites represent drainage basins with specific land uses, such as agriculture, mining, and urban/recreation, and six sites have drainage basins

with multiple land uses (Spahr and others, 1996). Two sites represent

background conditions and generally are unaffected by human activities. Personnel from the U.S. Fish and Wildlife Service assisted with

fish collection. Collection was done by electroshocking a stream reach

450 to 650 feet in length at wadeable sites and 1,500 to 3,000 feet in

length at nonwadeable sites. The nonwadeable sites were sampled

using fish-shocking equipment from a boat. Fish were identified,

measured, weighed, and released back to the stream. A single reach of

stream was sampled at each site, except for three sites where multiplereach sampling was conducted. Multiple-reach sampling consisted of

electroshocking two additional reaches at a site that had similar geomorphic channel units (that is, riffles, pools, and runs) and were adjacent to the primary reach. Multiple-reach sampling was done to

determine variability of abundances and types of fish species within a

stream segment 1 to 2 miles long. Type, trophic class, and relative

abundance of native and nonnative fish species are listed in table 2.

Fish communities can have a high degree of variability because

of geographic distribution of species, human modifications of streams

and the surrounding landscape, presence or absence of nonnative

species, and natural effects. Natural variability in fish communities can

be attributed to differences in elevation, water temperature, physical

habitat, water quality, and other important characteristics of the environmental setting.

Low abundances and types of fish species may be a re

quality and habitat that can be affected by the surrounding 

No fish were present at French Gulch (site 2) and Dry For

(fig. 1; tables 1 and 2). Site 2 is a mining site, and cutthroa

present upstream from the mined area (Jay Skinner, Color

of Wildlife, oral commun., 1997); but fish are not present 

from the mined area to the mouth of the stream. High diss

concentrations and low streamflow are associated with site 

ground site. Absence of fish at site 10 might be attributed 

streamflow and associated habitat than to water-quality con

abundance and type of fish species at the Blue River site (s

ing land-use site, were low compared to other sites in the 

Rocky Mountains province. Lower abundances and fewer 

present at the Reed Wash site (site 14), an agricultural lan

compared to the other sites in the Colorado Plateau provin

Eleven of the 13 sites with fish contained native and nonna

Only nonnative species were present at two sites, site 3 an

Gunnison River below Gunnison Tunnel (site 7). Site 3 is 

from a mined area, and site 7 is downstream from a series 

The multiple-reach sites are designated as sites A, B, 

Baker (site 1), Gore (site 4), and Dry Creek (site 12) in tab

greatest difference in the number of fish species among th

pled reaches occurred at site 12, where the number ranged 

among sampling reaches. The greatest difference in the tot

fish occurred at site 4, where abundances ranged from 115 

among sampling reaches.

COLORADO

PLATEAU

SOUTHERN

ROCKY

MOUNTAINS

UPPER COLORADO RIVER

BASIN STUDY UNIT

EXPLANATION

FISH COMMUNITY SAMPLING LOCATION

 AND NUMBER—Color refers to sites located

 in tables 1 and 2

0

0 20 40 KILOMETERS

20 40 MILES

38°

39°

109°

40°

106°

107°

108°

COLORADO

UTAH

7

10

15

13

11

7 6

5

8

12

14

2 3 4

9

1

Table 1. Fish community sampling sites in the Upper 

River Basin

[Color represents land use; green = background; yellow = mining; o

 recreational; red = multiple land use; purple = agriculture]

Site

number1

Site

name2

US

1 Colorado River below Baker Gulch (Baker) 

2 French Gulch at Breckenridge (French) 0

3 Blue River near Breckenridge (Blue) 39294

4 Gore Creek at Dowd Junction near Minturn 

(Gore) 0

5 East River below Cement Creek (East) 0

6 Gunnison River at County Road 32 

(Gunn 32) 3831

7 Gunnison River below Gunnison Tunnel 

(Gunn Tun) 0

8 Uncompahgre River near Ridgway 

(Ridgway) 0

9 Colorado River at Dotsero (Dotsero) 0

10 Dry Fork at upper station, near De Beque 

(Dry Fork) 0

11 Colorado River near Cameo (Cameo) 0

12 Dry Creek at Begonia Road near Delta 

(Dry Creek) 0

13 Gunnison River near Grand Junction 

(Gunn GJ) 0

14 Reed Wash near Mack (Reed Wash) 0

15 Colorado River near Colorado-Utah 

State line (State line) 0

1

Site number refers to numbers in figure 1.

2Names in parentheses are site-name abbreviations.

0

Figure 1. Location of Upper Colorado River Basin study unit,

physiographic provinces, and fish community sampling sites.
Table 2. Type, trophic class, and relative abundance of native and nonnative fish species collected at fish community sa

sites in the Upper Colorado River Basin1

[Blue shading represents native species; tan shading represents nonnative species. I, invertivore; O, omnivore; H, herbivore; P, piscivore]

Fish

type

(Common

names)

Scientific

name

(Genus and

species)

Number of individuals at sampling sites2

Southern Rocky Mountains province Colorado Platea

Trophic Class3

Baker A (1)4

Baker B (1)Baker C (1)

French (2)

Blue (3)

Gore A (4)Gore B (4)Gore C (4)

East (5)

Gunn32 (6)

GunnTun (7)5

Ridgway (8)

Dotsero (9)

Dry Fork (10)

Cameo (11)

Dry Cr A (12)Dry Cr B (12)Dry Cr C (12)

Trout Salmonidae

Brown trout Salmo trutta I 81 47 73 2 137 142 65 100 12 51 5 13 6 1 5 3 

Rainbow trout Onchorhynchus mykiss I 67 22 23 3 16 65 20 4 

Brook trout Salvelinus fontinalis I 19 38 56 36 5 3 1

Cutthroat trout Onchorhynchus clarki I 1 11

Kokanee salmon Onchorhynchus nerka I 62 5

Mountain whitefish Prosopium williamsoni I 18 29

Sculpin Cottidae 

Mottled sculpin Cottus bairdi I 18 8 14 162 34 26 45 1 3 3

Sucker Catostomidae

Longnose sucker Catostomus catostomus O 2 1 1 107 7

White sucker Catostomus commersoni O 8 10 71 31 17 30 7 

Bluehead sucker Catostomus discobolus O 11 7 48 22 36 34 

Flannelmouth sucker Catostomus latipinnis O 30 100 18 42 48 

Minnow Cyprinidae

Roundtail chub Gila robusta H 65 5 13 2 

Common carp Cyprinus carpio O 18 

Speckled dace Rhinichthys osculus I 1 2 46 31 94 

Longnose dace Rhinichthys cataractae I 3

Fathead minnow Pimephales promelas O 17 5 

Sand shiner Notropis stramineus O 

Colorado squawfish Ptychocheilus lucius P 

Sunfish Centrarchidae

Green sunfish Lepomis cyanellus I 162 

Largemouth bass Micropterus salmoides P 3 

Smallmouth bass Micropterus dolomieu P 

Catfish Ictaluridae

Channel catfish Ictalurus punctatus I 

Total number of fish 121 93 144 0 38 371 201 115 167 152 116 91 152 0 306 135 164 188 

Number of species 5 3 4 0 2 4 4 4 5 7 2 5 9 0 11 9 8 6 

1Tyus and others (1982).

2Site numbers and names and colors correspond to site numbers in figure 1 and table 1.

3

Schrader (1989) and R.M. Goldstein (U.S. Geological Survey, oral commun., 1997).

4Letters A, B, and C correspond to multiple-reach sampling sites.

5Site 7 is hydrologically represented as a Southern Rocky Mountain province site.
Trophic class information can be useful in distinguishing differences among sites. Fish are categorized by trophic classes based on

their type of diet. Data for this fact sheet were based on a generalized

trophic classification for each species. Ninety-four percent of the total

number of fish in the UCOL basin were classified as invertivores (I) or

omnivores (O) (fig. 2; table 2). The remaining 6 percent were classified

herbivores (H) or piscivores (P). Invertivores are fish that consume

mostly invertebrates, whereas omnivores consume invertebrates, fish,

and plants. Herbivores consume mostly plants, whereas piscivores consume mostly fish (Schrader, 1989).

Distinct fish communities are associated with the two physiographic provinces. Invertivore species are predominant at sites in the

Southern Rocky Mountains province. Omnivore species are predominant at sites in the Colorado Plateau province. Herbivore and piscivore

species were present only at sites in the Colorado Plateau province.

Overlap of species is observed in a transition zone, which is located

along the division line of the two physiographic provinces. The sites

located closest to the transition zone are a Gunnison River site (site 7),

the Uncompahgre site (site 8), and the Dotsero site (site 9). Overlap of

trophic classes occurs at two of these sites (sites 8 and 9) as shown

in figure 2. Site 7 is downstream from a large dam, and although physically located in the Colorado Plateau province, it is hydrologically

represented as a Southern Rocky Mountains province site. Cold-water

releases, low concentrations of dissolved solids and suspended sediment, and a suitable habitat at this site provide conditions for trout

species that more typically occur at high-elevation sites in the Southern

Rocky Mountains province.

The Gunnison River at County Road 32 (site 6) and site 9 have

representation from both dominant trophic classes. The invertivore

species are similar at these two sites; however, the composition of the

omnivore species differs between sites. Site 6 has a high-elevation,

cold-water sucker species, whereas site 9 supports primarily lowelevation, warm-water sucker species. Fish communities at site 6 may

be affected by fishing pressure on trout and by increased pooled areas

at the upper end of the downstream reservoir, which provides habitat

conditions favorable to sucker species. Invertivore and omnivore

trophic classes are represented more evenly at site 12 than 

sites; however, 90 percent of the total number of invertivo

species collected were minnows, which are characteristic 

conditions in the Colorado Plateau province. The herbivor

piscivore species also are characteristic of habitat conditio

Colorado Plateau province.

Relation Between Water

Quality and Fish Communities

Water temperature and concentrations of dissolved so

and suspended sediment generally are lower in the Southe

Rocky Mountains province when compared to the Colorad

province (figs. 3A, B, C). Elevation is considerably lower 

Colorado Plateau (fig. 3A). Median concentrations of diss

solids and suspended sediment change noticeably near the 

zone between the two provinces. Changes in the geology f

crystalline bedrock in the Southern Rocky Mountains prov

sedimentary deposits in the Colorado Plateau province can 

one factor for the changes in concentrations (Apodaca and 

1996).

Water temperature is inversely related to elevation in 

as elevation decreases, water temperature increases (fig. 3

ture is one major controlling factor in fish community com

the UCOL study unit. Selected water-temperature conditio

a favorable habitat for selected fish species (Coutant, 1977

water of the Southern Rocky Mountains province is favora

and sculpins, and the warm water of the Colorado Plateau 

favorable to suckers, minnows, and sunfish (table 2).

Dissolved solids is a measure of the concentration of 

(calcium, magnesium, sodium, and potassium,) and anion

ate, sulfate, and chloride) in water (Hem, 1992) and comm

referred to as salinity. Dissolved-solids concentrations are 

sites in the Colorado Plateau province than at sites in the S

Rocky Mountains province (fig. 3B). Sucker species are m

of the higher concentrations and, therefore, were more pre

Figure 2. Percentage of total numbers of fish for the trophic classes represented at sampling sites in the Upper Colorado R

Basin (I, invertivore; O, omnivore; H, herbivore; P, piscivore).
the Colorado Plateau province. Changes in species composition also

were observed between sites in the Colorado Plateau province in comparison to sites in the Southern Rocky Mountains province.

Suspended sediment is the solid material transported in the

streamflow, either in suspension or along the stream bottom. Many

nutrients, trace elements, and pesticides adhere to these particles

and are transported downstream. The omnivorous species, primarily

present in the Colorado Plateau province, can tolerate high concentrations of suspended sediment. In general, as concentrations of suspended sediment increased (fig. 3C), numbers and types of omnivorous

fish species also increased in a downstream direction in the Colorado

Plateau province. Comparison of selected water-quality constituents

and fish communities indicated a relation.

Relation Between Stream

Habitat and Fish Communities

One important aspect of stream habitat is substrate ty

and others, 1993b). The relative abundances of coarse (bo

gravel) and fine (sand/silt/clay/muck) bed materials at site

physiographic provinces are shown in figure 4. These perc

based on a qualitative habitat assessment using techniques 

NAWQA (Meador and others, 1993b). Invertivore species 

abundant in streams with cobble, gravel, and boulder subs

because these substrates provide space for invertebrates an

vide food for fish. Most of the cold-water species need gra

ble to shelter their eggs during reproduction. As streams l

headwater regions of the Southern Rocky Mountains prov

substrates consist mostly of coarse material, the substrate 

includes finer materials mixed with some coarse materials

materials account for most of the substrate in streams of th

Plateau province. Sand, silt, clay, and muck are a natural p

stream bottom, having been deposited mainly as a result o

and runoff from fields and streambank material. However, 

finer materials can decrease available habitat for aquatic p

White sucker (typical omnivore species present in the 

Plateau province).

Figure 3. (A) Relation of water temperature and elevation;

(B) dissolved-solids concentrations; and (C) suspendedsediment concentrations for fish community sampling sites

in the Upper Colorado River Basin.

Typical stream setting in the Colorado Plateau provinc
October 1997 Fact Shee

organisms by filling in spaces between rocks, which results in

loss of cover for fish and their food sources and for spawning areas.

Warm-water omnivorous species can tolerate the food-source and

spawning areas that are present in streams in the Colorado Plateau

province. Comparison of bed substrate and trophic classes (figs. 2

and 4) indicated a relation between fish communities and their

habitat.

Summary

Differences in fish communities in the Upper Colorado River

Basin study unit reflect the water quality and habitat that characterize

the physiographic provinces. Fish communities are invertivores at high

elevation, forested, high-gradient, cold-water sites in the Southern

Rocky Mountains province and mostly omnivores at lower elevation,

less vegetated, low-gradient, warm-water sites with high concentrations of dissolved solids and suspended sediment in the Colorado

Plateau province. Invertivore species, such as trout, more commonly

are present in the swift, clear, cold-water streams with boulder/cobble/

gravel substrates in the Southern Rocky Mountains province. Omnivore, herbivore, and piscivore species, such as suckers, minnows, and

sunfish, tolerate slow, turbid, warm-water streams with sand/silt substrates in the Colorado Plateau province.

References Cited

Apodaca, L.E., Driver, N.E., Stephens, V.C., and Spahr, N.E., 1996,

Environmental setting and implications on water quality, Upper

Colorado River Basin, Colorado and Utah: U.S. Geological Survey

Water-Resources Investigations Report 95–4263, 33 p.

Berkman, H.E., Rabeni, C.F., and Boyle, T.P., 1986, Biomonitors of stream

quality in agricultural areas—Fish versus invertebrates:

Environmental Management, v. 10, no. 3, p. 413–420.

Coutant, C.C., 1977, Compilation of temperature preference data: Journal

of the Fisheries Research Board of Canada, v. 34, p. 739–746.

Driver, N.E., 1994, National Water-Quality Assessment Program—

Upper Colorado River Basin: U.S. Geological Survey Open-File

Report 94–102, 2 p. [Water Fact Sheet].

Hem, J.D., 1992, Study and interpretation of the chemical characteristics

of natural water (3d ed): U.S. Geological Survey Water-Supply

Paper 2254, 263 p.

Meador, M.R., Cuffney, T.F., and Gurtz, M.E., 1993a, Metho

pling fish communities as part of the National Water-Qu

ment program: U.S. Geological Survey Open-File Repo

40 p.

Meador, M.R., Hupp, C.R., Cuffney, T.F., and Gurtz, M.E., 1

ods for characterizing stream habitat as part of the Nati

Quality Assessment program: U.S. Geological Survey O

Report 93–408, 48 p.

Moyle, P.B., 1994, Biodiversity, biomonitoring, and the struc

fish communities, chap 10 of Loeb, S.L., and Spacie, A

logical monitoring of aquatic systems: Boca Raton, Fla

lishers, p. 171–186.

Schrader, L.H., 1989, Use of the index of biotic integrity to e

communities in western Great Plains streams: Fort Coll

State University, Master’s thesis, 120 p.

Spahr, N.E., Driver, N.E., and Stephens, V.C., 1996, The Upp

River National Water-Quality Assessment program surf

monitoring network: U.S. Geological Survey Fact Shee

Tyus, H.M., Burdick, B.D., Valdez, R.A., Haynes, C.M., Lyt

and Berry, C.R., 1982, Fishes of the Upper Colorado R

Distribution, abundance, and status, in Miller, W.H., Ty

and Carlson, J.A., eds., Fishes of the upper Colorado R

Present and future; proceedings of a symposium presen

annual meeting of the American Fisheries Society in A

New Mexico, September 18, 1981: Bethesda, Md., Wes

of the American Fishery Society, p. 12–18, 64–70.

Fish collection on the Uncompahgre River near Ridgw

Figure 4. Percentages of types of bed substrate for fish

community sampling sites in each physiographic province.

Information on technical reports and hydrologic dat

to the NAWQA program can be obtained from

Upper Colorado River Basin NAWQA

Manager

U.S. Geological Survey

Bldg. 53, Denver Federal Center

Mail Stop 415, Box 25046

Denver, CO 80225–0046

(303) 236–2101 ext. 224

email: nedriver@usgs.gov

www: http://webserver.cr.usgs.gov/nawqa/ucol/ucol_h