9317 ‎(2)‎

• UCREFRP Catalog Number: 9317
• Author: Spahr, N. E., L. E. Apodaca, J. R. Deacon, J. B. Bails, N. C. Bauch, C. M. Smith and N. E. Driver.
• Title: Water Quality in the Upper Colorado River Basin, Colorado, 1996-98.
• USFW Year: 2000.
• USFW - Doc Type: Denver.
• Copyright Material: NO

Study-unit frequency of detection, in percent
1 National frequency of detection, in percent

l'Lead .
20 11
o 41
25 41
100 100
100 100
100 99

Study-unit sample ~il

5
2
8

..
-
~Q-

--1'*:..-.,-
-....- ~
-.

Mercury'
20 71 -+=l
50 59
62 80 .~~.:1
100 82 ..~F9=
100 97 -..
100 93 . ..
Nickel' ..
40 42 -==-
0 44
38 50 --00---
100 100 -.;..-
100 100 -:I---
100 100 ....-;c
Selenium'
100 99 --~.
100 100 -
100 99 --.~...-.-.
100 100 ~;:=I.
100 100
100 100 . ....

Zinc'

100 100
100 100
100 100
100 100
100 99
100 100

....-
-
. .. ,----.....

---c.-~.
p-'
... ~

0.01

0.1 10 100 1,000

CONCENTRATION, IN MICROGRAMS PER GRAM
(Fish tissue is wet weight, bed sediment is dry weight)

3
2
6
5
2
8
3
2
6
5
2
8
3
2
6
5
2
8
3
2
6
5
2
8
3
2
6
10,000

Undeveloped
Agricultural
Urban
Mixed

Undeveloped

Agricultural

Urban

Mixed

Undeveloped
Agricultural
Urban
Mixed

BIOLOGICAL INDICATORS

Higher national scores suggest habitat disturbance, water-quality
degradation, or naturally harsh conditions. The status of algae,
invertebrates (insects, worms, and clams), and fish provide a
record of water-quality and stream conditions that water-
chemistry indicators may not reveal. Algal status focuses on the
changes in the percentage of certain algae in response to
increasing siltation, and it often correlates with higher nutrient
concentrations in some regions. Invertebrate status averages 11
metrics that summarize changes in richness, tolerance, trophic
conditions, and dominance associated with water-quality
degradation. Fish status sums the scores of four fish metrics
(percent tolerant, omnivorous, non-native individuals, and percent
individuals with external anomalies) that increase in association
with water-quality degradation

Biological indicator value, Upper Colorado River Basin, by
land use, 1996-98
. Biological status assessed at a site

National ranges of biological indicators, in 16 NAWQA Study
Units, 1994-98

_ Streams in undeveloped areas

_ Streams in agricultural areas

_ Streams in urban areas

_ Streams in mixed-land-use areas

75th percentile

25th percentile

Algal stat\ls indicator

. ~::j

Invertebrate stalJJs indicator

Do . L="==.

L

10 20 30 40 50 60 70 80 90 100

Fi,h """' ;,dlm'" '.~

=--::~-~-

=

o

10

15

20

Water-Quality Data in a National Context 33