WSP02811

• File Number: 8200.766
• Description: Gunnison River General
• State: CO
• Basin: Gunnison
• Water Division: 4
• Date: 1/1/1991
• Author: USGS
• Title: Reconnaissance Investigation of Water Quality-Bottom Sediment-and Biota Associated with Irrigation Drainage - Gunnison and Uncompahgre River Basins and Sweitzer Lake - West Central Colorado
• Water Supply Pro - Doc Type: Report/Study

002341

collected major-ion, dissolved-solids, and iron data since 1931 at that
station. Mean dissolved-solids concentration (1931-88) was 1,006 mg/L and was
a mixed-cation sulfate water type. In 1975, the station was included in the
U.S. Geological Survey's National Stream Quality Accounting Network, and
comprehensive trace-element data have been collected on a routine basis for
that program. Selected trace-element data are listed in table 2, and the
dissolved-selenium concentrations are plotted in figure 9. The apparent trend
of decreasing selenium concentrations at station 09152500 might have been
caused by greater than average stream discharge of the Gunnison River from
1983-87. The overall collection period for the data listed in table 2 is
1975-88, except for boron, which is 1951-79.

Table I.--Summary of selected total trace-element concentrations for
Gunnison River at Delta, Uncompahgre River at Ridgway,
and uncompahgre River at Delta

[Analyses by Colorado Department of Health; concentrations are in micrograms
per liter; concentrations were reported as total or total recoverable.
Data-collection period is 1968-88.]

Constituent

Number of samples

Median

GUNNISON RIVER AT DELTA

Arsenic
Boron
Cadmium
Chromium
Copper

49
58
100
7
97

o
60
.3
o
5

Lead
Mercury
Molybdenum
Nickel
Selenium
Zinc

100
9
18
7
56
113

5
.5
o
50
o
10

UNCOMPAHGRE RIVER AT RIDGWAY

Arsenic
Boron
Cadmium
Chromium
Copper

96
47
98
7
95

10
40
.31
o
28

Lead
Mercury
Molybdenum
Nickel
Selenium
Zinc

101
8
17
7
38
100

7
.5
o
50
o
120

21

Maximum

Minimum

93
210
3.0
6
24

o
o
o
o
o

42
.5
18
100
10
450

o
.5
o
o
o
o

20
190
3.7
6
360

o
o
o
o
o

260
.5
IS
100
5
480

o
.5
o
o
o
o