WSP11975

• File Number: 8146.100
• Description: Pueblo Dam - Project Description
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 1/1/1986
• Author: US DoI BoR
• Title: Physical Chemical and Biological Characteristics of Pueblo Reservoir Colorado 1985 - 1986
• Water Supply Pro - Doc Type: Report/Study

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78 Be
AUGUST 1987

SITES
5C 48

38 28 18

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U
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~
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OJ
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is 50
5;1-60
wW
t3~ 70
a: ~ 80
;: 90
0
~
w 100
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:J: no
t-
o. 120
w
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OCTOBER 1987
0
ui 10
U 20
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~~ 80
;: 90
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~ 100
w
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:J: 110
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0.
w
0 no

........... RESERVOIR
BOTTOM

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I

............ RESERVOIR
BOTTOM

1<0
o 2 3 4 5 6 7 8 9 10
APPROXIMATE DISTANCE UPSTREAM FROM
DAM, IN MILES

SITES
78 Be 5C 48
SEPTEMBER 1987

38 28 18

............. RESEAVOIR
BOTTOM

o 2 3 4 5 6 7 8 9 10
APPROXIMATE DISTANCE UPSTREAM FROM
DAM, IN MILES

EXPLANATION
- 10 - LINE OF EQUAL TURBIDITY-Dashed where
inferred. Number is turbidity in
nephelometric turbidity units. Contour
interval is variable.

Figure 9, Monthly turbidity-measurement profiles of Pueblo Reservoir, December 1986 and March through
October 1987--Continued.

temporal variations of the chemical characteristics of
Pueblo Reservoir.

Dissolved Oxygen and pH

Dissolved-oxygen concentration and pH are
important properties of water. Dissolved oxygen is:
(I) essential to the metabolism of most aquatic organ-
isms, (2) necessary for the aerobic decomposition of
organic matter, and (3) a controlling factor in the
amount of nutrients and trace elements that might be
released from the bottom sediments into the water col-
umn. Dissolved-oxygen concentrations in Pueblo Res-
ervoir can be affected by photosynthesis, surface
aeration, respiration, decomposition, water tempera-
ture, and the oxygen content of the Arkansas River.

Inflow from the Arkansas River typically is well oxy-
genated.

Values of pH are a measure of the hydrogen-ion
activity. The biological activity of many organisms and
the solubility of many chemical constituents, including
trace elements, are pH dependent The pH of water in
Pueblo Reservoir is altered by the processes of photo-
synthesis and respiration and the pH of water entering
Pueblo Reservoir from the Arkansas River. The pH of
inflow from the Arkansas River typically ranges from
8.1 to 8.8.

The dissolved-oxygen and pH data for 1985
through 1989 indicate that dissolved-oxygen concen-
trations and pH vary temporally and spatially within
the reservoir (Ugland and others, 1988, 1990: Edel-
mann and others, 1991), Dissolved-oxygen concentra-
tions in the epilimnion are consistently near or greater

CHEMICAL CHARACTERISTICS 23