Environmental Engineering Reference
In-Depth Information
0
0
5
5
10
10
15
15
20
20
25
25
30
30
35
35
40
40
65
70 75 80
Water temperature (°F)
85
0
1
2
3
4
5
Dissolved oxygen concentration
(mg L
-1
)
FIGURE 14.6
Variation of water temperature and dissolved oxygen concentration, speciic conductance,
and pH at Lake Bruin, LA, September 24, 1997. (From Ensminger, P.A., Bathymetric survey and physical
and chemical-related properties of Lake Bruin, Louisiana, February and September 1997, from Water-
Resources Investigations Report 98-4243, U.S. Geological Survey, Baton Rouge, LA, 1998.)
where
o
s
(
T
, 0) is the saturation concentration of DO in freshwater at 1 atm (magnesium peroxide per
liter) and
T
a
is the absolute temperature (kelvin), where
T
a
=
T
+ 273.15. The effect of elevation is
accounted for by Equation 14.8:
ln (,)
oT
s
0
oT
(,
elev)
=
e
(
100001148
.
H
)
(14.8)
s
where
H
is the elevation in meters. The impact of temperature and elevation on saturation concen-
trations is illustrated in Figure 14.7.
Oxygen saturation
16
14
12
10
8
Sea level
6
5000 m
4
2
0
0
30
40
10
20
Te mperature (°C)
FIGURE 14.7
Oxygen saturation concentrations at sea level and at 5000 m.
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