WSP04999

• File Number: 8054
• Description: Water Salvage
• State: CO
• Basin: Statewide
• Date: 6/1/1975
• Author: Utah Water Research
• Title: Water Salvage Potentials in Utah - Volume II - Evaporation Suppression by Reservoir Destratification
• Water Supply Pro - Doc Type: Report/Study

Table 3. One season mixing of Lake PoweU.

C alend ar
Month

Monthly %
Su~pression
Idealized Final

Accumulative
"7. Annual
Suppression

Decrease in Surface
Temperature due to
Mixing (0C)
Idealized Final

Residual
Heat
(OC)

First Year (mixing from A pril through October)
4 29 28 02 5.21
5 43 39 06 8.58
6 50 44 11 11.00
7 S2 42 18 12.09
8 49 36 24 11.15
9 38 22 27 7.73
10 26 09 28 4.66
II 14 -04 28 2.27
12 05 -11 27.3 0.79
Second Year (no mixing)
13 -16
14 -14
15 -13
16 -11
17 -07
18 -05
19 -04
20 -03
21 -02
22 -02
23 -02
24 -01

27-
27
26
26
25
24
24
23
23
23
22.5
22.5

4.90
7.59
9.21
9.28
7.64
4.08
1.42
-0.54
-1.60

. Nelsuppression at end of 1st year is 27.3% of 628.100 = 171,500 ac ft.
Net 1st year suppression after heat decay during 2nd year is 22.5qj:, = 142.173 ac ft.

0.31
0.99
1.79
2.81
3.51
3.64
3.24
2.81
2.39

2.04
1.82
1.53
1.14
0.90
0.68
0.51
0.39
0.31
0.26
0.22
0.19

Table 4. Sequential mixing of Lake PoweU.

Salvage
Percent Residual During Year
Year Suppression Heat (OC) (Acre Feet)
1 27.3 2.39 171,500
2 23.2 2.82 145,800
3 22.4 2.90 141,100
4 22.3 2.91 140,200
over 4 22.3 2.91 140,200
N+la -6.0 0.2 -36,000

a.-rhe year after mixing is stopping evaporation of 6% over
normal will oc(ur.

Supp. = 57.37 + 9.085 Log (D) - 9.896 Log (EI)

This function has a correlation coefficient of 0.87.
Because of the significant decrease in correlation
when flow is ignored the model selected for

application to other Utah reservoirs was the lirst of
the three functions given. Even though flow index
data are not available for many Utah reservoirs, it
appears better to use a function for which flow can
be used where available and estimated at an
average value where it is missing.

Figure 15 displays the best lit regression model
using maximum depth, flow index, and elevation
as dependent variables with flow index constant at
.29 (a typical value for other than major reservoirs
with high carryover storage). Figure 16 shows the
variation of suppression with flow index, ignoring
elevation.

AppUcadon of Regression Model to
Utah Resenoln

The regression model was used to extend the
results of the detailed 6-month model to all other

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