Dames & Moore, 1999 - USDA Forest Service

TABLE 4.33
AVERAGE MONTHLY POTENTIAL EVAPOTRANSPIRATION (PET) AT HOLDEN MlNE 8 RAlLROAD CREEK BASIN
HOLDEN MlNE RllFS
DAMES 8 MOORE JOB NO. 17693405419
January
February
March
April
May
June
July
August
September
October
November
December
Month
Total Annual PET
Holden Villagea
-5.7
-2.6
0.7
4.2
8.55
12.55
15.7
15.8
11.5
5.9
0.9
-5.4
Temperature (CO) Absolute Humidity (Pt)'
Estimated Potential Evapotranspiration (PET)'
Railroad Basinb
-7.7
-4.6
-1.3
2.2
6.55
10.55
13.7
13.8
9.5
3.9
-2.9
-7.4
Holden Village
3.07
3.77
4.70
5.94
7.94
10.37
12.80
12.89
9.67
6.65
4.23
3.13
Railroad Basin
2.68
3.30
4.1 1
5.20
6.95
9.08
11.20
1 1.28
8.46
5.82
3.70
2.74
Maximum Hours
of Sunlightd
8.8
10.2
11.8
13.6
15.2
16
15.6
14.3
12.6
10.9
9.5
8.3
- Notes:
(a) - NOAA climatological data for Holden Village (data collected from 1962-1997).
(b) - estimated from Holden Village temperatures with an assumed lapse rate of -2' C per 1000 foot increase in elevation.
(Holden Village elevation is 3200 R, where as average basin elevation is 43M) R.)
(c) - maximum water holding capacity of air at given temperature.
(d) - computed for latitude 48 degrees.
(e) - percent of cloud cover estimated from data average taken in Seattle and Yakima. Washington.
(9 - PET = 0.26 x (Pt) x (H) x (1112) x (1125.4) x (dayslmonth)
from (Hamon (1963) as reported in Satterlund and Adams (1992)
Page 1 of 1
Percent Cloud
Cover'
0.31
0.41
0.52
0.59
0.62
0.61
0.74
0.71
0.63
0.48
0.33
0.26
Possible Hours of
sunlighth
2.73
4.18
6.14
8.02
9.42
9.76
11.54
10.15
7.94
5.23
3.14
2.16
Holden Village (inches)
0.22
0.38
0.76
1.22
1.97
2.58
3.90
3.45
1.96
0.92
0.34
0.18
17.86
Railroad Basin (inches)
0.19
0.33
0.67
1.06
1.73
2.26
3.41
3.02
1.71
0.80
0.30
0.16
15.63