26 
COLORADO EXPERIMENT STATION. 
In Kern lake, Mr. Schuyler also made observations from Aug. 
4th to Sept. 29th. In a tank near the shore, the daily evaporation 
was .30 of an inch. In a tank near the shore in a depth of 5 feet of 
water, the daily loss during the same time was .21 of an inch per 
day. The temperature of the water as given was the same in each 
case, and varied from 78° to 88°. About noon the air was consid- 
erably warmer. From Oct. 2nd to Dec. 20th, a period of seventy- 
nine days, evaporation amounted to 9.66 inches from Kern river. 
Cal. This was determined from weekly observations. The temper- 
ature of the water in the pan varied from 55° to 80°. The average 
daily loss was .12. 
At Sweetwater reservoir, near San Diego, California, an evapora- 
tion tank was put in place by J. D. Schuyler and has since been con- 
tinued by and under the direction of H. N. Savage, C. E. The reser- 
voir was visited by the writer in 1891. At that time a circular tank, 
floated in the lake, was used. A Piche evaporometer was used for 
comparison. When the pan gave out in 1892, it was not renewed, 
,and the records were made from the Piche instrument until 1897, 
when Mr. Savage had the pan replaced. As the records with the 
Piche evaporometer do not show the evaporation from free water sur- 
face, they are not used in the table which follows, and only those de- 
pending on the records from the tank are given. Mr. Savage has 
furnished the record up to date. 
TABLE XIV.— EVAPORATION FROM SWEETWATER RESERVOIR. 
Near San Diego, California. Latitude, 32° 40' ; longitude, 117° ; elevation, 220 feet. 
Jan. 
Feb. 
Mar. 
April 
May 
June 
July 
Aug. 
Sept. 
Oct. 
Nov. 
Dec. 
Year. 
1889 
1.99 
3.34 
3.38 
4.96 
5.82 
6.81 
8.22 
7.26 
7.81 
4.52 
3.96 
.95 
59.02 
1890 
1.59 
2.21 
3.28 
4.14 
6.14 
7.30 
7.38 
9.02 
6.48 
4.92 
5.. 54 
1.84 
59.84 
1891 
3.61 
1.35 
3.08 
3.71 
5.60 
6.03 
6.. 50 
8.89 
6.15 
6.31 
4.10 
2.75 
58.08 
1892 
2.54 
1.39 
3.08 
5.82 
4.67 
6.48 
8.81 
6.54 
6.27 
6.56 
4.77 
2.61 
59.54 
1897 
2 12 
1.64 
2.91 
5.99 
5.69 
7.90 
6.25 
6.61 
5.53 
6.27 
4.24 
3.75 
58.90 
Mean 
2.37 
1.99 
3.15 
4.92 
5 58 
6.90 
7.43 
7.66 
6.45 
5.72 
4.52 
2.38 
59.07 
The water temperature ranged from an average of 80 to 82 degrees, in the warmest month, to 
50 degrees, in the coolest. 
§ 33. A valuable series of observations is being carried on by H. 
B. Hedges, C. E., of San Bernadino, Cal., at the Arrowhead reservoir 
in Little Bear valley. This is at an elevation of 5,160 feet above 
sea level, and near enough to San Diego to furnish some comparison 
between the evaporation at those two places and indicating the effect 
of elevation. 
In this case the evaporation was measured in a three-foot pan 
floated in a concrete basin separate from the reservoir. Measure- 
ments are made twice daily at 6 a. m. and 6 p. m. in summer. It 
will be noticed that the evaporation is much less than at San Diego. 
