LOSSES FROM CANALS BY SEEPAGE. 
26 
Bulletin 45, on Losses from Reservoirs, page 12. It was 
found when the water was 20 ft. deep, the loss amounted to 
.15 inches per day; when 25 feet to .24 inches; when 30 It. to 
.46 inches, but on lowering the water it was found that the 
loss did not become as small as the same depth before the 
reservoir had been filled. The loss at 20 ft., after the reser- 
voir had been full, remained at .28 inches instead of reduc- 
ing to .15 inches observed before. 
Some observations by Keelhoff on small ditches have 
already been mentioned. In these more loss was found 
when the water was 10 inches deep than when 2 inches deep. 
In the case of the North Farm Lateral, where two 
measurements were made with different amounts of water 
in the canal, a greater depth of loss is shown with the larger 
head. The depth of loss averages .8 with the head of 200 
sec.-ft., and .4 ft, with a head of 90 sec. -ft. 
By arranging the losses according to the amount af 
water in the canal, we find that the observations given in 
table VI show clearly that the smaller the amount of water 
the less is the depth of loss, though the greater the per cent, 
the loss is to the amount in the ditch. 
Omitting the days on which the water had dropped, in 
which cases the water returning from the saturated banks 
reduces the apparent loss, and likewise leaving out of ac- 
count those days in 1894 on which doubt is cast by showers, 
the following table is obtained; 
Amount of Water, 
in Ditch, 
0 to 2 sec. ft. 
2 to 4 
4 to 6 
G to 9 
No. Cases Taken. Loss in Carriage. 
per Cent. 
4 50 
estimated 26 
G 19 
G 17 
Loss in Depth. 
Inches. 
4.5 
6.3 
7 5 
8.5 
THE EFFECT OF TEMPERATURE ON LOSSES. 
It is undoubtedly true that the amount of seepage will 
be affected by the temperature of the water, and though the 
temperature was always taken, no attempt is made to allow 
for the temperature in the present report. The effect of 
temperature is evident in the increased fiow into streams as 
shown in Bulletin 33, in drains, and it causes a correspond- 
ing effect on the loss from canals. 
Using the equation representing the effect of tempera- 
ture on the velocity of flow as given in bulletin 33, p. 46, 
and considering the amount of seepage at freezing tempera- 
ture as unity, the loss at other temperatures may be ex- 
pected to be approximately as the following amounts:* 
* Note in Engineering News, by L. (L Carpenter, 39:422. Also note 40:26, 
July 14, 1898, by Allen Hazcn, yiving praciically same ratios from his own meas- 
urements. 
