LOSSES FROM CANALS BY SEEPAGE. IQ 
Erie canal are more favorable to small losses than are those 
of irrigation canals. The Erie canal is in a more humid 
climate, with a rainfall about 2)4 times as great as that of 
Colorado and this lends to keep the water table nearer the 
surface and thus lessen the percolation. More than that, 
the Erie canal in this stretch is almost level (3 ft. fall in 60 
miles) and the slow movement of the water is favorable to 
silt deposition. The irrigation canals have falls ranging 
from 2 ft. upward per mile, and the beds are scoured by the 
running water. 
Mr. Walter James, who has been for many years the 
engineer of the canals in Kern county, California, writes* 
that their experience shows that they deliver 70 per cent 
of the water turned in at the head of the canals at the late- 
ral side gates, measurements sometimes being made from 
one to three miles from the main ditch at the lands where 
the water is used. There is one point on the Calloway 
canal where there is a loss of 75 cu. ft. per sec. in a distance 
of half a mile.f 
The canals referred to by Mr. James are from 6 to 25 
miles in length, and from two to three feet in depth. In 
their experience they find that an allowance of 2 per cent, 
per mile of main canal approximates fairly well to the 
loss to be counted upon. 
On the Carpentras canal of Vaucluse in Erance, taking 
water from the Durance, the lo^s was found to be great, 
though the waters of the Durance are thick with mud ordi- 
narily. The canal passes along the flank of calcareous 
slopes. The soil is generally thin. The banks were walled 
and the canal paved in many places. After these remedies, 
the loss is still considered to be about 30 per cent of the 
amount taken by the canal. J: 
The canal carries 210 cu. ft. per second. The loss cor- 
responds to a depth of 1.2 feet over the length of the canal, 
which is 40 miles. 
The Marseilles canal in Southern Erance, which had 
cost $9,000,000 up to 1878, at first lost about 20 per cent., not- 
withstanding that the water supplying the canal is excep- 
tionally muddy, so much so that it was necessary to build 
settling basins at considerable cost. The loss was reduced 
to 10 per cent, by works protecting the banks, made at a 
* June 13, 1898. 
tThis is equivalrnt to a daily loss of .10 feet in doplh. 
^Salvador, Itydrau'iqae Agricole, (1898) 2:492. 
