4? 
SEEPAGE Oil RETURN WATERS FROM IRRIGATION. 
1895 some material was taken from the bed of the canal to 
strengthen the banks. 
§ 40. A new section had been built on the same canal to avoid 
a long flume on the old line. Water had been running in the new 
portion for three weeks at the time it was visited. The total length 
of the new portion is 10,100 feet, including 400 feet of flume. A 
measurement was made of the water of this section, both at the 
upper and lower ends. Some water was running through the old 
flume. The amount decreased from 109.15 second-feet, to 97.67 
second-feet, in passing through the new channel, or there was a loss 
of 11.48 second-feet. The new flume was so nearly water tight that 
its leakage may be neglected. 
§ 41. In these two cases we may estimate the rapidity of the 
flow of water through the soil. In the first case, the loss of twenty 
feet took place in a distance of 7.4 miles. The average width of the 
channel was 45 feet, hence the area of the canal in this distance 
was nearly forty-one acres. The loss corresponds to a layer of water 
of 11.7 inches deep in twenty-four hours. As the water occupies a 
space of about one-third of the sand, its velocity through the sand 
is three feet per day. It is unquestionably true that the loss takes 
place at unequal rates in different portions of this stretch, so that 
this rate, as in those which follow, is an average one for the section 
considered. 
In the second case, the loss was 11.48 second-feet in a distance 
of 9,700 feet of channel. The average width was forty feet, giving 
an area of nine acres covered by the water. This corresponds to the 
loss of a layer of water 2.53 feet deep over the whole area of the 
canal. For half of this distance the canal extends along the sand 
bluffs which line the west side of Bijou creek, and is from thirty to 
ten feet above the channel of the creek. It is in a compact mate¬ 
rial, some of which needed to be blasted in constructing the 
channel. On the east side of the creek, it passes through a loose 
sandy soil, which slopes about one per cent, toward the creek. From 
evidence since obtained from the canal superintendent, Mr. Ding- 
man, it seems probable that the loss from the west side is small or is 
insensible. A hole bored under the channel, and within a few 
inches of the water, was perfectly dry. If the loss is from the east 
side only, the rate must by twice as great as if from both sides, or 
would correspond to a layer five feet in depth per day over this 
portion of the canal. This would correspond to a velocity through 
the sand of about fifteen feet per day. 
§42. On the Hoover ditch, running at the base of sandy 
bluffs, but with the bottom of the ditch covered with a fine silt, the 
loss in a distance of 1,500 feet was at the rate of 1.2 feet in depth 
for twenty-four hours, or a velocity of 3.6 feet per day through the 
sand. 
