26 
SEEPAGE OR RETURN WATERS FROM IRRIGATION. 
that any water reaches the Platte through their channels, the only 
times being after heavy rains or sudden and violent storms on the 
higher grounds on either side. In these cases, the plains shed 
water as a roof, and the channels bring down violent floods, danger¬ 
ous, it may be, to travelers. The area drained by these channels is 
great. As in most cases, the channels are confined by ridges of 
rock, it was thought that there might be some indication of 
underground increase from these streams, even if no visible surface 
inflow. Accordingly in 1894 it was tested by measuring the river 
above and below the points where the creeks debouch into the bot¬ 
toms, with results given later. 
For a portion of the lower course of the stream, it is lined on 
•one or both sides by a strip of sand hills and dunes, molded and 
blowm by the wdnd, back of which is a country free from sand. 
§ 18. The bed of the stream is a bed of sand, of varying fine¬ 
ness—in some places and at some times quicksand—and shifting 
with the current, which changes from one side to the other. For some 
miles below the mouth of the Poudre, the stream is in one channel. 
It is then gradually broken up by sandbars and by small islands 
into smaller channels, increasing in number. At the State line 
there were sixteen channels where we measured in 1895. These 
channels are constantly shifting by bars forming or washing away 
in the rapid current, so that they change their importance and fre¬ 
quently their position. The general location of the bed seems to be 
fairly stable. The river requires bridges some 600 to 1,000 feet in 
length. The slope of the bed of the river averages about eight feet 
per mile between the mouth of the river and Julesburg, being 
greater at the upper portion and less at the lower end. When there 
is much water this fall is sufficient to give the current great velocity, 
constantly carrying along the sand, depositing, removing and shift¬ 
ing it. 
§ 19. The principal ditches along the course of the river are 
shown on the map (Fig. 3). It will be noted that the area limited 
by the outermost ditch under irrigation does not cover a wide strip. 
Many of the ditches are small, some used to irrigate only the bot¬ 
tom lands. Others, like the Fort Morgan, the Weldon Valley, the 
Platte and Beaver, and Pawnee Canal systems, irrigate considerable 
areas of excellent land and are almost the only ones passing out of 
the bottoms. 
If the water reaches the river from the land irrigated, it may 
be expected to drain into the river following the lines of surface 
drainage, though remaining unseen. It cannot cross the ridges 
between the channels. As a rule, wherever the facts are 
knowm, the ridges are of rock which is higher than the bottoms of 
the channels. With the system of ditches, there is then some pos- 
