COLORADO IRRIGATION WATERS AND THEIR CHANGES. 57 
gard to this sample than in the other cases, and it is not feasible 
for me to gather the facts in this case with the completeness and 
accuracy that would permit me to make any explanatory state¬ 
ments, therefore I content myself with recording the results of the 
analysis which is given later. 
§ 106. Fortunately the Poudre river was gauged in 1902, a 
few days before my samples were taken, and we have very excel¬ 
lent data enabling us to calculate the results indicated by our 
analyses, with the assurance that they are correct within narrow 
limits. On July 27, the flow at the pump house above Greeley 
was 24 second-feet, at the mouth of the river it was 29 second-feet. 
We will use the latter figure in calculating the total work done by 
the Poudre river as an irrigation stream. This flow delivers near¬ 
ly 2.4 acre-feet per hour, or 57.6 acre-feet per day. At the pump 
house the flow amounted almost to 48 acre-feet per day. As the 
supply of water during the season of 1902 was very short, we may 
consider the following figures as representing the minimum effect 
of the stream. 
§ 107. With a flow of 57.6 acre-feet daily, it carries a total 
of 79.75 tons of salts into the Platte river. A like quantity of 
water, as it flows through the canyon of the Poudre, would con¬ 
tain only 3.25 tons, or a gain of 76.5 tons, but the flow at the 
mouth of the river is not the same as in the canyon, it being much 
greater. The following figures will show the total salts carried 
through the canyon in solution, and will also give an idea of the 
daily consumption of water taking place between the canyon and 
the mouth of the river. The weight of the salts carried through 
the canyon of the Poudre on this date was 32.5 tons. The amount 
delivered to the Platte was 79.75 tons, a difference of 47.25 tons. 
This naked statement of end results does not give a fair idea of the 
work accomplished. The water had all been taken out of the 
Poudre, together with the return water, and at a point six miles 
above its mouth, just below the Camp ditch, it was entirely dry. 
Yet, there was a discharge of 29 second-feet at its mouth carrying 
8° (79.75) tons of salts, all of which must have come into the 
river within the intervening six miles. 
§ 108. To show still further how inadequate this way of 
presenting the matter is, I will take the analysis of the sample 
from above Greeley, where the flow was 24 second-feet and the 
total solids 114.5 grains per imperial gallon. There were accord¬ 
ingly 100.8 tons of salts being carried past this point daily, but 
the gaging shows that there was an increase of 21 second-feet 
between this point and the Camp ditch, which of course increased 
the quantity of salts being carried by the river. The Camp ditch 
took all of the water in the river at this point and consequently 
took not only the 101 tons of salts, but much more, including the 
