SEEPAGE OR RETURN WATERS FROM IRRIGATION. 61' 
Also see reports of the State Engineer of Colorado, 1885-6, p. 
205-208; 1889-90, p. 559-570; 1891-92, p. 51-65; 1893-4, p. 176- 
192. 
In bulletin No. 38, of Utah Experiment Station, Prof. Fortier 
has given some measurements for one year, showing the amount on 
some Utah streams, and leading to essentially the same conclusions 
as Vigan. Prof. Fortier’s study is a valuable contribution to the 
subject. 
A discussion by Senator David Boyd of the applicability to the 
Arkansas valley of conclusions from the Platte measurements, 
occupies part of a report of a special committee on the State Canal 
No. 1, Tenth General Assembly, p. 40-49. 
In the Annales des Ponts et Chaussees, 1883, p. 34-60, M. Bazaine 
has a study on L’Influence des Irrigations sur VAltitude d’une nappe 
souterraine occasioned by the observations of the effect of irrigation 
from the sewage of Paris on the ground water of the sewage farms 
of Gennevilliers. It has little application to the present discussion, 
except as it deduces the equation of the surface of the underground 
water, which is parabolic. 
CONCLUSIONS. 
We may draw the following conclusions from the observations 
and considerations shown. The facts are presented in sufficient de¬ 
tail to show the bases of these conclusions, or to enable independ¬ 
ent conclusions to be reached, if the reader so desires: 
1. There is a real increase in the volume of the streams as 
they pass through the irrigated sections. 
2. There is no such increase in the streams as they pass 
through the unirrigated sections. On the contrary, there is an act¬ 
ual loss, even when the drainage of a large area enters. 
3. The increase is more as the irrigated area is greater. 
4. The increase is approximately proportional to the irrigated 
area, and it seems probable that with more intimate knowledge of 
the amount of water applied and the features of the drainage, the 
proportions would be found to be close. 
5. The amount of the increase depends very slightly, if at 
all, upon the rainfall, and, so far as it does, it is influenced princi¬ 
pally by the rainfall on the irrigated lands. Only where the lands 
are already saturated, is the rainfall sufficient to cause seepage. 
6. There is no perceptible underflow from the side channels, 
even where they drain several thousand square miles. 
7. The inflow is practically the same throughout the year. It 
is more in summer, less in winter, principally because of the effect 
of the temperature of the soil. 
