SEEPAGE OR RETURN WATERS FROM IRRIGATION. 
45 
Where there is a periodical change in the head supplying the water, 
as in the case of the canals, there may be a series of underground 
waves affecting the height of the ground water. The rise and fall 
of such a wave, which started years before, may be mistaken for 
the rise and fall due to the periodical rise in the canal. 
Thus the case of the Natron ponds, which* rise in March, and 
are located thirty-five miles from the Nile, and which Storer {Agri¬ 
culture, 1:56) attributes to the rise of the Nile of the previous Sep¬ 
tember, is probably such a case. 
§ 33. The best case met with was near Montrose. A deep 
gulch starts in the mesa below the Montrose canal. Passing across 
this depression the glistening in the moonlight of the alkaline 
deposit on the shale at the bottom attracted my attention, and on 
inquiry it was learned that this began to show slightly two years 
after the canal was used, and in considerable quantity in three years. 
The distance from the canal is three miles. This would make the 
speed about one mile per year. 
§ 34. Direct experiment on the rapidity under field conditions 
have been unsatisfactory or inconclusive. Col. E. S. Nettleton, as 
Chief Engineer of the U. S. Irrigation Investigation ior the Depart¬ 
ment of Agriculture, aided by W. W. Follett, attempted to deter¬ 
mine the rapidity in the sands of Cherry creek, and on the Rio 
Grande, but with inconclusive results, except to come to the con¬ 
clusion that the velocity was very slow. * 
In the sands of the Fountaine qui Bouille, Mr. D. C. Henny 
concluded that the water had a velocity of about seven feet per 
hour, t The method of arriving at this determination is not given. 
From other evidence it would seem to be excessive. 
Water Commissioner J. T. Hurley, of Orchard, reports that 
under the Weldon Valley canal the seepage has progressed one and 
one-half miles in five years. In one case under the Larimer 
«/ 
County canal, according to Mr. N. C. Alford, it was five years before 
seepage showed at a distance of forty rods from the canal, though 
the slope was considerable. In one case near Greeley, according to 
Mr. S. A. Bradfield, it seems to have taken about ten years to go two 
and one-half miles. 
§ 35. The rate is certainly slow, and observers throughout the 
State whose attention has been called to it now agree upon its small 
progress. A few years ago most of them believed in a rapid flow, 
as still do most of the adherents in the belief that there is a great 
‘‘ underflow ” under the plains. 
Comparison with familiar facts would lead one to expect slow 
progress. The water in passing through sand and gravel must 
* Final report Artesian and Underflow Investigation ; Pt. 2, p. 34. 
t Quoted by J. D. Schuyler, report as consulting engineer to the Pueblo 
Gravity Water Co. 
