The Waters oe the Rio Grande 13 
The nature of the land irrigated with the water taken from the 
Rio Grande, as it abounds in alkali salts, practically precludes the pos¬ 
sibility that return waters should have the composition of that applied 
as irrigating water. There are, it is true, two classes of water which 
might be considered as furnishing an increase in the flow of the river, 
i. e., waters previously used for irrigation, yielding what we usually 
understand as return waters, and artesian waters. The latter class of 
waters occur throughout the greater part of the cultivated portion of 
the valley. I am informed that, up to the present time, some 5,500 
artesian wells have been sunk in the valley. The fact that some of these 
wells are not flowing at the surface does not necessarily preclude their 
discharge of water into the valley in such a way as to affect the water 
problems of the soil and the river. The great majority of these wells 
are, however, flowing freely and but few of them are cased for more 
than a few feet, leaving the waters entirely free to fill up any strata 
not already full and to affect in this way the general water problems 
of the valley. 
While our problem clearly contains these factors, we assume that 
the waters, the river being for the most part actually higher than the 
neighboring portions of the valley, retain their character because there 
is actually no admixture of other waters. This assumes that the Rio 
Grande actually fails to drain the valley. I believe that this assump¬ 
tion is essentially correct and consider the results obtained in the 
analyses of the water as positively indicating this condition. 
There are two classes of artesian waters, white and brown. If 
the former class should find their way into the river through strata of 
sand, or as springs, they would not affect the character of the river 
water. The flow of the river might be increased in this way and the 
character of the water not changed any more than we find indicated by 
our analyses, namely, a slight increase in the quantity of the solids 
held in solution without any essential change in their character. In 
making this statement I am not forgetful of the fact that the increase 
in the amount of solids contained in the water may be accounted for 
by evaporation. It must be remembered that the increase found is 
only 3.5 grains per imperial gallon in samples taken at points in the 
river 100 miles apart. While shall n°glect the effects of evapora¬ 
tion it is evident that it may be an important factor. 
Prof. L. G. Carpenter gives, in a bulletin not yet issued, the re¬ 
sults of river gaugings in August, 1898, which show a total gain be¬ 
tween the U. S. Gauging Station above Del Norte and the State 
Bridge, of 15.75 ft.; in 1900, a total gain of 63.06 ft.; in 1901, a total 
loss of 11.01 ft.; in 1902, a total loss of 37.7 ft.; and in 1910, a total 
gain of 46.19 ft. Our samples of river water were taken in 1908 for 
