The Waters of the Rio Grande 51 
A REVIEW OF THE HYDROLOGICAL FACTS 
In this work we find that the river water is characterized by a 
composition peculiar to mountain waters which is the result of the ac¬ 
tion of pure water on the rocks of the mountains, or the gathering 
grounds of the rivers. There are but comparatively few minerals con¬ 
cerned in the reactions which it is necessary to consider in this con¬ 
nection, in fact, we can confine our consideration to the plagioclase 
felspars, because these are the minerals that play the predominant part 
in these reactions. It is scarcely necessary to state that it does not 
matter whether the felspar constitutes a part of a metamorphic or an 
igneous rock, though its association and physical condition may affect 
the rate of alteration. Our white artesian water, especially from the 
shallower flows, differs but little from the mountain water, in fact, 
the water from a depth of 923 feet from the Bucher Well at Alamosa, 
carries only about three times as much mineral matter in solution as 
the Rio Grande water taken just above Willow Creek, but otherwise 
it is similar, exchanging lime for soda. 
The residue from the water of this deep well contains 50 percent 
silicic acid, 14 percent carbonic acid (CO2) and 23 percent sodic oxid, 
with some lime. The river water contains 43 percent silicic acid, 13 
percent carbonic acid and 20 percent lime with 6.8 percent soda. The 
great change here is the exchange of lime for soda. When we pass 
from the area of white waters to that of the brown waters we find a 
further change in the elimination of the silicic acid and an increase in 
the amount of soda present with an almost complete elimination of the 
lime. The brown color is accidental for we have almost colorless 
water from this same area very rich in sodic carbonate. These pecu¬ 
liarities of composition are maintained by the different flows. The 
shallower flows may not be so deeply colored nor so heavily charged 
with mineral matter, but the composition of the mineral matter has 
the same peculiarities—absence of silicic acid and lime with sodic car¬ 
bonate very strongly predominant. This is true of shallower wells, 
15 feet in depth, which yield a white water carrying about 20 grains 
of total solids to the imperial gallon. Fifty percent of this was found 
to be sodic carbonate. The sulfates were not determined in this sam¬ 
ple. This is an agreeable, cool water used for domestic purposes. The 
excellent quality of this water seems remarkable, for the whole coun¬ 
try in this section is quite alkaline, in fact, there is a piece of land 
within a short distance of this well that is in very bad condition and 
white alkali is very abundant. The prevalent unproductive condition 
of the land and the area of sodic carbonate-bearing artesian water, 
usually brown in color, are nearly if not altogether coincident. 
It is true in both areas, that of the white acid artesian waters and 
that of the brown alkaline waters, that the deeper flows are richer in 
