PUB00068

• Year: 1952
• Title: A Hundred Years of Irrigatioin in Colorado, 100 Years of Organized and Continuous Irrigation
• Author: CWCB
• Description: Irrigation history of Colorado
• Publications - Doc Type: Historical

.J!9-..

~nderground Nate~ Res~~ of Colorado

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W. E. Code
Associate Irrigation Engineer, Colorado A & M College

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This setting is a most appropriate one to discuss the subject of
ground water. There is probably no place in the state where the people
are more conscious of that kind of water than those here in the San
Luis Valley. The water shortage of last year resulted in certain crop
losses but had it not been for the ready availability of ground water,
the financial loss would have been tremendous. Because of the unique
method of sub-irrigation employed here, .the condition of the water table
whether up or down, is always a subject of considerable concern. This
situation is rather a puzzle to those in other parts of the State not
familiar with sub-irrigation. Many would be greatly alarmed with water
standing at 2 feet below the surface. In no other part of the State
and in few parts of the United States is there s~ch a means of controlling the
height of the water table. But with a short water supply there are times
when control can be lost; the irrigation method must then be changed and
resort made to the pumps. . Last year of course was an outstanding example
of use of ground water. The amount of water pumped was at least twice that
of any previous year.

There are two main types of ground water occurrence recognized by
hydrologists. One. is that in which the water is confined by impervious
strata and is under pressure --we call it artesian water. Many are of the
opinion that artesian wells are only those that flow at the surface but
this is not necessarily a criterion. It is only a fortunate circumstance
that wells flow. They flow only because the land surface is lower than
the pressure head on .the confined water. Out on the edges of an artesian
basin the pressure may not be sufficient to tr.ing it to the surface but
the undersurface conditions may be the same. The other type of occurrence
is that of a free water table. The water level in a well in such a
formation stands at about where it was first encountered. Ground water of
this type is by far of the greater importance.

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Artesian conditions of economic importance occur in several parts of
the State. I will not take them up in order of importance but rather
geographically. In Baca County in the southeast corner of the State the
Ground Water Division of the United States Geological Survey in a recent
survey found 38 flowing wells. There are numerous artesian wells in otero
County, many of them flow. Such water is particularly valuable to that
area because of the poor quality of other water sources. There is a good
business around LaJunta in selling this water in tank trucks to farm homes.
There is also a small area of flowing wells around Canon City. Although
flowing wells are found here and there to the north on the eastern sl)pe,
only the Denver area is of real importance. There are many artesian wells
in the Denver Basin, some flow, some do not. Before the City of Den~er
provided an ample water supply to its environs, these wells were of very
great importance. They still are of importance but their usefulness has
been impaired greatly. by a 300-foot drop in pressure head since the first
ones drilled before the turn of the century. The weak artesian flows in
the Grand Junction and Montrose areas are of considerable importance because