PUB00055

• Year: 1961
• Title: Public Water Supplies of Colorado
• CWCB Section: Interstate & Federal
• Author: Gregg, Meyer, Targy, Moulder
• Description: Summary of statistical data describing the source, treatment and volumes of water used for public supplies by Colorado cities and towns
• Publications - Doc Type: Tech Report

platte River basin, the greatest concentration being in the
Denver metropolitan area. Other concentrations of use also
correspond with concentration of population: the next largest
populated drainage basin, which includes COlorado Springs and
Pueblo, used about 80,000 acre-feet or 24 percent of the total.
The use in other basins was relatively small.

Water sources.--The source of water supply selected by communi-
ties appears to be dependent largely upon its availability and
the size of the community. The largest cities generally do not
have an adequate source of ground water available nearby: whereas,
their readily available surface-water supply was adequate for
many years. When the nearby supplies became inadequate, they
were supplemented from other and more distant surface sources.
COnsequently, the use of surface water predominates. About
84 percent of the total amount of water used for municipal sup-
plies is from surface-water sources although about 55 percent
of the cities and towns utilize ground-water sources. Table 1
summarizes the supplies by sources. Ground-water use predomi-
nates in the eastern third of the State (fig. 2) where that
source is adequate to meet the demands and is generally of better
quality and more dependable than the available surface-water
sources. Elsewhere in the state, the selection of a source has
been generally a matter of economics. Ground water is generally
cheaper to develop than surface water because it requires less
treatment.

Water qualitv.--The study revealed that at least 100 communities
are using water that has concentrations of certain chemical con-
stituents greater than those recommended by the U.S. Public
Health Service for drinking water (see p. 23). The chief con-
stituents found in excessive concentrations were iron (Fe),
sulfate (SO ), and fluoride (F). Samples from 51 communities
showed excetsive iron: 34, excessive sulfate: and 32, excessive
fluoride. one or more of the sources for 27 communities yields
water containing more than 1,000 ppm (parts per million) dis-
solved solids. However, part of the supply for some of these
communi ties is of good quality. only three communi ties had
water exceeding the recommended limits for nitrate (N03).

The analyses show that at least 90 communities have a source
that yields hard water. Less than 10 communities soften the
water before it enters the distribution system. The severity
of the problem in some areas is demonstrated by the fact that
18 communities have water containing more than 500 ppm hardness
and two communities, Iliff and Las Animas, have water containing
more than 1,000 ppm hardness.

Sanitation of water supplies is another prOblem worthy of
mention. Table 1 shows that 167 of the 244 municipal supplies
are chlorinated. This safeguard to bacterial contamination is
generally less needed for ground-water supplies than it is for
surface-water supplies. However, shallow sources of ground

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