WSP10994

• File Number: 8210.470
• Description: Pacific Southwest Interagency Committee
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 3/1/1962
• Author: PSIAC
• Title: Stock Water Facilities Guide - March 1962
• Water Supply Pro - Doc Type: Report/Study

GJ1498
The consumpt ive us e of water by vegetation for the 6 to 8 month
summer per iod, as shown by table 1, approaches one-half to three~fourths
of the total annual free water evaporation. Applying these loss 'rates to
areas of phreatophytes growing at or near springs, it can be seen that
whenever such an area approaches 0.4-0.5 acre in the north and 0.2-0.3
acre in the south, sufficient water is being wasted to supply the drinking
requirements for a herd of 100 cattle during the summer grazing period,
provided the water can be salvaged and properly conserved and used. As
the actual salvage will be dependent on local condit ions, it is imposs ible
to give any quantitative data on expected savings.

Increas ing the usable flow of springs by eliminating waste can be
accomplished in several different ways. In many instances the utility of
the spring can be substantially increas ed by merely collecting the discharge
into some type of suitable container or trough where it becomes readily
available for livestock use rather than let it spread through a muddy or
swampy area where stock must drink from hoof prints or other similar
temporary depressions. Salvaging water being used by vegetation may be
accomplished by preventing the water from reaching the plants, lowering
the water table to a depth whel'e the plant use is small, or by destruction
of the plant.

Where the spring issues from a single opening, the water may be
prevented fr,om reaching the plants by enclos Lng the opening in some type
of box from which the flow is piped to a suitable ,trough',or storage tank.
Cienega or swampy areas having no well-defined openings are most amenc
able to treatment by lowering the water table. Installation of drain tile or
use of open drains, or the French drains, are effective for this purpose.
Destroying vegetation for salvage of water will be most effective when aug-
mented by installation 6f a drain and collection system, otherwise the
treatment is likely to result in a higher water table with an: accompanying
increased loss from evaporation from the ground surface and an early
regrowth of the phreatophytes. In a few cases it has been found that
removal of one or more large trees from the spring area was sufficient
to increase the flow to acceptable needs without the installation of a drain-
age system. It should be emphas ized that salvage of water by preventing
its use by plants is a continuing task and periodic efforts will be needed to
destroy new growth and to keep the system in repair so that plants are not
allowed access to the spring flow.

In general, treatment of a spring to increase the yield is a techni-
cal problem involving ecologic, engineering, and geologic principles and
should be undertaken only with the advice of experienced and competent
specialists. This applies particularly to attempts to increasing flow by
blasting the spring opening, a procedure which for some reason seems to
have unusual appeal to many, yet which experience shows more often results
in reduct ion of flow rather than incr eas e. Throughout the Pacific Southwest

7

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