FLOOD09513

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: Fountain River Survey Report
• Date: 1/1/1951
• Prepared For: CWCB
• Floodplain - Doc Type: Flood Documentation Report

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The Survey Report states that the effect of the proposed program on the
availability of water for irrigation in the Arkansas River Basin has been considered
and evaluated. However, we find in our review that:

a. While the report states that the extent of water loss due to the
program has been estimated and evaluated on the basis of increased net
income per acre resulting from irrigation, and that this loss amounting
to $3,100 annually has been 'deducted from total benefits attributable to
the program, there are no substantiating data included in the report.

b. That water rights to the use of the water within the basin will
be purchased. However, there is no statement as to the location or amount
of the rights which will be purchased.

c. While the report states that installation of the program will cause
an increase in ground water within the Fountain River Watershed, the discussion
of ground water is extremely brief and no quantitative data are included.

d. The report contains considerable discussion of the 83,339 acres of
land in the Fountain River Watershed which have been set aside as water supply
areas for municipal water source. However, no data are presented as to the
effects of the proposed program upon the yield of water from these source areas.

~. The report states that on range land the proposedcp:'ogram will increase
forage by about 30 percent, on dry land farming areas the average yield will be
increased by about 25 percent, and on the area of privately owned woodlands the
program will provide favorable growing~onditions and greatly increase the
presently low annual growth rate. fresumably this increase of forage production~
crop yields, and woodland growth would. result'ih:the'use:coil."'aconsiderable
amount of water on the plains area, thereby depleting any increased storage of
water in the soil and probably resulting in a decrease in the net yield of
streamflow from this portion of the watershed. No data are presented of
evaporation, transpiration, or consumptive use.

f. The effect of the 2,800 small detention dams upon water yield for
irrigation is not analyzed. A recent study by the,United States Geological
Survey for the Cheyetme River Basin in South Dakota inGlfucated that the con-
struction of small detention dams with average storage capacity of 6.5 acre-feet
per square mile on that watershed could result in as much as 30 percent reduction
in the average streamflow.

g. In speaking 01: the mountainous portion of the watershed which consti-
tutes the major source of streamflow, the report discusses the proposed re-
forestation of a considerable area, the control of grazing, and fire protection.
It is to be expected that such measures would result in a reduction of sediment
yield and also in a reduction of the water yield. However, no evaluation is
presented from either viewpoint.

It is noted that United States Department of Agriculture Technical Bulletin No.
968, November 1948, prepared by H. G.Wilm and E. G. Dunford of the Rocky Mountain
Forest and Range Experiment Station at Fort Collins, Colorado, stated that selective
timber cutting in the lodgepole pine type of the Central Rocky Mountains exerts
a real and immediate influence on the amount of water available for'streamflow from
forested watershed lands. According to their study, this benefit can be accomplished

without significant increase in erosion. It is suggested that the United States

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