WSP09910

• File Number: 8281.960
• Description: Colorado River Studies and Investigations -- Lower Colorado Comprehensive Framework Study
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 6/1/1971
• Title: Lower Colorado Region Comprehensive Framework Study -- Appendix XVIII - General Program and Alternatives
• Water Supply Pro - Doc Type: Report/Study

SUMMARY OF FINDmGS

o
...-)
..... The Lower Colorado Region includes most of Arizona, and parts of
'""'" Nevada, New Mexico, and Utah comprising 4.8 percent of the contiguous
en United states. The Region is richly endowed with favorable climate,
W abundant land, mineral, and other resources and leads the Nation in
population growth rate as well as in several other economic indices.
The population is concentrated principally in central Arizona and the
Las Vegas, Nevada areas. The remainder of the Region is sparsely
settled and much is uninhabited.

Inventories and appraisals of resources and development of the
Lower Colorado Region were prepared for a base year, 1965, and a 55-
year projection time frame with three target years, 1980, 2000, and
2020. National interregional projections which equated national demand
and supply together with consistent regional projections based upon
historical trends in interregional production relationships, were
developed by the Office of Business Economics, U. S. Department of
Commer~e, and the Economic Research SerVice, U. S. Department of
Agriculture. These projections, referred to as OBE-ERS projections
in this study, were based upon specific assumptions. A primary
assumption was that the population of the United States will grow at
the U. S. Census Series C rate which is substantially below the 1962-
65 rate but above more recent rates. Other basic assumptions are
included in this and the other fUnctional appendixes relative to the
partic~lar resource aspect being considered. The OBE-ERS prOjections
for the Region were modified somewhat to more closely reflect regional
trends. These "Modified OBE-ERS" projections have been used in
development of the Lower Colorado Region comprehensive framework pro-
gram. A comparison of the Modified OBE-ERS and OBE-ERS projections
is included in the latter part of Appendix IV, Economic Base and
Projections.

i
I
I

Water Supply

Though land is abundant, the Region probably comes closer than
most any other to utilizing the last drop of available water for man r S
needs. The Region's economy is sustained by utilizing ground-water
reserves accumulated over thousands of years. In 1965, the depletion
rate of these reserves reached 2.5 million acre-feet annually largely
due to the lack of facilities for ,enabling the Region to utilize its
unused share of Colorado River water. The ongoing Southern Nevada
Water Project, presently under construction, the Central Arizona Project,
and the Dixie Project in Utah must be completed at an early date in
order for the Region to utilize the remainder of the available renewable
water supplies. However, in the absence of an imported water supply,
ground-water overdraft is expected to continue and the regional water
deficiency is projected to reach 4.50 million acre-feet annually by

i