WSP06362

• File Number: 8210.470
• Description: Pacific Southwest Interagency Committee
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 11/1/1971
• Author: PSIAC
• Title: Pacific Southwest Analytical Summary Report on Water and Land Resources based on Framework Studies of Four Regions - November 1971
• Water Supply Pro - Doc Type: Report/Study

Economic Projections

The estimated 1965 population, employment, and
personal income of the Pacific Southwest, along with
1968 OBERS projections of these parameters, are
sl;1own in table 6.
The resource requirements to support the pro.
jected population and production were estimated by
each region. The water requirements for municipal
and industrial use, the needs for fish and wildlife and
recreation activities, and the requirements for flood
control and shoreline protection and development
were estimated as a function of population. The land
requirements and the water requirements for irriga.
tion were related directly to the production of
specific quantities of agricultural products, giving due
regard to expected technological advances in agri-
culture during the time frames of the projections.

BASE PLAN PROJECTIONS

After analyzing the 1968 OBERS projections and
comparing them with historic data, the California,
Lower Colorado, and Upper Colorado Regions each
developed another set of projections which they
believed would more closely reflect what could be
expected in the future. These are the base plan
projections. The Great Basin Region did not develop
alternatives to the OBERS projections but did
analyze the economic impacts of maintaining Pyra-
mid and Walker Lakes. The new projections resulted
in higher levels of food and fiber production in eac/1
of the three regions relative to the 1968 OBERS level.
In the California Region, a population distribution
shift from south to north was made, but total
population remained in agreement with the 1968
OBERS level. However, a change in the regional share
of national crop production from the OBERS level
caused irrigation of agricultural lands to be increased
by 1.2 million acres with a resulting need for
additional 7.2 million acre.feet of irrigation water.

In the Lower Colorado Region, population and
irrigated acreage both were increased over the 1968
OBERS levels as a result of a net reduction in the
level of food and fiber imports. In addition, mining
and electric power outputs were increased. The
modified projection would require a more rapid rate
of water-related development until year 2000, and
then a reduced development rate until 2020 as the
two projections converge to within 15 percent of
each other.

The Upper Colorado Region developed new pro.
jections for food and fiber in the agricultural crop
sector which provided sufficient crop production in
the Region to supply the feed for the projected
livestock population. Additionally, increased activity
was projected for forestry, electric energy, minerals,
and all other sectors for which interdependent rela.

36

tionships indicated increased output would be reo
quired.
The difference in water requirements between the
1968 OBERS projections and the base plan water
requirements for the Pacific Southwest in 2020 is
substantial and amounts to 9 million acre.feet of
water annually.
Estimates of electric power requirements were
based on an analysis of 30 years of recorded classified
sales data, on population projections, on use per
customer, on number of customers, and on other
factors.
Projections of commercial navigation tonnage were
obtained from existing Federal navigation documents
and studies. They were updated to include the period
1965 through 2020.

OTHER PROJECTIONS

1969 OBE projections were developed for each
region based upon regional comments regarding the
1968 OBERS projections. Changes were relatively
minor, however, a'nd since the projections were
developed rather late in the study period, little
analysis of their impact was made.
Each of the "other projection" levels discussed
below was studied in a single region and is, therefore,
not susceptible to summarization on a Pacific South.
west basis.
The California Region analyzed the impact of
what is termed "Series D 1970" population pro.
jection. Both the base plan and the 1969 OBERS
projections were based on a U.S. Census Series C
projection. The Series D 1970 population projection
was based on a growih rate more indicative of recent
trends, with population reaching 45 million instead of
54.9 million by 2020.
In the Lower Colorado Region the Economics
Work Group developed an estimate of electric energy
requirements amounting to 32.2 percent of the
requirements as estimated by the Electric Power
Work Group and as used in the base plan. Total
electric power requirements under the two projec-
tions were 181,515 glgawatt.hours and 564,540
gigawatt.hours.
The Upper Colorado Region, in addition to the
framework (regional interpretation of 1968 OBERS)
plan projections, developed four alternatives. The
first was an alternative with an associated use of 6.0
million acre-feet of water; the second was an alterna.
tive use for the 6.5 million acre.feet of water used in
the framework plan; the third developed a use of 8.16
million acre.feet; and the fourth developed use of
9.4 million acre-feet. The base-line projections
involved the same increased crop production relative
to 1968 OBERS as did the regional interpretation
plan, but not the increased production in the noncrop