WSP01059

• 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 VI - Land Resources and Use -- Appendix VIII - Watershed Management
• Water Supply Pro - Doc Type: Report/Study

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SUMMARY

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~ The basic purposes of the Land Resources and Use and Watershed
Manage~ent appendixes are to express the interrelationships of land and
water and to provide, for the years 1980, 2000, and 2020, a broad guide
to the wise use, treatment, and management of land resources in the
Lower Colorado Region to"maintain and improve the productivity and
enviroIllllental stability of the land base. The information presented in
this appendix should provide most of the land-oriented data required
for the other appendixes and for the Main Report.'

The Lower Colorado Region, as defined for purposes of this water
and related land resource study, occupies 90,328,000 acres (141,137
square miles) in the Pacific Southwest area of the United States. The
1965 population of the Region was 1,847,300 (hydrologic area).

Elevations within the Region range from slightly under 100 feet
above sea level near Yuma., Arizona to over 12,500 feet on Humphreys
Peak near Flagstaff, Arizona. Although aspect, latitude, prevailing
winds, and storm patterns directly influence temperature and precipi-
tation, .the range in elevation is the major influence. A combination
of these factors present variable management problems related to the
associated activity, vegetation, erosion, water yield, etc.

The Lower Colorado Region has a wide variation in vegetal cover
types. .The forest types extend from the small alpine areas' on top of
the highest mountain peaks; through the coniferous forest zones of
spruce-fir, Ponderosa pine, and the pinon-juniper and oak woodlands,
and the chaparral types. The rangeland type extends from the forest
type through the northern and southern desert shrubs, the northern and
desert grasslands, down through a small area of true desert near the
mouth of the Colorado River on the boundary between Mexico and Arizona.
Scattered throughout the Region are areas of cultivated land, including
irrigated pasture, with the largest blocks in the lower Gila and the
southern half of the Lower Main Stem subregions. More than 500,000
acres of the Region are developed as urban and industrial areas. More
than 340,000 acres of the Region are occupied by water in the form of
streams, lakes, impoundments, and reservoirs.

About 52 percent of the total land is federally owned, 12 percent
is in state and other public ownership, and 36 percent is private land.
About one-half of the latter is in Indian reservations held in trust by
the federal goverIllllent.

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