WSP08006

• File Number: 8221.112.A
• Description: Central Arizona Project
• State: AZ
• Basin: Colorado Mainstem
• Date: 6/7/1963
• Title: Supplemental Report: Central Arizona Project
• Water Supply Pro - Doc Type: Report/Study

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Hork on updatinG DJ1d reevaluating the Central Arizona Project plan was

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undertaken by the Bureau of Reclamation in May 1961 under the terms

of the previously mentioned contract of April 24, 1961, between the

United States and the Arizona Interstate Stream Commission. The

results of these investigations were presented to the Commission in an

appraisal report dated January 1962. The appraisal report prepared for

the States of Arizona and New Mexico was based on the assumption of a

water diversion of 1,200,000 acre-feet annually from the Colorado

River. This is the same assumption that was used in the 1947 report

and also in this supplemental updating report.

Present Conditions

Studies show that the present economy of central Arizona is now

supported by essentially full utilization of the local surface-water

supplies and by excessive pumpage and resultant depletion of the

ground-water resources of the area. Present ground-water pumping is

about 4,300,000 acre-feet annually, of which about 2,200,000 acre-feet

represents an overdraft, or mining, of the ground-water basin. Water

levels are dropping progressively year by year and, unless remedial

measures are taken without delay, the present econODW will suffer

before an additional water supply can be brought into the area.

Since 1951, when Congressional hearings were last held regarding the

project, the population of the project area has approximately doubled.

OVer one million people now live in the area and large areas of land,

formerly irrigated, have been subdivided for or have been converted

into urban developments. Official census reports show that the

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