WSP08666

• File Number: 8221.112.I
• Description: Central Arizona Project
• State: AZ
• Basin: Colorado Mainstem
• Date: 3/19/1982
• Title: Final Environmental Impact Statement: Water Allocations & Water Service Contracting - Central Arizona Project
• Water Supply Pro - Doc Type: EIS

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SUMMARY

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I. PURPOSE AND NEED

The Secretary of the Interior proposes to allocate waters developed by
the Central Arizona Project (CAP) and to enter into water service contracts
for the delivery of such water. Through a system of pumping plants, canals,
dams, and reservoirs, the CAP will deliver Arizona's remaining entitlement to
Colorado River water as well as develop locally available surface waters from
the Gila River and its tributaries.

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A final allocation of CAP water is required so that identified CAP users
may design and construct the facH ities required to treat and del iver the CAP
water. Considerable lead time is required if users are to be ready to receive
CAP water when it comes on 1 ine to make water del iveries to the Phoenix and
Pinal County areas in 1985.

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II. DISCUSSION OF ALTERNATIVES

In order to assess the environmental impacts of the CAP water
allocations, estimates as to the availability of Colorado River water had to
be made. Differences exist between the Arizona Department of Water Resources
(DWR) and the Bureau of Reclamation (Bureau) estimates due to differing
methodologies as well as differing estimates of future water resources
development in the Upper Colorado River Basin. The DWR estimates of CAP water
availabil ity are greater than Bureau estimates.

It was agreed that a. Bureau sequence would be used to estimate water
availability, provided that the chosen sequence produced a long term average
supply approximating theDWR estimate. The sequence chosen for this EIS
produces ,a long term average Co] orado Ri ver water availabil ity of 1,298,000
acre-feet perye,ar.

A. Alternatives Considered

There are six alternatives being considered for allocating Arizona's
remaining entitlement of Colorado River water.

I. No Action

The "No Action" plan would allocate CAP water using the
philosophy in place at the time of the authorizing act (1968): M&I
del iveri es at 82,000 acre-feet, 232.000 acre-feet, and 312,000
acre-feet, in years 1975. 1990, and 2000 and after, respectively, in
the metropol itan Phoenix and Tucson areas (Senate Report No. 408,
1967). The remainder would go .to agricultural users (both Indian
and non-Indian) shared pro-rata on aCreage developed for irrigation.

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