WSP07784

• File Number: 8221.112.I
• Description: Central Arizona Project
• State: AZ
• Basin: Colorado Mainstem
• Date: 4/29/1983
• Title: Draft Environmental Impact Statement: Regulatory Storage Division - Central Arizona Project
• Water Supply Pro - Doc Type: EIS

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SUMMARY

I. PURPOSE AND NEED FOR THE ACTION

A. Background

This environmental impact statement (EIS) describes and
evaluates the proposed construction and operation of the Regulatory
Storage Division of the Central Arizona Project (CAP) Construction of
the CAP Regulatory Storage Division was authorized by Section 301(a)(3)
of the Colorado River Basin Project Act (P.L. 90-537) of 1968. This
feature of the CAP is being investigated under the title Central Arizona
Water Control Study (CAWCS).

The CAP was authorized on September 30, 1968; its principal
purpose is to furnish water for irrigation, municipal, and. industrial
use in central Arizona and western New Mexico through the importation of
water from the Colorado River and conservation of local surface waters.
Because of its large size and complexity, the CAP is divided into
several features serving separate but interrelated functions. Six
features, including the main aqueduct system (Granite Reef, Salt-Gila,
and Tucson Phase A) are currently completed or under construction. Five
remaining features, including the Regulatory Storage Division, are in
the planning stage.

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An overall EIS was filed for the entire CAP on September 26,
1972 which committed the Bureau of Reclamation (Reclamation) to prepare
site-specific EIS's for individual CAP features. The six alternatives
for the Regulatory Storage Division described in this EIS address
regulatory storage of CAP water and flood control of the Salt and Gila
Rivers through metropolitan Phoenix.

The EIS also describes concurrent and coincident aspects of
the Safety of Dams (SOD) program. The 1978 Reclamation Safety of Dams
Act (P.L. 95~578) directs the Secretary of the Interior to preserve the
structural safety of Reclamation dams and related facilities by
performing modifications that may be reasonably required. Since the
construction and operation of the CAP Regulatory Storage Division and
SOD features will involve common timing and locations, the purposes of
both authorizing legislations have been combined in the CAWCS.

The EIS is supported by 15 technical reports covering all
aspects of CAWCS planning, designs, public involvement, social and
envi ronmenta 1 impact assessment, economi cs, and hydro 1 ogi ca 1 ana lyses.
Supporting documents are available for review at the Arizona Projects
Office of the U.S. Bureau of Reclamation. Copies of the Draft
Environmental Impact Statement may also be obtained from Reclamation by
those requiring more detailed information than is presented in this
summary.