WSP01501

• File Number: 8221.112.I
• Description: Central Arizona Project
• State: AZ
• Basin: Colorado Mainstem
• Date: 7/15/1982
• Title: Final Environmental Impact Statement: Tucson Aqueduct Phase A - A Feature of Central Arizona Project
• Water Supply Pro - Doc Type: EIS

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subsidence and fissuring. Land subsidence and earth fissuring are prominent
in the Eloy area west of the Picacho Mountains in the Phase A area and
imminent in the Avra Valley and the greater Tucson area which will receive CAP
water through Phase B of the aqueduct, Litigation between the various
competitors for the dwindling ground water has already begun and is likely to
intensify. Effluent from the urban areas would become more valuable and
possibly be applied to highest-bidder water demands. Existing agricultural
uses could be reduced or discontinued to alleviate the ground water overdraft.
CAP water would not solve these problems, but would allow orderly economic
adjustments to be made.

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2. Locally Implemented Alternative

This alternative is not actually within the jurisdiction of the
Bureau. The only Federal action required under this alternative is a
Secretarial allocation of water to the Tucson Aqueduct service area. Assuming
that some time before 2005 CAP water would become economically attractive for
M&I users in the Tucson area, a consortium of municipal and industrial users
would construct an aqueduct from the terminus of the Salt-Gila Aqueduct to the
Tucson area. This aqueduct would probably follow an alinement similar to one
of the two least-cost alternatives described in the draft EIS (Alternative 1
or 2). Environmental impacts would therefore be similar to those described
for Alternatives 1 and 2, although deferred for about 15 years.

As in the "no action" alternative, irrigation districts in northern
Pinal County, including the northern portion of the Central Arizona Irrigation
and Drainage District (CAIDD), could receive water via gravity from the end of
the Salt-Gila Aqueduct. It is not expected that the other agricultural
entities in Pinal County, or those within the Tucson AMA would have the
financial capability to contract for CAP water. Because this locally
implemented alternative would generally not serve the water users in the
Phase A area, it cannot be considered as an actual alternative to Phase A.
This alternative would serve only that function of Phase A which serves as a
connection for the Phase B facilities.

3. Aqueduct Alternatives

All the aqueduct alinements are expected to have similar impacts, so
the impacts of the alternatives will be discussed together, with differences
due to alinements pointed out. Table 1 shows a comparison of the net impacts
of the three alinement alternatives.

a. Biota

The main impacts due to canal construction would be loss of
habitat, drowning of wildlife in the canals, severance of wildlife movement
patterns, and some loss of wildlife species listed in "Threatened and Unique
Wildlife of Arizona" (Arizona Game and Fish COlill1ission, 1978).

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