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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and the Buckeye and Holly Acres subdivision areas. Numerous infrastructure and
transportation networks and facilities are also located in the floodplain area.

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IV. ENVIRONMENTAL CONSEQUENCES OF ALTERNATIVES

Tables 4. 5, and 6 provide a description of the environmental consequences
of the alternative plans, focusing on the significant resource categories
identified during scoping. These tables summarize the analysis in a large
number of CAWCS supporting documents, including Sta e III Methodolo for
Environmental Qualit Assessment. Environmental Im acts and Effects of Plans 7
vols. , Social Impacts and Effects of C WCS Plans, and Economics-Financial
Supporting Document.

A. Methodology

1. Impact Assessment

The procedure for assessing impacts of the plans involved
aggregating impacts of the elements (Cliff. New/Modified Roosevelt,
New/Modified Stewart Mountain, Confluence, New Waddell Dams) that compose the
plans. The impact assessment methodology consisted of a series of steps
whereby environmental conditions without the project were compared to
conditions with the project. The measured difference between the two
conditions for a factor (i.e., stream-oriented recreation) is the impact. The
basel ine condition without the project is a projection of all the relevant
environmental factors into the year 2000. This future-without condition would
occur if there were no project action and is therefore the condition associated
with Plan B, the No Action Alternative. The condition that would occur with
each of the action alternatives (Plans 1, 2, 3, 6, 7) was compared against thi.s
future-without condition to arrive at the impact.

All aspects of project action were considered in assessing
impacts, including construction, reservoir inundation, operation/maintenance,
and secondary use.

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2. Effects Evaluation

While the impact is the measured difference between
future-without and future-with conditions for a factor, the effect is the
interpretation of the significance of the impact. Effects were determined on
the basis of the impact's direction (beneficial or adverse), duration
(short-term or long-term), magnitude (degree of change), and the quality of the
affected resource. Beneficial effects indicate that the quality of the
resource is improved; adverse effects indicate the quality is degraded.
Depending on the characteristics of the impact, one of the following effect
levels has been assigned:

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Insignificant (I): small, ephemeral change, usually affecting a
low-quality resource

Significant Beneficial (SB): major improvement in a condition,
usually long-term and affecting a high-quality resource

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