WSP08927

• File Number: 8141.600.20
• Description: Fryingpan-Arkansas Project - Studies - Environmental Studies
• State: CO
• Basin: Arkansas
• Water Division: 5
• Date: 10/12/1983
• Author: US DoI BoR
• Title: Draft Supplement to the Final Environmental Statement Fryingpan-Arkansas Project Colorado
• Water Supply Pro - Doc Type: EIS

0042

2.14

2.4 Summary of Impacts for Alternatives ,Considered in Detail

The following tables summarize the impacts and issues associated with the

alternatives. Table 2.2 contains both quantitative and qualitative data

derived from the text in Chapter IV, Environmental Consequences, and from

appendix material. Table 2.3 presents a qualitative assessment of whether,

and how well, the public issues and concerns are addressed by the

alternatives.

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The various environmental effects of the different alternatives are due

to differences in the amount of water sold from Ruedi, and differences in the

timing of the release of water from the reservoir. Alternatives 2 and 3 would

produce contracts for the largest amounts of water (over 70,000 acre-feet),

followed by Alternatives 4, 5 and the preferred (over 50,000 acre-feet) and

then Alternatives 6 through 10 (from 39,000 to 45,000 acre-feet). Even with

the largest volumes of water sales, there would not be any effects on erosion

or scour of stream channels because flow rates would never exceed the

threshold necessary to move bed materials in the rock and cobble controlled

stream channels. Significant flow changes greater than + 10 percent occur for

several months under all alternatives, but Alternatives 4 and 5 have the most

months of altered stream flows, followed by Alternatives 2, 3, 7 and the

Preferred, and then by Alternatives 6, 8, 9 and 10, which have the fewest

number of months with significantly altered stream flows.

The encouragement of water deliveries in the winter in order to avoid

significant reservoir drawdown in the summer recreation season, is best accom-

plished by Alternatives 3, 5, 6, 8, 9 and 10, and less so by Alternatives 2,

4, 7 and the Preferred. The capability to deliver water in the winter in

spite of possible icing conditions was judged adequate for all Alternatives

except 2 and 4, which have winter flow rates low enough that icing might pose

a problem in dry years.

The effects of the alternatives on fisheries were evaluated largely by

the amount and duration of habitat losses, with the alternatives falling into

three groups; one, Alternatives 2, 4, and 5 showed the greatest number of

months with significant trout habitat losses (more than 10 percent), followed

by Alternatives 7 and the Preferred, followed by Alternatives 3, 6, 8, 9 and

10 with the fewest months of habitat loss.

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