WSP09857

• File Number: 8200.400
• Description: Colorado River Basin Briefing Documents-History-Correspondence
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/1999
• Author: DOI-BOR
• Title: Programmatic Environmental Assessment-Rulemaking-Offstream Storage Colorado River Water - Development-Release Intentionally Created Unused Apportionment - Lower Division States - Final-Appendices A-G
• Water Supply Pro - Doc Type: Report/Study

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evaluating, processing, and executing a SIRA must be funded in advance by the authorized
entities which are party to that agreement.

II, PROPOSED ACTION AND ALTERNATIVES

A. Prooosed Action

The proposed action is the promulgation of a new rule to set forth the procedural framework for
the Secretary to follow in considering, participating in, and administering a SIRA among the
Lower Division States that would pennit State-authorized entities to store Colorado River water
off stream, develop ICUA, and make ICUA available to the Secretary for release and use in other
Lower Division States, The Rule will provide the authority for State-authorized entities to enter
into a SIRA and for the Regional Director of the Lower Colorado Region to be a party to and
execute a SIRA on behalf of the Secretary, The Rule would facilitate the interstate component of
the A WBA program and comparable measures that may be enacted in the future by other Lower
Division States,

B. Alternatives Analvzed

1, No Action Alternative:

Entities within each Lower Division State are entitled to consumptively use the quantity of
Colorado River water apportioned for use in that State. In a normal year, 7.5 million acre-feet
(mat) is available for consumptive use in the Lower Basin, divided as follows: 2,8 mafto Arizona.
4.4 mafto California. and 0,3 mafto Nevada, California's use has been exceeding its 4.4 maf
basic annual apportionment because the Secretary, in accordance with the Decree, has annually
released for consumptive use within California the Colorado River water apportioned to but
unused by Arizona and Nevada, However, this past use has not established any rights in the State
of California to future use of water in excess of California's annual apportionment of 4 ,4 maf. In
1996, AWBA initiated efforts to store Arizona's unused Colorado River water off stream in
Arizona, Arizona used its entire 2,8 mafapportionment in 1997 through a combination of direct
use and off stream storage, Under this alternative, Colorado River water will continue to be
diverted by existing facilities along the Colorado River including the CAP. Arizona will continue
to divert and store its unused Colorado River water off stream in existing facilities for its own use.
Without the Rule, A WBA would be unable to implement the interstate component of the Act and
enter into a SIRA, The A WBA would not be able to store Colorado River water for a State-
authorized entity in California or Nevada or develop ICUA for these entities.

Under the No Action Alternative, Nevada's consumptive use of Colorado River water will
continue to increase and Nevada users are expected to fully utilize Nevada's apportionment by
2004, Nevada will continue to divert its basic apportionment through existing diversion and
delivery facilities at Lake Mead, Nevada's diminishing unused apportionment will continue to be
subject to release for consumptive use in either California or Arizona. Nevada has anticipated the

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