WSP11852

• 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 - Appendix H-Section I
• Water Supply Pro - Doc Type: Report/Study

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Comment: Oirstream storage of surplus water will decrease the likelihood that water from
flood control releases will reach the Gulf of California, thereby reducing the quantity of water that
othetwise would be available for environmental restoration in the delta.

Response: Flood control releases are projected to average 788 kaflyear during the period
1999-2015. Oirstream storage could decrease flood control releases reaching Mexico by an
average of23 kaf/year during this time. The probability of occurrence offlood control releases
could decrease by 0.83 percent. These decreases fall within the range offlood control projections
previously consulted on in the 1996 Biological Assessment of Operations, Maintenance, and
Sensitive Species of the Lower Colorado River.

Please refer to the previous discussion of adequacy of the environmental assessment under
the Environmental Concerns section of the Public Comments on Proposed Rule and Responses
to General Issues.

Efficiencv ImDrovements

Comment: Efficiency improvements in river management and the storage of Colorado
River water in underground aquifers mean less water is available for environmental purposes, such
as the riparian and aquatic ecosystems of the river, including the river and delta region in Mexico.

Response: Please refer to the previous discussion of efficiency improvements under
Public Comments on Proposed Rule and Responses on General Issues,

Storaee Alternatives

Comment: It is not clear what storage options are available under the rule, or how the
rule would apply if there are changes in Arizona's laws or if California or Nevada enact
conflicting laws.

Response: The Department has modified this final rule in response to comments from
several State agencies, a water district, and a water authority. This final rule now provides in
~ 414.3(a)(2) and ~ 414.3(a)(3), respectively, for the storage of basic or surplus apportionment of
the Storing State, not othetwise put to use by entitlement holders within the Storing State, or
storage of the unused basic or surplus apportionment of the Consuming State. Ifunused
apportionment from the Consuming State is to be stored under a Storage and Interstate Release
Agreement, the rule provides that the Secretary will make that water available to the storing entity
in accordance with the terms of a Storage and Interstate Release Agreement and will not make
that water available to other entitlement holders, The final rule has been drafted to apply
uniformly to all three Lower Division States and the Department will not speculate about potential
changes in Arizona's laws or whether California or Nevada may enact conflicting laws,

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