WSP11719

• File Number: 8220.101.10.D
• Description: Glen Canyon Dam/Lake Powell
• State: AZ
• Basin: Colorado Mainstem
• Date: 10/19/1994
• Title: CWCB Agenda Item 21 ‎(c)‎ - Experimental Flow ‎(Spike Release)‎ - Flood Frequency Reduction
• Water Supply Pro - Doc Type: Board Memo

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Charles A. Calhoun - Glen Canyon Dam operations
September 23, 1994
Page 2

long-term yield to the upper Basin from reserving exclusive flood
control space in the reservoir by using lower storage levels.

Apparently, the comments to the DEIS (which we have not seen) were
to the effect that the environmental impacts of installing the
flashboards were not adequately analyzed in the DEIS. If this is
true, then it is equally obvious that the environmental impacts of
reserving "flood control space" have not been analyzed. In fact,
there is no analysis in the DEIS of the environmental impacts
associated with this alternative. Therefore, this alternative
could be implemented only after the preparation of a supplemental
draft EIS. Although the surface level of Lake Powell does
fluctuate widely in the course of normal operations, the Lake level
would not be as high, and would be lower on a more frequent basis,
if "flood control" space were expanded.

Perhaps more importantly, the alterative of "reserving additional
exclusive flood control space" is specifically prohibited by the
terms of the Grand Canyon Protection Act. Therefore, this
alternative cannot be implemented absent a change in the Law of the
River. The Act provides that interim and long-term operations at
Glen Canyon Dam must be undertaken:

[I]n a manner fully consistent with and subiect to the
Colorado River Compact, the Upper Colorado River Basin
Compact, the Water Treaty of 1944 with Mexico, the Decree
of the supreme Court in Arizona v. California, and the
provisions of the Colorado River storage Project Act of
1956 and the Colorado River Basin Project Act of 1968
that govern allocation, appropriation, development, and
exportation of the waters of the Colorado River Basin.

Grand Canyon Protection Act, section 1802(b).

In order to make it clear that operations of Glen Canyon Dam are
subject to the Law of the River, the Act specifically provides that
the long-term criteria be "separate from and in addition to
operations specified in section 602(b) of the Colorado River Basin
Project Act of 1968." section 1804(c) (1) (A). Operating criteria
under the Grand Canyon Projection Act are prepared only after the
preparation of annual operating plans specified in section 602(b)
of the Colorado River Basin Project Act of 1968. The determination
of operations related to "flood control" under section
602(a)(3)(iii) is part of the overall river operations, to which
operations under the Grand Canyon Protection Act are subject, and
subservient.

This interpretation of the Grand Canyon Protection Act of 1992, and