WSP13003

• File Number: 8282.500
• Description: Coordinated Long Range Operation of Colorado River Reservoirs
• Basin: Colorado Mainstem
• Date: 3/29/2005
• Author: Federal Register
• Title: Long-Range Operating Criteria 6th Review Initiated 1/15/2002 Federal Register notice
• Water Supply Pro - Doc Type: Publication

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Federal Register /Vol. 70, No. 59/Tuesday, March 29, 2005/Notices

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believes that neither the structure,
format, nor content of the Operating
Criteria require significant revisions as a
result of actual operating experience. By
this Federal Register notice, based on
information submitted for review by the
Department of the Interior, the Secretary
has made a number of limited
modifications to the text of the
Operating Criteria. The bases for the
changes are: (1) Specific change in
Federal law applicable to the Operating
Criteria, (2) language in the current text
of the Operating Criteria that is
outdated, and (3) specific modifications
to Article IV(b) of the Operating Criteria
that reflect actual operating experience.
Comment No. 33-(Letter No. 18): We
do not object to the changes proposed in
the Federal Register notice.
Response: Comment noted.
Comment No. 34-(Letter No. 18): The
Upper Colorado River Commission does
not endorse the assumption and
objective in the Operating Criteria of a
minimum release of water from Lake
Powell of 8.23 million acre-feet every
year. If such a number is used in the
Operating Criteria, it must be
understood that this is a planning
objective which may be modified in the
Annual Operating Plan (AOP) to reflect
current conditions and in accordance
with Colorado River Compact
requirements. We remain concerned
about the drought and depletion of
storage at Lake Powell. It is imperative
that the Operating Criteria be
interpreted to have sufficient flexibility
to allow for modifications in the AOP as
needed to reflect critical conditions and
Colorado River Compact requirements.
Response: Article III of the Colorado
River Compact contains several
provisions relating to the release of
water from the Upper Basin to the
Lower Basin. The specification of a
minimum annual release objective from
Glen Canyon Dam is found only in
Article 1I(2) of the Operating Criteria
which states that" * * * the objective
shall be to maintain a minimum release
of water from Lake Powell of 8.23
million acre-feet * * *."
Because the minimum annual release
objective is higher than inflow during
periods of drought, storage in Lake
Powell is drawn down during a drought.
The more severe the drought, the more
significant the drawdown is at Lake
Powell. Storage in Lake Powell recovers
during normal or wet years. Lake Mead
storage decreases during drought as
well, but does so at a slower rate
because of the presence of the minimum
annual release objective from Lake
Powell.
Representatives of the seven Colorado
River Basin States, Reclamation, and the

Western Area Power Administration are
investigating impacts of prolonged
drought where reducing the release from
Lake Powell below the 8.23 million
acre-foot per year objective would
protect the minimum power pool at
Lake Powell and the water supply for
the Upper Division States of Colorado,
New Mexico, Utah, and Wyoming. The
2005 Colorado River Annual Operating
Plan (AOP) calls for an April 2005 mid-
year review of the 2005 annual release
amount from Lake Powell to determine
if the runoff forecast warrants an
adjustment to the annual release for
water year 2005.
Determinations of Upper Basin annual
deliveries (annual releases from Lake
Powell) are made in the AOP. The AOP
is prepared each year by the Deparhnent
of the Interior through the Bureau of
Reclamation in consultation with the
seven Basin States Governors'
representatives; the Upper Colorado
River Commission; Native American
tribes; appropriate federal agencies;
representatives of the academic and
scientific communities, environmental
organizations, and the recreation
industry; water delivery contractors;
contractors for the purchase of federal
power; others interested in Colorado
River operations; and the general public
through the Colorado River Management
Work Group. The Department, through
Reclamation, will continue to address
issues related to low reservoir storage
caused by drought in the AOP
consultation process.
Comment No. 35-(Letter No. 18):
Decisions regarding the timing for the
next review should be left open.
Response: The Department has made
no decision regarding the timing of the
next review of the Operating Criteria.
Comment No. 36-(Letter No. 19): It is
critical for the Operating Criteria for
reservoir operations to uphold the intent
of the 1922 Colorado River Compact.
The Operating Criteria should be
flexible and responsive to variations in
hydrologic conditions, and should not
jeopardize the interests of the Upper
Basin.
Response: See response to Comment
No. 34.
Comment No. 37-(Letter No. 19): The
1922 Colorado River Compact
anticipating fluctuating hydrologic
conditions specified Upper Basin water
deliveries as a 10-year progressive
series. We note that the existing
Operating Criteria dictate the minimal
annual release of 8.23 million acre-feet
which is counter to Article III(d) ofthe
1922 Colorado River Compact.
Response: See response to Comment
No. 34.

Comment No. 38-(Letter No. 19): We
are also concerned that the Operating
Criteria contain a requirement to
equalize Lake Mead with Lake Powell
during times of Upper Basiu water
surpluses, but that there are no
provisions to equalize the level of Lake
Powell with Lake Mead during times of
Upper Basin drought for so long as the
Upper Basin is conditionally satisfying
its 10-year water delivery obligations.
Response: Article 1I(3) of the
Operating Criteria contains a
requirement that releases greater than
8.23 million acre-feet be made only
when reservoir storage in the Upper
Basin is greater than 602(a) Storage.
Article 1I( 1) of the Operating Criteria
describes 602(a) Storage.
There is no provision in the Operating
Criteria to equalize the level of Lake
Powell with Lake Mead during times of
drought when reservoir storage in Lake
Powell is lower than Lake Mead.
However, river simulation modeling of
the Colorado River system shows that in
the future there will be times when Lake
Powell storage will be greater than Lake
Mead. This will occur because of the
application of 602(a) Storage provisions.
See Colorado River Basin Project Act at
section 602(a). Following a drought, the
602(a) Storage provision in the
Operating Criteria allows Lake Powell to
refill to a level sufficient to protect the
Upper Basin from future droughts.
Releases greater than the objective
minimum are not made from Lake
Powell until this level of storage is
achieved. It is likely that when the
current drought comes to an end, during
a year (or series of years) with above
average inflow to Lake Powell, reservoir
storage in Lake Powell will exceed that
of Lake Mead.
In 2004, an Interim 602(a) Storage
Guideline was adopted that set 14.85
million acre-feet of storage (elevation
3,630 feet) at Lake Powell as the
minimum level for 602(a) Storage
through the year 2016. See 69 FR 28945
(May 19,2004). Under this interim
guideline, releases greater than the
minimum objective release will not be
made when Lake Powell is projected to
be below elevation 3,630 feet. Thus,
while Lake Powell storage decreases
faster than Lake Mead during periods of
drought, the 602(a) Storage provision
allows Lake Powell storage to rebound
quicker than Lake Mead when there is
a return to average or wetter than
average hydrology. In addition, see
response to Comment No. 34.
Comment No. 39-(Letter No. 19):
Presently, there exists a large imbalance
between the water volumes in Lake
Mead and Lake Powell (14.3 million
acre-feet to 8.8 million acre-feet), which