Coordinated Long Range Operating Criteria--Colorado River Reservoir (1970)

The Coordinated Long-Range Operating Criteria for Colorado River Reservoirs were promulgated pursuant to Section 602(a) of the 1968 Colorado River Basin Project Act by the Secretary of Interior and noticed in the Federal Register on June 10, 1970.

These operating criteria control the coordinated long-range operation of storage reservoirs and projects in the Colorado River Basin constructed under the authority of:

Colorado River Storage Project Act (i.e. Powell, Flaming Gorge, Aspinall Unit, Navajo, and participating projects),

Boulder Canyon Project Act (i.e. Lake Mead)

Colorado River Basin Project Act (i.e. Central Arizona Project).

The operating criteria require a determination by the Secretary of Interior of the amount of water required to be in storage in order to assure that beneficial consumptive use of water in the Upper Basin is not impaired ("602(a) storage requirements").

If active storage is less than 602(a) storage requirements or if active storage in Lake Powell is less than active storage in Lake Mead, then the objective release from Lake Powell for the coming year will be 8.23 million acre-feet.

However, if Lake Powell storage exceeds 602(a) storage requirements and is higher than Lake Mead's, then releases greater than 8.23 million acre-feet will be made to maintain the active storage in Mead and Powell at approximately equal amounts (equalization).

The operating criteria also provide for the release of water from Lake Mead to meet Mexican Treaty obligations, reasonable consumptive use requirements of mainstem users in the Lower Basin, net river losses, net reservoir losses, and regulatory wastes.

Until such time as these demands exceed 7.5 million acre-feet in the Lower Basin a normal water supply condition exists in the Lower Basin. Criteria for determining surplus and shortage conditions are also contained in the criteria.

It has been demonstrated that the yield of the Colorado River System is less that what the 1922 compact negotiators originally believed.

At Lee Ferry the yield only averages 15.0 million acre-feet annually.

To the Upper Basin this means that its compact entitlement may be reduced by one-half the Mexican Treaty obligation or 750,000 acre-feet. While the Upper Basin states do not agree with this interpretation, the operating criteria still contain a minimum annual objective target release for Lake Powell of 8.23 million acre-feet annually.

When Reclamation further considers the yield to the Upper Basin during the critical period of record (drought period) the yield to the Upper Basin may only be 6.0 million acre-feet annually. An Upper Basin yield of only 6.0 million acre-feet means Colorado would only be entitled to consumptively use 3.079 million acre feet annually.

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