WSP09215

• File Number: 8281.300
• Description: Colorado River Studies and Investigations - Colorado River Consumptive Uses and Losses Report
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1982
• Title: Plan of Study - Colorado River System Consumptive Uses and Losses Report 1976 - 1980
• Water Supply Pro - Doc Type: Report/Study

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The ~eport will contain a caveat that nothing in it is intended to

interpret provisions of any other legislation, compacts, decrees, or treaties.

Previous Study

The first study to be prepared under the legislation covered the reporting

period 1971-1975, inclusive. After initial meetings with representatives of

the Lower Basin States and the Upper Colorado River Commission, a proposed

Plan of Study was presented for co~ent. Comments received largely concerned

water accounting procedures, particularly the lack of uniformity and consistency

within the system. In November 1974, a preliminary report was prepared which

included estimates of beneficial consumptive use. Comments received from the

States were essentially the same as for the Plan of Study. In the Upper

Basin, the principal comment concerned the use of 1965 data bases developed

for the Upper Colorado Region Comprehensive Framework Study, particularly

irrigated acreage. In the Lower Basin, the main concerns were the lack of

credit for unmeasured return flows originating from mainstream diversions ~
,

the failure to quantitatively recognize that ground water overdraft in the

Gila River Basin satisfies a major portion of the beneficial consumptive

use, and the lack of uniform procedures in the Upper and Lower Basins for the

determination of water uses.

The first report was completed in May 1977 and distributed to the President

and Congress on October 27, 1977.

Responsibilities

The authorizing legislation directed the Secretary of Interior to prepare

the report. It has been assumed that the Bureau qf Reclamation has the

responsibility for preparing the report for the Secretary. As was the case

for the previous report, consumptive use and loss values for the Upper

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