WSP08437

• File Number: 8220.105.LJ
• Description: Navajo Reservoir
• State: NM
• Basin: San Juan/Dolores
• Date: 12/1/1983
• Title: Draft Hydrologic Determination - December 1983 - Water Availibility from Navajo Reservoir and the Upper Colorado River Basin for Use in New Mexico
• Water Supply Pro - Doc Type: Report/Study

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A.

Study Approach

The present operation of the reservoirs of the Colorado River System in accor-

dance with Public Law 90-537 Operating Criteria is based on a simple formula

approach that indicates water available for Upper Basin consumptive use would be

limited to an average of 5.8 MAr annually if delivery to the Lower Baain of 8.25

MAF is maintained during low flow periods similar to the most critical of

record. The formula, considering total water supply, available reservoir

storage, and total demands, is shown below:

Allowable Annual Upper Basin Depletion. (Useable Reservoir Capacity ~number of

years in critical period) + average

annual streamflow at Lees Ferry for

critical period - annual delivery to

Lower Basin + average annual shortage

Calculation of the 5.8 MAr Upper Basin depletion limit is explained as follows:

Reservoirs
Lake powe 11
Flaming Gorge
Navajo
Blue Mesa
Morrow Point
_ Crystal

(l,OOO's of acre-feet)
Minimum Power Pool
6,124 -
273
673
192
75
12

Available
20,876
3,516
1,036
749
42
13
26,232

Storage
27,000
3,789
1,709
941
117
25

The bottom line figure, 26.232 MAr, is added to the total virgin flow during the

most critical 34-year period (1931-1964) of 439.417 MAr. This equals 465.649

MAr. In essence, this means that the storage project adds water during the moat

critical period flow. Therefore, the most critical period flow with the storage

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