WSP01381

• File Number: 8281.300
• Description: Colorado River Studies and Investigations - Colorado River Consumptive Uses and Losses Report
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 2/2/1989
• Title: Hydrologic Determination 1988 - Water Availability from Navajo Reservoir and the Upper Colorado River Basin for Use in NM
• Water Supply Pro - Doc Type: Report/Study

~ Additional analyses were made at the request of the Upper Basin states
minimum reI eases set at 7.5 MAF annually. The difference between relea
can be translated directly into increased yield to the Upper Basin. Mas
balance analyses similar to those described above were made using both
20.197 MAF of storage ("empty" at top of inactive pools') and 23.141 MAF
("empty" at bottom of inactive pools). The firm yields for the basin (n
shortages) were calculated at 6.28 MAF and 6.40 MAF respectively. Figur
5 and 6 show the relationships between yield, shortages and probabilitie
As indicated in the earlier examples, these should be considered
approximate relationships.

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B. Conclusions and Recommendations

Table 2 shows a .summary of the results of this investigation.

Study
1967 study

Hydrology
Virgin Flow

Current Studies
Maintain
Min. Pools

CRSS Nat'l
CRSS Nat'1

Use
Min. Pools CRSS Nat'l
CRSS Nat'l
1/ Yield has approximately a
about a 6% shortage.

TABLE 2

Summary Results

Storage
(MAF)
26.232

Min.
Release
(MAF)
8.25

Without
Shortages
(MAF)
5.45

Yield
With Tolerable
Shortages II
(MAF)
5.80

20.197 8.23 5.55 6.00
20.197 7.5 6.28 6.77
23.141 8.23 5.67 6.09
23.141 7.50 6.40 6.88
98.5% probability of being sustained with

Use of the eRSS hydrology data base and system storage availability as
determined from the use of CRSS indicate that the Upper Basin firm yield,
without acceptable shortages, is about 100,000 acre-feet greater than was

10