WSP09055

• File Number: 8281.100
• Description: Colorado River Studies and Investigations -- Availability of Water-Hydrologic Determination
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1988
• Title: Hydrologic Determination - 1988 - Water Availability 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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',Additional analyses were made at the request of the Upper Basin States with
minimum releases set at 7.5 MAF annually. The difference between releases
can be translated directly into increased yield to the Upper Basin. Mass
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 (no
shortages) were calculated at 6.28 MAF and 6.40 MAF respectively. Figures
5 and 6 show the relationships between yield, shortages and probabilities.
As indicated in the earlier examples, these should be considered
approximate relationships.

B. Conclusions and Recommendations

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

TABLE 2

Summary Results

Study
1967 Study

Hydrology

virgin Flow

Storage
(MAF)
26.232

Min.
Release
(MAF)
8.25

Yield
with Tolerable
Shortages ,!/
(MAF)
5.80

Without
Shortages
(MAF)
5.45

Current Studies
Maintain
Min. Pools

8.23
7.5

5.55
6.28

6.00
6.77

CRSS Nat'l
CRSS Nat'l

20.197
20.197

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

5.67
6.40

23.141 8.23
23.141 7.50
98.5% probability

6.09
6.88

of being sustained with

Use of the CRSS 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