9570

• UCREFRP Catalog Number: 9570
• Author: U.S. Department of the Interior.
• Title: Preliminary Analysis
• USFW Year: 2000.
• USFW - Doc Type: Wayne N. Aspinall Unit Operations and the Federal Water Right Claim, Black Canyon of the Gunnison National Park.
• Copyright Material: NO

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A Base: This model run reflects current operations without attempts to provide peaks for a
reserved right or for endangered fish.
B M_5,000: Peak in May, with Morrow Point releases limited to power plant capacity of
5,000 cfs.
C M_6,500: Peak in May, with Morrow Point releases limited to power plant and bypass
capacities totaling 6,500 cfs.
D M_UNLTD: Peak in May, with Morrow Point releases from power plant, bypass, and
spillway.
E J_5,000: Same as Run B, except peak in June.
F J_6,500: Same as Run C, except peak in June.
G J_UNLTD: Same as Run D, except peak in June.
Runs E, F, and G provide peaks in June to take advantage of higher Blue Mesa Reservoir
elevations.
Attachment B contains the following summary tables from the hydrology runs:
B-1 Peak Flows, Gunnison River below Gunnison Tunnel (Black Canyon)
B Peak Flows, Gunnison River at Delta
B-3 Peak Flows, Gunnison River near Grand Junction (Whitewater)
B-4 Average Monthly Flows, Gunnison River below Gunnison Tunnel (Black Canyon)
B-5 Average Monthly Flows, Gunnison River near Grand Junction (Whitewater)
B-6 Blue Mesa Reservoir, End-of-Month Water Elevation
B-7 Annual Shortage Volumes below Redlands Diversion
B-8 Frequency of Flows less than 300 cfs below Redlands Diversion
Results show NPS desired flows could be met in about 30 percent to 60 percent of the years
modeled. Runs which used only the Morrow Point power plant (B and E) met the desired flows
about 30 percent of the time. Using both the Morrow Point power plant and bypass (C and F)
resulted in NPS desired flows being met about 55 percent of the time. When the Morrow Point
spillway was used (D and G), the frequency the desired flows were met increased to 60 percent of
the time.
The maximum capacity of Blue Mesa bypass outlet and power plant is approximately 6,000 cfs.
The Blue Mesa spillway cannot be used to release water until the reservoir elevation is above
7,487.9 feet. During times when desired peak flows are being requested (May or June), it is
often necessary that Blue Mesa Reservoir be at a lower elevation to provide flood control. NPS
desired peaks greater than about 6,500 cfs cannot be provided with current operating criteria
because of flood control and/or physical limitations of reservoir outlets. Spring peaks greater
than approximately 10,000 cfs would occur only when Blue Mesa was nearly full and unable to
provide flood control. Those higher peaks would result from unusual hydrologic conditions and
not from intentional operation of the reservoir. Table B-1 in Attachment B contains summary
results of spring peak hydrology model runs.
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