BOARD02433

• Board Meeting Date: 3/22/2005
• Description: WSP Section - Aspinall EIS Update
• Board Meetings - Doc Type: Memo

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Agenda Item 32
March 22 - 23,2005 Board Meeting
Page 7 of 13

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Aspinall Unit Statistics*

Blue Mesa Morrow Point Crystal
Capacities (acre-feet)
Dead storage . 111,200 165 7,700
Inactive storage 81,070 74,905 4,650
Active storage 748,430 42,120 12,890
Live storage 829,500 117,025 17,540
Total storage 940,700 117,190 25,240
Outlet capacities (cubic
feet-per-second [cfs])
Power plants (max) 2,600-3,400 5,000 2,250
Bypass 4,000-5,100 1,500 1,900-2,100
Combined (max) 6,100 6,500 4,100
Soillway 34,000 41,000 41,350

*

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o Live storage is the combination of the active and inactive storage. It represents storage that physically can be
released from the reservoir.
o Crystal powerplant capacity may be adjusted following testing; the new capacity may affect fleea .eHlre1
reservoir targets.
. Blue Mesa Reservoir shares one penstock for both river outlet and powerplant releases; the combined releases of
. these two are constrained to about 6,100 cfs.
o The hydraulic capacities shown in the table assume full reservoir conditions. At lower elevations, the hydraulic
capacity would be less. Also system efficiencies may affect the hydraulic capacity.
. Full capacity may not always be available due to scheduled maintenance or equipment malfunction.

. Aspinall Unit in place, regulating the river using current operating practices as a guide, and
operating for Unit purposes under highly variable annual inflow conditions. These current
practices include:

o Filling Blue Mesa Reservoir at end of runoff season-Full reservoir is 7519.4 feet;
operations designed to reach around 7517 feet which provides a safety factor for
controlling the reservoir in case of sudden flood events such as thunderstorms or high
snowmelt rate.

o Existing spring flood control operations (being proactive to keep 14,000 cfs or
[normally] considerably less at Delta (Delta City area above the Uncompahgre
confluence)-15,000 cfs is official number at this time). March 31 target, which is
variable based on forecasted inflow, maintained to reduce flooding and reduce
powerplant bypasses. Blue Mesa winter icing target-'---7490 feet at end ofDecember--
met to reduce chances of ice jams causing upstream flooding in the Gurmison area
around Dos Rios.

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o Peaking power operations at Morrow Point and Blue Mesa, re-regulating at Crystal
through constant releases. Blue Mesa releases range from 0 to 3AOO cfs; Morrow Point
releases range from 0 to 5,000 cfs. When Crystal powerp1ant is operating at full
Flood Protection. Water Project Planning and Finance. Stream and Lake Protection
Water Supply Prot~tion. Conservation Planning