WSP00886

• File Number: 8407
• Description: Platte River Basin - River Basin General Publications
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 4/16/1990
• Author: BOR
• Title: Annual Operating Plans - North Platte Project Water Years 1989-1990
• Water Supply Pro - Doc Type: Report/Study

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through Flatiron Unit 3 for testing purposes, which produced
7,049 kilowatt hours of energy.

A tota 1 of 69,206 acre-feet of water was pumped to Carter Lake duri ng
the water year which was 86 percent of average. This required
22,100,000 kilowatt-hours of energy.

Horsetooth Reservoir

Completed in 1949, with four dams, Horsetooth Reservoir has a total
constructed capacity of 156, 700 acre~feet. Inflow of PrOject water is
from Flatiron Reservoir via the Charles Hansen Feeder Canal.

Horsetooth Reservoir storage of 70,166 acre-feet at the start of water
year 1989 was near the 30-year normal of 71,800 acre-feet.

During early October, most Project water brought over from the Colorado
River was pumped to Carter Lake due to the schedu 1 ed pressure tunne 1
work. Maintenance on the 550 ft3/s section of the Charles Hansen Feeder
Canal, during the October 1 to October 14 period, prevented transfer of
water to Horsetooth.

Normal transfer of water to Horsetooth Reservoir through the foothills
system of the Project began on October 14 when the 550 ft3/s section
of the Charles Hansen Feeder Canal became available. This operation
continued through mid-September when the 930 ft3/s section of the
Charles Hansen Feeder Canal was shut down for the annual slab replacement.
Dille Tunnel was then utilized for the remainder of September to deliver
water to Horsetooth Reservoir. For water year 1989, the maximum
Horsetooth Reservoir storage of 134,131 acre-feet (water surface
elevation 5418.44 feet) was reached on April 6. This was 6.66 feet
below the current restricted maximum water surface elevation of
5425.10 feet (146,900 acre-feet).

Project water deliveries began on April 25 and were near 225 ft3/s by
the end of the month. May water deli veri es from Horsetooth Reservoi r
were 461 percent above average due to an extremely dry spring, for a
total of 23,500 acre-feet.

Water deliveries were 121 percent and 137 percent of average in June and
July, at 9,400 acre-feet and 38,500 acre-feet, respectively. August
project water deliveries of 30,800 acre-feet were below normal at
94 percent of average. September project water deliveries decreased to
55 percent of average. Total seasonal water de 1 iveri es (October-September)
for 1989 were 26,300 acre-feet above normal at a total of
119,500 acre-feet.

The September 30 end-of-water-year storage totaled 63,778 acre-feet
and thi s was 8,022 acre-feet be 1 ow the 1959-1985 average. The actual
operat ions for the Co 1 orado-Bi g Thompson Project for water year 1989
are summarized in table 3.