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

Emergi ng from Alva' i3. Adams Tunne 1 into the East Portal Reservoi r, the
water flows across Aspen Creek Valley in a siphon and then under Rams
Horn Mountain through a tunnel. At this point, it enters a steel
penstock and falls 205 feet to Marys Lake Powerplant. This powerplant
is located on the west shore of Marys Lake, which provides afterbay and
forebay capac i ty for re-regu 1 at i ng the flow. Between Marys Lake and
Estes Powerplant, on the shore of Lake Estes, the water is conveyed by
Prospect Mountain Conduit and Prospect Mountain Tunnel.

Lake Estes, below Estes Powerplant, is formed by Olympus Dam constructed
across the Big Thompson River. The afterbay storage in Lake Estes and
the forebay storage in Marys Lake enable the Estes Powerplant to meet
daily variations in energy demand.

Water from Lake Estes and some Big Thompson River floodwaters are
conveyed by Olympus Siphon and Tunnel and Pole Hill Tunnel and Canal to a
penstock through which the water drops 815 feet to Pole Hill Powerplant.
It is then routed through Pole Hill Powerplant Afterbay, Rattlesnake
Tunnel, Pinewood Lake, and Bald Mountain Pressure Tunnel, and dropped
1,055 feet through two penstocks to Flatiron Powerplant. This
powerp 1 ant charges into Flat iron Reservoi r, whi ch regu 1 ates the water
for release to the foothills storage and distribution system. The
afterbay storage in Flatiron Reservoir and the forebay storage in
Pinewood Lake enable Flatiron Powerplant to meet daily power loads.

Southward, the Flatiron reversible pump lifts water from Flatiron
Reservoir, a maximum of 297 feet, and delivers it through Carter Lake
Pressure Conduit and Tunnel to Carter Lake. When the flow is reversed,
the unit acts as a turbine-generator and produces electric energy.

The St. Vrain Supply Canal delivers water from Carter Lake to the Little
Thompson River, St. Vrain Creek, and Boulder Creek Supply Canal. The
latter delivers water to Boulder Creek and Boulder Reservoir. The South
Platte Supply Canal, diverting from Boulder Creek, delivers water to the
South Platte Kiver.

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Northward, the Charles Hansen Feeder Canal transports water from
Flatiron Reservoir to the Big Thompson River and Horsetooth Reservoir.
The canal crosses the Big Thompson River in a siphon above the river and
highway. Water from the Big Thompson River can be diverted into the
canal by Dille Diversion Dam and utilized for power generation at Big
Thompson Powerplant.

Project water del iveries and Big Thompson River water to be returned
to the river are dropped through a chute from the feeder canal ahead of
the siphon crossing, or are passed through the Big Thompson Powerplant
to convert the available head to electric energy.

Horsetooth Reservoir is west of Fort Collins between two hogback ridges,
where Horsetooth Dam closes the gap at one end. Soldier, Dixon, and
Spring Canyon Dams and Satanka Dike close the remaining gaps.

An outlet at Soldier Canyon Dam supplies water to Fort Collins, rural
water districts, Colorado State University, and the Dixon Feeder Canal
for the irrigated area cut off from its water supply by the reservoir.

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