Pump Plants

Colorado-Big Thompson Project Pump Plants

As water is collected, stored and transported through the Colorado-Big Thompson Project, pump plants lift the water vertically in several locations on both sides of the Continental Divide in order to deliver C-BT Project water to Northeastern Colorado.

Farr Pump Plant 

Located on the north shore of Lake Granby, the Farr Pump Plant lifts water from Lake Granby into the Granby Pump Canal where it flows by gravity into Shadow Mountain Reservoir. The lift height at the Farr Pump Plant varies from 92 to 186 vertical feet depending upon the elevation of Lake Granby. Once it has reached Shadow Mountain Reservoir, water flows through a connecting channel to Grand Lake, then into the West Portal of the Adams Tunnel and beneath the Continental Divide on its journey to Northeastern Colorado water users.


The Farr Pump Plant utilizes three vertical shaft pumps and three 6,000-horsepower motors. Constructed between 1947 and 1951, the plant cost $8.1 million to build.

Equivalent to a 16-stories in height, the plant’s reinforced concrete building is 187 feet tall, but nearly 140 feet of it are underground. The plant’s base slab is made of 3,100 yards of reinforced concrete and is nearly 9 feet thick.

Farr Pump Plant
Farr Pump Plant

Originally known as the Granby Pump Plant, it was renamed in 1994 to honor the Farr family of Weld County for its contributions to natural resource conservation, water development and agricultural innovations in Colorado.

Powering the Plant 

Power for the plant is generated by passing C-BT Project water through the Estes Power Plant turbines on the East Slope and from Blue River water passing through turbines at the Green Mountain Power Plant on the West Slope. Power from the Estes Power Plant is delivered to the Farr Pump Plant via an electrical transmission line that runs through the Adams Tunnel.

Willow Creek Pump Plant.
Willow Creek Pump Plant

Willow Creek Pump Plant 

The Willow Creek Pump Plant is located on the Willow Creek Pump Canal west of Lake Granby. Willow Creek Reservoir, two miles west of Lake Granby, captures snowmelt runoff in the Willow Creek Basin. Willow Creek enters the west end of the reservoir and exits the east end at the dam before flowing into the Colorado River. Water from the reservoir enters the Willow Creek Pump Canal and flows east to the Willow Creek Pump Plant, where it is lifted 175 feet and delivered to Lake Granby.

Willow Creek Reservoir, the pump plant and canals were built between 1951 and 1953, during the last major construction phase of the C-BT Project's West Slope collection system.

Aerial view of the Flatiron Power Plant.
Flatiron Power Plant

Flatiron Power Plant Unit 3

The Flatiron Power Plant is located on Flatiron Reservoir northwest of Carter Lake. The plant’s Unit 1 and Unit 2 produce hydroelectric power as water from the Flatiron Penstocks flows through both units’ turbines and into Flatiron Reservoir, the power plant’s afterbay. Unit 3 at the plant is a reversible pump used to lift water from Flatiron Reservoir 297 vertical feet through a pressure conduit and tunnel to Carter Lake. If flow is reversed through the pressure conduit and tunnel, Unit 3 is designed to act as a turbine-generator to produce hydroelectricity. Throughout the history of the C-BT Project, Unit 3 has been used almost exclusively to lift water from Flatiron Reservoir to Carter Lake.

Windy Gap Project Pump Plant

The Windy Gap Project is located in Grand County on Colorado’s West Slope. The project consists of a diversion dam on the Colorado River, a 445-acre-foot reservoir, a pump plant and a six-mile pipeline to Lake Granby. Windy Gap water is pumped and stored in Lake Granby, part of the Colorado-Big Thompson Project, before it is delivered to water users via the C-BT system.

Windy Gap Pump Plant

During periods of high flows in the Colorado and Fraser rivers, water is pumped from Windy Gap Reservoir via the Windy Gap Pump Plant into Lake Granby, where it is stored for delivery through the C-BT Project facilities to water users on the Front Range. The Windy Gap Pump Plant and reservoir are located just west of the Town of Granby on the West Slope. Operated from a control center at the Farr Pump Plant, the Windy Gap Pump Plant pumps water through a 6-mile pipeline to Lake Granby. Learn more about the Windy Gap Project.

Windy Gap Pump Plant
Windy Gap Pump Plant