West Portal Colorado River water enters the West Portal of the Adams Tunnel from Grand Lake. The Adams Tunnel conveys water beneath the Continental Divide to the East Slope distribution system.
Grand Lake Grand Lake is the last stop for Colorado-Big Thompson water collected on the West Slope before diversion to the East Slope. It is the largest natural lake in Colorado.
Shadow Mountain Reservoir Shadow Mountain Reservoir is a regulating reservoir, connected to Grand Lake through an open channel. The reservoir keeps the level of Grand Lake within one foot of capacity while water is diverted through the Adams Tunnel.
Lake Granby Lake Granby is the largest storage reservoir in the Colorado-Big Thompson Project and the second largest water body in the state. From Lake Granby water is pumped to Shadow Mountain Reservoir.
Farr Pumping Plant The Farr Pumping Plant lifts water from Lake Granby to Shadow Mountain Reservoir. Three quarters of the 187-foot tall building is underground.
Willow Creek Reservoir Willow Creek Reservoir captures snowmelt runoff in the Willow Creek basin. The water is pumped up into Lake Granby for delivery through the C-BT system.
Green Mountain Reservoir Located on the Blue River, Green Mountain Reservoir provides replacement storage for western Colorado. Water is released from Green Mountain when the C-BT is diverting water to the East Slope.
