Flatiron Reservoir, a central distribution point for Colorado-Big Thompson Project water, is located southwest of Loveland and north of Carter Lake. Water flows from Pinewood Reservoir through Bald Mountain Tunnel, down the Flatiron Penstocks and into the Flatiron Power Plant, which discharges into Flatiron Reservoir.
Flatiron Reservoir serves as the afterbay for the Flatiron Power Plant to briefly store C-BT Project water for delivery to the Big Thompson River and Horsetooth Reservoir via the Hansen Feeder Canal. Water is also pumped from Flatiron Reservoir through the Carter Lake Pressure Tunnel to Carter Lake. From there deliveries are made to the Little Thompson River, St. Vrain Creek, Boulder Creek, South Platte River and Southern Water Supply Project pipeline.
The reservoir was built between 1951 and 1953 and cost $1.2 million.
Flatiron Reservoir has a capacity of 760 acre-feet, 47 surface acres, 2 miles of shoreline and its maximum depth is 18 feet.