Boulder, Colorado, is famous for the Flatirons, hiking trails, and sunny outdoor lifestyle. But some of Boulder’s most fascinating stories are found in its lakes, reservoirs, and historic water systems.
From an Ice Age lake high in the mountains to pioneer irrigation ditches and the beloved Boulder Reservoir, local water tells a story of geology, survival, engineering, and recreation.
The Ice Age Giant: Glacial Lake Devlin
Long before Boulder became a city, glaciers shaped the mountains west of town. During the Pinedale glaciation, a glacier moving through the North Boulder Creek valley blocked the mouth of Caribou Creek, creating an ice-marginal body of water known as Glacial Lake Devlin.
Geological research led by U.S. Geological Survey geologist Richard F. Madole found that Lake Devlin stretched nearly two kilometers and reached depths of roughly 30 to 69 meters, or up to about 225 feet, depending on location. Later research indicates that the lake existed from approximately 31,000 to 14,000 years ago…