Barker Reservoir and the Silver Lake Watershed
The city receives approximately two-thirds of its water supply annually from direct flow and storage rights on Middle Boulder Creek and North Boulder Creek.
Each spring, melting snowpack fills the city’s reservoirs, including Barker Reservoir, Silver Lake Reservoir, and numerous smaller reservoirs upstream of Silver Lake.
Water from North and Middle Boulder Creeks and the city’s reservoirs is treated at the Betasso Water Treatment Plant. As the water moves through the city’s raw water and treated water pipelines, it also generates hydroelectric power.
Colorado-Big Thompson and Windy Gap
The remaining one-third of the city's water supply comes from the Colorado-Big Thompson (CBT) and Windy Gap projects, operated by Northern Water.
These two projects divert water from the upper Colorado River on the western slope and deliver it through a series of tunnels, canals and reservoirs to northeastern Colorado cities, farms and industries. CBT and Windy Gap water is delivered to Boulder Reservoir and via pipeline directly to the Boulder Reservoir Water Treatment Plant.