Carter Lake Outlet

Carter Lake is located in the foothills west of the town of Berthoud. In 2008, Northern Water and the U.S. Bureau of Reclamation finished constructing a second outlet at the reservoir. The new structure supplements but does not replace the original Carter Lake outlet, which was built in the early 1950s.
Carter Lake is part of the Colorado-Big Thompson Project and provides water to thousands of acres of agricultural land and more than 300,000 municipal and industrial users in Larimer, Weld, Morgan, Boulder and Broomfield counties.

Carter Lake Outlet
Carter Lake Outlet intake tower

Year-round Water Deliveries Prior to 1995, Northern Water delivered water from Carter Lake only during the crop irrigation season (April through October). During winter months, crews maintained and repaired the outlet when it was not in use.

In 1995, Northern Water completed the Southern Water Supply Project, a pipeline that carries Carter Lake water year-round to cities and towns within Northern Water’s boundaries. Year-round municipal and industrial water deliveries represent Northern Water’s largest and fastest growing constituency.

A New Outlet NeededCarter Lake’s original outlet was intended for large-volume water deliveries during the irrigation and growing season. Year-round releases severely limited Northern Water’s ability to maintain and repair the aging structure.

A February 2004 inspection of the outlet revealed substantial corrosion requiring repairs. Northern Water, with Reclamation's agreement, began planning a new outlet specifically designed for year-round use. 

Carter Lake Outlet map





Greater Operational FlexibilityThe new $10 million outlet at Carter Lake provides Northern Water with valuable operational flexibility. The new structure consists of:
  • A 110-foot-tall multi-level intake tower
  • An 800-foot-long tunnel
  • A 400-foot-long penstock (above-ground pipe) connecting the outlet to the St. Vrain Supply Canal
Carter Lake’s newest outlet is essential for delivering reliable water supplies to municipal and industrial users within the central and southern portions of Northern Water boundaries.

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