Boulder, Colo., completes $46 million phase of main sewer upgrade
(UI) — The City of Boulder has finished the largest phase of its Main Sewer Improvements (MSI) Project, a $46 million upgrade that adds a parallel wastewater line from Valmont Road and Butte Mill Road to the Water Resource Recovery Facility (WRRF) near 75th Street and Jay Road. The work, funded with city bonds, also replaced aging mains that serve the Gunbarrel area.
City engineers say the new pipeline increases flood resilience and lowers the risk of overflows during extreme weather. The original line, installed in 1968, has endured multiple floods, including the 2013 Front Range disaster.
“This phase improves the sewer system’s operation and reliability,” project managers said in a statement. Smaller branch lines were added in Gunbarrel to boost local service.
A final phase—scheduled to start in 2029—will rehabilitate the remaining portion of the 1968 sewer between 61st Street and the WRRF and a segment near 55th Street and Valmont Road.
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