City of Boulder completes Alpine-Balsam flood mitigation channel, improving neighborhood safety and connection

The City of Boulder and the Mile High Flood District have completed the Alpine-Balsam flood mitigation channel, marking a major milestone in the Alpine-Balsam Area Plan. The project removes the Alpine-Balsam site from the flood zone, reducing risk for community members and businesses while strengthening the area's long-term resilience to climate impacts.

The channel was designed as more than flood infrastructure. In addition to standard drainage features, the completed channel transforms a functional floodway into a neighborhood amenity incorporating landscaping, ecological function, mobility improvements and high-quality public spaces alongside its core flood protection role.

"Community members in this neighborhood have lived with flood risk for decades - this channel is one of a number of important projects to change that," said City Manager Nuria Rivera-Vandermyde. "Beyond flood protection, we've created safer crossings, better bike connections and green spaces that the community can use right now."

Key project features include:

• Flood mitigation and climate resilience: The channel removes the Alpine-Balam site from the floodplain and improves long-term resilience to flooding and climate impacts, reducing risk for the surrounding neighborhood.
• Improved walking and biking connections: The project creates safer, more accessible connections from Broadway to North Boulder Park, including improved pedestrian crossings, enhanced bicycle access, B-Cycle amenities and Lime Scooter access for shared mobility users.
• New public spaces and gathering areas: A new plaza, pedestrian improvements and landscaped areas create a more welcoming neighborhood environment. The project also preserves views and green spaces that community members identified as priorities across multiple phases of community engagement.
• Urban habitat and ecological restoration: Native vegetation, shade trees and habitat feature support pollinators, birds and other urban wildlife while transforming the channel into a genuine neighborhood amenity rather than a purely functional drainage corridor.
• Foundation for future use: By removing the remainder of the site from the floodplain, the project ensures that future affordable homes and other uses can be safely located outside flood risk areas, supporting long-term safety and sustainability goals identified during community planning.

The project reflects years of community input through the Alpine-Balsam Area Plan, translating priorities like flood safety, walkability, green space preservation and mobility connections into reality. This work is also part of broader continued improvements to the Upper Goose Creek watershed.

Learn more about the Alpine-Balsam Implementation Project.

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