Projects - Infrastructures
Trails and Paths: Pedestrian Underpasses

Wonderland Creek Underpass at Diagonal Highway
Boulder, Colorado

LORIS served as the prime consultant for this $1.8 million pedestrian underpass on the Wonderland Creek Greenway in east Boulder. This 152-ft. long, 24-ft. wide underpass provides path users with convenient access beneath the busy Diagonal Highway (State Highway 119) and 30th Street intersection in east Boulder. The project was federally funded and administered through a CDOT Local Agency contract and was developed to meet all the corresponding federal and state requirements. The underpass structure is a combined-use facility for path users and creek flow. The project included the relocation of city-owned water lines and the rerouting of the Farmer's Ditch lateral. Wetlands impacts were mitigated at an off-site location and followed CDOT and City of Boulder requirements. Impacts to the riparian corridor were mitigated according to Senate Bill 40 and coordinated with CDOT. The proximity of the 30th Street intersection to this Diagonal Highway location presented construction-phasing challenges because of heavy vehicular traffic during construction. LORIS coordinated this project with several City of Boulder on-call consultants to provide various documents including City of Boulder wetlands permit, a floodplain development permit, right of way plans, landscape plans, and irrigation plans.

Client:  City of Boulder