Projects - Infrastructures
Trails and Paths: Pedestrian Underpasses

Elmer's Twomile Creek Underpass at Iris Avenue
Boulder, Colorado

LORIS provided complete engineering services for this federally funded 83-ft. long, 20-ft. wide underpass crossing Iris Avenue in west Boulder. The underpass structure is a combined-use facility for path users and creek flow. Geometry is very tight on the north side of the project, which required close coordination with a homeowner's association for location of retaining walls and trail access points. Several utilities within the corridor further complicated the design. High groundwater and the existing streambed elevation required that a lift station be used to accommodate drainage. The project also included on-site wetlands mitigation.

Client:  City of Boulder