St. Vrain Greenway Longmont, Colorado

Navigating the area’s 100-year floodplain and sensitive natural habitat, the St. Vrain Greenway added an 11.5-mile trail corridor with several pedestrian structures to the communities around Longmont, Colorado. In leading the design across numerous phases, Otak also provided environmental science and construction support to continue growing this active transportation asset for the community.

Extending a Trail Corridor While Minimizing Impact to Habitat

Over two decades of work have shaped the St. Vrain Greenway. Several pedestrian structures—including a 140-foot and another 240-foot-span bridge over its namesake St. Vrain Creek—are found along the miles of new trail. A pedestrian underpass was also designed for safe passage underneath CO 119. With nesting Bald Eagles, wetlands, and other sensitive natural areas, multiple alternative path alignments were considered in the conceptual design to prioritize minimizing impact. With historic flooding taking place during the course of this work, the trail also adds resilience to those affects with features designed to not conflict with the 100-year floodplain.  To account for steep grades as well as varying groundwater elevations and trail geometry, different retaining wall types were utilized throughout the trail. The sites for each segment each required unique solutions that blended various structure and wall types to ultimately create an altogether cohesive journey for trail users.