When severe rains hit the Front Range in 2013, flooding through the constrained Big Thompson Canyon washed out major sections of US 34, mimicking failures that had occurred 37 years prior in the 1976 floods. CDOT undertook an emergency repair effort to reopen the road within 3 months, then undertook longer term permanent repairs emphasizing full restoration and resiliency. The scale of this project required substantial innovation and collaboration between CDOT, FHWA, US Forest Service, US Army Corps of Engineers, Colorado Parks and Wildlife, FEMA and consultant teams. The collaborative response to this crisis situation won multiple design and emergency management awards. This field trip will highlight pre-flood conditions, the immediate response effort, post-flood resiliency and stream restoration work, and long-term monitoring efforts, including fish and macroinvertebrate populations.
During the tour, attendees will learn about the 1976 flood and how roadway damages associated with that flood mimicked the 2013 flood and how the importance of considering river dynamics, functions, and needs during the final post-flood design and construction of the river and roadway after the 2013 flood. Highlights will include locations where a fish barrier, the Idlewild Reservoir and dam was removed, resulting in fish passage between lower reaches of the Big Thompson and upper reaches of both the Big Thompson and North Fork of the Big Thompson. Attendees will also learn how the river has recovered in terms of both populations and health of fish and macroinvertebrates, comparing pre-flood and final post-construction sampling results. To wrap up the tour, guests will receive CDOT's publication of "The River and the Road," a book dedicated to the people who lost their lives during the Big Thompson Canyon folds of 1976 and 2013. It's a story of the enduring struggle to forge and maintain a transportation connection through the Big Thompson Canyon to Estes Park, constructed more than 100 years ago.