The largest stormwater project undertaken by the City of Fort Collins since the 1997 flood involved design and construction of $20 million of stormwater improvements in the heart of the City directly upstream of Colorado State University. The project included extensive public outreach, including mailings, open houses, and a project website to educate the public.
The project involved reducing spills from three drainage ditches that affected more than 175 homes during a potential 100-year storm event. The project included complex hydrologic and hydraulic modeling (using SWMM and unsteady HEC-RAS) to determine ditch spill quantities and mapping of the existing floodplain.
The project included the design of five regional detention/water quality ponds and more than 4,000 feet of large diameter (up to 102 inches) storm sewer and associated laterals and inlets. Inlets include Snouts and upstream sweeper sections to improve water quality in downstream receiving waters. The project included the design of a round, aesthetically enhanced version of the Bureau of Reclamation Type 10 hanging baffle structure.
The Colorado Association of Stormwater and Floodplain Managers honored the project as the 2012 Grand Award for Engineering Excellence winner.