Running through the heart of the City of Bozeman, Bozeman Creek has been narrowed and straightened, its banks armored with rock and concrete, its riparian vegetation removed or reduced to a thin green line. A coordinated effort led by community organizations, city, state, and federal partners, consulting professionals and landowners began in 2010 with a vision to create a naturally functioning and connected creek corridor with healthy riparian areas and floodplains. To serve as a planning, design, and permitting tool for on-going and future channel and habitat enhancement projects, AESI created a HEC-RAS hydraulic model of Bozeman Creek through downtown Bozeman.
The hydraulic model was geo-referenced using HEC-GeoRAS and included several bridges and other hydraulic structures. Additionally, AESI determined natural bankfull channel geometry for the highly altered stream system to serve as a benchmark for future channel design. Finally, a proposed conditions model was created to estimate the effects from naturalizing the channel geometry, creating an inset floodplain, and replacing a small bridge with a larger structure for a small reach near City Hall. Key project features include:
- Ground survey: 64 cross sections and 11 bridges;
- Processing 2007 LiDAR data to establish a digital terrain model of the floodplain;
- Development of an existing conditions model in HEC-RAS of roughly 4800 feet of Bozeman Creek;
- Development of a HEC-RAS model representing proposed channel modifications; and
- A comparison between the existing conditions model and the FEMA effective model.