TOWN OF OKOTOKS 32ND STREET CROSSING; A MULTIFACETED PROJECT ON THE SHEEP RIVER

摘要

The Town of Okotoks' 32nd Street Crossing Project (the Project) involved designing and building a new arterial roadway connecting north and south Okotoks. The Project was completed in 2010 at a cost of $27 M within tight timelines set by the federal Infrastructure Stimulus Fund. The Project included 1.4 km of roadway, bridges over Canadian Pacific Railway (CPR) tracks and the Sheep River, a unique major river realignment, regional pathways, and a long-term channel and aquatic habitat monitoring program. ISL Engineering and Land Services Ltd. led a multi-disciplinary consulting team that included Golder Associates Ltd. who contributed key expertise in river hydraulics, flood management, and aquatic biophysical studies. Early in the design process it was decided to permanently realign a 750 m reach of the Sheep River to a historic river course located approximately 150 m south from the then-current alignment. This innovative idea straightened a meander in the river, reduced river migration potential, and mitigated possible future flood damage to downstream areas. Additional benefits included optimization of functional planning and revising the roadway alignment to a single, large radius curve over both the rail tracks and Sheep River crossings. Aesthetics were also enhanced as the revised Project conforms naturally to the contours and vegetation of the river valley, and provides users with sweeping vistas of the valley and hills beyond. The design included guidebanks to define the bounds of the new river alignment, a guide channel, and fish habitat elements as required by Fisheries and Oceans Canada. In spring 2011, the river experienced a large flood resulting in alterations to bed and bank morphology and realignment of the channel to a more natural course. The Project team, in conjunction with regulators, continues to monitor and evaluate the evolution of this unique Project.