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Big Chute GS


The Big Chute Generation Station was the first station owned by Ontario Hydro, purchased in 1914. Station had four double runner horizontal Francis turbines. The new redevelopment consisted of demolishing the existing generation station and replacing it with the new hydroelectric generation station with the single 9.9 MW turbine, full Kaplan , S-turbine. The powerhouse was constructed of reinforced concrete. Other project elements included a concrete power canal, concrete intake structure and two steel penstocks with a surge tank. The original station utilized a water flow of 37.6 cubic meters per sec to generate  4.15 MW.  

Deterioration of the existing turbine-generator units as well as the existing structure necessitated the project redevelopment. Station hydraulic capacity was increased  to 70 cubic meters per sec for new station.

The project planning and implementation have been influenced by the fact that the project area is an environmentally sensitive area and by the large number of tourist who visit the project site. The Big Chute area has been designated as Area of Natural and Scientific Interest (ANSI).The area is known for its outstanding diversity of flora. The site is located on the Trent-Severn Waterway and is the location of North America’s largest marine railway that transport boats via a rail car between the tail pool and headpont , a difference of 17 meters. Approximately 100,000 tourist visit the site every year. 

The Big Chute Generation Station Redevelopment had a large number of regulatory issues to resolve. The major issues were navigation and preservation of the original project’s heritage values. The unique features have been developed to meet the regulatory requirements. The draft tube conduit coupled with downstream channel improvement had resolved the navigation concerns. 

The provision of a hydro museum adjacent to the new power house containing some of the salvaged old equipment was very unique. Saving a portion of the existing structure and hydroelectric equipment has retained some of the heritage values of the existing structure and also provided an opportunity to demonstrate hydroelectric power to the public. Old equipment was installed on the concrete slab next to the powerhouse. A triangular viewing platform cantilevered from the steel superstructure was build and adjacent portion of the power house wall had a window to allow people to see new equipment installed inside of the power house. Actually it’s really very interesting to compare the new S-unite with old turbine; you could see how the technology of hydro changed with the time.


The construction of a 93 m long sunken draft tube conduit with side openings to smooth out and distribute the flow discharged into a recreation boating holding pond where small bots wait for the transit over marine railway lift lock. Conduit had a combination of cast in place concrete and precast concrete. The use of precast concrete was maximized to allow the installation schedule to be minimized. The conduit size was established to achieve the required head loss criteria.  

Power house was constructed from reinforced concrete with a structural steel super structure with precast concrete panels sliding. The longest duration of work was the power house concrete, each concrete lift was planned. A total of 38 lifts were requires for first stage concrete, second stage concrete was placed in two slow pours, to prevent any deflection of the turbine embedded parts. A total of 2480 cubic meters was placed in the power house between December 17, 1992 and March 3, 1993.

Development of unique design features coupled with careful scheduling of the project and value engineering has enabled the project to proceed on schedule and below the budget. Construction started in October 1991 and project was in-service in November 1993 on time and under budget.   

Design team consisted of the Engineering Manager Whitney Hall , project engineer Magdi Chidiac, Senior Structural Engineer Lev Bulkovshteyn, Senior Geotechnical Engineer Tim Orpwood, Engineers K. Wong and Richard Carrinton, draftsman’s Brian Rose and John Henri.

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