Ontario Power Generation, Toronto, will issue an open request in July for turnkey proposals for construction of a 6.5-mile-long, 39-ft-dia tunnel to increase water flow to hydroturbines at the 2,150-MW Sir Adam Beck Generating Station. An August 2003 feasibility study found there is not enough water on the Canadian side of the Niagara River to justify construction of a third generating station. The $446-million project would expand annual electricity output at the station by 1,600,000 MW-hours or about 15%. The precast-concrete-lined tunnel is to be bored largely through Queenston shale under the city of Niagara Falls to divert water from the Niagara River to the station. Construction should begin in 2006 and be completed in 2009.