Don't see any parts of a Power Plant here. No transformer yard or power line right of way. Can't think of any that park sailboats out front. Several Communication towers out back and just to the north. Bee boxes are square and grouped together. Ground monitoring wells (hydrocarbon contamination) is a suggestion - but too numerous and large an area? A historic air photo - or talking to a local would be my suggestion.
http://www.toronto.ca/involved/projects/toronto_island_water_supply/pdf/2009-02-11-n-12_qa.pdf