As you can see from the map at http://www.glerl.noaa.gov/data/bathy/ont_bathy.gif Lake Ontario drops off fairly quickly. Bear in mind that 20 metres is about 65 feet. While it comes in 4th of all the Great Lakes in maximum depth, it is second only to Lake Superior in average depth.
There is concern for native breeding puffins, peregrine falcons and guillemots, even though the filming schedule was approved by the National Parks and Wildlife Service.
Interesting. I've lived in the Rochester area all my life and I only knew nine of these 15 secret things. Also, the entry about Francis Tumulty is a bit misleading. He didn't murder Jack the Ripper. He was suspected of being Jack the Ripper.