Anyway, I was generally following 'Walking Tour 1', though occasionally meandering off on my own. I walked through the part I usually eat lunch at, then decided to go in the opposite direction of the Gallery, and guess what was there!
These locks are part of the Rideau Canal, which connects the Rideau and Ottawa Rivers. It's part of a system of waterways connecting Ottawa and Kingston (towards the south west). They were constructed between 1826 and 1832, part of a military defense plan thanks to the US and the War of 1812. The military man behind the design was smart enough to design them with commercial and military purposes in mind.
Today the canals and locks are still used. And are operated manually. I saw them (and you will too). They are a UNESCO World Heritage Site. Apparently the fee for a season pass to use all of the Federal Canals in Canada is only like 200 (Canadian) dollars. Not too bad.