While to the south lies the St. Lawrence river, with the Iroquois lock, a bit farther to the west is the Rideau Canal. Between 1826 and 1832, an old canoe route was transformed by a quite amazing engineering feat into a waterway linking Kingston on Lake Ontario with Ottawa. The oldest continuously operating canal in North America, the locks are operated today much as they were a century and a half ago when the canal was first opened in 1832. The canal was originally conceived, following the hostilities of 1812, as a means to provide the British army with a safe route for supplying its inland garrisons. Designed by Lt. Colonel John By of the British Royal Engineers, the canal connects the Cataraqui and Rideau rivers and a series of lakes, with locks where necessary. Construction was undertaken by independent contractors under By’s supervision and was completed by hundreds of labourers in less than six years.
As it turned out, the canal was not needed for its intended purpose and today the boats plying its waters are recreational, not military crafts. Last week, I visited the lock west of Kemptville in the little hamlet of Burritts Rapids. When I arrived, a boat had just completed “locking up” and was motoring out of the lock.
The water in the lock was at the upstream level and the upper gates were cranked open to allow the boat to leave. Once the boat was clear of the lock, the upper gates were closed behind it. I was fortunate that a second boat had just arrived, also travelling upstream, so I was able to see the process repeated. The water, now at the upstream level, had to be lowered to the downstream level to allow the new boat to enter.
The lock staff opened valves in the lower gates that allow water in the lock to drain from the chamber into the downstream river.
When the water in the lock reaches the downstream water level, the lower gates are opened.
The second boat entered the lock and the lower gates were closed behind it. The lock staff then moved to the upstream end of the lock, where they slowly opened the upper sluice valves, allowing water to enter the lock through tunnel sluices. I didn’t stay to watch the second boat rise with the water to the upstream level. At the height of the summer season, as many as 22 watercraft may be lifted in the lock at once.
There are 45 locks along the Rideau plus two more locks at the entrance to the Tay Canal. The lift from Kingston to Upper Rideau Lake, the highest point on the system, is 164 feet (50 m) in 14 locks. The lift from Ottawa to Upper Rideau Lake is 273 feet (83.2 m) in 31 locks. The canal extends 202 kilometres (125 miles) from Ottawa to Kingston. Each lock operates by means of a combination of water, gravity, human muscle power, and a basic system of levers and gears. The Rideau Canal was designated a UNESCO World Heritage Site in 2007.