The Eight Locks

The eight locks situated at Entrance Valley mark the beginning of the 202-km journey down the Rideau Canal from Ottawa to Kingston. Designed and constructed in proper military fashion, the locks were built with purpose and functionality, but with little thought towards ornate visual detail. It took from 1827 until 1832 to complete the locks, and the entire process was slow and dangerous. Workers were delayed by explosions, fires, disease, faulty equipment, and other challenges. On August 6,1830, both banks of the newly excavated canal caved in simultaneously, and although no one was hurt, the collapse provided another example of how unpredictable the work on the canal could be. When Lt. Col. By’s wider canal proposal was approved by British Parliament, they were even forced to backtrack and remove masonry that had been painstakingly laid just months before. By the time construction was completed and opened for use in 1832, total expenditure for the Bytown Locks had risen from the estimated £58,889 to £70,643 – an overrun that would contribute to landing Lt. Col. By in serious trouble with his superiors.

Points of Interest

Drawing of a plan and section of a single lock for the Rideau CanalEnlarge

[Source: Unknown Artist, Plan of a Lock, n.d, Ordnance Department,The National Archives of the UK, MPH1-238 (1)]

Plan and Section Drawing of a Single Lock

A lock system essentially acts as a “water elevator,” allowing vessels to pass safely from higher elevations to lower ground (and vice versa) by connecting uneven watersheds. The drawing above shows a plan, section, and cross-section of a single lock for the Rideau Canal. Each lock measures 33 feet (10 metres) wide by 134 feet (41 metres) long.

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Drawing of a plan and section of the eighth gate of the first eight locks of the Rideau CanalEnlarge

[Source: Unknown Artist, Lock Gate (II), n.d., Ordnance Department, The National Archives of the UK, MR1-502 (2)]

Lock Gate Drawing

The locks on the Rideau Canal form part of a slack water system. Slack water is water without any current or pull, and it is recreated in the pool between two closed lock gates. A boat floating in a lock will therefore not list in any direction, as it is not affected by the water beyond the closed lock gates. Above is a drawing of the eighth lock gate at Entrance Valley.

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Drawing of a section of the pointed cill and recess of the combined locksEnlarge

[Source: Unknown Artist, Pointed Cill and Recess (II), n.d., Ordnance Department, The National Archives of the UK, MPH1-238 (3)]

Plan of Sluice Channel

The locks along the Rideau Canal use a basic system of small tunnels under the waterline, which add or drain water away from underneath the boat. These tunnels are called sluice channels and are controlled by a separate, smaller gate system called sluice gates. Above is a plan of the pointed sill found at the threshold of each individual lock, with the sluice channel visible on the left-hand side.

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[Source: Great Britain Army Corps of Royal Engineers, “Plan of the Approved Locks for the Rideau Canal, Lt. Col. By Commanying Royal Engineer John By, Lt. Colonel Roy’l. Engrs. Com’g. Rideau Canal, 8th July 1828”, [1828], Library and Archives Canada, NMC-21893; “Tour of the Eight Bytown Locks” [Animation]. Dr. Stephen Fai. Carleton Immersive Media Studio. 2012.]

Duration: 59 seconds
Download "Tour of the Eight Bytown Locks" (.mp4 23 MB) View the transcript of this video.

Tour of the Eight Bytown Locks

This series of eight locks is the most complex along the canal and resolves an 80-foot (24-metre) difference in the elevation between the Ottawa River and the Rideau Canal. A lock system essentially acts as a “water elevator,” allowing vessels to pass safely from higher elevations to lower ground (and vice versa) by connecting uneven watersheds.

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[Source: Maule Family / Earl of Dalhousie fonds. “36 plans and abstract of the estimate of expenditure of the Rideau Canal”, 1828. National Archives of Scotland. GD45/3/9.]

Duration: 43 seconds
Download "Drawing of the Bytown Locks by Lt. Col. By" (.mp4 21 MB) View the transcript of this video.

Drawing of the Bytown Locks by Lt. Col. By

This letter, dated May 5, 1828, and signed by Lt. Col. By, accompanied technical drawings, maps of the canal route, and a progress report of the Rideau Canal project. In the letter, By outlines some of the technical aspects involved with the eight locks at Entrance Valley. He writes that the lower walls of the eight locks are built two feet (less than a metre) thicker than the others “as they have to be raised above the floods of the Ottawa River which have been known to rise 24 ft. [7 metres]” He also points out that the excavation of these locks is expected to be more expensive than others, given the nature of the stone.

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