Friday, May 26, 2023

Beauharnois Canal, Locks, Dam and 1932+1951+1961 1.9gw Powerhouse

Lower Lock: (Satellite)
Upper Lock: (Satellite)
Powerhouse: (Satellite)
Dam: (Satellite, actually, the powerhouse is the dam)
Herbert Suspension Bridge: (Satellite)
Road Tunnel: (Satellite)
RR Bridge: (Satellite, it looks like a bobtail (offset swing) bridge)
A-30 Bridge: (Satellite)

stlawrencepiks has maps and several construction photos of the locks.

The rapids that this canal bypasses "has a series of rapids, formed by four slope breaks totaling a drop of 25,6 [84'] meters over 12,8 kilometers [8 miles]." [CanalDeSoulanges] So each lock probably has a lift of 42' (12.8m).

This Seaway canal along the south side of the river replaces an 1899 canal along the north side of the river.


Street View, Oct 2022

Note the suspension bridge on the right.
Street View, Oct 2022

Street View, Oct 2022

After heading north from the bridges over the tailrace of the powerhouse, one comes to the tunnel under the Seaway canal. It looks like they moved more rock in the cuts to the approaches than from the tunnel itself.
Street View, Jun 2022

In the foreground is the railroad drawbridge and Lock #2. I looked at every street view available, and the upper rail hid Lock #1 and the top of the powerhouse in each one.
Street View, Aug 2022

This satellite image allowed me to identify the railroad drawbridge as a bobtail bridge. But what makes this particularly noteworthy is that one of the miter gates has been augmented by sector gates. I've seen sector gates before in rather low-lift locks, but this lock has a rather high lift. Judging from some of the photos, they normally use the miter gates.

The plant was built in three phases. The first phase was completed in 1932 and included the headrace canal and 14 generating units. The second phase finished in 1951 and added 12 units. The third phase added 10 units by 1961
The plant is 926m (0.58 miles) long.

HydroQuebec_history, 1956-1961 on the timeline.

"The Beauharnois Power Station is capable of generating 1,911 MW at a maximum flow of 8,200 m3/s.[1m3 = 35.3cu.ft. so the flow is 290kcfs. (Can fill 3 Olympic-sized pools every second.)]...There are 36 turbines in total, 26 of which are Francis Turbines and a further 10 conventional blade [Kaplan] turbines....The Beauharnois canal brings water from Lake Saint-Francis to the dam. It is 24,5 km [15 miles] long by approximately 1 km [0.6 mile] wide for a maximum depth of 9m [30m]. In front of the dam the depth can reach 20m."

That flow is just a fraction of the river's flow. There is another hydroelectric plant in the river itself.



The draft of ships using the St. Lawrence Seaway is 8m (26') [Dennis DeBruler], so the 9m depth of the headrace canal could handle the Salties. Thus the Seaway construction simply had to add a couple of locks on the west side of the headrace.

Looking Southish or upstream:

Looking Northish or upstream:
Michael Restoule posted
Ecosse ,Miss MJ and Vigilant 1 in the upper and lower Beauharnois locks Quebec

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