Comparing Canals: Lake Washington Shipping Canal and the Canal du Midi

It will come as a surprise that Queen Anne Pioneer Thomas Mercer had something in common with the Roman Emperor Nero. It turns out, though, that he actually does. Mercer, who on July 4, 1854 gave Lake Washington and Lake Union their names, dreamed of a connection from Lake Washington through Lake Union to the sea. Nero, who lived in the first century C.E. dreamed of a connection from the Mediterranean Sea to the Atlantic Ocean across the south of France. Mercer’s idea waited over 50 years for its opening day; Nero’s had to wait almost 17 centuries.

Comparing the Lake Washington Ship Canal to the Canal du Midi is a stretch, but as I write this cruising down the Canal du Midi with a group of Seattle friends, I am pleased to consider the similarities.

Both projects seemed like outlandish ideas when they were proposed, both required revolutionary engineering, both were great commercial successes, both were gigantic projects that local government couldn’t undertake, both eventually lost their commercial value and both now serve successful and lucrative tourist purposes.

Naturally, I am drawn to the Canal du Midi both for the great tourism opportunity and the rare chance to put our neighborhood canal into a broader historic context.

The Canal du Midi opened to commercial shipping in 1681. Louis XIV, the Sun King, who ruled France from 1643 when he was five years old to 1715, embraced this canal as one of his first improvements to the infrastructure of France. Stretching some 240 kilometers, it joins the Atlantic Coast of France with its southern edge along the Mediterranean. It eliminated the need to go around Spain and through the Straits of Gibraltar. Joining the two coasts of France through French territory cut more than ten days off the trip.

Pierre-Paul Riquet, the architect/builder of the Canal du Midi, had no training in architecture, hydrology or road building. He was simply driven by crazy passion, maybe a bit like Hiram Chittenden, the designer of the Lake Washington Ship Canal. Convincing Louis XIV to fund his canal was easy, even though the king’s support wasn’t enough to finish the job. Riquet, a tax collector for the state, had to invent endless schemes to pay for his canal and to support the 12,000 workers who dug it.

Riquet’s great invention, not unlike Hiram Chittenden’s 1917 replumbing of the Black River and the reversal of the flow of water through Lake Washington, involved channeling mountain streams over long distances to fill the canal. No one had ever previously imagined such a solution.

Unlike the rather short Lake Washington Ship Canal which barely changes in elevation, the Canal du Midi had to go over a relatively low ridge to the place dividing where water flowed west to the Atlantic and east to the Mediterranean and, unlike our canal which has only one lock, the French one has over 91 of them, many with multiple basins.

Riquet was lucky when it came to designing the locks themselves. About a hundred years before his huge project, Leonardo da Vinci had invented the miter lock, which uses the pressure of the water flowing downstream to close and seal the two side panels tight at a 45o angle. Lockkeepers empty the locks on the Canal du Midi by opening small doors on the bottom of the downstream gates. To fill them and raise boats, they close the doors on the lower lock gates and open those on the upper ones.

Going down each nine foot high lock takes about 5 minutes. Going up takes a bit longer. Tying up and untying adds a minute or two top and bottom. The early-20th-c. Ballard Locks (now named for Hiram Chittenden) work pretty much the same way as Riquet’s 17th-c. locks, although at 20 feet they are significantly higher. I should also note that the salt water west of the Ballard Locks, the need to separate the salt water from the fresh water, and the dimensions of the big lock make the 20th-c. locks more complicated than what Leonardo invented, but not much. On your next visit to the Ballard Locks, make sure you look at the 45o angle of the closed locks and think of Leonardo.

Much as the two canals are alike, they differ in a few other ways. Chittenden built the Lake Washington Ship Canal with drawbridges (Ballard, Fremont, University at first, followed later by Montlake) that allowed tall masted boats unobstructed passage. The Canal du Midi has no drawbridges. Riquet designed 126 elegant humpbacked bridges that infrequently connected the two shores of the canal. Seagoing vessels entering the canal lowered their masts to avoid the low bridges, and turned propulsion over to horses (and sometimes men) to pull the vessels from the towpath. Chittenden did not anticipate a need for a towpath. The boats in his day were all self-propelled.

In the mid-19th-c., the advent of the railroads eliminated commercial traffic on the Canal du Midi. Oddly, when it opened, the Lake Washington Ship Canal precipitated the demise of the little railroads around Lake Washington, while the eventual depletion of the forests and the advent of much cleaner coal than what could be pulled from Roslyn and Newport mines ultimately ended most of the commercial traffic on Seattle’s canal.

Now both canals are incredibly active with tourism. Privately-owned boats seem to navigate the Lake Washington Ship Canal, while the Canal du Midi attracts huge numbers of rented boats that slog east and west at a leisurely 6 mph.

Approaching the end of our trip at Béziers, we spent an hour passing through the giant Fonsérannes Locks with seven basins, one of the engineering marvels of the 17th c. The incredible seven-step staircase requires two lockkeepers and lots of patience. While the entire canal is a World Heritage Site, only these locks are recognized by the French government as historic monuments.

After some 160 kilometers and countless locks, I am still thrilled by the enormity of Pierre-Paul Riquet’s astonishing achievement. I waffle a bit when it comes to Hiram Chittenden’s. His Lake Washington Shipping Canal is but a modest achievement when compared to Riquet's, but his genius may lie in having known how to keep his project short and to the point!