Some friends in Ottawa think of this as the saddest time of year: the days in October when the Rideau Canal is drained in preparation for the skating season, still months away.

Just weeks ago, the temperatures were hot, the sun was bright, and the canal locks full.

But on October 9 — the day after Thanksgiving Monday — there were telltale signs that the water levels were dropping. Notice the bit of river bank on the opposite side? It wasn’t there the last time I bicycled by.

Sure enough, a half kilometer upstream, where the Rideau Canal diverts from the Rideau River at Mooney’s Bay, the dams at Hogs Back Falls had been lowered, and the river came rushing through.

At Hartwell Locks — the upper end of what will become the 7.8 km Rideau Canal Skateway — the locks that were used to lift or lower boats on their way along the system…

… are now open, dry, and used for boat storage.

The water that is permitted to flow through the canal bypasses the locks.

A few weeks ago, that outflow was below the water surface.

In a couple of months, this same spot will mark the end of the Rideau Canal Skateway.

At the other end of this stretch of canal, where the locks descend to the Ottawa River just below Canada’s Parliament Buildings and the Chateau Laurier, the sluices are opened. Here’s the locks at the height of the boating season.

From May until October, the Rideau Canal is enjoyed by boaters.

They’d have a rough time navigating it now!

Big seasonal changes at the Dow’s Lake Pavilion.

In a couple of months, the Canada geese and the ducks will be replaced by skaters.

And like the poet said, “When winter comes, can spring be far behind?”

Why does the National Capital Commission drain the Rideau Canal at this time of year?

Partly for maintenance purposes: the original stonework was laid in the 1830s and there’s always something that needs attention. I guess it must be easier to make masonry repairs without trying to work under water!

Partly because the pressure of the freezing water on a full canal would push against the canal walls and make maintenance even more of a problem.

Partly to battle the zebra mussels — an invasive species that, in recent years, has been choking up the waterways of Eastern Canada.

And, of course, the infrastructure of boating season must be replaced with the infrastructure of skating season.

But right now, there’s not enough water in the canal to form a skateway.

After a few weeks and some freezing temperatures, Parks Canada allows more water into the canal — enough to form the foundation of at least 10 cms of ice, with plenty of water below the ice. At night, National Capital Commission crews pump water onto the surface. It freezes and maintains the skating surface.

So the sad days when the canal is drained…

…will soon become the season for skating on the canal.