Thursday, December 13, 2012

3D Thursday: 3D through the aqueduct, part 1 of 2

Today's 3D Thursday blog post is one I've been working on for a while. It's a two-part series—with lots of 3D content—on the aqueduct that runs through LeBreton Flats. URBSite did a great (2D) post on the history of the Fleet Street pumping station, which is the subject of part 2, coming next Thursday. Reminder: 3D photos are best viewed full screen with a dark backdrop.

The first image that comes to my mind at the thought of the word "aqueduct" is a high stone-arch wall dating from the Roman empire. But really, it's just any conduit that carries water, usually by gravity. In fact, as this Discovery Channel special shows, most of the Roman aqueducts were on, or under, the ground level.

Ottawa's aqueduct is in a channel and partially buried under what are technically considered bridges. In the 3D photo above, taken from atop the escarpment, you can see the bottom end of the aqueduct, where it leads to the historic Fleet Street water pumping station and Pooley's Bridge in the foreground, and you can sort of follow it backwards along the line of trees through LeBreton Flats, curving back to the Ottawa River behind the condos of 250 Lett Street on the right. I don't expect you to see all that from the vantage point of the photo above, though if you zoom in close (zoom gradually if you can so your eyes can adjust along the way) you can make out the parkway bridge over the aqueduct inlet.

Here's where it comes off the Ottawa River, first passing under a prefabricated steel bridge that carries the Ottawa River Pathway. Nepean Bay in the Ottawa River is at the left, and the water headed to the aqueduct flows toward the right.

It then continues under the Ottawa River Parkway, er, the Sir John A Macdonald Parkway:

The water makes its way under yet another bridge of much lower profile, turning diagonally into the aqueduct. You can see the stone arch of that bridge in the distance.

Stepping back a bit—and taking off the 3D glasses—here's a look at the Parkway bridge from downsteam along the aqueduct. While it doesn't look like one, there is actually a bridge here, the Canada Central Railway Bridge, which you've probably never heard of unless you were around before the trains left LeBreton Flats. Or if you've been on one of David Jeanes' talks on the railway heritage of LeBreton Flats. Partly this is because it's such a wide bridge, and all that runs under it is unnavigable water, and all that seems to run over it is grass and dirt.

The water flows under the Parkway in the distance, toward the headworks (the building at right, ostensibly at 116 Fleet Street), and under our feet. This building is behind a locked fence, but you can get within spitting distance via the path north of the "Eric Darwin commemorative gate" at Albert and Preston, at least before it all closes for the NCC's soil remediation project and the City's LRT project. There is also a path connecting from the Ottawa River Pathway, where it splits off at the Parkway.

The aqueduct comes out on the southeast side of the Bridge into the open trench. A newer watermain runs under the aqueduct trench, which is seen here mostly drained. The watermain comes from the Lemieux Island Water Treatment Plant further west on the other side of Nepean Bay, with fresh drinking water for much of the city.

In May 2012, prominent local rail and heritage enthusiast David Jeanes led a Jane's Walk on the railway history of Lebreton Flats. When he took us along it, the aqueduct was still full. It was drained later on in the Summer for some maintenance work. Here we're standing on top of the Canada Central bridge, looking east-ish across LeBreton Flats toward downtown Ottawa. Of the series of five stone-arch bridges along the aqueduct, the next one down—in the middle of the photo—is the bridge crossing where Broad Street used to be.

When we take the water out, we can see the large diameter feedermain that is running through the aqueduct to supply much of Ottawa with its water. The water that flows freely in the aqueduct around the watermain is not for drinking! When this photo was taken, some PVC pipes were being laid alongside it, the nature of which I'm not sure.

Continuing east, we reach the Broad Street bridge, which has been cut off on the south side by the Transitway. A water main extends over the aqueduct alongside the bridge. Broad Street was the site of a Chateau-style C.P.R. station, though if you want to know more about that, you'll have to talk to David (or if we're lucky he'll reprise his talk next year!). David is the one in the brown hat on the right, waiting for the tour group to assemble for the next segment of the tour.

So then let's go around again and look at the Broad Street bridge from Booth Street, next to the LeBreton transitway station. Here in early May, a couple days before David's talk, the water is not all the way up, but does a nice job of reflecting what's around it.

Mostly drained in mid-August, the exposed rock seen at the same angle makes for a drearier look, so let's switch back to 3D mode! The trees on either side really pop out, as does the pipe in the trench.

Here's the same stretch of water on the same day, looking east from Broad toward Booth. If you zoom in and look under the Booth Street bridge, you'll notice that the aqueduct takes a turn to the left. (As always, click the photo to see it larger)

Here's a closer look at that turn, taken from the Booth Street bridge looking east. At the left is the 200-250 Lett St condos, and at the right is the Transitway curving up to Albert Street. The Transitway is on an embankment that is being held back from eroding away by a layer of chicken wire. That bridge right in front of us is the Lloyd street bridge, named after another long-gone street of LeBreton Flats.

Little known is that there is a second aqueduct running underground, parallel to the open channel one. You can see the curved concrete top of that second aqueduct tunnel exposed here under the pathway that used to connect Booth Street to the escarpment (before the path was abandoned in favour of the one installed along the river after the parkway was realigned in the early 2000s). For orientation, we're looking east toward downtown, along the former Ottawa street (there's a good aerial photo of that street here), in line with the downtown segment of Albert Street. Saint Vincent Hospital is at the right atop Nanny Goat Hill. The aqueduct we've been following in previous photos is running underground, parallel to this broken up pathway, immediately to the right. Note the white bicycle pavement markings on the pathway section. I don't know when they were installed but I suspect they were just used for testing.

Like the Canada Central at the other end of the aqueduct (and again with thanks to David Jeanes), the Lloyd Street bridge not easily recognized as a bridge because it's such a long tunnel, and it's mostly covered over by shrubs and grasses. On paper, this is not one block-long bridge, but three bridges: one at Lloyd Street, one at Lett Street, and the gap between connected by J.R. Booth's Grand Trunk Railway bridge, whose trains crossed it at an angle. There'll be a bit more on this in next week's post.

Seen here from the sidewalk along the Transitway at LeBreton station, the Lloyd Street bridge disappears under a mess of wild bushes. The aqueduct follows underneath it, toward the grey Fleet Street Water Pumping Station in the distance. The Juliana Apartments on Bronson are at the right, and something big and yellow is in the distance to the left, protected from this no-man's-land by a berm of broken stone and asphalt.

Next week we'll cross under this bridge and see some great 3D views of the Fleet Street pumping station, the last bit of the aqueduct, and the tailrace (as well as some 2D photos of those and more!)

[Tune in on Thursdays at noon for a new 3D image. View the 3D label for other posts with 3D images]

[2019-11-14 edit: Added links/anchors, fixed typo]

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