Picking up from the last entry, getting beyond the relatively small (yet steep and intimidating) slide of Double Ducker ended up requiring the use of some rope. It’s common for cities to add features like ladders, handrails or even stairs to allow workers to get up and down sloped sections like this, but I’ve yet to see anything like that here in Montreal.

So this time with nel58 and controleman along for the ride, we hammered a
steel piton into the gap where two sections of concrete pipe met, attached a knotted rope and made our way down. Easy peasy, quick and easy.

Controleman making use of the rope. The picture makes the drop look a lot smaller than it actually is. (Photo by nel58)

After the three of us reached the bottom, we headed down around the bend through the four foot pipe. A few minutes later, we arrived at what we had expected this would lead to: the Cote St-Luc Collector (CSLC) sewer. Here, the flow of Double Ducker enters a junction chamber from the right-hand side. A larger conduit, the main section of the CSLC, sits on the left side, perched on top of a slide. The contents of the two sewers flow smoothly over the sloped floor of the chamber eventually emptying into a single ten foot high pipe.

The junction where Double Ducker (on right) flows into the Cote St-Luc collector.

Worth noting here is how you can see this same junction in the river on older maps where a smaller creek veers off towards the West. The sewer system has effectively reversed their roles, though. Now it’s this smaller arm that carries the majority of the river’s flow.

Like its official name implies, the CSLC carries the waste from the predominantly residential community of Cote St-Luc as well as the more industrial areas found towards the lower reaches in Lachine. By Montreal’s standards its a medium-sized sewer, no more than ten feet in height.  It consists mainly of a horseshoe-shaped concrete pipe, perhaps put in place during the early 1960s to accommodate the increasing number of subdivisions being built at the time.

Not wanting to bother with yet another slide, we decided to take the easy route and head downstream first.  After tip-toeing carefully down the sloped floor of the chamber, we began sloshing our way through the concrete pipe that lay before us.

A few minutes later we arrived at an impressive junction chamber which picks up the flow from two other pipes leading into it. One sitting at higher elevations gracefully spills over a ledge into the CSLC creating a tranquil waterfall. It kind of gives the chamber a bit of a Tiki lounge. Les Baxter’s music and drinks served in coconuts would fit in well here. Whenever I think of this section, I can’t help but think of the word Shangri-la.

Looking upstream from a portion of the Shangri-la chamber.

Heading further downstream, it started to become clear that we’d be walking through relatively featureless concrete pipe for quite some time before seeing anything out of the ordinary. We decided to turn around, head back upstream to junction we came in through, and try to get up the slide on the left hand side.

Fortunately, this wasn’t going to require any rope to get up. Its edges were relatively dry and we were able to make it to the top and into the next section of concrete pipe.

Of course, a few hundred feet or so beyond this point, we encountered a much more formidable obstacle, and while it might not look like much in the photo below, it’s one of the more intense slides I’ve ever seen. It’s steep and unlike the other two slides encountered in this system, the water comes down violently, barreling down  through two sections of RCB; a good sign that the sewer was sitting directly below a set of train tracks. If this was in Toronto then there would have been a nice railing or something to hold onto, but like I said,  Montreal tends to lack such underground conveniences.

Looking up into the super steep slide. Note: it's actually far worse than it looks here. (Photo by nel58)

I stood at the bottom about twenty feet behind Controleman, who perhaps not realizing what he was about to get himself into, started climbing upwards. For a moment or two it actually looked as though we’d all be able to make it to the top of this thing. He made it about a third of the way up, but when he ventured from the dry shoulder of the slide and into the water, that’s when he lost control. He started sliding downwards a little, which would have been fine had his one foot not slipped out from underneath of him. Poor Controleman took a bit of a fall, then managed to get back up, at which point he started sliding again, straight towards me. Being a fair bit heavier than myself, I thought he was going to end up knocking me clear off my feet, but I was able to catch hold of him before the situation became any worse.

So now with Controleman thoroughly soaked (and maybe a little bit shaken up too), we decided it would probably be a good time to start heading back out. If we wanted to get past this particular section, it was going to require finding another way past it, perhaps through a manhole further upstream. We gathered up our stuff, climbed back up our rope and made our way towards the infall we entered.

Lessons learned: don’t step out into the middle of a slide, and when in doubt use a rope.

Finally, here’s a very aproximate path of both the Cote St-Luc collector (shown here in red) and the stretch of Double Ducker that leads into it. You can zoom out in order to see the full extent of the system.

View Larger Map

Don’t worry, we’ll get through this thing eventually.

From a distance, the drain (which I’ve named Double Ducker) beginning at the edge of the Meadowbrook Country Club doesn’t really appear to be much. In fact, if it wasn’t for the old limestone construction of its inlet, then I wouldn’t have bothered looking at it more carefully in the first place. The two entry points are all of two feet high. Rarely does that sort of size suggest anything good lies beyond.

It wasn’t until I got closer that I realized that the two channels are actually double this height. Over the years, sediment and other debris has more or less created a dam of sorts, but beyond this it soon dips down and opens up to reveal the full height.

Four feet isn’t all that comfortable a height to walk through, but it’s better than two feet. So I slipped on my chest waders, squeezed through the left side and crouched through 75 feet or so of what appeared to be hastily cut limestone blocks.

I was now passing underneath the original mainline of the Canadian Pacific Railway built in 1886. It smelled less like a man made drain and more like an old cave.

Looking back through to the entrance inside one of the limestone channels.

When CPR built a rail yard parallel to the main set of tracks in the late 1940s, more of the river required covering.

Detail of 1952 map showing Riviere St. Pierre (and its tributaries) passing under CPR's rail yards.

By this time the construction material of choice wasn’t limestone, but concrete. So at this point, the two channels come to an end and a rather ruddy–looking concrete section in the shape of an arch begins; its floor looking as though it had been quickly slathered in place. At this point I could finally stand up. The smell of sanitary flow wafting in from up ahead gave a good indication as to where all this was heading.

At the end of the limestone section with a drillhole in the ceiling bringing in a touch of natural light.

A few feet further and the concrete arch suddenly increases in size with enough room to stand up in and then some.

Looking a little forlorn while standing inside the largest concrete arch section. (Note the imprints left from the wooden forms used during construction.)

Only to become slightly smaller again thirty feet later.

Looking through to the smaller stretch.

And then things get really small with the start of a section built using RCP less than four feet high. None of this really makes sense. Much like actual rivers, sewers have a tendency to get larger as you head downstream in order to accommodate the increasing amounts of water picked up along the way. This small > large > larger > small > smaller sequence is still a bit confusing.

Looking ahead (but not forward) to the upcoming stretch of small RCP.

So at this point, I had effectively crossed the width of the entire railway yard above me. The more refined looking section of pre-fabricated RCP that lay ahead was obviously added more recently. 1973 is the last map I have that shows the river flowing past this point. It was around this time when the city began to implement a more comprehensive wastewater management plan. This stretch was most buried as a part of that effort.

Shining my spotlight down the small pipe, I saw no end in sight, but could hear the rumble of water suggesting bigger (perhaps more interesting) things lay ahead.

I decided to keep going. Here, the concrete is smooth, almost polished. Combined with a fine layer of sanitary “scum” on its bottom and the slight downward slope, it was slippery enough for me to lose my footing a couple of times. After crouching through about 250 feet of this pipe, I eventually reached the source of the rumbling: a seven foot high slide.

Normally getting past something like this would be kid’s play. Even when civil engineers don’t thoughtfully add ladders or step-irons, you can often make your way down safely enough by keeping to the dryer edges. But here there’s no ladder, and given the slipperiness of things, I came to the conclusion that even if I could get down safely (and dryly), I might not be able to get back up so easily.

So I did what any prudent drainer would do: I decided to wait and come back another day, with a couple of friends, a bit of climbing gear and a length of rope.

Coming up in our next episode: Double Ducker meets Ovalflow. Stay tuned.

Standing below a bit of natural light pouring in from above a manhole shaft.

Judging by the pre-fabricated sections of reinforced concrete pipe, it looks as though this portion was constructed a bit more recently. Sometime around the 1970s, perfectly round RCP seemed to have become the standard material for sewers and storm drains in Montreal. It can make for somewhat dull underground experiences, especially when long stretches of the stuff are involved. Fortunately, this particular sewer ended up having a nice combination of other features to help break the monotony.

The visibility was fairly poor, which we’d later discover was the result of cold air blasting in through a little 6″ pipe. During the autumn and winter months, the air inside sewers stays a few degrees warmer relative to aboveground temperatures. When outside air finds a way in, it can can lead to somewhat unfavorable exploring conditions. In this case, a dense “fog” had filled the sewer. The lights of our headlamps only penetrated a few feet in front of us. Regardless, we began making our way northwards underneath Cote-St-Luc.

Sloshing our way through the shin-deep water, we eventually arrived at a nice wide junction chamber. Nothing too fancy or out of the ordinary, but at least at this point the fog had subsided enough to make it a bit more practical to be able to take a photograph or two.

nel58 and myself lighting things up.

We chose to follow the smaller pipe to the right out of which we could hear the rumbling of water; a sign that something a bit more interesting lay ahead.

Fifty feet or so in, we found ourselves inside a  rusted corrugated metal pipe. I have no idea why the change occurs, but it’s there. Maybe it’s a culvert that existed beneath a roadway before the rest of the sewer was put in place. As the picture below can attest it was a bit on the dirty side. I’m always having problems convincing people that sewers aren’t as bad as they might imagine them to be. I’ll admit that a photo like the one below does little to support my claims. Fortunately, these places never smell as bad as they look. Honest.

Being careful not to get a dangling condom, piece of toilet paper or god-knows-what-else in the face, we pressed forward.

We eventually reached a lovely little chamber responsible for the noises we had started hearing from the previous junction.

Accidental modernism found forty feet below.

Sometimes it’s the little stuff that helps make things more interesting. In this case, a curtain of water falling over a diagonal ledge or reinforced concrete beams. As much as traveling through pipes is a part of  underground exploration (which I’ll admit can sometimes get boring), it’s this sort of stuff that we look forward to discovering the most.

Since neither of the two pipes ahead of us were tall enough to stand up in and would likely only get smaller, we decided to head back.

After returning to the first junction, we started heading up the pipe that ran off to the left. It didn’t take long before we realized it would probably be some time before we came across anything other than RCP.  A basic system map from the 1960s  shows the main arm of the sewer continuing on to the northern boundary of Cote-St-Luc. Reaching that point would involve walking against the current for a good 3 kms from where we were standing. Not feeling up to that particular task, heading back downstream from our entry-point seemed like the more appealing option.

Roughly fifteen minutes later, this is what we arrived at this strange little room:

Odd engineering found at the end of the line.

Two relatively dry CMPs veer off to the left and the rest of the wastewater flows through the four foot high square section seen on the right. Shining my spotlight up through this part revealed no end in sight. I figured it was most likely going to be like this for the entire width of the railway yard sitting directly above us. Regardless, I started to crouch down through it.  Soon afterwards, I found that the bottom of the floor dropped off abruptly to the point where I was now up to my waist in water. Realizing my backpack (and more) would probably get soaked if things got much deeper, we decided it would be best to turn around and call it a day.

Next up: Downstream towards Lachine.

Inside the Rockfield combined sewer overflow conduit

Picking up from where we last left off, this stretch takes us through the inside of the Cote-St-Luc collector sewer at the northern edge of Lachine. From here it snakes its way southwards towards the Lachine canal, never straying too far from the original course of Riviere St. Pierre. Approximate round-travel distance: 4 kilometers.

I never look forward to having to cover larger distances inside sewers here in Montreal. The depth will vary, but 2-3 feet tends to be the norm. That might not seem like a lot, but when you factor in the speed at which it’s flowing and the amount of gear these types of trips can entail, it doesn’t take long before it starts to feel like a solid cardiovascular workout. This is especially true when you’re walking against the flow.

Here’s a general overview showing the CSL collector (the dark red line), the estimated path of Riviere St. Pierre and a few of the features described below.

View Larger Map

For the first kilometer and a half, this portion of CSL collector is pretty straightforward: 8×10 feet in diameter with a shape that’s typical of concrete sewers built in Montreal between the 1920s and 1970s. A smooth horseshoe-shaped arch covers a course aggregate floor that that slopes towards the edges. During dry weather, the edges of these types of sewers are usually dry. City plans define this section the “sidewalk”; but that term’s a bit misleading. Due to the angle, it’s actually terrible to have to walk on.

Typical Montreal-style sewer with 'sidewalk'

Because of the broader arc of the sewer and for some of the features described below, I decided to name this length of the CSL Collector “Ovalflow.”

It’s unclear when the sewer replaced this portion of Riviere St. Pierre. While bits and pieces seem to have been covered as early as the 1930s, I suspect everything was eventually reconstructed during the mid-1960s when the entire area’s sewers were integrated into a much broader system.

By the time the sewer reaches the area of Lachine known as Rockfield, things start to get a bit more interesting.

Rockfield regulator chamber.

At this point the CSL collector officially comes to an end inside a rather unusual chamber containing a number of interesting features. As seen in the photo above, on one side of the channel are four cells. All the water flows into the cell closest to the camera at which point it falls down a sinkhole into an even larger sewer- the appropriately named St-Pierre Collector, which we’ll get to in future entries.

Detail of city planning map showing chamber and connecting sewers.

The other three cells contain a metal cylindrical object suspended directly above a three-foot wide hole, one of which is entirely blocked up with sludge. Above these are a number of counterweights and a mechanism (shown here) likely designed to lower each cylinder so that it covers the hole. Since each hole seems to lead to the same sewer further below, I’m not sure what purpose these things actually serve. A water monitoring device (or flowmeter) sits high in one corner of the chamber, but it’s unknown if it has any connection to the large plugs or if it simply sends an alert whenever water levels start to rise.

One of the three 'plugs' positioned above a sinkhole.

Also found in this chamber is the beginning of a rectangular shaped conduit situated roughly eight feet above the main channel of the sewer. The principle here is simple: when the water inside the sewer reaches a certain height, the surplus flow is diverted through this tunnel and out into the open water- in this case, the Lachine Canal.

Entrance point of the Rockfield overflow.

This is one of the drawbacks of a combined sewer system. Most of the time everything gets sent off to the treatment plant as intended, but during heavy rainstorms, the system can become overburdened to the point where sewage spills out into the open water. Fortunately, these events only seem to happen a few times a year, but they’re still a source of significant water contamination. If you’ve been warned not to swim in the Lachine Canal (or elsewhere on the island), combined sewer overflow events are likely the reason why.

Midway point inside the overflow conduit approaching the Lachine Canal.

This eleven by five foot high conduit (known as the Rockfield Overflow) runs for a quarter of a kilometer, but because the outfall at the canal is submerged, one can only travel about two thirds that distance. Any further and you’re soon up to your chest in canal water.

At this point your only choice is to turn around.

Next up: Eastbound Traffic.