Since returning from Dublin, I’ve developed a theory that Ireland is called the Emerald Isle because the plants are so well watered. Whether the sky is overcast or sunny, it seemed as if I could expect a stray shower to pop up at a moment’s notice. Frequent rains, combined with the island’s mild climate, create a perfect combination that allows plants to grow so lush.
It also makes Ireland the perfect destination for a trench drain blogger.
Old World Trench Drain
Dublin’s traditional style makes it hard to install trench drain, if not to preserve the look than to spare the inconvenience. Cobblestone is everywhere. Instead of seeing a trench drain system in the historic districts, visitors are much more likely to walk over stone trough drains or slot drains.
The trough drain above lives in Dublin City Centre. The stone trough is the same color and material as the surrounding walkway, but instead of being concave tile like some of the other stone trough drains I saw, this drain rose up in the middle to minimize tripping hazards. It really looks more like a grateless low profile (shallow) trench drain.
The trough drain is even segmented like a modular trench drain. I didn’t measure it, but since the drain was made in Europe it is likely a meter long – about 40 inches by standard measurement. It’s only half an inch deep, but walking over that uneven surface can be a tripping hazard – or I may be a clutz. I wish I could tell you more about the drain, but unfortunately I could not find a manufacturer marking.
The recessed stone trough theme is even popular with downspout drainage. In the U.S., it is more common to see a downspout drain straight into a small catch basin (see our previous blog about residential downspout drainage here). In Dublin, however, it is just as common – if not more popular – for water to drain across the sidewalk toward the curb via a shallow groove cut into the stone sidewalk.
You do see trench grating on downspouts in modern districts where the sidewalks are concrete instead of stone. The photo below shows just one example I found. The grate has diagonal slots, but I can’t tell whether the circles were meant to be screw holes or part of the pattern. Either way, the entire drain is so filled with sediment that moss grows on its surface and grass sprouts from the outlet. Water overflows the sidewalk when it rains, watering the unintentional urban landscape as it seeks its level.
Every so often the trough drains run into a section of trench drain like the one shown below. Recessed into the stone walkway, these drains have a cast iron grate with plenty of open surface area to gather water. The grate itself is set inside a frame, which is made of the same material and elevated just above the sidewalk’s surface.
It almost seems as if contractors purposefully sloped the sidewalk toward this point on either side, but since drain is set higher than its immediate surroundings the overall effect is dulled. When it rains, water first settles in the grouts before overflowing into the drain. You can tell because of the sticks and leaf bits beginning to fill the space, clog the grate and sprout plant life.
Merging Old World Style with Paver Drains and Slot Drains
Every now and then I did see a channel drain installed along a stone walkway. The contractor involved with the trench drain system below installed the drainage system at a radius where two types of stone sidewalk met. The drains are standard modular drain channels set slightly askew to create the effect.
It must’ve been a complex installation. Intermittent lines of slot drain run up to the radius drain before ending in catch basins. Slot drain companies often make the claim that the diminutive surface area of slot drains, combined with their wide channel bodies, makes the drainage systems more effective at carrying water while preventing clogs. This might be the case, but they still use catch basins to collect water and allow workers to clean out the drain.
Now, let me show you a good reason to be careful installing trench drain systems into a stone walkway. The photo below is the same faux radius drain as the photo before. It’s basically a paver drain system, and it needed proper installation to keep the trench drain from separating from the stone.
See how the stone slabs dip and expose the trench drain’s galvanized steel railings? This exposes the drain to weathering and allows water to drip between the stone and the channel wall. Cold weather will stress the channel, which is not built to bear weight coming at it from the side, eventually leading to a buckling drain and a broken channel.
Not only that but major portions of the trench drain’s channels are full to its gills with dirt, making it nearly impossible for the channel to drain effectively. I suspect this is because the trench drain systems throughout Dublin were neutral sloped systems. A pre-sloped system might help with the sediment buildup if, but as of now the water left on the surface during rainfall makes the smooth stone walkway slippery – and this time I know it’s not just me.
The city is split between a traditional downtown, dotted with 16th century cathedrals and castles, and the modern districts where new apartments and roadways make city life possible. All in all, I’d say city planners did a brilliant job integrating a traditional look into the realities of a modern city. I had a lot of fun visiting Dublin, and I saw some lovely trench drains along the way.
I’d love to hear your thoughts on Dublin trench drains, so leave a comment below! If you have any questions about paver drains, downspout drainage, slot drains or installing radius drains, feel free to email me! Or, call a specialist at Trench Drain Systems (610-638-1221).