[00:01] Niagara Falls is one of the most spectacular&nbsp; waterfalls in the world. With a vertical&nbsp;&nbsp; drop of more than 50 meters or 164 feet&nbsp; and a flow rate that often exceeds 2800&nbsp;&nbsp;
[00:13] cubic meters per second or 100,000 cubic feet per&nbsp; second, it’s one of North America’s crown jewels.&nbsp;&nbsp; Roughly ten million people visit the falls every&nbsp; year just to catch a glimpse of the curtains of&nbsp;&nbsp;
[00:26] water pouring over the edge and the constant&nbsp; clouds of mist at the bottom. But Niagara Falls&nbsp;&nbsp; isn’t just a tourist attraction. The special&nbsp; geology and hydrology of this region, situated&nbsp;&nbsp;
[00:39] between Lake Erie and Lake Ontario, have resulted&nbsp; in some fascinating feats of infrastructure,&nbsp;&nbsp; from shipping to electricity to water control.&nbsp; It’s basically a microcosm of all the things&nbsp;&nbsp;
[00:51] I love. The falls themselves have required&nbsp; quite a bit of engineering over the years,&nbsp;&nbsp; and they’ve even been shut off for maintenance.&nbsp; Let’s take a little tour of the Niagara Peninsula&nbsp;&nbsp; aren’t usually listed in a guidebook. I’m&nbsp; Grady, and this is Practical Engineering.
[01:21] This is a map of&nbsp;the isthmus. We’ve got Lake Erie to the south,&nbsp;&nbsp; Lake Ontario to the north, Buffalo and western&nbsp; New York to the East, and Ontario, Canada,&nbsp;&nbsp;
[01:33] to the west. The Niagara River runs northward,&nbsp; connecting the two great lakes. And right in the&nbsp;&nbsp; middle, it plunges off the Niagara Escarpment,&nbsp; creating the famous falls. On the US side,&nbsp;&nbsp;
[01:45] there are the American Falls and the smaller&nbsp; Bridal Veil Falls. And on the Canadian side is&nbsp;&nbsp; the Horseshoe Falls where a majority of the river&nbsp; flows. It’s pretty impressive to see in person,&nbsp;&nbsp; but it’s actually not entirely a benefit. Because&nbsp; these falls pose a major problem for shipping.
[02:02] The Great Lakes form the largest inland freshwater&nbsp; transportation system in the world. Since the 19th&nbsp;&nbsp; century, they’ve served as the backbone for&nbsp; moving iron ore, coal, grain, and manufactured&nbsp;&nbsp;
[02:14] goods between the American heartland and the&nbsp; Atlantic Ocean. Ore from Minnesota and grain&nbsp;&nbsp; from the Midwest can travel by ship all the way to&nbsp; steel mills or export terminals on the East Coast.&nbsp;&nbsp;
[02:26] Barges and freighters are efficient at moving&nbsp; bulk cargo in a way rail and trucks can’t match.&nbsp;&nbsp; For a time, the Niagara Escarpment was a natural&nbsp; bottleneck between Lake Erie and Lake Ontario,&nbsp;&nbsp;
[02:38] preventing goods from moving directly between&nbsp; the upper lakes and the Atlantic. Freight had&nbsp;&nbsp; to be offloaded and portaged around the falls&nbsp; before it could continue its journey. The Erie&nbsp;&nbsp; Canal solved the problem somewhat, starting in&nbsp; 1825, bypassing Lake Ontario. But it could only&nbsp;&nbsp;
[02:55] accommodate smaller vessels, and even before the&nbsp; Canal opened, another solution was being planned. The Welland Canal runs through the&nbsp; peninsula west of the Niagara River,&nbsp;&nbsp; connecting two massive areas by shipping traffic&nbsp; for the first time in 1829. The canal fueled the&nbsp;&nbsp;
[03:12] early growth of cities along the Great Lakes&nbsp; and St. Lawrence River - including Cleveland,&nbsp;&nbsp; Detroit, Milwaukee, Chicago, Toronto, Montreal,&nbsp; and Quebec City - and it’s been rebuilt and moved&nbsp;&nbsp; several times over its life. The Welland Canal&nbsp; is really a titanic engineering achievement and,&nbsp;&nbsp;
[03:29] were it not positioned next to one of the natural&nbsp; wonders of the world, it would probably be famous&nbsp;&nbsp; in its own right. Because of the huge difference&nbsp; in elevation between the two lakes created by the&nbsp;&nbsp; escarpment, eight separate locks are required&nbsp; to allow ships to traverse between them. And&nbsp;&nbsp;
[03:44] all different kinds do - from personal leisure&nbsp; craft to the lakers that stay in fresh water&nbsp;&nbsp; to the salties that travel between the lakes&nbsp; and the ocean through the St. Lawrence Seaway. Starting on the upstream, Lake Erie side of the&nbsp; canal, the first lock isn’t really for lifting&nbsp;&nbsp;
[04:00] or lowering ships so much as for control. The&nbsp; level of Lake Erie actually fluctuates throughout&nbsp;&nbsp; the year, and there are longer-term trends as&nbsp; well. Wind storms also raise the level locally&nbsp;&nbsp; similar to the way storm surge works during&nbsp; hurricanes. The control lock does just that:&nbsp;&nbsp;
[04:16] it controls the level in the downstream&nbsp; canal. It prevents excess water from&nbsp;&nbsp; rushing down the canal when the lake&nbsp; is high, kind of like an airlock on a&nbsp;&nbsp; spaceship keeps air from rushing out when&nbsp; astronauts step outside for a spacewalk.
[04:30] Downstream of the control lock, the canal&nbsp; splits in two. The original pathway of the&nbsp;&nbsp; canal flows through the eponymous town of Welland,&nbsp; while the larger and newer section of canal,&nbsp;&nbsp; the Welland Bypass… well, it bypasses&nbsp; Welland to the east. If you look carefully,&nbsp;&nbsp;
[04:45] you’ll also notice a small river, the&nbsp; Welland River, which passes underneath&nbsp;&nbsp; both the original and bypass canals. On the&nbsp; way downstream from Lake Erie to Lake Ontario,&nbsp;&nbsp; shipping traffic passes over aqueducts that pass&nbsp; over a natural river. A hydrological wonderland!
[05:02] Continuing downstream from the aqueducts,&nbsp; the remaining seven locks are lift locks,&nbsp;&nbsp; more like what you think of when you imagine&nbsp; a lock. Notice how they’re clustered tightly&nbsp;&nbsp; around the terrain and not distributed evenly&nbsp; along the length of the canal. That’s the Niagara&nbsp;&nbsp;
[05:16] escarpment, the same geological feature&nbsp; that the water cascades down at the falls.&nbsp;&nbsp; This is the elevation diagram of the entire Great&nbsp; Lakes and St. Lawrence Seaway system from Lake&nbsp;&nbsp; Superior to the Atlantic Ocean, and you can see&nbsp; that this drop is the biggest one of the whole&nbsp;&nbsp;
[05:33] thing. And that’s pretty important for another&nbsp; part of the infrastructure on the peninsula. The power available from a moving fluid&nbsp; is directly proportional to the flow rate&nbsp;&nbsp; multiplied by the height of the drop. In most&nbsp; hydropower applications, that height is created&nbsp;&nbsp;
[05:49] artificially by a dam. There aren’t that many&nbsp; places in the world where you have both a&nbsp;&nbsp; large volume of flowing water and a significant&nbsp; natural drop in elevation. But that combination&nbsp;&nbsp; made Niagara Falls the birthplace of large-scale&nbsp; electric power in North America.
[06:07] opened the Edward Dean Adams&nbsp; Power Plant, built with Westinghouse AC generators&nbsp;&nbsp; based on the ideas and patents of Nikola Tesla.&nbsp; The plant served as the basis for the modern&nbsp;&nbsp;
[06:20] electrical grids we have today, and many of the&nbsp; fundamental concepts are basically unchanged. But the power infrastructure at Niagara&nbsp; Falls definitely has changed. Where the&nbsp;&nbsp; Adams Power Plant put out about 40 megawatts&nbsp; of power in 1895, now the combined capacity&nbsp;&nbsp;
[06:37] from the region is in the neighborhood&nbsp; of 5 gigawatts. But in both cases,&nbsp;&nbsp; it wasn’t as simple as putting a turbine&nbsp; at the base of the falls. While it might&nbsp;&nbsp; be technically possible to generate power by&nbsp; placing a water wheel directly in the stream&nbsp;&nbsp;
[06:50] of a waterfall like a kid’s bath toy, it’s&nbsp; not the most efficient way (plus it would&nbsp;&nbsp; take away from the beauty). The water used to&nbsp; power the hydroelectric plants on both the US&nbsp;&nbsp; and Canadian sides of the Niagara River is water&nbsp; that never actually flows over the falls. Instead,&nbsp;&nbsp;
[07:06] it’s diverted into five massive tunnels - two&nbsp; on the US side and three on the Canadian side. Like most tunnels, you can’t really&nbsp; see the extent of the hydro tunnels&nbsp;&nbsp; at Niagara Falls. There are a few conspicuous&nbsp; clues though, like these gigantic buildings.&nbsp;&nbsp;
[07:22] These interesting protrusions from the landscape&nbsp; house enormous steel doors, nearly 60 feet tall,&nbsp;&nbsp; that can drop down into the tunnels and close&nbsp; off the flow for inspections and maintenance.&nbsp;&nbsp;
[07:34] Both the Ontario and New York sides of&nbsp; the river feature similar structures. From the tunnels, water flows into major&nbsp; hydropower plants on both sides of the border:&nbsp;&nbsp; the twin Adam Beck stations on the Canadian&nbsp; side and Robert Moses station on the US side.&nbsp;&nbsp;
[07:49] Then it’s released into the the lower part of&nbsp; the river below the falls. When you add them up,&nbsp;&nbsp; that’s 39 turbines with a combined&nbsp; capacity of more than 4000 megawatts.&nbsp;&nbsp; It’s a tremendous amount of power generation in&nbsp; one place. But actually, that’s not all of it.
[08:06] These tunnels divert 50-75% of the flow of the&nbsp; Niagara River. That wide range in percentage of&nbsp;&nbsp; diversion isn’t because we don’t know how much&nbsp; is diverted, but because we actually control&nbsp;&nbsp;
[08:18] how much water is diverted, depending on the&nbsp; tourist requirements agreed upon in a treaty&nbsp;&nbsp; by both nations. During the day in peak tourist&nbsp; season, more water is allowed to flow over the&nbsp;&nbsp; falls to ensure the grandeur of the falls is on&nbsp; full display for the huge crowds of tourists that&nbsp;&nbsp;
[08:34] visit every year. At night and during the winter,&nbsp; more of the flow is diverted to generate power.&nbsp;&nbsp; That’s all managed by this structure upstream&nbsp; of the falls: the international control dam.
[08:46] across the river. But it doesn’t need to. This&nbsp; structure’s not meant to create a reservoir;&nbsp;&nbsp; it just subtly adjusts the level in the river&nbsp; to control how much water flows over the falls&nbsp;&nbsp;
[09:00] versus into the hydropower intakes. The US&nbsp; side of the Niagara River is pretty shallow,&nbsp;&nbsp; so that side acts kind of like an uncontrolled&nbsp; spillway. Then, the gates on the Canadian side&nbsp;&nbsp; can be adjusted to balance the competing&nbsp; demands on water between tourism and power.
[09:16] But there’s one big problem with those competing&nbsp; needs: they both have the same timing. We want&nbsp;&nbsp; thunderous cascades of water over the falls&nbsp; during the day when tourists are visiting,&nbsp;&nbsp; but daytime is also when the demand for&nbsp; electricity is highest. It’s like if solar&nbsp;&nbsp;
[09:31] panels only worked at night. To accommodate&nbsp; this, both the US and Canada have pumped&nbsp;&nbsp; storage plants. At night, excess electricity&nbsp; is used to pump diverted water into reservoirs,&nbsp;&nbsp;
[09:44] essentially storing both the power and the&nbsp; extra water that’s available during off-peak&nbsp;&nbsp; hours. Then, during the day, the water is released&nbsp; back into the forebay of the power plants. You get&nbsp;&nbsp; a little extra power from that drop out of the&nbsp; reservoir into the forebays, so both sides have&nbsp;&nbsp;
[10:00] small hydropower facilities to capture that.&nbsp; But more importantly, you get a lot more water&nbsp;&nbsp; during the day than would otherwise be available&nbsp; to run through the big plants, making more power&nbsp;&nbsp; when it’s needed most. And there’s just something&nbsp; funny to me that the infrastructure is duplicated&nbsp;&nbsp;
[10:17] on both sides of the river, like neither country&nbsp; was willing to be one-upped by the other. All of this diversion noticeably&nbsp; reduces the flow of water over the&nbsp;&nbsp; falls. Even when they are at ‘full blast’&nbsp; during the day in the tourist season,&nbsp;&nbsp;
[10:30] only 50% of the flow of the Niagara River makes&nbsp; it over the falls. You can imagine how powerful&nbsp;&nbsp; the falls would be if 100% of the flow were to&nbsp; cascade over. It might seem like this diversion&nbsp;&nbsp;
[10:42] detracts from the majesty of the falls, but&nbsp; in another sense, it actually preserves it. All waterfalls undergo some degree&nbsp; of erosion as the water and sediment&nbsp;&nbsp; suspended in it scours away the rocks and&nbsp; soil underneath. Without any diversion,&nbsp;&nbsp;
[10:56] Niagara Falls would be receding towards Lake&nbsp; Erie at a rate of about 3 feet every year. At&nbsp;&nbsp; the end of the last ice age, the falls were&nbsp; right at the edge of the Niagara Escarpment,&nbsp;&nbsp; but thousands of years of erosion have caused them&nbsp; to work their way upstream. You can actually see&nbsp;&nbsp;
[11:12] how far it’s already progressed by looking at this&nbsp; elevation map. Over the last 12,000 years or so,&nbsp;&nbsp; the falls have migrated by erosion to&nbsp; their current location. By diverting a&nbsp;&nbsp; significant portion of the flow, the power&nbsp; plants have actually slowed the rate of&nbsp;&nbsp;
[11:28] erosion to approximately one foot per year, which&nbsp; will help preserve the falls for a longer period. While flow on the falls is downregulated by&nbsp; diversion for hydropower, the falls are never&nbsp;&nbsp; ‘turned off’...except for the one time in the&nbsp; 1960s. The smaller American Falls (and nearby&nbsp;&nbsp;
[11:44] Bridal Veil Falls) have a pile of loose rocks&nbsp; and boulders, called talus, at their base.&nbsp;&nbsp; This pile of rocky debris actually extends&nbsp; a good fraction of the way up the falls, and&nbsp;&nbsp; officials worried that the falls might ultimately&nbsp; transition into a series of rapids cascading down&nbsp;&nbsp;
[12:00] the slope of talus rather than remaining a&nbsp; majestic waterfall. So, in 1969, the Army&nbsp;&nbsp; Corps of Engineers built a temporary cofferdam&nbsp; between the New York shoreline and Goat Island,&nbsp;&nbsp;
[12:12] diverting the water over the Canadian Horseshoe&nbsp; Falls and leaving the American Falls dry(ish)! After the engineers got a chance to inspect the&nbsp; situation, they determined that the best course&nbsp;&nbsp; of action was just to leave the majority of the&nbsp; talus in place, since it seemed to be stabilizing&nbsp;&nbsp;
[12:29] the cliff face. Sometimes, doing mostly&nbsp; nothing is a decision you make as an engineer,&nbsp;&nbsp; even if you have to do a monumental amount&nbsp; of work to come to that conclusion. So the&nbsp;&nbsp; cofferdam was taken out, and water has flowed&nbsp; continuously over all the falls since then.
[12:45] It really highlights the complexity&nbsp; of Niagara Falls. On the one hand,&nbsp;&nbsp; you have one of the natural wonders of the world,&nbsp; an absolutely enormous set of waterfalls that&nbsp;&nbsp; inspire awe and wonder in the countless travelers&nbsp; who are lucky enough to take in the view. The&nbsp;&nbsp;
[13:01] same thing that makes it impressive for tourists&nbsp; (the big drop) makes it valuable for power and a&nbsp;&nbsp; major challenge for shipping. And out of that&nbsp; comes all kinds of fascinating infrastructure,&nbsp;&nbsp;
[13:13] not only to facilitate the tourism but the other&nbsp; stuff too: a major canal with locks and aqueducts,&nbsp;&nbsp; the international dam control gates, pumped&nbsp; storage reservoirs, epic tunnels, towering gates,&nbsp;&nbsp;
[13:26] massive hydropower plants, and so much more. It’s&nbsp; really a pretty remarkable place for engineering. My wife and&nbsp;&nbsp;I actually visited the falls back in 2018, and&nbsp; even crossed the Rainbow Bridge to the Canadian&nbsp;&nbsp;
[13:39] side for coffee with a view. Like I always do&nbsp; when I’m in unfamiliar territory, I turned on&nbsp;&nbsp; a VPN at the coffee shop before connecting to&nbsp; their WiFi. This is kind of wild, but I’ve been&nbsp;&nbsp; using today’s sponsor, NordVPN for 7 years now.&nbsp; Life’s changed a lot, but my VPN provider hasn’t.
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