What is Waterfallogy?

Waterfallogy is the study of waterfalls! It includes aspects of geology, hydrology, engineering, history, social science, art, travel and adventure. Waterfallogists are interested in how all of these disciplines relate to waterfalls.

Interestingly, you won't find the term 'waterfallogy' in in textbooks or academic journals. A google search of 'waterfallogy', conducted in late 2022, came up with only 39 hits. In fact, some of the first results are articles that quoted a long-lost predecessor of this page. You can see a PDF of the 2004 article.

We used the term in the first edition of the Waterfalls of Ontario book. Could it be that 'waterfallogy' originated right here from the Waterfalls of Ontario project? I would find that hard to believe, but thus far I haven't found it appearing in any earlier documents.



Geographer Brian J Hudson, of the Queensland University of Technology, has written extensively about waterfalls. While he has referenced the term 'waterfallogy', he points out that "Unlike cave research, known as speleology, which also involves many different disciplines, the study of waterfalls is not generally regarded as a distinct branch of knowledge." ("Waterfalls, Science and Aesthetics" in Journal of Cultural Geography, vol 30: 356-379.). You can purchase one of Dr. Hudson's books called Waterfall: Nature and Culture.

In my humble opinion, the Waterfalls of Ontario book includes one of the better introductions to waterfallogy, certainly as far as Ontario waterfalls are concerned. Some of its contents are summarized and provided below. There are several other waterfall web sites that do a good job of describing waterfall formation and structure. As an example, Matthew Conheady includes a great glossary of waterfall terms at NYfalls.com

While my approach to 'waterfallogy' typically focuses on the natural environment, you can also read about the History of Waterfalling in Ontario. This describes how waterfalls went from being meeting places for First Nations people, to being perceived as terrible obstacles, and then later to tourism hotspots. It also outlines some of the academic work completed about waterfalls in Ontario.

Geology

Natural waterfalls are geologic features. In the Waterfalls of Ontario Project, waterfalls exist where a watercourse flows over bedrock. Bedrock is found everywhere under Ontario. In much of the province, however, the bedrock is covered and hidden by layers of sediment. It is only where a river (or a glacier) has stripped away enough of the sediment that a waterfall can form. This is why there may be no waterfalls near you.

Most of Ontario's population lives in the southern part of the province. In this area, the bedrock consists of flat-lying sedimentary rock, like limestone, dolostone, sandstone, and shale. These are usually dull grey or brown. Of these rocks, shale is very weak and easily eroded; you can often crumble it in your hands. When a stronger rock overlies shale, we often see it undermined as the shale is eroded away. This can create vertical rock faces, like the Niagara Escarpment.

A superb example of a harder layer of limestone or dolostone, underlain by weaker layer of shale, which is coloured rusty-red at this site. The shale erodes faster, leaving the stronger rock to protrude over top. This forms a short but vertical drop.

Any stream that reaches the edge of the escarpment will tumble over the edge, forming a waterfall. As the river erodes into the rock, the rock is slowly carried away and a gorge is formed. This is exactly what happens at Niagara Falls. So powerful is the force of erosion, that the waterfall has 'retreated' 11 km upstream in about 12,000 years. The original location of the falls was at the edge of the Niagara Escarpment, located downstream at Queenston, Ontario. What will happen if the river erodes all the way to Lake Erie?

The Niagara Escarpment, as it appears on Manitoulin Island. What would happen if a river happened to flow towards the edge of the escarpment?

Most of the waterfalls around the GTA, Niagara, Owen Sound, and Manitoulin are formed where creeks flow over the Niagara Escarpment. Many of the waterfalls in eastern Ontario are formed on similar sedimentary bedrock. But since there is no escarpment, most of the waterfalls are much shorter. (eg. Pakenham Falls ). The classification system published (2021) in the Waterfalls of Ontario book describes most of these falls as either "caprock plunge", "step", or "washboard" falls.

Once we move out of southern Ontario, the nature of the landscape changes. The bedrock is no longer formed of flat-lying sedimentary rock. Instead, it is dominated by more colourful crystalline rocks of the Canadian Shield. Though there are exceptions, most of the falls in northern Ontario are not vertical. Some waterfall experts in other jurisdictions might not even consider these to be "true" waterfalls. But this is what makes Ontario so cool... our landscape is so varied. Once you hear the roar of the falls, you will understand why early settlers considered these to be waterfalls all the same.



Most people can spot the pinkish-coloured, sparkly nature of granite, but a whole host of other rocks are also found. For example, gneiss is very commonly mistaken for granite. Its big difference is that it appears banded. These were formed when rocks like granite or sandstone were heated and squeezed so much that their minerals were realigned. This is an example of a metamorphic rock. To make things even more complicated, some of these 'metamorphic rocks' appear layered like sedimentary rocks. These specific ones occur where pre-existing layered rocks like sandstone or limestone were metamorphosed into new rocks. Sometimes the rock is dark, usually due to a volcanic origin.



Unlike the rocks of southern Ontario, the rocks of the Canadian Shield are very resistant to erosion. In most cases, river erosion simply isn't powerful enough to erode deep gorges into the rock. See the example shown for Onaping High Falls below. Where waterfalls with deep gorges do exist in the Canadian Shield (eg like Kakabeka Falls), the bedrock is actually sedimentary in nature, though still part of the Canadian Shield.



The classification system published (2021) in the Waterfalls of Ontario book classifies most of the falls in the Canadian Shield area as "cascades" or "troughs". Troughs occur where layered bedrock is tilted and redirects the flow of water.

Hydrology

Very few waterfalls have a constant supply of water. Flows rise and fall through the seasons, based on climate and the nature of the waterfall's watershed. Understanding how these factors function can help you to know what to expect when you visit a waterfall, and when it might be a good idea to delay your visit.

All rivers get their flow from rain and snowmelt. But the rate and path that rain takes to get to a river will impact its flow. In summer, for example, many streams and rivers exhibit very low flow. This is because much of the rain that lands on the ground surface evaporates, or, is used by plants for transpiration. In contrast, many streams have their greatest flows during spring, right after the snowpack melts.



The nature of the watershed feeding a waterfall can impact its flow. A watershed is the area of land that drains towards a river. Precipitation that lands in the watershed will start to flow towards the river, though some of it will be lost due to evaporation, depression storage or human usage.

A larger watershed will usually produce a larger river, because it intercepts more water. In many cases, though not always, a very small watershed is more prone to drying out during periods with low precipitation. This is why some of the smallest waterfalls in Hamilton, for example, are dry through much of the year.

You can read more about waterfallogy in the Waterfalls of Ontario book. A more academic treatment of some waterfallogy concepts is provided by Andrew Goudie (2020) of the University of Oxford, presented in "Waterfalls: Forms, Distribution, Processes and Rates of Recession" , Quaestiones Geographicae Vol 39, p. 59-77.