This One Lake Holds 22% Of All Surface Fresh Water

And it's not one of North America's Great Lakes

Big area, but relatively small depth.

Here’s something new that I learned over the last few weeks! So I’ve been pulling together a video for YouTube on Australia’s great lakes, or rather the lack of them, and during that research I started looking at other continental great lakes. I’m a geographer so I typically just start to dig around in any given topic I might be researching! And one lake, in particular, sparked my interest: Lake Baikal! Mostly because this single lake is home to more water than ALL of North America’s official Great Lakes. Which is astounding!

The Great Lakes of North America — Superior, Michigan, Huron, Erie, and Ontario — collectively form the largest group of freshwater lakes by surface area in the world. And, of course, these lakes stretch across the U.S.-Canada border, covering a vast area of about 94,250 square miles (244,106 square kilometers). Lake Superior, the largest of the five, alone spans over 31,700 square miles (82,100 square kilometers), making it the largest freshwater lake by surface area globally. Not that it needs to be said, but these lakes have become incredibly important to both the U.S. and Canada through the centuries. And, during an age of climate change, the shear amount of surface fresh water they hold could prove to be literally life saving for the people who live near them.

So given their vastness in area size and incredible prominence on any given map you might look at, you would be right to assume that they probably have the most fresh water of any group of lakes out there. But you’d be wrong!

Lake Baikal, located in Siberia, Russia, is much less prominent than the combined surface area of the North American Great Lakes, covering only about 12,248 square miles (31,722 square kilometers). However, despite its smaller surface area size, Baikal holds more water than all five Great Lakes combined. Lake Baikal contains approximately 5,662 cubic miles (23,615 cubic kilometers) of water, whereas the Great Lakes collectively hold about 5,439 cubic miles (22,671 cubic kilometers). This is due to the unique depth and geologic history of Lake Baikal.

Lake Baikal is the deepest freshwater lake in the world, plunging to a depth of around 5,387 feet (1,642 meters). In contrast, the deepest of the Great Lakes, Lake Superior, reaches a maximum depth of 1,333 feet (406 meters), significantly less than Baikal’s abyss. Baikal’s vast depth allows it to store an enormous volume of water, even though its surface area is much smaller. And not only that but Baikal is much older having been formed around 25 to 30 million years ago, which has allowed it to develop into a unique ecosystem and accumulate vast volumes of water over a geologic period of time that the Great Lakes have not. The Great Lakes have only really been around in their modern form since the retreat of the last ice age around 12,000 years ago.

Because of this, the Great Lakes are relatively shallow in comparison. While they cover a large surface area, much of their volume is spread out horizontally rather than vertically. Their relatively lower depths limit the overall water volume they can contain, despite their massive surface coverage. Lake Michigan and Lake Huron, for example, are part of the same hydrologic system, yet neither comes close to matching the depth of Baikal. Additionally, Baikal’s steep-sided rift valley, formed by tectonic activity, is the primary reason for its impressive depth and, consequently, its water-holding capacity. The North American Great Lakes were not created due to a rift valley and, as such, simply can’t get nearly as deep (and likely never will).

This rift valley is pretty important to the overall story of why and how Baikal is so deep! Basically, it means that Baikal is gradually getting deeper over time due to the tectonic activity pulling the valley apart. This process continually contributes to its depth and, by extension, its water volume. The Great Lakes, on the other hand, were formed primarily by glacial activity during the last Ice Age, which carved out the basins the lakes now occupy. These basins, while expansive, do not have the same depth potential as Baikal’s rift.

What’s perhaps most interesting in all of this though is that, unlike North America’s Great Lakes, Lake Baikal never really established a major population center on its shores. The Great Lakes, of course, are home to Chicago, Toronto, Detroit, Cleveland, and many other cities. Baikal’s closest major city would be Irkutsk which is home to only about 600,000 people and, even then, it’s located about 40 miles away from the lake. There’s probably an interesting story for why this is the case, but that will have to wait for another article on another day.