Misconception – Rivers Flow South

There are many misconceptions about geological concepts. There is a list here, developed by Kent Kirby of the University of Minnesota. This post is to debunk one of those misconceptions. There will be others. Find them here.

Misconception: Rivers flow south – sometimes modified to rivers in northern hemisphere flow south, while those in southern hemisphere flow north

For some of you, there is a facepalm coming on. For others, this is a serious conundrum. This is where it’s important to step back and consider where these misconceptions arise.

By convention, we always put north ‘up’ on a map. Thus, when you hold the map out in front of you, north is up and south is down. And we all know water flows downhill.

This is the origin of the misconception: since south is downhill, rivers must flow only to the south.

It’s actually not all that intuitive that the proper way to hold a map is horizontally, with the top of the map pointing toward true north. I know this to be true, because I have observed it over and over again in my introductory geology classes .Once you hold your map horizontally, it becomes a little more obvious that the downhill direction can be any direction.

All rivers flow toward the oceans. If the ocean is north of the landmass over which the river flows, the river will flow to the north.

Rivers do flow to the north. Take the Genesee River that runs right past my office. It flows north directly into Lake Ontario. The Nile River flows north as well.

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So while it might seem obvious to some, it is not all the obvious to everyone that it is perfectly possible for rivers to flow to the north.

5 thoughts on “Misconception – Rivers Flow South

  1. And somehow, it’s one of those things still taught in school despite learning about the Nile early… which immediately disproves it.

    I grew up on the Yellowstone in Montana, which feeds into the Missouri, which feeds into the Mississippi. It takes a heck of a long time for that river system to stop going gradually northeast before it turns south. 🙂

  2. Would it be correct to say that glaciers generally flow south from the north pole in the northern hemisphere? The melt water from the retreating glaciers is not going to flow up and over the glacier towards the pole. The flow will be away from the glacier, and not north. Little meltwater streams make larger rivers. Of course not all rivers are formed by glaciers, and not all glaciers head straight south, but probably most melting glaciers in North America receded from South to North.

  3. If you’re talking about continental glaciers (AKA ice sheets), then sure, those flowed generally southward because all the ice was accumulating to the north. However, mountain or alpine glaciers flow downhill like rivers and are just as likely to flow north if they’re on the north face of a mountain. ~pH

  4. But in the northern hemisphere, snow and ice on the southern side of mountains will melt in larger quantities since the Sun is to the South. Meltwater then begins building up momentum toward the South primarily. Barring spiral arms eminating from the mountain, it would seem to tend to continue moving that direction. Large hills could redirect it, but small hills would erode with time due to The southward momentum. Rocks would take very much longer to erode.

    So melt water primarily begins building momentum toward the south, but it takes the path of least resistance toward the ocean, being redirected by anything solid enough to maintain its integrity over time.

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