Why do almost all rivers in the world flow North to South?

[sevensages]

TL;DR Summary

Why do almost all rivers in the world flow from North to South?

I recently heard the narrator of a podcast state that the current of almost all rivers in the world flows from North to South. The narrator said the Nile River is one of very few rivers in the world that flows from South to North.

I cannot figure out why almost all rivers in the world have a current that flows from North to South. It is my understanding that gravity is the force that drives the current in rivers. Gravity causes the water in a river to move toward the lowest ground possible. So if almost all rivers in the world flow North to South, it seems like the lowest ground at the end of almost all rivers would be at the southern most point of the river. But why would the lowest point at the end of almost all rivers be at the southern most end of a river? To me, I don't see any reason why the flow of rivers would not be divided roughly equal with approximately 25% flowing to the South, 25% flowing to the North, 25% flowing to the East, and roughly 25% flowing to the West.

Why does the current of almost all rivers in the world flow from North to South?

 

[PeroK]

Why does the current of almost all rivers in the world flow from North to South?

They don't.

 

[sevensages]

They don't.

I've heard otherwise

 

[pasmith]

Other rivers which flow northwards include the Trent, the Mersey, the Rhine, the Garonne, the Elbe, the Oder, and the Vistula. If you look at northern Siberia on google maps, you'll see no end of rivers which flow northwards into the Arctic Ocean; the same is true of Canada.

 

[sevensages]

Other rivers which flow northwards include the Trent, the Mersey, the Rhine, the Garonne, the Elbe, the Oder, and the Vistula. If you look at northern Siberia on google maps, you'll see no end of rivers which flow northwards into the Arctic Ocean; the same is true of Canada.

Ok.....maybe the narrator was wrong

 

[sevensages]

They don't.

After thinking about this further, you are probably right.

 

[pasmith]

It's entirely possible that most rivers in Africa flow southwards, due to the fact that most of northern Africa, where the north-flowing rivers would otherwise be, is occupied by the almost entirely riverless Sahara Desert.

 

[PeroK]

It's entirely possible that most rivers in Africa flow southwards, due to the fact that most of northern Africa, where the north-flowing rivers would otherwise be, is occupied by the almost entirely riverless Sahara Desert.

For the four longest rivers in Africa, there is no prevailing direction: the Nile flows north; the Congo flows northwest then southwest; the Niger flows north then south; and, the Zambezi is east flowing.

 

[BWV]

Actually the opposite is true, of this list:

https://a-z-animals.com/blog/the-15-largest-rivers-in-the-world/

only the Mississippi and Mekong flow N to S

I do believe, however, that there is a general tendency for them to flow downhill

 

[Vanadium 50]

I do believe, however, that there is a general tendency for them to flow downhill

And South is at the bottom of the map. Simple logic,

 

[Baluncore]

There is less land in the Southern Hemisphere, so most rivers flow in the Northern Hemisphere.

Which way does Coriolis force turn a horizontal flow?

There is less rain in colder climate because cold saturated air contains less water.
So rivers in the arctic, that flow North, tend to carry less water, than do the southern rivers. The northern rivers flood during the thaw.

 

[Vanadium 50]

There is less land in the Southern Hemisphere, so most rivers flow in the Northern Hemisphere.

That is definitely true.

But "downward" explains much. The Amazon flows east, the Orinoco northeast, and the La Plata south. From the highlands to the sea.

 

[Baluncore]

But "downward" explains much.

You only need to look at the Ebro River in Spain to realise that is true. The Ebro flows from the mountainous North coast, on the Atlantic, Bay of Biscay, all the way down to the Mediterranean in the South.

Cities grow from trading, through ports where transport modes change. Ports tend to be on rivers, not exposed coastlines. Trade does not flow well through the icy northern ports in winter, so we focus our population and attention on the more southern estuaries. The music and the food of New Orleans can really draw your attention, and bias your judgement.

 

[DaveC426913]

Rivers flow southward for the same reason continents and islands flow southward.

Every school child knows about the science behind Continental Drip.

I thought this was a science site.

 

[256bits]

TL;DR Summary: Why do almost all rivers in the world flow from North to South?

I recently heard the narrator of a podcast state that the current of almost all rivers in the world flows from North to South. The narrator said the Nile River is one of very few rivers in the world that flows from South to North.

What was the podcast about?
Major rivers regarding economic activity, population, fresh water mass flow...
Perhaps he was talking about something completely different than just 'major rivers'.
What is a major river in his definition would be one of the items to explain here in this posting.

North America

https://upload.wikimedia.org/wikipe..._map.png/1024px-Mackenzie_River_basin_map.png

Here is a map of the MacKenzie River Basin in western Canada comprising the land of northern Alberta, a section of northern Saskatchewan, part of British Columbia, the Yukon, and the North West Territory. The drainage basin is east of the Rocky Mountains, of which the Athabasca and Peace Rivers drain much of the basin east of the Rockies.
Note that the river system drainage has a general flow towards the north, but individual rivers can be flowing south, east and west into the main branch.

Bordering watersheds include the Yukon river system which flows westward into the Bering Sea off of Alaska, the Fraser system flowing south westward, and the Columbia River system both of which flow south westward into the Pacific Ocean.

Southward into Saskatchewan, and even further into the United States, Montana and North Dakota, the Saskatchewan River Qu'Appelle, Assiniboine and Red River systems drain north and westward into the Hudsons Bay.

Further eastward into the North American continent we have the Great Lakes, the Mississppi River, the St-Lawrence River basins and watersheds, draining eastward and southward.

 

[snorkack]

Further eastward into the North American continent we have the Great Lakes, the Mississppi River, the St-Lawrence River basins and watersheds, draining eastward and southward.

Saint Lawrence flows southwest to northeast. Niagara flows north.

 

[Baluncore]

https://en.wikipedia.org/wiki/List_of_rivers_that_flow_north

 

[Howlr]

Er….your geography only knows US rivers, doesn’t it? Open your eyes to the ROW (rest of world)! Amazon, Nile, Seine, Polish rivers, Spey, Yukon, St Lawrence…..

 

[russ_watters]

I do believe, however, that there is a general tendency for them to flow downhill

While this got a laugh, the northern and southern hemispheres have different geographical biases; there's more land in the north, more ocean in the south. Rivers flow towards the ocean/seas, not from them (except inland seas). So a bias in river flow direction would not be shocking.

 

[DaveC426913]

https://en.wikipedia.org/wiki/List_of_drainage_basins_by_area

 

[BWV]

While this got a laugh, the northern and southern hemispheres have different geographical biases; there's more land in the north, more ocean in the south. Rivers flow towards the ocean/seas, not from them (except inland seas). So a bias in river flow direction would not be shocking.

Sure, but if you look at the geography and coastlines of Eurasia and N America, there is more landmass N,E and W than south, so one could naively presume S is the least important direction (supported by the list of 15 largest rivers I posted). No one thinks of N because no one lives on the Mackenzie or Ob, but these are huge river systems. Also should define ‘flowing south’ does this mean the outlet is merely south of the headwaters, or the predominant direction of flow? Does the Ganges, for example, flow East or South?

 

[Astronuc]

Look at the Murray-Murrumbidgee-Darling system in SE Australia.
https://en.wikipedia.org/wiki/Murray–Darling_basin

Or Red River in N US; it flows north along the borders of US States Minnesota and North Dakota into Manitoba, Canada, where it empties into Lake Winnipeg.

Or the Gambia River in W Africa
https://en.wikipedia.org/wiki/Gambia_River

Or the Amazon River - mostly eastward; the tributaries to the north of the Amazon flow to S/SE, while the tributaries to the south of the Amazon flow N/NE to the Amazon.
https://en.wikipedia.org/wiki/Amazon_River

Or the Missouri River, which flow north/NE, then east, then E/SE to the Mississippi River, which does flow more or less from north to south.
https://en.wikipedia.org/wiki/Missouri_River

The Clark Fork River in NW US flow to the NW to the Columbia River.
https://en.wikipedia.org/wiki/Clark_Fork_River

and the Columbia and Kootenay Rivers, which do U-turns upstream. The Columbia and Kootenay, starting on opposite sides of the same mountain range flow in opposite directions, but eventually meet 100s of miles SW from their sources.
https://en.wikipedia.org/wiki/Columbia_River
https://en.wikipedia.org/wiki/Columbia_River#/media/File:Columbiarivermap.png
https://en.wikipedia.org/wiki/Kootenay_River

or all the others cited that do not flow from north to south.

 

[russ_watters]

Sure, but ... Also should define ‘flowing south’

Lol, I don't care anywhere near enough about this subject to put any effort into it.

 

[DaveC426913]

While this got a laugh, the northern and southern hemispheres have different geographical biases; there's more land in the north, more ocean in the south. Rivers flow towards the ocean/seas, not from them (except inland seas). So a bias in river flow direction would not be shocking.

As Russ points out, the land masses are not evenly distributed over the surface of the Earth. Generally, the land masses of the Earth are distributed more thusly:

So there is a little more southward "downhill" than northward "downhill".Note also that, if Antarctica weren't frozen solid, any rivers it had would all flow North, swinging the balance of river direction back toward a more neutral direction.

 

[Vanadium 50]

Since this thread has turned into "whaddabouts", what about the Chicago River? It's direction was reversed by some serious civil engineering. Which way does it flow?

And does it matter that it is sometimes de-reversed?

 

[BWV]

As Russ points out, the land masses are not evenly distributed over the surface of the Earth. Generally, the land masses of the Earth are distributed more thusly:

View attachment 337140

Um, no - if you look at a Map of Earth you can see there is far more land to the north of the Northern Hemisphere for rivers to flow than at its Southern edge
_;)

 

[jtbell]

Continental Drip.

And the puddles coalesce and freeze over, et voilà, Antarctica!

 

[Vanadium 50]

f you look at a Map of Earth you can see there is far more land to the north of the Northern Hemisphere for rivers to flow than at its Southern edge

True, but the Mercator projection overstates the case. Greenland looks bigger than South America, even though South America is 8x larger.

 

[BWV]

True, but the Mercator projection overstates the case. Greenland looks bigger than South America, even though South America is 8x larger.

I meant that tongue in cheek - the circumference of the 30th parallel is about 2.5x that of the Arctic Circle, but I do think the geography of the N hemisphere- particularly Asia, with the Himalayas, means more water flows outside of the Southern edges of the map

 

[BillTre]

Note also that, if Antarctica weren't frozen solid, any rivers it had would all flow North, swinging the balance of river direction back toward a more neutral direction.

There are rivers there.
They are just frozen and move so slowly that they are storing a lot of water there above sea level.
This will change if they melt.

 

[DaveC426913]

I meant that tongue in cheek ...

Ah. That was not at all apparent.

 

[BWV]

Ah. That was not at all apparent.

There was a ;) in the post

 

[DaveC426913]

There was a ;) in the post

Not that I can see. (And I had checked first, cuz I was gonna suggest a smiley might be warranted.)

 

[BWV]

Not that I can see. (And I had checked first, cuz I was gonna suggest a smiley might be warranted.)

;)

 

[BWV]

Here is a global map of continental divides, alot of drainage to N,W and E