A River Runs To It

January 14, 2024 8:03 AM

These entrancing maps capture where the world’s rivers go. When Hungarian cartographer Robert Szucs looked online for a map of the world’s rivers based on their ocean destination, he found nothing on a global scale with high resolution. “It’s like, how does this thing not exist? So, I just instantly put it on my to-do list."

(I was going to quibble with his classifications of Australia to point out that he'd omitted the Southern Ocean, until I discovered that my home country has its own bespoke definition of it. Still, nobody can convince me that the rivers on Tasmania's west coast drain into the Indian Ocean.)

posted by rory (23 comments total)

I got briefly Internet famous in 2013 for a map like this I made. I was inspired by Ben Fry's All Streets map and made an All Rivers map instead. Then put it up on Flickr with a permissive license so every media organization re-ran it, and I'm happy to say most managed to attribute it properly. Readers Digest even ran it, my grandmother would have been very proud.

It's important to note Szucs' maps (and mine) are of flow lines, not actual rivers. These are where water would flow if there were water, it's calculated from an elevation map where an algorithm finds what looks like natural channels and drainage paths. I took a crack at an Australian map where I colored actual running rivers blue (vs. brown for dry channels) that's a more true picture of actual rivers.

Folks have done the "color by watershed" thing before, it's a nice effect although the palettes always tend to this ice cream shop look. What I think is novel here is he did this for the whole planet, probably calculating his own flowlines from a freely available digital elevation model. Szucs has been at making this kind of map for awhile, he's got a nice little business selling prints.

Another shop selling this kind of map (regional, mostly the US) is Muir Way. I like their US map.
posted by Nelson at 8:25 AM on January 14 [23 favorites]

These are neat. The first thing that jumped out at me looking at the North American maps is that in addition to the east/west continental divide between the sides of the US that drain to the Atlantic vs Pacific, there is a north/south continental divide in the vicinity of the US/Canada border. Thinking about it, it's kind of obvious, but I wasn't aware of that divide before.
posted by Dip Flash at 8:30 AM on January 14 [3 favorites]

Zoom in and find Triple Divide Peak, the only point on earth known to drain to three oceans.
posted by rh at 8:31 AM on January 14 [8 favorites]

This is cool! I did have the Southern Ocean question, too, rory, so thanks for providing a partial answer to that. I also loved seeing how many areas around the world are endorheic and don't actually flow to the oceans.

Nelson, your maps are very cool, too. Thank you for reminding us that these are current flowlines based off of current DEMs, not true maps of channels.

Another set of river maps are Harold Fisk's maps of the Mississippi River showing its changing channels over time. I have the first one in that article on the wall next to me right now.
posted by hydropsyche at 8:47 AM on January 14 [1 favorite]

Thanks! I love Fisk's map too: awhile back I stitched them together with a slippy map interface. (Click the Terrain button for a base map).

Another visualization in this genre are colored LIDAR images of river basins. A lot of these are from Dan Coe, dating back to his 2013 Willamette Valley map (or before). Greg Fiske has also recently been doing Arctic LIDAR maps.
posted by Nelson at 9:43 AM on January 14 [2 favorites]

Also in this space is the Sam Lerner’s river runner app, which started out US centric, but is now global.

(I helped build the API that makes the U.S. part of the river runner app possible)
posted by rockindata at 9:52 AM on January 14 [7 favorites]

So, I'm now fascinated by how ocean definitions seem important and obvious if you're in, say, Mexico, but seem about as arbitrary as time zones when you're way out in the oceans themselves, especially in those linear border-waters.

Makes me wonder if there's some other (potentially more complicated) map that tries to classify waters based on rules that seem less arbitrary. Maybe you first have to settle on a definition of what a continent is before you can even "seed" the map with ocean names? Like, surely Cuba has at least two major directions that water can flow, but because it's not an official continent, we ignore the differences in where the water ends up (?).

Could you have a more swirly map that agrees generally on major oceans and continents (ideally using some minimally arbitrary definitions) but then does the ocean shading based on what river-shed its water content was most likely to have originated from, modally?

Maybe hydrological topologists have already thought through this and I'm poorly re-investigating some existing wheel.
posted by wolfpants at 10:16 AM on January 14 [1 favorite]

This is really neat. It's wild that waters from deep European Russia, Rwanda, Montana, and Peru can all end up in the same place.
posted by dusty potato at 10:23 AM on January 14

(Then again... is it really somehow more true to say the Mediterranean drains into the Atlantic than to say the Atlantic commingles with the Pacific?)
posted by dusty potato at 10:24 AM on January 14

wolfpants, some ideas for more motivated maps of the oceans..

One is a topographic map of the ocean floor (aka bathymetry), see here or here for another take. These highlight the continental plates.

Another would be something based on ocean currents, I like this one or this one. These highlight how the North and South are fairly separate waters in both the Pacific and the Atlantic. Also the Indian Ocean is quite separate from the Southern Ocean.

The challenge with ocean data is it tends to be quite low resolution, particularly the currents. One thing that makes Szucs' map so visually interesting is it combines very high resolution data (10 meter elevation grid creating flowlines) with very low resolution pattern (watersheds).
posted by Nelson at 10:33 AM on January 14 [4 favorites]

There is, essentially, one Ocean, with massive oceanic currents all around it that have flows in the tens of cubic kilometers per second (the amazon has a discharge of about 0.224 cubic kilometer per second). The names with give parts of the Ocean are just useful mnemonics.
posted by Monday, stony Monday at 10:36 AM on January 14

(Then again... is it really somehow more true to say the Mediterranean drains into the Atlantic than to say the Atlantic commingles with the Pacific?)

The Mediterranean doesn't but sort of does drain into the Atlantic. The general flow of water is from the Atlantic Ocean into the Med because the evaporation rate from the Med is greater than the inflow of all the freshwater rivers around it. But because the Med is so much more saline than the Atlantic, there's a layer of more salty water below the less salty inflow that's basically being pushed out of the Med into the greater Atlantic Ocean through the Strait of Gibraltar.
posted by Your Childhood Pet Rock at 10:39 AM on January 14 [9 favorites]

It’s nice but I’m color-blind and I can’t distinguish between the colors for the Atlantic and Pacific oceans plus watersheds… I’m assuming color-blindness is the reason rather than geographers lying to me about the continental divide, haha.
posted by Whale Oil at 12:42 PM on January 14 [2 favorites]

Triple Divide Peak

Just out of curiosity has anyone mapped out a day-hike where you can pee in to all three creeks in one day? Uh not that I would just wondering.
posted by saladin at 1:24 PM on January 14 [3 favorites]

Another page on ocean circulation patterns. On the surface they are kind of like a set of interlocking gears -- this is the view that tracking things that fall out of shipping containers is so good at, and there's a great popular science book and webpage by Ebbesmeyer. But scroll down a bit on the NASA site and the 3D pattern that links everything with deep water currents is also shown.
posted by clew at 1:55 PM on January 14

Saladin, I don't know if there's a dayhike. It looks like Triple Divide is around 10 miles and significant elevation from the nearest trailhead, and if you want to summit, you will have to leave the trail and climb up there. But there are lots of multi day backpacking trips that would let you pee in all three watersheds.

If you had a car, you could start in East Glacier and drive through the park on the Going to the Sun highway, and hit all three.
posted by surlyben at 3:03 PM on January 14

This is neat, I learned a new word, endorheic basin.
posted by teece303 at 5:12 PM on January 14 [3 favorites]

XKCD related to ocean circulation
posted by TedW at 6:52 PM on January 14 [1 favorite]

The projection looks weird on the Canada-focused ones. The US seems massive in comparison.
posted by transient at 9:58 PM on January 14

Re: Triple Divide peak. This depends on whether Hudson Bay is part of the Arctic or Atlantic Oceans. I am more used to Snow Dome, on the Columbia Icefield, being referred to as the hydrological apex of North America - but this follows from defining Hudson Bay as a marginal sea of the Atlantic, whereas the Montana pretender candidate considers Hudson's Bay to be part of the Arctic Ocean.

I personally think it makes more sense for Hudson's Bay to be part of the Arctic (having spent a few summers working in and around it -- it's definitely got an Arctic vibe!), but Snow Dowe and the Columbia Icefield are just so much more impressive and striking than the Lewis Range that I want to give it to Alberta.
posted by bumpkin at 9:00 AM on January 15 [1 favorite]

Here in Pittsburgh the topography prevents a grid layout of roads and this makes newcomers very confused. I point out that you can classify all the roads as either river roads (following stream channels), ridge roads (flattish roads along the tops of the hills), and connectors (steep roads from one to the other). This helps them for a while until they realize that now they have to learn all the creeks and streams too.
posted by hypnogogue at 10:09 AM on January 15 [3 favorites]

Mod note: We were just going with the flow when we added this post to the Best Of blog!
posted by Brandon Blatcher (staff) at 6:55 AM on January 20 [1 favorite]

Just noticed that—awesome, thanks!
posted by rory at 3:59 AM on January 26