Shi En Kim

Reporter

A few years ago, Hungarian cartographer Robert Szucs poked around the internet for a global map of the world’s rivers, one that categorized them based on their ocean destination. He came across maps of the major rivers plus others that captured the local footprint of individual streams. But 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,” he says.

After several months of painstaking labor, Szucs finished sorting the world’s rivers according to their ocean drainage basins, and he has new maps to show for it. In his latest creations, he has colored the tens of thousands of rivers based on where the water goes: the Pacific, the Atlantic, the Arctic, the Indian Ocean—or stalled on land and never making it to sea.

Determining which river ends up where is not so straightforward. “It’s not as simple as just drawing a straight line through a continent,” says Ellen Wohl, a fluvial geomorphologist at Colorado State University. The topography obviously plays a dominant role, but other factors including the climate and human interventions can influence river features.

Ocean Drainage Basin Map of the United States
Ocean drainage basin map of the United States Robert Szucs / Grasshopper Geography

Szucs runs Grasshopper Geography, a tiny family business between just him and his partner. He wields his cartography skills to create new maps in the name of both science and art, while his partner manages marketing and some administrative aspects of their venture. In 2019, he created his first map of all the world’s natural rivers. With each watershed emblazoned in a different color, the overall effect was psychedelic. Now, his latest maps unify these rivers according to their ending place.

Ocean Drainage Basin Map of Canada
Ocean drainage basin map of Canada Robert Szucs / Grasshopper Geography

To make his newest work, Szucs used open-source satellite imagery to find rivers and analyze their flows. Where he couldn’t obtain the data he needed, he modeled the 3D elevation of a locale using publicly available data and simulated where rivers drain. On top of his global master map, he has zoomed into several specific countries whose rivers radiate into surrounding oceans. He’s created 45 of these regional maps, he estimates.

“This is a rigorous piece of art,” says Nicholas Pinter, a geomorphologist at the University of California, Davis. A few years ago, he bought one of Szucs’ river maps for his home. “I loved it,” he said. “Nature is the best inspiration for art.”

Ocean Drainage Basin Map of Asia
Ocean drainage basin map of Asia Robert Szucs / Grasshopper Geography

The new maps show how interconnected the world’s waterways are—how far-flung rivers from different continents eventually reach the same ocean expanse. The ocean boundaries themselves are also essentially human constructs. After all, the world’s four named oceans are essentially one body of water—and one gigantic drainage basin on a planetary scale.

Szucs hopes his maps can help raise awareness of environmental problems that arise from the connectivity of the Earth’s arteries. “You can live in Minnesota, and your plastic still can go into the Arctic Ocean,” Szucs says. These rivers connect communities upstream and downstream, inland and coastal, sometimes thousands of miles away.

Ocean Drainage Basin Map of Africa
Ocean drainage basin map of Africa Robert Szucs / Grasshopper Geography

From these maps, several hydrologic patterns stand out. Asia is Szucs’ favorite continent because it’s visually the most striking—the only continent whose rivers spill into all four oceans. The river he finds most memorable is the Nile, which starts quite far south and traverses a vast swath of the African continent. “It had so many chances to get lost, … dry up or end up in the Indian Ocean,” Szucs gushes. Instead, the Nile pushes determinedly north until it hits the Mediterranean. “That’s very cool to see.”

The maps are just a snapshot, but they hint at the rich stories of rivers in various corners of the world. For example, people often forget the existence of rivers that flow northward into the Arctic Ocean, Wohl says: “Northern Rivers have some very distinctive characteristics.” Polar rivers such as the north-spanning Mackenzie River in Canada stay frozen at the mouths longer than at their sources. The spring often brings floods and ice jams, when meltwater from the warmer upstream is obstructed by jagged-edge riverine glaciers. “You see gouges in streambanks, and it looks like somebody went through with an enormous weed whacker and hit the trees,” Wohl says. Alaska’s Yukon River, which flows east to west, doesn’t have these effects given it thaws in the spring all along the river at once, so no ice jams build up.

Ocean Drainage Basin Map of South America
Ocean drainage basin map of South America Robert Szucs / Grasshopper Geography

The maps display the natural river courses shaped by topography, but other factors such as human activity also dictate where and how a river meanders. One of the most famous examples of human tampering is the Colorado River. As Pinter puts it, “every drop is spoken for and oversubscribed.” This is a river so tightly managed that it no longer discharges into the ocean, although Szucs’ maps still indicate that it does. This is also true for other once-perennial waterways such as China’s Yellow River and India’s Indus River, which too are overexploited.

Ocean Drainage Basin Map of Australia
Ocean drainage basin map of Australia Robert Szucs / Grasshopper Geography

Viewers will be quick to notice that Szucs’ maps omit Antarctica and Greenland. The artist explains that the elevation data of these regions isn’t detailed enough for him to construct a map of their river networks. Moreover, these places are mostly frozen year-round, so they don’t usually form permanent rivers on the surface.

All that could change with the rise of global temperatures. These frozen land masses harbor rivers that run beneath the ice sheets, and they may become surface rivers as the ice above melts. “That process is very actively occurring,” Wohl says. As rising sea levels eat into the coastlines, tundra will transform into a terrestrial landscape, and a new ecosystem will sprout on the exposed banks. Will we need a new river map in the future? “Maybe in a bit longer than 100 years,” Wohl says. “I hope it’s not quite that fast.”

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Shi En Kim

Shi En Kim is a Washington, D.C.-based freelance science journalist. Her work has appeared in National Geographic, Scientific American, the Atlantic, Popular Science and others. In 2021, she interned at Smithsonian magazine as an AAAS Mass Media Fellow.