Brazilian rivers, reservoirs and seas, found on the map

Fifteen rivers, four reservoirs, two lagoons and the ocean, all of them written. Nine of the rivers belong to one basin, and the point of the map is the scale of that: the Madeira alone carries more water than any river in Europe or North America, and it is a tributary.

24 to find, 8 a run.

3 rounds, 6 of 8 to pass each. Pass one and its places are yours.

⚔️ Challenge someone to Brazilian rivers, reservoirs and seas

24 rivers, reservoirs and seas · 3 regions

What the map tells you about each one

The paragraph the game shows when you find each one. Reading them first is not cheating.

North and Center-West12 on the map

Amazon: The Amazon carries about a fifth of all the river water that reaches the oceans, roughly 209,000 cubic meters a second, which is more than the next seven largest rivers together. Its plume of fresh water is detectable in the Atlantic a hundred kilometers offshore, and there is no bridge anywhere along its main stem.
Araguaia: It splits in two for 320km around Bananal, the largest river island in the world at about 19,000 square kilometers, which floods every wet season and is home to the Karajá. The two branches rejoin, and the river then runs on north to meet the one it is a tributary of.
Baía de Marajó: The southern channel of the Amazon delta, with Belém on it, and the island it runs around is about the size of Switzerland. The tide meets the river current here hard enough to raise the pororoca, a bore wave that runs upstream for kilometers and can be heard before it is seen.
Branco: The main tributary of the Negro, and its opposite: white with sediment washed off the Guiana highlands rather than stained black by the forest. It is the river of Roraima, and in the dry season it drops far enough that boats stop running and the state depends entirely on its single road.
Juruá: About 3,280km long and even more sinuous than its neighbor, winding so much that steamers in the rubber boom took weeks to cover a few hundred kilometers of forest. Most of its length is in Brazil and it drains one of the least populated parts of the country.
Madeira: The largest tributary of the Amazon by volume and about 3,250km long counting its headwaters in the Andes. It carries roughly half of all the sediment the Amazon delivers to the sea. Two run-of-river dams built on it after 2008 flooded far less land than a reservoir would have and still cut the fish migrations that the towns upstream lived on.
Negro: The largest blackwater river in the world, stained by decaying leaf litter and so acidic that it carries few mosquitoes, which is one reason a city of two million grew on it. Where it meets the paler Solimões at Manaus the two run side by side for about six kilometers without mixing, because they differ in speed, density and temperature.
Purus: One of the most meandering rivers on earth: about 3,200km of channel covering roughly half that distance in a straight line. The loops cut themselves off and leave crescent lakes across the floodplain, and the map of it is redrawn every few decades because the river moves.
Tapajós: A clearwater river, blue-green rather than brown, that meets the Amazon at Santarém in another line where two colors run together. Its lower course is deep enough for ocean ships, which is why the soy grown 1,000km south of it now leaves the country through the Amazon rather than by road to the southern ports.
Tocantins: About 2,450km long, and not a tributary of the Amazon at all: it reaches the sea through a separate channel beside the delta, which is a distinction Brazilian geography insists on. The Tucuruí dam near its mouth was the first large hydroelectric project built in the rainforest, and it flooded 2,850 square kilometers.
Tucuruí Reservoir: The first large dam built in the Amazon basin, completed in 1984. It flooded about 2,850 square kilometers of forest, and much of the timber was left standing under the water, where it is now cut by divers with hydraulic saws and sold as hardwood.
Xingu: About 1,980km long, and the site of Belo Monte, which has the third largest installed capacity of any dam in the world but produces far less than that for much of the year because the river is seasonal. The fight against it ran for thirty years and is the reason Kayapó leaders in feather headdresses are a familiar image outside Brazil.

Northeast Brazil5 on the map

Atlantic Ocean: Brazil has about 7,400km of Atlantic coastline and most of its people live within a couple of hundred kilometers of it. The country was reached from the sea in 1500 and administered from it for four centuries, which is the argument the capital was moved inland in 1960 to settle.
Baía de São Marcos: The tidal range here reaches about seven meters, among the largest in the Atlantic, which is why the port on it can load the deepest-drafted ore ships afloat and why the city beside it was built where it is. São Luís sits on an island in the bay.
Parnaíba: About 1,400km long and the border between Piauí and Maranhão for nearly all of it. Its mouth is a delta of more than seventy islands spread across 2,700 square kilometers, one of the only open-sea deltas in the Americas, with dunes moving over the top of the channels.
São Francisco: About 2,900km long and the only large river that runs through the northeastern drought country, which is why Brazilians call it the river of national integration. It flows north for 1,500km before turning east, and the canals built after 2007 to divert part of it into four drier states are among the most argued-over public works in the country.
Sobradinho Reservoir: One of the largest artificial lakes in the world at about 4,200 square kilometers, filled in 1978. It moved roughly 70,000 people off four towns and the land around them, and it holds the flow of the river steady for the power stations and irrigation schemes downstream.

South and Southeast7 on the map

Doce: In November 2015 a tailings dam on one of its tributaries collapsed and sent around 40 million cubic meters of mine waste down this river, killing 19 people and reaching the Atlantic 650km away in seventeen days. It is the worst environmental disaster in Brazilian history, and the river has not recovered.
Furnas Reservoir: Locals call it the sea of Minas: about 1,400 square kilometers of drowned valleys with a shoreline thousands of kilometers long. It was finished in 1963 to power the industrial boom in the two states below it, and it is now as much a holiday coast as a power scheme.
Itaipu Reservoir: The dam finished in 1984 is shared with Paraguay and produces more electricity in a year than almost any other. Filling it in 1982 drowned the Guaíra falls, which had been one of the largest waterfalls in the world by volume, and the rock was later dynamited for navigation.
Lagoa dos Patos: The largest lagoon in South America, about 10,100 square kilometers, separated from the Atlantic by a sandbar 240km long and joined to it by one narrow opening. Porto Alegre stands at the top of it, and everything the state exports has to pass through that single gap.
Lagoa Mirim: About 3,750 square kilometers of shallow water shared with Uruguay, and the border runs through it. It drains into the larger lagoon to the north through a channel, and the flat country around both is where most of Brazil’s rice is grown.
Paraná: The second longest river in South America, and the most dammed: a staircase of reservoirs runs down it. The Itaipu dam near the border with Paraguay generates around a tenth of Brazil’s electricity and nearly all of Paraguay’s, and the basin below it carries the barge traffic out of the interior to the sea.
Uruguay: It rises in the coastal mountains of southern Brazil and forms about 400km of the border before leaving the country. The river is shallow and rocky along that stretch and floods hard, and the dam at Salto Grande, built jointly with Argentina and Uruguay downstream, is one of the earliest binational hydroelectric schemes anywhere.

Now find all 24 on the map

How this one works

How many rivers, reservoirs and seas are on the map?

24. Every one of them is on the map, and a run asks 8 of them. Pass a round and the places you found in it drop out of the pool, so the next run is what you have left.

What is a round?

A run of 8 questions, and 6 right passes it. 3 rounds cover the whole map, and the counter at the top of the Brazil page counts the ones behind you. Passing is what banks a round's finds: miss the mark and nothing is taken off the map, so every place that round asked about is still there to be asked again. A round is always the places you have not found yet, and when fewer than five are left it is topped up with a few you have found as review, so the last round is never one or two questions. Three quarters of it passes it.

Can I start the map over?

Yes. "Reset this map" under the counter puts all 24 back in the pool and sets the rounds to zero the moment you press it, so the whole map is there to be found again from nothing. It clears this map only; the other maps of Brazil keep their progress.

Do I need an account?

No. The game plays in the page, and a guest's progress is kept in their own browser. Signing in carries it between devices and earns XP for a run.

What happens when I get one wrong?

The map names what you actually hit, then lights up the right answer in green and tells you something about the place. Missing one is how most of this map gets learned.

The other maps of Brazil

Brazilian states27 to find Brazilian cities33 to find

The same map for other countries

South America

North America

Oceania

All of Brazil’s maps together on the Brazil atlas page, the country itself on the Brazil guide, and the other two hundred on the world map.