Blackwater river in the context of "Nanay River"

The Rio Negro (Spanish: Río Negro [ˈri.o ˈneɣɾo] "Black River"), or Guainía as it is known in its upper part, is the largest left tributary of the Amazon River (accounting for about 14% of the water in the Amazon basin), the largest blackwater river in the world, and one of the world's ten largest rivers by average discharge. It originates in the tepuis of the department of Guainía, Colombia, and then flows southeastward before finally entering Brazil. Despite its high flow, the Rio Negro has a low sediment load (5.76 million tonnes per year on average in Manaus).

The Meeting of Waters (Portuguese: Encontro das Águas) is the confluence between the dark (blackwater) Rio Negro and the pale sandy-colored (whitewater) Amazon River, referred to as the Solimões River in Brazil upriver of this confluence. For 6 km (3.7 mi) the waters of the two rivers run side by side without mixing. This phenomenon is one of the main tourist attractions of Manaus. The river then flows another 60 km (37 mi) before mixing fully, but the phenomenon persists incompletely for another 30 km (19 mi).

This phenomenon is due to the vast differences in temperature, speed, and amount of dissolved sediments in the waters of the two rivers. The Rio Negro flows at near 2 km/h (1.2 mph) at a temperature of 28 °C (82 °F), while the Rio Solimões flows between 4 and 6 km/h (2.5–3.7 mph) at a temperature of 22 °C (72 °F). The light-colored water is rich with sediment from the Andes Mountains, whereas the black water, running from the Colombian hills and interior jungles, is nearly sediment-free and colored by decayed leaf and plant matter.

The Amazon biome (Portuguese: Bioma Amazônia) contains the Amazon rainforest, an area of tropical rainforest, and other ecoregions that cover most of the Amazon basin and some adjacent areas to the north and east. The biome contains blackwater and whitewater flooded forest, lowland and montane terra firma forest, bamboo and palm forest, savanna, sandy heath and alpine tundra. Some areas of the biome are threatened by deforestation for timber and to make way for pasture or soybean plantations.

A whitewater river is classified based on its chemistry, sediments and water colour. Whitewater rivers have high levels of suspended sediments, giving the water a pH that is near-neutral, a high electric conductivity and a pale muddy, café au lait-like colour. Whitewater rivers are of great ecological importance and are important to local fisheries. The major seasonal Amazonian floodplains known as várzea receive their water from them.

The best-known whitewater rivers are Amazonian and have their source in the Andes, but there are also whitewater rivers elsewhere in South America and in other continents.

The Ashley River is a blackwater and tidal river in South Carolina, rising from the Wassamassaw and Great Cypress Swamps in western Berkeley County. It consolidates its main channel about 5 miles (8 km) west of Summerville, widening into a tidal estuary just south of Fort Dorchester. The river then flows for approximately 17 mi (27 km) along the historical banks of the City of North Charleston before reaching peninsular Charleston. The much wider Ashley joins the Cooper River off the Battery in Charleston to form Charleston Harbor before discharging into the Atlantic Ocean. As of 2012 the land around the Ashley River (or in Ashley Barony, as the original land grant was called) is mostly undeveloped.

The river was named for Anthony Ashley Cooper, 1st Earl of Shaftesbury and chief Lord Proprietor of the Carolina Colony by explorer Robert Sandford. In 1675 Cooper was granted 12,000 acres (4,900 ha) of land along the river after a permanent settlement was made at Albemarle Point in 1670. This settlement was the “first permanent European settlement” in South Carolina and today Albemarle Point is known as Charles Towne Landing. The settlement would be moved to its current peninsular location across the river ten years later and is well known as Charleston.

The Cooper River is a mainly tidal river in the U.S. state of South Carolina. The cities of Mt. Pleasant, Charleston, North Charleston, Goose Creek, Moncks Corner, and Hanahan are located along the river. Short and wide, the river is joined first by the blackwater East Branch and then farther downstream at the tidal Wando River. Almost immediately thereafter, the Cooper River widens into its estuary and unites with the Ashley River to form the Charleston Harbor.

Long used as an important commercial waterway, the West Branch of the Cooper River was initially connected to the Santee River near its navigation head by the Santee Canal, built in the late 18th century. Though the West Branch still rises as a blackwater swamp in central Berkeley County, its main headwaters have been shifted to Lake Moultrie by the 1940s vintage Tail Race Canal. Lake Moultrie is, in turn, fed from Lake Marion by a diversion canal built around the same time period. This artificial rerouting of the Cooper River basin has essentially unified the Santee and Cooper River systems into a single hydrological drainage entity.

The Suwannee River (also spelled Suwanee River or Swanee River) is a river that runs through south Georgia southward into Florida in the Southern United States. It is a wild blackwater river, about 246 miles (396 km) long. The Suwannee River is the site of the prehistoric Suwanee Straits that separated the Florida peninsula from the Florida panhandle and the rest of the continent. Spelled as "Swanee", it is the namesake of two famous songs: Stephen Foster's "Swanee River" (1851) and George Gershwin and Irving Caesar's "Swanee" (1919).

The Siak is a river of Riau province, in the east of Sumatra, Indonesia, about 1000 km northwest of the capital Jakarta. Approximately 370 kilometres in length, the Siak is a blackwater river which owes its brown color to dissolved organic matter (DOM) leached from surrounding, heavily disturbed peat soils; it is heavily polluted, notably by the petroleum industry. It flows through the town of Pekanbaru before emptying into the Strait of Malacca.