A blackwater river is a type of
river with a slow-moving channel flowing through forested
swamp
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s or
wetlands. As vegetation decays,
tannins leach into the water, making a transparent, acidic water that is darkly stained, resembling
black tea. Most major blackwater rivers are in the
Amazon Basin
The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Bolivi ...
and the
Southern United States. The term is used in
fluvial
In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...
studies,
geology,
geography,
ecology, and
biology. Not all dark rivers are blackwater in that technical sense. Some rivers in temperate regions, which drain or flow through areas of dark black
loam
Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–sil ...
, are simply black due to the color of the soil; these rivers are ''black mud rivers''. There are also black mud
estuaries.
Blackwater rivers are lower in nutrients than
whitewater rivers and have
ionic concentrations higher than rainwater. The unique conditions lead to flora and fauna that differ from both whitewater and
clearwater rivers.
The classification of Amazonian rivers into black, clear, and whitewater was first proposed by
Alfred Russel Wallace
Alfred Russel Wallace (8 January 1823 – 7 November 1913) was a British naturalist, explorer, geographer, anthropologist, biologist and illustrator. He is best known for independently conceiving the theory of evolution through natural se ...
in 1853 based on water colour, but the types were more clearly defined by chemistry and physics by from the 1950s to the 1980s.
Although many Amazonian rivers fall clearly into one of these categories, others show a mix of characteristics and may vary depending on season and flood levels.
Comparison between white and black waters
Black and
white waters
White Waters is a 2007 Nigerian slice of life drama film directed by Izu Ojukwu. The film received 12 nominations and won four awards at the 4th Africa Movie Academy Awards including winning Best Director, Best Cinematography, Best Sound and Best ...
differ significantly in their ionic composition, as shown in
Table 1. Black waters are more
acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
ic, resulting in an
aluminum concentration greater than that of the more neutral white waters. The major difference is the concentrations of
sodium,
magnesium,
calcium, and
potassium; these are very low in black waters. This has ecological implications. Some animals need more calcium than is available in blackwaters, so for example,
snails, which need much calcium to build shells, are not abundant in blackwaters. The lack of dissolved ions in black waters results in a low
conductivity, similar to that of rainwater.
Black and white waters differ in their
planktonic fauna and flora.
Tables 2 and
3 compare the number of planktonic animals caught in black and white water localities only a few meters apart. The black water was not as extreme an example as the
Rio Negro system. However, it can be seen that the black water held greater numbers of
rotifer
The rotifers (, from the Latin , "wheel", and , "bearing"), commonly called wheel animals or wheel animalcules, make up a phylum (Rotifera ) of microscopic and near-microscopic pseudocoelomate animals.
They were first described by Rev. John H ...
s but fewer
crustaceans and
mites. These crustaceans are important foods for
larval fish
Ichthyoplankton (from Greek: ἰχθύς, , "fish"; and πλαγκτός, , "drifter") are the eggs and larvae of fish. They are mostly found in the sunlit zone of the water column, less than 200 metres deep, which is sometimes called the epip ...
. The zones where the two waters mix are attractive to
ostracods and young fish. These mixing zones tend to have many animals. The abundance is shown in Table3, which compares animals in of water.
Comparison between clear and black waters
Blackwater rivers resemble
clearwater rivers in having a low conductivity and relatively low levels of
dissolved solids, but clearwater rivers have water that often only is somewhat acidic (typical pH ~6.5)
and very clear with a greenish color.
The main Amazonian clearwater rivers have their source in the
Brazilian Plateau (such as
Tapajós,
Tocantins,
Xingu and some right tributaries of the
Madeira
)
, anthem = ( en, "Anthem of the Autonomous Region of Madeira")
, song_type = Regional anthem
, image_map=EU-Portugal_with_Madeira_circled.svg
, map_alt=Location of Madeira
, map_caption=Location of Madeira
, subdivision_type=Sovereign st ...
), but some originate in the
Guiana Shield
The Guiana Shield (french: Plateau des Guyanes, Bouclier guyanais; nl, Hoogland van Guyana, Guianaschild; pt, Planalto das Guianas, Escudo das Guianas; es, Escudo guayanés) is one of the three cratons of the South American Plate. It is a ...
(such as
Nhamundá,
Paru, and
Araguari).
Blackwater rivers of the world
Amazonia
*
Apaporis River: a tributary of the
Japurá River
The Japurá River or Caquetá River is a river about long in the Amazon basin. It rises in Colombia and flows eastward through Brazil to join the Amazon River.
Course
The river rises as the Caquetá River in the Andes in southwest Colombia.
Th ...
*
Arapiuns River
The Arapiuns River is a river in Pará state in north-central Brazil. It is a tributary of the Tapajós, and merges into the latter river about before Tapajós merges into the Amazon River. Arapiuns is a blackwater river.
See also
*List of rivers ...
: a tributary of the
Tapajós River
The Tapajós ( pt, Rio Tapajós ) is a river in Brazil. It runs through the Amazon Rainforest and is a major tributary of the Amazon River. When combined with the Juruena River, the Tapajós is approximately long. It is one of the largest cle ...
*
Coari River
Coari River is a tributary of the Amazon River ( Solimões section) in the Amazonas state in north-western Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South Am ...
*
Mazaruni River
The Mazaruni River is a tributary of the Essequibo River in northern Guyana. Its source is in the remote western forests of the Pakaraima Mountains and its confluence with the Cuyuni River is near Bartica. As it descends from the Guiana Highlands ...
*
Mirití-Paraná River
Mirití-Paraná is a town and municipality in the southern Colombian Department
Department may refer to:
* Departmentalization, division of a larger organization into parts with specific responsibility
Government and military
*Department (admi ...
*
Piorini River
The Piorini River ( pt, Rio Piorini) is a river in Amazonas state in north-western Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. ...
*
Potaro River
The Potaro River is a river in Guyana that runs from Mount Ayanganna area of the Pakaraima Mountains for approximately before flowing into the Essequibo River, Guyana's largest river. The renowned Kaieteur Falls is on the Potaro.
Features
Nine ...
: a tributary of the
Mazaruni River
The Mazaruni River is a tributary of the Essequibo River in northern Guyana. Its source is in the remote western forests of the Pakaraima Mountains and its confluence with the Cuyuni River is near Bartica. As it descends from the Guiana Highlands ...
*
Rio Negro: The largest blackwater river in the world; one of the largest Amazonian tributaries.
*
Tahuayo River
*
Tefé River
*
Uatumã River
*
Urubu River
*
Vaupés River
Orinoco basin
*
Morichal Largo River
Morichal Largo River is a river of Venezuela. It is part of the Orinoco River basin.
See also
*List of rivers of Venezuela
This is a list of rivers in Venezuela.
By drainage basin
This list is arranged by drainage basin, with respective tribut ...
*
Atabapo River: from the
Guiana highlands
The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories:
* French Guiana, an overseas department and region of France
* G ...
of
Venezuela west into the
Orinoco
The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wor ...
*
Caroní River: from the Guiana Highlands of Venezuela north into the Orinoco.
*
Caura River: from the Guiana Highlands of Venezuela north into the Orinoco
*
Inírida River
The Inírida (, Spanish: Río Inírida) is a river in the north-west of South America, in the territory of Colombia, the largest tributary of the Guaviare (the Orinoco River basin).
The length of the river is , of which are navigable for small ...
: from
Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...
northeast into the
Guaviare River which flows into the Orinoco
*
Ventuari River
The Ventuari River is the largest tributary of the Orinoco in southern Venezuela. The Ventuari flows from south-central Venezuela in the Guiana Highlands southwest into the Orinoco River. It is long and its major tributary is the Manapiare River.
...
: from eastern Venezuela southwest into the Orinoco
*
Vichada River: from Colombia east into the Orinoco
*
Tomo River: from Colombia east into the Orinoco
*
Tuparro River: from Colombia east into the Orinoco
Southern United States
*
Ashepoo River
Ashepoo River is a short blackwater river in South Carolina, United States. It rises in a confluence of swamps south of Walterboro, flows in a southeast direction and empties into Saint Helena Sound at . The entire course of the river lies withi ...
: along with the
Edisto
Edisto Island is one of South Carolina's Sea Islands, the larger part of which lies in Charleston County, with its southern tip in Colleton County. The town of Edisto Beach is in Colleton County, while the Charleston County part of the island is u ...
and the
Combahee Rivers in South Carolina makes up the
ACE Basin National Wildlife Refuge.
*
Big Cypress, Black Cypress, and Little Cypress and the small rivers in the watershed of
Caddo Lake in
Texas and
Louisiana
*
Blackwater River: a tributary of the
Chowan River in Virginia
*
Blackwater River: a major river in the western
Florida panhandle
The Florida Panhandle (also West Florida and Northwest Florida) is the northwestern part of the U.S. state of Florida; it is a Salient (geography), salient roughly long and wide, lying between Alabama on the north and the west, Georgia (U. ...
*
Blackwater River, West Virginia: Located in the
Blackwater Canyon in Tucker County. Blackwater Falls, a five-story waterfall, is located along this river with rapids ranging from ClassIII-V+.
*
Black River: a tributary of the
Pee Dee River
The Pee Dee River, also known as the Great Pee Dee River, is a river in the Carolinas of the United States. It originates in the Appalachian Mountains in North Carolina, where its upper course, above the mouth of the Uwharrie River
The Uwharri ...
in
North and South Carolina
*
Cape Fear River, North Carolina: flows into the Atlantic Ocean.
*
Cashie River
This is a list of rivers in the U.S. state of North Carolina.
By drainage basin
This list is arranged by drainage basin, with respective tributaries alphabetically indented under each larger stream's name.
Atlantic Ocean
* North Landing Rive ...
, North Carolina: flows into
Albemarle Sound.
*
Caloosahatchee River,
Florida: flows west from
Lake Okeechobee to the
Gulf of Mexico.
*
Chowan River, North Carolina: flows into
Albemarle Sound.
*
Edisto River, South Carolina: flows into the Atlantic Ocean.
*
Econlockhatchee River, a
tributary of the
St. Johns River
The St. Johns River ( es, Río San Juan) is the longest river in the U.S. state of Florida and its most significant one for commercial and recreational use. At long, it flows north and winds through or borders twelve counties. The drop in eleva ...
in Central Florida.
*
Forked Deer River: located in West Tennessee
*
Four Hole Swamp
Four Hole Swamp is a small blackwater river that is a tributary to the Edisto River in South Carolina. The swamp rises in Calhoun County and flows to the confluence. The river is noteworthy for its unusual braided pattern; it has no well-defined ...
, a tributary of the Edisto River in South Carolina.
*
Little Manatee River, Florida: flows into
Tampa Bay.
*
Great Coharie Creek, North Carolina: flows into the Black River.
*
Little Pee Dee River
The Little Pee Dee River is a tributary of the Pee Dee River (which originates in the Appalachian Mountains where it is known as the Yadkin River). The Little Pee Dee technically arises near Laurinburg, North Carolina as Gum Swamp, which flows so ...
, South Carolina: flows into the
Pee Dee River
The Pee Dee River, also known as the Great Pee Dee River, is a river in the Carolinas of the United States. It originates in the Appalachian Mountains in North Carolina, where its upper course, above the mouth of the Uwharrie River
The Uwharri ...
.
*
Lynches River, South Carolina: flows into the
Pee Dee River
The Pee Dee River, also known as the Great Pee Dee River, is a river in the Carolinas of the United States. It originates in the Appalachian Mountains in North Carolina, where its upper course, above the mouth of the Uwharrie River
The Uwharri ...
.
*
Lumber/
Drowning Creek: located in North and South Carolina. Part of
Lumber River State Park
*
Myakka River: 66 mile-long river with its headwaters in
Manatee County, Florida
Manatee County is a county in the Central Florida portion of the U.S. state of Florida. As of the 2020 US Census, the population was 399,710. Manatee County is part of the North Port-Sarasota-Bradenton Metropolitan Statistical Area. Its county ...
. The Myakka River discharges into
Charlotte Harbor.
*
Obion River: located in Northwest Tennessee
*
Ochlockonee River: a river in northern Florida
*
Ogeechee River: a 245-mile river in eastern
Georgia that passes to the south of the city of
Savannah
A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the Canopy (forest), canopy does not close. The open canopy allows sufficient light to rea ...
and enters the Atlantic Ocean at
Ossabaw Sound.
*
Ohoopee River
The Ohoopee River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed April 21, 2011 river in east-central Georgia in the United States. It is a tributary of the Altamaha River, which ...
: a 119-mile-long (192 km) river in east-central
Georgia. It is a tributary of the
Altamaha River, which flows to the Atlantic Ocean.
*
Pasquotank River: a river in Northeastern
North Carolina. Located between Camden and Pasquotank counties, the Pasquotank connects directly to the
Albemarle Sound and is part of the Intracoastal Waterway via
Elizabeth City.
*
Peace River
The Peace River (french: links=no, rivière de la Paix) is a river in Canada that originates in the Rocky Mountains of northern British Columbia and flows to the northeast through northern Alberta. The Peace River joins the Athabasca River in th ...
: located in central Florida, flows into
Charlotte Harbor.
*
Pithlachascotee River: a small river in central
Florida
*
Pocomoke River
The Pocomoke River stretches approximately U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed April 1, 2011 from southern Delaware through southeastern Maryland in the United States. At it ...
: a river in southern
Delaware and southeastern
Maryland on the
Delmarva Peninsula. The river is a tributary to the
Chesapeake Bay.
*
Santa Fe River: a river in northern Florida
*
Satilla River: a river in southeast
Georgia that flows through the city of
Waycross and empties into the Atlantic Ocean near
Cumberland Island.
*
Scuppernong River: a small river in
Washington and
Tyrrell Counties in eastern
North Carolina at
Pettigrew State Park
*
Sopchoppy River
The Sopchoppy River is a minor river in the Florida Big Bend. A tributary of the Ochlockonee River, it is approximately in lengthBoning, Charles R. 2007. ''Florida's Rivers''. Sarasota, Florida: Pineapple Press, Inc. and nearly entirely within ...
: a river in northern Florida
*
St. Mary's River (Florida–Georgia): a 130-mile river located in southeast Georgia and is bordered by the Satilla River Basin to the north and the Suwannee River Basin to the west.
*
St. Johns River
The St. Johns River ( es, Río San Juan) is the longest river in the U.S. state of Florida and its most significant one for commercial and recreational use. At long, it flows north and winds through or borders twelve counties. The drop in eleva ...
: The largest river in Florida. Flows north through
Jacksonville and into the Atlantic.
*
St. Sebastian River
The Saint Sebastian River is a river in the U.S. state of Florida, a tributary of the Indian River west and north of the city of Sebastian.
Dredging
Dredging
Dredging is the excavation of material from a water environment. Possible re ...
, Indian River County, Florida.
*
Suwannee River
The Suwannee River (also spelled Suwanee River) is a river that runs through south Georgia southward into Florida in the southern United States. It is a wild blackwater river, about long.U.S. Geological Survey. National Hydrography Dataset hig ...
: a large river in southern
Georgia and northern Florida flowing into the Gulf of Mexico
*
Upper Little River, North Carolina: flows into the
Cape Fear River.
*
Upper Nanticoke River, Delaware and Maryland: flows into the Chesapeake Bay.
*
Village Creek, a 63 Mile long stream in the
Big Thicket region of southeast Texas: flows into the
Neches River
The Neches River () begins in Van Zandt County west of Rhine Lake and flows for through the piney woods of east Texas, defining the boundaries of 14 counties on its way to its mouth on Sabine Lake near the Rainbow Bridge. Two major reservoirs, ...
.
*
Waccamaw River
The Waccamaw River is a river, approximately 140 miles (225 km) long, in southeastern North Carolina and eastern South Carolina in the United States. It drains an area of approximately 1,110 square miles (2886 km²) in the coastal plain ...
, North and South Carolina: flows into the Atlantic Ocean.
*
White Oak River
The White Oak River is a blackwater river, close to 48 mi (77 km) long, on the coastal plain of southeast North Carolina in the United States. It empties in the Atlantic Ocean.
Course
It rises in the White Oak Pocosin in northern Onslo ...
, North Carolina: flows into the Atlantic Ocean.
*
Wolf River: arises in Northern Mississippi and runs through southwest Tennessee/Memphis into Mississippi River
Northern United States
*
Black River,
New York
New York most commonly refers to:
* New York City, the most populous city in the United States, located in the state of New York
* New York (state), a state in the northeastern United States
New York may also refer to:
Film and television
* '' ...
: a river starting in the western
Adirondacks that flows into
Lake Ontario.
*
Black River (Gogebic County),
Michigan: a river in the far western
Upper Peninsula that flows into
Lake Superior. The northern section of the river is listed as a
National Wild and Scenic River.
*
Mullica River and its tributaries from the
Pine Barrens,
New Jersey, where the dark water is called cedar water
*
Gooseberry River
Gooseberry River is a 23-mile stream in Lake County, Minnesota, USA, draining into Lake Superior. It is known for its waterfalls, near its mouth in Gooseberry Falls State Park. The Gooseberry, like many of its neighboring streams, has an irregula ...
: a river in northern Minnesota that leaches from peat bogs and pine forests
*
Ocqueoc River
The Ocqueoc River ( ') is stream in Presque Isle County in the northeastern part of the lower peninsula in the U.S. state of Michigan. It is longU.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map acc ...
, Michigan: a river in the northern Lower Peninsula that flows in
Lake Huron
Lake Huron ( ) is one of the five Great Lakes of North America. Hydrology, Hydrologically, it comprises the easterly portion of Lake Michigan–Huron, having the same surface elevation as Lake Michigan, to which it is connected by the , Strait ...
*
Tahquamenon River,
Michigan: a river in the
Upper Peninsula that flows into
Lake Superior
*
Tuckahoe River,
New Jersey: a short river in southern New Jersey that flows into
Great Egg Harbor
Great Egg Harbor Bay (or Great Egg Harbor) is a bay between Atlantic and Cape May counties along the southern New Jersey coast. The name derives from Dutch explorer Cornelius Jacobsen May's description of the plentiful birds laying eggs, naming th ...
Africa
* Most
Congo
Congo or The Congo may refer to either of two countries that border the Congo River in central Africa:
* Democratic Republic of the Congo, the larger country to the southeast, capital Kinshasa, formerly known as Zaire, sometimes referred to a ...
and
Lower Guinean rivers that flow through rainforests are blackwater.
* The Congo basin lakes
Mai-Ndombe and
Tumba are blackwater.
* The
New Calabar and
Sombreiro River
''Clitoria fairchildiana'', the ''sombreiro'', is a flowering plant species in the genus '' Clitoria'' found in Campina Grande, Brazil.
The rotenoid
Rotenoids are naturally occurring substances containing a cis-fused tetrahydrochromeno ,4-bhro ...
s (both exiting in the
Niger River Delta
The Niger Delta is the delta of the Niger River sitting directly on the Gulf of Guinea on the Atlantic Ocean in Nigeria. It is located within nine coastal southern Nigerian states, which include: all six states from the South South geopolitical ...
) are blackwater.
Australia
*
Gordon River,
Tasmania: a river rising in the center of the island and flowing westward, emptying into
Macquarie Harbour on the
West Coast West Coast or west coast may refer to:
Geography Australia
* Western Australia
*Regions of South Australia#Weather forecasting, West Coast of South Australia
* West Coast, Tasmania
**West Coast Range, mountain range in the region
Canada
* Britis ...
*
Pieman River
The Pieman River is a major perennial river located in the west coast region of Tasmania, Australia.
Course and features
Formed by the confluence of the Mackintosh River and Murchison River, the Pieman River rises in what is now known as L ...
, Tasmania: a river on the West Coast which leaches from rainforests and heathlands
*
Davey River, Tasmania: a relatively small river in the southwest corner of the island which runs through extensive heathlands, peat bogs and
button grass plains
*
Noosa River
The Noosa River is a river situated in South East Queensland. The catchment starts in the Como Escarpment near Mount Elliott in the coastal Great Sandy National Park and meanders south through a lakes district around Tewantin.
Lakes situated on ...
,
Queensland: a small section of the Noosa River running between Lake Cootharaba and Lake Cooroibah
Other rivers in Australia may experience infrequent 'blackwater events' associated with flood waters connecting to forested floodplains and these events may be associated with hypoxic waters
ow oxygen Examples include the
Murray River,
Edward River,
Wakool River and
Murrumbidgee River.
Indonesia
*
Sabangau River
Sabangau National Park (sometimes spelled Sebangau) is a national park in Central Kalimantan, a province of Indonesia in Kalimantan, the Indonesian part of the island of Borneo established in 2004. Between 1980 and 1995 the site was a massive l ...
Images of blackwater rivers
Amazon blackwater.JPG, Amazon tributary classified as blackwater
Bald Cypress.JPG, Cluster of bald cypress trees in Trap Pond State Park in Southern Delaware
Manaus-Amazon-NASA.jpg, Manaus
Manaus () is the capital and largest city of the Brazilian state of Amazonas. It is the seventh-largest city in Brazil, with an estimated 2020 population of 2,219,580 distributed over a land area of about . Located at the east center of the s ...
, the largest city on the Amazon River
The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile.
The headwaters of t ...
, from a NASA satellite image, surrounded by the muddy Amazon river and the blackwater Rio Negro
File:Blackwater and muddy water, Big Thicket NP. Jack Gore Baygall Unit, Hardin Co. TX; 3 Apr 2020.jpg, A cypress slough where baygall
A bayhead or baygall is a specific type of wetland or swamp habitat.Watson, Geraldine Ellis (2006) Big Thicket Plant Ecology: An Introduction, Third Edition (Temple Big Thicket Series #5). University of North Texas Press. 152 pp. Natural Communi ...
blackwater (left) mixes with the more typical muddy waters (right) of the region. Big Thicket National Preserve, Jack Gore Baygall Unit, Hardin Co. Texas; 3 April 2020
File:Caño Ceima Cachivera, Mitú, Vaupés.jpg, Caño Ceima Cachivera, Mitú, Vaupés: one of the most visited waterfalls and indigenous communities In Mitú, Colombia
See also
*
Bog
A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; a ...
*
Colored dissolved organic matter
References
{{Wetlands
Aquatic ecology
Rivers