© Shutterstock / Suriya99 / WWF

Rivers are lifelines for people and nature. From our earliest civilizations to the mega-cities of today, we have built along rivers due to the benefits they provide - water for drinking and irrigation,  fisheries, fertile floodplain fields, stable deltas, transportation and livelihoods - as well as their central role in so many of our cultures. They are also home to incredible biodiversity and sustain countless other species on land and in the ocean. Each month, we will profile one of the most extraordinary rivers. In 2022, we profiled a different river every week - feel free to navigate on the facts and stories that illustrate how these rivers are central to climate mitigation and adaptation and to safeguarding people and nature. 



#51 Hudson

Flowing 507 km from upstate New York to the Big Apple, the Hudson River serves as a physical boundary between New Jersey and New York before eventually emptying into the Atlantic Ocean. While the river was known to the Mahican Indians as Muhheakunnuk meaning “Great Waters Constantly in Motion”, it is named after the English explorer, Henry Hudson, who ‘discovered’ it while searching for a northern sea route to Asia. But before that dozens of Native American tribes had been using it as a source of water and food and as a major highway. Hudson’s expedition didn’t find a way to Asia but it did pave the way for the founding of the New Netherlands settlement on what is now Manhattan. And the rest, as they say, is history. As New York City developed, the Hudson suffered - increasingly polluted and overfished. In the 1970s, the American Shad and Sturgeon fisheries were closed due to overfishing, while Striped bass can no longer be commercially fished due to PCB pollution. The only species that can be fished commercially today are blue crab and the river haring. However, major efforts have been taken to restore the river and its watersheds, including in the Catskills, which provide much of NYC’s water. The Journey of Water in the Hudson River highlights the importance of investing in healthy river basins, which we rely on for drinking water, transportation and tourism. As you can see in our film, large amounts have been invested in Nature-based Solutions - with huge rewards for the City, people and nature in terms of water quality and ecosystem health. The Hudson still has a long way to go before it is fully restored but this river - flowing down through New York - shows that restoration is not only possible but an excellent investment.

© WWF Kenya


#50 Ewaso Nyiro

Flowing down from Mount Kenya to the dry plains that stretch East of the Great Rift Valley, the Ewaso Nyiro River flows 700 km before emptying out into a large network of wetlands known as the Lorian swamp. It supports economic development and livelihoods that reside along its banks. With a continuous water supply from the glaciers from Mount Kenya, it runs down through seven semi-arid counties: Meru, Laikipia, Samburu, Isiolo, Wajir, Garissa and Marsabit, serving as an important catchment for people and biodiversity. In the local community's language it means muddy or brown river. In the arid north of Kenya, water means life. The catchment became a main resource for both large and small scale farmers and their livelihoods. The Ewaso Nyiro river also provides water to the species of the Samburu National Reserve, Shaba National Reserve and Buffalo Springs National Reserve supporting species such as elephants, giraffes, hippos and cheetahs. Many Kenyans have no access to tap water and therefore depend on free flowing rivers. But water availability has decreased due to longer drought periods induced by climate change and unsustainable farming practices and degradation of forests which are key 'water towers.' The wetlands that are natural water filtrations systems and home to numerous species are under siege from negative human-related activities. The Journey of Water campaign navigates the delicate balance between scarcity and sustainability and advocates for governments, academics and communities to come together and take action to save the Ewaso Nyiro river for both people and biodiversity. Our freshwater lead for WWF Kenya, William O. Ojwang states, “Water requires coordination - a resource that we need to share as a country.”

© Refrain


#49 Amur River

The biggest river in Northeast Asia and one of the biggest free-flowing rivers in the world, the Amur River supports millions of people throughout Mongolia, Russia and China. Amur stems from the Mongolian name Amar meaning quiet or peaceful. Ironically, it was once a symbol of conflict, playing a pivotal role in the Sino-Soviet conflict. Today, the Amur forms a 30,000km border between China and Russia. For centuries, different ethnic groups including the Tungusic, Mongol, Ainu and Nivkhs have relied on the Amur for their livelihoods. The Amur is also known as one of the regions where pottery first appeared. The Nainai people of the Amur river were known as the “fish skin people,” wearing clothes and shoes made out of fish skin. Fishing and hunting were an integral way of life for the Nainai people - the whole community was part of the process of catching, preserving and storing salmon in summer and early autumn. But salmon stocks are now disappearing due to commercial fishing and water pollution. The Amur is home to 2,800 plant species and over 500 animal species, serving as a key habitat for many critically endangered wildlife such as the Siberian taimen, Amur pike, Amur catfish, softshell turtle, the red-crowned crane and the largest fish species in the Amur, the Kaluga sturgeon - weighing up to 1000 kg! The Amur is home to the Amur, Kaluga and Sakhalin sturgeons - all defined as critically endangered by the IUCN Red List of Threatened Species. WWF’s sturgeon initiative is working to protect these species and rebuild their populations by tackling the illegal caviar trade, while our Asian flyways initiative is working to protect migratory bird species. Both are dependent on the health of river systems such as the Amur.

© André Bärtschi / WWF



Rising in Peru, the Purus River runs 3,200km through the Acre province of Brazil and empties out as one of tributaries to the Amazon River. One of the most meandering streams in the world, the Purus River has huge floodplains and thousands of lakes. It forms a small section of the boundary between Peru and Brazil, where 90% of its drainage basin resides. Its name comes from the Purus province, one of the four provinces of Peru. In the heart of the most diverse, unexplored Amazon forests, the Purus river runs through the Alto Purus National Park, Purus Communal Reserve, the Abufari Biological Reserve, the Purus National Forest, the Medio Purus Reserve and several other nature reserves. The river floods from December to May and it is navigable for over 2,600km. Rich in biodiversity, the Purus harbours the red howler monkey, catfish, peccaries, giant otters, Amazon river dolphins, egrets, blue herons and water lizards. It is also home to at least eight ethnic groups and an unknown number of indigenous people in voluntary isolation. While the Purus river basin has relatively large protected areas, its waterways & wetlands are threatened by extensive floodplain logging, commercial fishing and flooded forest removal for agriculture. It is vital that the Purus River is restored and protected for the benefit of both people and nature.

© Famartin


#47 Delaware River

After flowing through New York’s Catskill mountains, Ponocos in Pennsylvania, and the New Jersey Highlands, the Delaware River finally spills into Delaware Bay. Running through five states, it provides drinking water to over 13 million people, including residents in New York City and Philadelphia. The longest remaining undammed river East of the Mississippi, the Delaware River supports communities with commercial fisheries & river towns that rely on ecotourism. This iconic river plays a key role in American history. It supported the largest American Shad commercial fisheries in the U.S.'s East Coast in the 19th century - referred to as “America’s founding fish.” In 1776, George Washington crossed the Delaware River, surprising British troops during the American Revolution - a famous crossing that solidified GW's role as a key leader. Incredibly rich in biodiversity, the Delaware River is home to over 400 bird species, 90 fish species as well as Endangered American eels, beavers, otters, minks and one of the world’s largest horseshoe crab populations. Recognized as one of the country’s Great Waters by the National Wildlife Federation, the Delaware River is home to the country’s first Urban National Wildlife Refuge. Its floodplain reduces the impacts of flooding on homes and businesses. Used heavily in daily freight transportation, the Delaware port is one of the largest freshwater ports in the world. In addition to pollution, land conversion and climate change threatens the Delaware River. As one of the few remaining free flowing rivers in the United States, it is imperative that we protect this route essential for migratory species, as well as for all who rely on its healthy waters.

© Mikko Nikkinen/WWF


#46 Hiitolanjoki River

Surrounded by coniferous and herb rich forests, the Hiitolanjoki River in South Karelia flows 53 km from Lake Simpele in Finland to Russian Lake Ladoga. In the 1700s it was known for milling and river rafting. In Finland, all migratory fishes have become endangered due to damming, and in the River Hiitolanjoki lives the only naturally reproducing land-locked salmon population that is left, now also critically endangered. Hiitolanjoki is a home to river otters and bird species such as white-throated dippers, common sandpipers, swans and grey herons. The three rapids on the Finnish side have been used to harness electricity for the past 100 years. In a joint project by the state, WWF and regional associations, the lowermost Kangaskoski dam was demolished in August & September 2021. This allowed the land-locked salmon and brown trout to return to their historic spawning grounds in the Finnish river for the first time in 200 years! The spawning took place just weeks after the dam removal and it was highly successful. In the summer of 2022, the densities of salmon and trout young in the newly opened rapid, were higher than ever recorded in any other river in Finland, free-running ones included. The second hydropower plant at Lahnasenkoski was stopped in August 2022 and its dam was removed the same autumn. The third, and last hydropower dam at Ritakoski rapid, will be demolished in the autumn of 2023. Sampsa Vilhunen from WWF Finland says the value of free flowing rivers and health of freshwater fish stocks are currently well recognized and acted upon by politicians in Finland. Enabling the development of high quality and responsible fishing tourism in the future, as well as other recreational activities.

© WWF Turkey


#45 Buyuk Menders

Covering 10 cities and 185 municipalities in southwestern Turkey, the Buyuk Menderes river has an annual water flow of 1.7 billion cubic metres. It supports key economic sectors such as textile, leather and agriculture in addition to fishing and tourism. The river delta has been recognized as a key bird & biodiversity area. The textile sector is important for the socio-economic development of the people living in the river basin. Surface and groundwater are used for urban, industrial and agricultural purposes , threatening water quality and quantity. The basin’s water availability is vulnerable to increasing population and climate change. The hydrological interventions and human-made embankments lead to destruction of this natural delta which took thousands of years to build up. WWF’s Turkey’s Water Stewardship Programme for textiles was initiated in 2017 with the aim to bring the water quality from low to good status, create a basin wide partnership with agreed conservation targets and protect freshwater habitats and species through effective wetland management and restoration. Collective action has been taken by farmers, textile manufacturers and local governments to protect the Buyuk Menderes from pollution and overuse. In 2020, regenerative agriculture pilot projects were initiated offering how farmers should care for the soil, use water and protect biodiversity. The aim is for all cotton farmers to adopt regenerative agriculture practices to sustain livelihoods and protect river basin health and the biodiversity it sustains.

© Pavel Špindler


#44 Orange

Rising in the Drakensberg mountains in Lesotho, the Orange River flows west through South Africa forming part of the border with Namibia before emptying out into the Atlantic Ocean. The Orange River is 2,200 km long - the largest river in South Africa. It is named the Orange River after the Dutch ruling family from the royal house of orange. The Orange river mouth is a Ramsar wetland site and the basin is home to 19 million people that rely on it for irrigation, mining, industrial use and hydropower - playing an important role in the South African economy. The Orange River is also used recreationally such as canoeing and rafting through the canyons of Richtersveld National Park home to leopards, brown hyenas, zebras and monkeys. Incredibly biodiverse, the Orange River is also home to numerous fish species such as the rock catfish and the smallmouth yellowfish and numerous bird species such as the African fish eagle and flamingos. However, much of the basin is experiencing severe water stress due to increasing irrigation, industrial and municipal use, soil erosion is destroying wetlands, nutrients from fertilisers are negatively affecting ecosystems and crops downstream, and dams are reducing natural river flows - all threatening the Orange River’s freshwater biodiversity. With the Convention on Biological Diversity (CBD) COP taking place this week, it is critical that we inform leaders of the importance of safeguarding freshwater biodiversity and that it has a secure spot on the new global framework for nature.

© WWF-Canon André BÄRTSCHI


#43 Ucayali

Descending from the Andes into the Amazon lowlands, the Ucuyali flows 2,700 km bringing huge volumes of water, nutrients and sediment with it. Considered one of the “mother” rivers of the Amazon basin, the Ucayali River meets the Maranon River, which marks the head of the Amazon. The most famous headwater of the Ucayali is the Sacred Valley where spectacular Inca ruins such as the Machu Picchu are located. For 4000 years, communities have relied on its waters for food, navigation and irrigation. Farmers depend on seasonal flooding to replenish the soils and maintain fisheries. Many communities raise their houses to ensure they stay above the flood. Incredibly rich in biodiversity, these waters have many endemic fish species. The Ucayali is also home to the Amazon river dolphin, giant otters and the Amazonian manatee. Threatened by deforestation, pollution, dam construction and hydromorphological changes, the Ucayali’s river health and biodiversity are  at stake. There are only a few small protected areas in the Ucayali basin. With the convention on biological diversity (CBD) COP coming up next week, it is an important reminder that rivers like the Ucuyali are protected and restored to maintain their biodiversity and all it provides to its people.

© Mailee Osten-Tan / The Third Pole


#42 Chao Phraya River

Flowing through Thailand’s central fertile plain and emptying out into the Bay of Bangkok, the Chao Phraya River is the symbol of Bangkok. Also known as the “River of Kings,” the Chao Phraya enabled the rise of the earliest civilizations of Southeast Asia, serving as a valuable waterway for the export of goods like teak and rice. Bankong has been called the “Venice of the East,” due to natural and manmade canals splitting off from the Chao Phraya River. For centuries, they have made use of its canal systems for irrigation, recreation, fishing, and hosting the iconic floating markets. The most historically significant and densely populated settlements reside along the river - dependent on its water for their livelihoods. The Chao Phraya basin is the most important river basin in Thailand, home to 40% of the country’s population and 78% of its workforce. The Chao Phraya River also boasts around 280 fish species including three of the largest freshwater fish in the world - the critically endangered giant barb, giant pangasius and giant freshwater stingray. Extensive habitat destruction due to pollution, dam construction and drainage systems for irrigation threatens the Chao Phraya River. In addition, the destruction of wetlands is threatening bird species such as the Asian openbill and the wintering black kite. The asian flyways initiative is supporting migratory bird species and conserving wetlands. Protecting wetlands will increase resilience for communities and cities.

© Jakub Krska


#41 Hucava River

Flowing from the ancient Volcano Polana, the Hučava River in Slovakia is a site of community interest and a special protected area under the Natura 2000 framework. Located in the Poľana Biosphere Reserve, the Hučava basin is rich in biodiversity - home to salmon, Eurasian otters and kingfishers. But the Hučava River has been modified throughout the years, including with two old barriers for irrigation that are now obsolete. These old barriers no longer serve any purpose but they still block the migration of species and natural sediment flow. In 2021, one of the dams was removed by WWF Slovakia in cooperation with the Slovak Water Management Enterprise and the State Nature Conservancy - reconnecting 25 km of river in total. In addition to providing renewed connectivity, dam removal also improves water quality, restores migratory species populations and allows the natural deposition of sediments. To further restore connectivity, a fish pass is being built at the second barrier. Since the dam removal, short and long distance migratory fish have been seen passing through the area where the barrier once was. This is an example for other European rivers, which are among the most fragmented rivers in the world. The European Commission aims to make 25,000 km of river free flowing by 2030. To restore Europe’s free-flowing rivers, dam removal projects such as this one are being undertaken in the EU. 

© Vyacheslav Argenberg


#40 Nile River

The longest river in the world, the Nile was at the heart of one of the world’s greatest early civilizations, ancient Egypt, providing it with water for drinking and agriculture. Every year until the advent of big dams, the Nile flooded in August, spreading nutrient-rich soil across its floodplains and delta, creating the perfect conditions for growing crops - enabling cities to sprout amidst the desert. During this time, the Egyptians have a two-week holiday called ‘Wafaa an-Nil’ to celebrate the flooding of the Nile. With CoP27 in Egypt this year, water is - unsurprisingly - high up the climate agenda. Today, more than 95% of Egyptians depend on the Nile River - serving as an important irrigation, transportation and trade route. But the Egyptians are not the only ones who depend on the Nile, which only becomes one river in Sudan where the White Nile from Lake Victoria merges with the Blue Nile from Ethiopia. Overall, the Nile flows through 11 countries, where another 102 million people depend on the river. The Nile River is also incredibly biodiverse - home to countless fish species, birds hippos and the Nile crocodile. Pressed by their growing populations and water needs, water scarcity threatens the upper Nile. Rising sea levels are leading to saltwater intrusion downstream, and warmer temperatures and deeper droughts due to climate change are stressing food security and political stability. Investing in healthy rivers is central to climate adaptation - to save a vital water source upon which so many livelihoods depend.

© Fernando Trujillo Fundacion Omacha


#39 Bita River

Colombia’s Bita River is the largest Ramsar site in Colombia & the first ever site to protect an entire free-flowing river and its basin. Incredibly rich in biodiversity, the Bita River is home to over 1,000 species of plants, over 200 fish and bird species, and 60+ species of mammals - including iconic species such as the Amazon river dolphin! A network of grasslands and seasonally flooded plains, the Bita’s associated wetlands are vital for the life-cycle of many migratory species. The connectivity of the Bita River is important as it allows the seasonal movement of river dolphins and the migration of freshwater fish. Flowing through Colombia and Venezuela, the Bita supports many local communities that rely on it for water, fishing, farming and tourism. Protecting free-flowing rivers like the Bita is critical to tackling both the climate and nature crises - and will be a key topic for discussion at the upcoming Ramsar COP14.

© Gerry Ryan WWF Cambodia


#38 Mahakam River

The Mahakam River is the second largest river in Indonesia and home to the last river dolphins in the country - with around 80 Irrawaddy dolphins or Pesut in Indonesian surviving in the river. Accidental entanglement in fishing nets has caused two thirds of dolphins deaths in the last 25 years. A WWF-supported pilot project put acoustic devices called pingers on fishing nets in the Mahakam River. The pingers create a sound that deters the dolphins from the fishing nets, preventing entanglement and deaths in nets. During the pilot project, no dolphins became entangled in pinger-protected nets. The pingers resulted in a 40% increase in average catches for fishers by keeping the dolphins away and have reduced costly damage to their nets, helping boost local livelihoods - a win-win! WWF is now helping to distribute pingers to fishers in all stretches of the Mahakam river with river dolphins. Expanding the pingers project is one of our biggest hopes for saving these incredible animals. Check out our river dolphins initiative page for more information on what we are doing and how you can get involved.

© © Martin Harvey WWF


#37 Mara

Flowing 365 km from the Kenyan highlands to Lake Victoria, the Mara River is globally iconic for its rich freshwater biodiversity. It has the highest density and diversity of large herbivores on Earth including the great wildebeest migration. Each year two million wildebeest, gazelles and zebras race across the crocodile-infested river in search of greener pastures earning the nickname “river of death.” The river flows through the world famous Masai Mara National Reserve and Serengeti National Park where human activity is limited to wildlife viewing, bringing in millions of dollars in tourism. Shared between Kenya and Tanzania, the Mara River provides ecosystem services to 1.1 million people living in the basin - it is a vital source for livelihoods . More than half of the inhabitants rely directly on the river for domestic water use and 60% get their water directly from the river. The Mara River is home to over 470 native freshwater species including hippos, otters, crocodiles and countless fish, bird and plant species. But the Mara River is under threat due to unsustainable agriculture, deforestation, water pollution and over-exploiting natural resources. Proposed dams and climate change also pose a future risk. Conservation of a healthy, free-flowing Mara River is essential to providing the blue heart of the economy and society in Kenya and Tanzania.

© Thor Morales WWF Mexico


#36 Usumacinta

Rising in the Peten of Guatemala, the Usumacinta River flows along the border with the Mexican state of Chiapas before entering the country  and continuing its path towards the sea. On its way, it crosses  through the Usumacinta Canyon ecological reserve, forming impressive canyons along its route. The Usumacinta is the largest river in Mesoamerica, draining almost half of Guatemala’s freshwater. Serving as important trade routes for Mayan civilization, the river separated the two rival Mayan settlements of Piedras Negras and Yaxchilan, where they traded salt, cacao, obsidian, jade, feathers and shells from Guatemala to the Gulf of Mexico. Named after the howler monkey, it is the largest and most biodiverse river in Central America and one of Mexico’s last remaining free-flowing rivers. Surrounded by mangroves and jungle, the Usumancita river is home to over 3,500 plant species, over 70 species fish species, and the iconic howler monkeys. Unfortunately, the Usumacinta is threatened by deforestation, mineral exploitation and hydroelectric development, altering flood frequency and land-use change due to agriculture. Two internationally recognized Ramsar wetlands, Guatemala’s Laguna del Tigre National Park and Tabasco’s Pantanos de Centla Reserve lie within the Usumacinta watershed. As of June 2018, a water reserve protects 93% of the Usumacinta’s water; nourishes forests and species, including jaguars; and strengthens two previous conservation decrees that promote the sustainable use of forest resources and prohibit exploration for oil and gas. The water reserve also protects important livelihood activities for basin inhabitants, such as aquaculture, seasonal agriculture and tourism.

© Bodrog Tokaj & Civertan Grafik


#35 Tisza

Located in the geographical heart of Europe, the Tisza River is the longest tributary of the Danube flowing through Ukraine, Slovakia, Romania, Hungary and Serbia. Originating in the Carpathian mountains, the Tisza River flows through the Great Hungarian Plains and out into the Danube with one third of the total river catchment lying in Hungary. The Tisza River is incredibly rich in biodiversity, with some species that are no longer found in other parts of Europe due to its relatively healthy floodplain forests, wetlands and grasslands. The Tisza River sustains over 300 species of birds, 59 species of fish, over 200 species of vascular plants, and a large number of invertebrate species. Annually, the annual ‘blooming of the Tisza’ attracts tourists to watch the spectacular synchronised swarming of millions of Tisza mayflies. Home to 14 million people throughout five countries, the river sustains livelihoods through agriculture, navigation, tourism and energy production. But the Tisza river is under threat from land-use change and river engineering, which has altered the natural structure of the river resulting in the loss of natural floodplains and wetlands leading to severe floods and droughts. The Tisza River is also being polluted with nutrients from farming and wastewater, and hazardous substances from mining and industry. Urgent efforts are needed to protect and restore the river - to safeguard the communities, nature and ecosystems it sustains. Check out WWF-Hungary’s Tisza River page for more information.

© Tanya Doody


#34 Murray

The Murray River is Australia’s longest river extending over 2,500 km and is the third longest navigable river behind the Amazon and the Nile. Hosting the world's longest canoe race each year, the Murray River rises from Australia’s highest mountains crossing through inland plains and drains out into the Southern Ocean. The Murray River is home to over 300 freshwater species including birds, frogs, snakes, lizards, turtles and fish such as the Spangled Perch. Home to the world's largest red gum forests, the Murray river basin sustains incredible biodiversity, including emus, koalas and kangaroos. The Murray river basin has also been home to human communities for tens of thousands of years and is still home to many Aboriginal nations today. Commonly referred to as the ‘Food Bowl of Australia’, the river provides water to 1.5 million households as well as farms and businesses - and even has its own flag. But the flag should be flying at half mast these days. Poor governance and over allocation for agriculture - combined with droughts - has sucked the Murray River dry. For decades, the river has struggled to reach the sea, threatening the people and nature (including numerous Ramsar wetlands) that rely on it. So far a major River Basin management plan for the joint Murray-Darling river systems has failed to solve the problems. Urgent and decisive action is needed since a healthy Murray River is essential to the economic, social and cultural well being of people across South Australia as well as the ecosystems and biodiversity it sustains.

© Gustavo Carrasco / WWF-Peru


#33 Amazon

The Amazon River doesn't need much introduction, as its fame precedes its magnitude - it's the world's largest river system and the greatest by water volume. The basin occupies almost 7 million km2 - nearly the size of the entire Middle East - from Peru's high snow-capped Andes to the vast Brazilian estuary where the river meets the Atlantic Ocean. With over 6,500 km, the Amazon River is the main stem of more than ten major tributaries. Along its way, it boosts life in the world's largest tropical rainforest and the highest biodiversity globally, including more than 400 mammal species, 1,000 birds, 350 reptiles, 400 amphibians, and 3,000 fishes. And many still to be discovered, bringing invaluable benefits - of the more than 40,000 plant species, many are known to be the basis for medicines manufacture. The basin has remarkable seasonal flood pulses, which can rise up to 15m during peaks, inundating floodplains and creating flooded forests. It also safeguards various wetlands and lakes - all supporting major fisheries and water supply. Humans have used the river's floodplains for over 11,000 years. Flowing through Peru (18%), Colombia (less than 2%), and Brazil (80%), it's the main artery for urbanisation, commerce, transportation, fisheries, and floodplain agriculture. In the Brazilian Amazon, around 30 million people depend on its waters, including more than 220 indigenous groups and local communities. The basin is also vital for climate regulation globally and regionally. Water vapours from Amazonia travel via air currents as far as Northern Argentina, known as "Flying rivers", which are responsible for much of the rain falling in Centre-West, Southeast, and South Brazil. But all these benefits are at risk. The Amazon River basin is losing surface freshwater annually due to human interventions such as hydropower dams, deforestation for cattle ranching and farming, and climate change. In addition to investing in renewable energy such as wind and solar, conservation efforts with local and indigenous communities can help protect this gigantic freshwater ecosystem, benefiting people and nature globally. 

© Visit Karlstad - My Newsdesk.com


#32 Klarälven

The Klarälven River is Sweden's longest river, flowing 460km from Norway, where it's called Trysilelva, through Sweden's Värmland county until it spills its life-giving waters into Lake Vänern - the largest in Sweden and Europe's third-largest. Together, River and Lake form the longest basin in Scandinavia, covering 10% of Sweden's area. The basin's waters feed smaller lakes and rivers, giving life to magnificent landscapes and biodiversity. The Klarälven is especially significant to the over 250,000 people living in Sweden's Värmland county. Meaning "The Clear River", it's suitable for bathing and internationally recognized as excellent for sport fishing. But this and all other benefits the river provides are at risk. A total of nine hydropower plants are spread across the Klarälven-Trysilelva system, negatively impacting many freshwater species, including the Vänern salmon. Lake Vänern has been a vital fishing lake for over 9,000 years, where its native freshwater salmon spawns, never entering the ocean. It is estimated that the lake's and river system's spawning stock is now only 5 % of its population at the beginning of the 19th century, and breeding programs aren't working as expected. In addition, the basin faces flood risk, erosion, and landslides. Spring floods are common, mainly caused by run-off from the snowy mountains in the basin's northern areas, but climate change increases these risks. The River basin includes Natura 2000 areas, national parks, and national interest areas - safeguarding several threatened species and environments. But efforts to keep the river and its people safe and healthy must contemplate Nature-based Solutions, alternative renewable energy, biodiversity, and cultural heritage.

© Jaap van der Waarde / WWF-Netherlands


#31 Sanaga

The Sanaga is the largest river in Cameroon, flowing 918km from its source on the Adamawa Plateau towards the Atlantic Ocean. Rich in waterfalls and rapids, Sanaga's gigantic basin covers a fourth of the country, giving life to various landscapes, biodiversity hotspots, and societies. The basin sustains savannah grasslands, fertile highlands with an exceptional range of endemic species, the Lake Ossa complex, and equatorial rainforests harbouring lowland gorillas, chimpanzees, and the world's largest frog. It also feeds sandy areas filled with swamp forests and wetlands rich in birdlife and home to a sizable population of West African Manatee, besides the Cross-Sanaga-Bioko Coastal Forests ecoregion with high biodiversity mangroves. The Fulbe (Fulani) are the main tribe in the sparsely populated basin, who are Muslims with a nomadic or sedentary livestock-rearing lifestyle. Although home to only 5-10% of Cameroon's 16 million people, the Sanaga sustains most of the country's electricity consumed – two hydropower plants on the river produce around 95% of the total consumed. The basin is also crucial to maintaining subsistence farming and the country's leading vegetable-producing region. Most people in the basin are poor, needing its waters for domestic use, fish, land fertiliser during floods, and sand as a building material. Poverty alleviation is central to the health and well-being of both people and the river's basin. The year 2022 is already marked by record droughts and fires occurring worldwide. Combined with Sanaga's increasing water demands, climate change will likely increase the risk of extreme droughts in the region. But there's still time to prevent such scenarios. The Sanaga River will only be able to provide all its benefits to people and nature if its resilience is built, e-flows maintained and the basin managed sustainably. 

© Bakkai


#30 YODO

The name "Yodo" might mean a stagnant river, but its basin brims with life. Although not fast-flowing, the Yodo River crosses through one of the world's most urbanised and developed areas. Its basin sustains Japan's megacities of Osaka and Kyoto - essential to the countries' economy, culture, and politics. Along its over 70km path, the Yodo has different names. It's the Seta where it rises, as the only natural river flowing out of Lake Biwa - Japan's largest freshwater lake and one of the oldest lakes globally. Around Kyoto is Uji, and when it meets Kizu and Katsura rivers, it becomes the Yodo until it spills into Osaka Bay. The basin's area, including Lake Biwa, is over 8,000 km2; half is a forest area, 30% agriculture, and less than 20% is housing and other activities. Lake Biwa, Yodo River, and Osaka Bay form unique water systems – the lifeline of people and nature, supporting extensive urban, industrial, and maritime activities. The Yodo basin also safeguards incredible biodiversity, like many endemic fish species. Japan's literature and art highlight some of them - the brilliant aquatic fireflies and both the extinct Japanese otter (Lutra nippon) and Japanese crested ibis (Nipponia nippon), which lived in the basin's vast floodplains. For more than 1000 years, Japan suffered frequent floods, so traditional control techniques have been used since Emperor Nintoku's time (A.D.257-339). These measures have contributed to many freshwater species conservation, but modern technology and methods do not consider biodiversity, dramatically degrading it. The dense forests of the tributaries and Lake Biwa function as a natural reservoir, river flow regulator, and gigantic filter producing high-quality water. But to reduce flood damage, the government uses grey infrastructure to control water levels. Combined with increasing water demand, climate change, pollution, and some 20 dams (including irrigation), Yodo's river basin health is at risk, and all the benefits it provides. Naure-based solutions for climate adaptation are a path to a healthy Yodo and its people and nature.t 

© Day's Edge Productions


#29 Orinoco

One of the longest rivers in South America, the Orinoco river flows for over 2000km from the Parima Mountains to the Atlantic Ocean in Venezuela. After the Amazon and Congo, it’s the largest river by discharge in the world. Covering over 980,000 km2, its mighty basin is shared by Colombia (35%) and Venezuela (65%) and is one of the most biologically, hydrologically, and culturally rich areas globally. Upstream, the flow of water and nutrients maintains and regulates hydro-ecological processes downstream in the Llanos floodplains. Along with the seasonal rains, the basin boosts life in important habitats like wetlands and vast biodiversity. It safeguards over one thousand birds, well-known animals like the jaguar and piranha, and rare and endangered species like the Orinoco crocodile and the Amazon river dolphin. The basin is also home to many indigenous peoples. On its Delta, the Warao – “the boat people” - named the river Orinoco – “a place to paddle” in their language. The river basin sustains fisheries, agriculture, energy, and industries, all dependent on its natural flows. But increasing pressures threaten the basin’s health. In addition to overfishing, the introduction of non-native species, and climate change, the unsustainable expansion of mining, oil and gas, agro-industry, and (dams) infrastructure are putting the river and its people at risk. Maintaining the Orinoco basin’s health is crucial to sustaining all the benefits it provides to people, the economy, and nature – and that’s what conservation efforts in the region are trying to achieve. 

© Grzegorz Kilian


#28 ODER

Like most large rivers, the Oder plays a crucial role in boosting life for its people and nature. One of the largest rivers in Central Europe, the Oder rises in its namesake Mountains in the Czech Republic. It flows for over 800km towards the Szczecin Lagoon, forming the border between Germany and Poland along the way and eventually spilling its waters into the Baltic Sea. Home to around 15 million people, the basin also safeguards enormous biodiversity recognized by the many protected areas at the European level. Despite the existing hydropower infrastructure in the basin, the Oder is one of the last European rivers through which fish and other animals can travel more than 500 km barrier-free to the sea. It is one of the most important ecological corridors for species migration and connection between distant areas in Central Europe. Nevertheless, the Oder is still at risk. Since the 18th century, the river has been regulated for navigation and flood protection. Nowadays, scientists show that rivers need room to help prevent unnatural floods. But there are still plans to build further navigation infrastructure along the Oder - the basin's most pressing threat. Poland and Czech Republic governments plan to create the E30 Waterway, which would turn the river into a channel and destroy river banks or deep holes - used by Critically Endangered sturgeon to overwinter and reproduce. It would also be detrimental to a broader range of aquatic biodiversity and completely alter the river's natural sediment flows. But we can still save the Oder and its benefits to people and nature. Governments could invest in improving existing rail infrastructure and nature-based solutions for flood prevention and climate adaptation, as well as strengthen the local economy through nature-based tourism.

© WWF Caucasus


#27 Rioni

Translated as "a large river", the Rioni River is the second largest in Georgia and one of the largest in the South Caucasus region. It flows for over 300km from the glaciers of the Greater Caucasus into the Black Sea. It boosts life across rare wetlands and cities of major cultural and economic importance like Kutaisi and Samtredia. Home to more than one million people, many livelihoods depend on the region's agriculture and livestock. The delta supports the city of Poti and its major seaport, giving the area strategic importance. The basin sustains vast richness also in other forms – from unique landscapes like its lowland peat bogs and swap alder forests to hot thermal waters and healing and mineral waters. The myriad of habitats attracts tourists, who can also glimpse incredible biodiversity, including vast migratory bird gatherings. The Rioni is one of the few rivers where the world's most threatened group species – sturgeons – still spawn in natural conditions. But, alarmingly, it is the last functioning one in Georgia and the Eastern part of the Black Sea basin – and one of the last chances for ship sturgeons, declared extinct in most of its native range. But the basin is at risk. A cascade of hydropower dams, irrigation for agriculture, pollution, poaching, illegal fishing and logging, and climate change threaten the integrity of the river's system. Fortunately, there's still some hope, as shown by the recent expansion of a protected area for sturgeon in the Rioni and the Black Sea. Only a healthy Rioni can continue to benefit people and nature, ensuring a stable economic environment.

© Sam Beebe



Representing the fastest free-flowing navigable river in North America, the Stikine is a glacial and transboundary river. Arising in Canada's British Columbia mountains, it flows for over 500 km towards the Pacific Sea on Alaska's coast. It cuts through sedimentary and volcanic rock on its path, forming an exceptional geological feature in Canada after aeons of river erosion – the Grand Canyon (of the North). But that's not the only stunning landscape the river basin supports. Its 52,000 km2 gives life to habitats extending from the delta's marshes and coastal rainforests to boreal forests and alpine ecosystems. It also holds a geothermal wetland, the Shakes Hot Springs – a popular recreational site. The enchanting landscapes are filled with incredible wildlife like wolves, moose, numerous birds, and salmon species, which the Stikine River Provincial Park aims to protect. Nearly pristine, the watershed has very little industrial development and is sparsely populated. It sustains local indigenous communities – the Tahltan Nation – who are the region's original settlers. Known as the "Great River" in the Tahltan language, the Skitine basin still supports the Tahltan's traditional resource harvest and preserves their cultural heritage - it's possible to find archaeological artefacts like obsidian and tools in the area. 

© Azamt Zhanturin


#25 ILI

The Ili River has a vast cultural, economic and ecological significance. In ancient times, the Ili River was part of the main route of the Great Silk Road (Semirechye), where cities were built and trade flourished. Rising in Xinjiang, it flows for around 1400km towards Kazakhstan’s Lake Balkhash, which became the largest Lake in Central Asia after the desiccation of the Aral Sea. The River's waters feed most of the Lake's annual inflow (70%-80%), forming the largest remaining natural delta and wetland complex at an inland lake in Central Asia – safeguarding a biodiversity hotspot. The 8000 km2 Delta mosaic of habitats was once home to the Caspian tiger, exterminated in the mid-20th century. It also harbours millions of birds, including breeding colonies of Dalmatian pelicans. Many fish species like the Critically Endangered Ship sturgeon live or spawn in the basin's waters. The Kazakhstani Ile-Balkhash basin is also home to 3.3 million people with another 4.62 million in the basin in China. It sustains fisheries, and its floodplains are extremely productive lands for hay and good pastures for livestock. Irrigation is the major water user, accounting for 85%. Due to this significant amount of water abstraction as well as dams in the basin, there are concerns that the Lake might shrink or even desiccate like the Aral Sea, and the wetlands degrade severely and shrink. In the 1970s, the Kapchagay Dam and Reservoir construction permanently altered the river's runoff – the water flowing into the lake shrunk, and the delta area reduced, lowering its groundwater level. But there's still hope. Kazakhstan declared the delta a wetland of international importance under the Ramsar Convention in 2012 and created the Ile-Balkhash Nature Reserve in 2018. Since 2019, WWF and the Kazakhstan government have been releasing Bukhara deer in the Reserve as an important stage in the program of reintroducing the Caspian tiger.

© ERN Roberto Epple


#24 Selune

The soon-to-be free-flowing Selune River rises in Saint-Cyr-du-Bailleul in France, flowing for over 85 km into the bay of the world-famous Mont Saint-Michel. This coastal river’s basin covers more than 1000 km2, but two hydropower dams have been blocking its upper part for the past 90 years. The Selune has a high ecological value and is the 3rd best French river in terms of “Salmon potential” - its waterways used to be a migratory route for many species like the Atlantic salmon, sea and brown trouts, European eel, pike, sea and river lampreys. Before the dams, migratory species could swim up and down the river’s catchment, between their spawning grounds and their feeding grounds out at sea. Fortunately, these obstacles will soon be gone. In 2017, the French government officially decided to bring these dams down. In 2020, the huge, 36m-high Vezins dam was removed, and the second one – La Roche Qui Boit – is currently being taken down. Dam removals improve the river’s water quality, re-naturalise sediment flows, and reconnect migration routes. Without Selune’s dams, scientists estimate a three-fold increase in juvenile salmon habitat and the number of adult salmon returning to the river to increase by more than 1400. 



#23 Kalambo

The Kalambo River rises in the Ufipa Highlands in south-central Tanzania, flowing towards one of Africa's Great Lakes - Lake Tanganyika. Drawing the border between Zambia and Tanzania in its lowermost third, the Kalambo river brings life to incredible biodiversity and one of the purest untouched sights of Africa – the Kalambo Falls. Kalambo's waters approach the edge of a steamy tropical gorge and plunge abruptly into a 212 metres dip, forming Africa's second highest uninterrupted waterfall. More than double the height of Victoria Falls, Kalambo's abyss is one of the breeding grounds of the rare and giant Marabou stork. But the river's journey does not stop there. It keeps going for over eight kilometres until it reaches the world's second-oldest freshwater lake. The river can broaden from three to impressive 20 metres wide during heavy rains from February to April, but after its free-fall, it never regains such composure, meandering through a narrow, steep-sided valley. The Kalambo River basin also safeguards one of the richest archaeological sites in Africa, where excavations found primitive tools from more than 100,000 years ago. Among the prehistoric stone and wooden tools are hand axes, cleavers, litchis, and iron slag. Nuts, seeds, and pollen have also been preserved. Located centrally in the basin, the site of Kalambo Falls has one of the longest history of human occupation in sub-Saharan Africa. Due to such invaluable nature and history, Kalambo Falls was included on the UNESCO list of tentative World Heritage Sites.

© Roland Dorozhani


#22 Vjosa

Rising as Aoos in Greece, the Vjosa River free-flows for over 270km through Albania until it drains into the Adriatic sea. The river boasts a variety of habitats as it crosses through high canyons, islands, and extensive wetlands in its lower stretch. Its basin safeguards incredible biodiversity, from migratory fishes and birds to endemic endangered plants, amounting to over 1,100 species. Home to such a wealth of wildlife, Europe’s last wild river also provides various economic and cultural benefits to local communities, including around 60,000 Albanians living along its shores. Its pristine beauty and potential for adventures drive a growing tourism industry. But the Vjosa is at the looming risk of fragmentation due to hydropower dams, like many other rivers in the Blue Heart of Europe. WWF’s 10 Rivers at Risk report released in September 2021 highlighted these dams would cause significant social and environmental damage in return for negligible amounts of electricity. But thanks to campaigns by local communities and international organisations, the future looks brighter for the Vjosa. Recently, Albania’s government and courts axed two destructive hydropower projects. And at the beginning of June 2022, the government declared the Vjosa River and its tributaries a future national park - a critical action to support the preservation of one of the last wild rivers in Europe. But we need to keep fighting for systemic change. This alarming study from 2020 shows that over 500 dams are planned in Protected Areas, and dead dams often come back from the dead. A combination of solutions is what we need to keep the Vjosa free-flowing. Besides halting high-impact hydropower and transforming key biodiversity areas into national parks, countries should choose a 21st-century path. This path is to invest in renewable alternatives, like solar and wind, that are LowCx3 Low cost, low carbon, and low conflict with rivers and communities. Together, these solutions would keep the Blue Heart of Europe beating for the benefit of people and nature.

© Patrick Bentley / WWF-US


#21 Cuando

The Cuando (alternately spelled as ‘Kwando’) River is one of the few rivers worldwide that remain undisturbed and naturally connected. Extending through an area of dry sandy woodland, its Basin is a "linear oasis" – it serves as the only water source within thousands of square kilometres for wildlife and people in southwest Africa. Rising in a remote area in Central-Southern Angola, the Cuando flows for over 220 km along the country's border with Zambia, crossing through Namibia and ending in the Linyanti Swamps on Botswana's border. Estimates show that over 250,000 people live in the Basin, many of whose subsistence depends on Cuando's healthy waters and flows. The Basin also safeguards savanna and open woodland habitats that serve as vital migration corridors for elephants, zebras, buffalo, and wildebeests. The River's banks are also home to many endangered species, such as the Southern African cheetah and Cape wild dog. As an important headwater tributary of the Zambezi River, it provides critical water resources to the heart of the Kavango-Zambezi Transfrontier Conservation Area (KAZA TFCA) - the world's largest transboundary conservation area. Due to such transboundary nature, coordinated efforts between the neighbouring nations are necessary to ensure sustainable management, use, and protection of the shared resource. Since 2020, WWF has embarked on a process to assess the state of the river basin. To strengthen transboundary governance in the Basin, WWF-US, WWF-Zambia, the Zambezi Watercourse Commission, the KAZA TFCA Secretariat, USAID, and the United States Department of State have developed the Cuando Basin Report Card, the State of the Cuando Basin Report, and the Kwando Joint Action Group. These efforts will help ensure inclusive and sustainable water resource management and increased water security for the benefit of people and nature in the Cuando River Basin and downstream in the Zambezi Basin.

© Stephen Kelly / WWF-US


#20 Ayeyarwady

Flowing for over 2000km from north to south, the Ayeyarwady River is one of Southeast Asia's last two long, free-flowing rivers. A lifeline for 34 million people in Myanmar, the river is also the engine of the country's economy. The Ayeyarwady's natural flow of water, sediments, and nutrients provides water for communities, cities, and companies to sustain productive freshwater fisheries. It also nourishes the country's rice paddies and keeps its fertile and densely populated delta from sinking and shrinking. The Ayeyarwady supports rich biodiversity, including fewer than 80 of the iconic and critically endangered Irrawaddy river dolphins. The river is one of the only places in the world where dolphins fish together with humans - a traditional method called "Cooperative fishing". But all these benefits are at risk. Unsustainable fishing decreases food sources significantly and kills other species (e.g., Irrawaddy river dolphin), while pollution and navigation threaten the Ayeyarwady's health. Loss of sediment upstream due to hydropower dams and sand mining is the main impact on Mekong's delta and are barriers to fish migration and nutrients. The world needs to factor in the diverse benefits of free-flowing rivers as well as the true social and environmental costs of hydropower on rivers, nature, and people. Renewables like solar and wind are low carbon, low cost, and low impact. These energy sources can provide power to the 50% of Myanmar's population who lack access to electricity while helping to keep Myanmar's lifeblood flowing freely. 



#19 Vistula

The Vistula is Poland's longest river, stretching for more than 1000km from the Carpathian Mountains to the Baltic Sea. Home to over 23 million people, the river has been at the heart of national life for hundreds of years. It has provided an important trade route in Europe, known by many as the "Queen of Polish rivers". Its basin covers close to 60% of Poland, mostly agricultural land. The river also provides for tourism and fishing – it is a corridor for migratory fish like the sturgeon and sea trout. Some sections of the Vistula are among Europe's most exceptional areas of natural value, including the Biebrza River valley and Luknajno and Karas Lakes, which harbour rare species of plants and animals. But all this is at risk. In addition to pollution, old and possibly new dams threaten to wreck much of what's left of the river's natural cycles. WWF's 10 Rivers at Risk report highlights a proposal to build a dam across the lower Vistula to create a reservoir to produce energy and, the developers claim, reduce flood risk. But environmental impact assessments show no impact on flood prevention. The new dam will supposedly protect an obsolete dam built in the 70s, but the old dam worsens the risk of flooding. This project would cost taxpayers €1 billion while only generating short-term profits for the developers rather than long-term benefits for Poland's people. Cutting off nearly 70,000 km of the river system from the Baltic Sea, the new dam will drastically alter natural flows and water quality and negatively affect local communities, tourism, and migratory fish populations that have already fallen by 93% across Europe. But there are alternatives: 44 wind turbines could generate the same amount of energy with none of the destructive social and economic impacts. Poland can opt for LowCx3 renewables - low carbon, low cost, and low conflict with rivers and communities –, scraping the new dam and removing the old one, which would cost less than a tenth of the current proposals. This 21st-century path would help tackle climate change, reduce flood risk and restore the health of the entire Vistula, benefiting people and nature across the country.

© Ghulam Rasool



Flowing 2800km from the Himalayas towards the Arabian Sea, the Indus River is one of the largest transboundary rivers in the world: shared by Pakistan, India, China, and Afghanistan. Its basin is the lifeblood of more than 300 million people who depend on the river for water supply, food security, and power generation. It sustains one of the world's largest contiguous irrigation schemes in Pakistan, on which the country relies for all sectors of the economy. Pakistan's Indus basin is also home to more than 225 significant wetlands - of which more than 19 are Ramsar Sites - and rich biodiversity, including over 190 freshwater species and many migratory and endemic species like the sacred Golden mahseer and the Endangered Indus river dolphin. But all this is at risk. Excessive water use - especially for agriculture in Pakistan, which consumes close to 90% of all currently available freshwater supplies - unplanned urban growth and upstream interventions like dams/infrastructures lead to a decrease in freshwater availability and increased the mismanagement of water and pollution in water bodies. The Indus delta is sinking and shrinking due to sediment loss, while, at its source in the Himalayas, climate change is melting the glaciers that keep the river flowing. Floods also create substantial losses, such as the devastating 2010 flood in Pakistan that took the lives of over 1,700 people and caused an estimated US$10 billion of economic damage. Pakistan and its people are particularly vulnerable to damages to the Indus basin's health, economically and regarding national disputes over its headwater areas. But not all is lost. Stakeholders need to tackle water security challenges for the basin's sustainable management. WWF and partners work to safeguard the Indus River Basin Landscape via initiatives like the River Dolphin Rivers, Resilient Asian Deltas and Asian Flyways, Collective Action, Water replenishment, water stewardship with the cotton and textile sectors, and our largest NBS project - Recharge Pakistan.

© Michel Gunther / WWF



Running through Brazil, Paraguay, and Argentina, the Paraná River flows for over 4500 km, having the second-largest basin on the continent. The River, its tributaries, and wetlands are of great economic, ecological and cultural importance to the region and the world. It forms geographic boundaries and links inland cities to the Atlantic Ocean. The River is named after the Tupi-Guarani Indigenous peoples, who first inhabited the basin, meaning "that resembles the sea" or "like the sea". Rising on the south-central Brazilian plateau, it is formed by the confluence of the Rio Grande and Paranaíba Rivers. After some 3500km, it unites its waters with the Paraguay River and flows for over another 1000km until it meets the Uruguay River, forming the extensive Río de la Plata estuary. The Paraná River Basin is home to some of South America's major population centres, harbouring approximately 100 million people who depend on the rivers' waters as a source for drinking, irrigation for agriculture, energy, industries, traditional fisheries, aquaculture, recreation, and tourism. The basin safeguards ecologically critical habitats in its Brazilian upper part like the Cerrado, Pantanal, and Atlantic Forest, and fantastic biodiversity, including the Neotropical otter and more than 450 fish species, like the migratory fish "Dourado". But all of this is under threat – much of the length of the Paraná and its tributaries have been impacted negatively by rapid urbanisation, agriculture, and hydropower development. The River holds the world's second-largest hydroelectric installation - The Itaipu Dam in Brazil, which reservoir has flooded around 100,000 ha of land. The basin's health also suffers from pollution, invasive species, and climate change. In 2021, the River's water levels hit their lowest since 1944. Urgent action needs to be taken to create strategies to restore and maintain Paraná River's health and flows on which people and nature rely.

© Nasa


#16 Imfolozi

South Africa’s Imfolozi is not one of the world’s most famous rivers but it should be! Not only does its basin include the extraordinary St Lucia wetland World Heritage Site, but the river is also the lifeblood of the Hluhluwe-Imfolozi Park - which famously saved the White rhino from extinction. As for the iMfolozi - its Zulu name is thought to describe the zigzag course of the river and its tributaries. Arising in the province of KwaZulu-Natal, the river is formed by the confluence of the Black and White iMfolozi rivers, before it meanders for 40km down to the Indian Ocean at St Lucia - a mix of lagoons and dunes that houses hippos, crocs and a wealth of birdlife and was saved at the end of last century from destructive mining by a huge public campaign. While the river basin is primarily given over to agriculture, particularly sugar cane farming, it still boasts incredible biodiversity in the Hluhluwe-Imfolozi Park, which is home to elephants, lions, buffalo, leopard and a host of non-Big 5 species as well as white and black rhinos. The Imfolozi’s waters are also essential for cities and irrigation for sugarcane and forestry. But all this is at risk. Large-scale cultivation, coal mining, and land degradation have altered the river's natural water flows and levels, while the St Lucia estuary has been separated from the river since the early 1950s due to canalisation, and the estuary now suffers from insufficient freshwater supply, worsened by increasing droughts. Fish and crustacean stocks in Lake St. Lucia have collapsed, while the loss of this nursery area - due to the estuary mouth silting up - has also impacted catches in adjacent coastal waters. Scientists say that the only way to assure the estuary's health is by reconnecting it to the river. And it’s not just the estuary that needs a healthy, naturally flowing river - so do all the people and nature that rely on it.

© WWF / Michel Gunther


#15 Danube

The Danube is the second-longest river in Europe and the world’s most international river, crossing through ten countries and draining the territory of 19  – an area over 800,000 km². It flows for over 2,850km from its headwaters in Germany’s Black Forest Mountains down towards the Black Sea. Home to 83 million people, the basin unifies and sustains a wealth of diverse cultures and traditions. With its outstanding landscapes, it provides multiple ecosystem services, including flood protection, fisheries, agriculture, tourism, and drinking water for more than 20 million people. The basin harbours Europe’s largest natural wetland – its Delta - and exceptional levels of biodiversity, including more than 5,000 species of animals and plants like the white pelican, beavers, and five sturgeon species on the brink of extinction (one species already extinct). The Danube has been drastically altered in the past 150 years: more than 80% of the river has been regulated, its natural floodplains with marshes, meadows and floodplain forests drained or cut from the river. For hydropower generation, flood protection or water supply purposes over 940 dams, ramps/sills built on the Danube basin on rivers with catchments larger than 4000 km2. Rapid economic growth further reduced the basin’s health through gravel extraction, navigation, and pollution from domestic waste, industry, and agriculture. And now climate change poses new threats to Danube’s wildlife and people. But this doesn’t have to continue. WWF works with partners to bring life back to the river through initiatives and larger programmes like the Living Danube Partnership and Living European Rivers which interventions include dam removals, river and floodplain restorations,  Nature-based Solutions, as well as fighting against new deterioration caused by infrastructure projects. The Sturgeon initiative and Life for Danube Sturgeons engage in sturgeon protection measures in Danube countries - this critically endangered migratory fish is an indicator of the river’s continuity and status. 

© Robin Darius / Felis


#14 Ganges

The Ganges is one of the most revered rivers in the world. It has a vast spiritual and cultural significance, represented by the variety of festivals that celebrate the legends of the river. But the river is mighty for many other reasons. Rising from the Gangotri glacier in the Himalayas, the Ganges River flows for over 2500 km until the Bay of Bengal. Its basin is the 5th largest globally, shared by Nepal, India, and Bangladesh. Home to more than 500 million people, it is the most populated river basin in the world, providing a variety of benefits from water for homes, agriculture and industry to freshwater fisheries for riverside communities. Together with the Brahmaputra river, it forms the world's largest delta, which is amongst the most fertile regions globally. But the Ganges is also among the world's most biodiverse river basins, safeguarding rich aquatic and terrestrial ecosystems and biodiversity, including the iconic Ganges river dolphin and many other rare and endemic species. Nevertheless, excessive water abstraction for agriculture as well as hydropower dams affect water and sediment flows in the river, contributing to the sinking and shrinking of its delta. Reduced freshwater flows also affect the health of the river, impacting people and nature. But at least the threats to the Ganges are starting to be acknowledged and addressed. Governments and civil society organisations are doing their bit to mitigate the threats to the river and ensure the survival of the ecosystems and species it sustains. The Government of India’s Initiatives like Namami Gange, Project Dolphin and WWF's Iconic Free-Flowing Rivers and River Dolphin Rivers, are helping to restore the river's flows and health for the benefit of people and nature.

© Federico Valido


#13 Río Gallegos

Río Gallegos is a 300km long river in the Argentinian province of Santa Cruz. Named in 1520 after one of the pilots of Ferdinand Magellan's expedition, Blasco Gallegos, the river flows from its source in the Andes mountains towards its estuary on the Atlantic Ocean, where the city of Río Gallegos now sits. The capital of Santa Cruz with around 80,000 inhabitants, it's the second-largest city on the Patagonian coast, with an economy based on livestock farming and extensive commercial and port activities. The Gallegos river boasts two important tributaries - the Chico and the Turbio - and its upper course runs through Argentina's most important coal basin. It is one of the rivers with the highest economic value in the region, thanks to the presence of trout, which is popular among fly-fishing tourists. However, trout were introduced in the region, and are now threatening native species. But the basin is still home to incredibly rich biodiversity, including the red fox and the unique Hooded grebe, which uses the estuary as one of its few wintering grounds. It also safeguards a great diversity of native plants, including a dazzling array of flowers, which can be seen on the front of many houses. Río Gallegos' flow of sediments accumulates in the basin's estuary, which sustains numerous salt lakes and marsh vegetation, forming a dynamic system that is crucial for people and nature. Depending on seasonal snow melt, the Río Gallegos is vulnerable to climate change. It also faces a number of other threats, but it's possible to tackle these before it's too late. Indeed, it is not only possible but essential since only a resilient and healthy river can continue to give life to its namesake city and all the people and wildlife that depend on it. 

© Brent Stirton / Getty Images


#12 Sepik

Stretching for over 1100km, the Sepik is Papua New Guinea's longest free-flowing river and one of the most pristine river systems in the Asia Pacific. The Sepik waters run through tropical rainforest and lowland mangroves, sustaining extraordinary biodiversity and over 400,000 people who depend almost entirely on these habitats for their livelihoods. The basin provides them with food, water, transport, and plants and animals that are the basis of the local economy - built on the sale of sago, fish, freshwater prawns, eels, turtles, and the eggs, skins, and meat of crocodiles. The River is the beating heart of diverse communities and cultures, with more than 300 languages spoken in an area the size of France. But as flagged by WWF's 10 Rivers at Risk report, plans to develop the largest mine in the country on one of its major tributaries threatens the future of the Sepik and its people and nature. The gigantic plan includes an open-pit copper mine, a massive tailings dam, and a hydropower dam to power the project. Little of the promised revenue would end up in the Sepik region, while local communities would bear the social and environmental costs. Toxic chemicals would poison the River and surrounding ecosystems, while the hydropower dam would impact the Sepik's natural flow. And there's a high risk of a disaster, as it's an area of high seismic activity and extreme rainfall. But the people of the Sepik River are fighting for their River. In an unprecedented move, chiefs representing 78,000 people joined forces in a campaign to Save The Sepik, publicly calling for the project to be stopped. 

© Wild Wonders of Europe / Dieter Damschen / WWF


#11 Elbe

The Elbe is the fourth-largest river basin in Central and Western Europe. It flows for over 1000km from its source in the Krkonoše (Giant) Mountains of the Czech Republic, crossing through Germany until it spills its waters into the North Sea. The river basin is home to about 25 million people and boasts world-famous cities, including Prague, Berlin, and Hamburg. The Elbe River Landscape is Germany's largest inland UNESCO biosphere reserve and one of the last near-natural river landscapes in Central Europe. Numerous plants and animals are dependent on the Elbe's waters, like the Elbe beaver, fire-bellied toad, and the European sea sturgeon, which is currently being reintroduced. But much of the Elbe has been regulated for navigation and dammed in the Bohemian stretch - the incision of the river bed due to the continued maintenance of the waterway is one of the key problems of the middle Elbe, affecting the river, its floodplains, and their water regime. Poor water quality is also an issue, although it has greatly improved over the last 30 years - in the early 1990s, the Elbe was in some stretches classified "ecologically dead". While the floodplain ecosystems depend on regular floods, the river is infamous for devastating extreme flood events (2002 and 2013), but it is also suffering more regularly from too little water (droughts). Climate change will likely increase the frequency of floods while also increasing the risk of droughts, with adverse impacts on several sectors, including water supply, agriculture, industry, navigation, and recreation. But this doesn't have to happen. WWF’s Nature-based Solutions include initiatives like the Lödderitz dike relocation to enhance the health and resilience of the river basin, including by restoring freshwater habitats by removing dams and making room for the river.

© Griffin Shanungu/WWF Zambia


#10 Zambezi

The Zambezi River is the largest in Southern Africa and the fourth largest river system in Africa. Rising in Zambia’s Kalene hills, it flows for over 3,500km towards the Indian Ocean. The eight countries it crosses are home to more than 30 ethnic groups, whose cultural roots are deeply intertwined with the seasonal life of the river. In Zambia, the Kuomboka people celebrate their seasonal movement as the flood waters expand and then recede. Around 40 million people rely on the river’s abundant ecosystem services, including clean water, fish stocks, fertile soils, and flood and erosion control. Tourism alone has a total annual direct value of US$515 million in the basin with people being lured to the river by its incredible biodiversity and natural wonders, particularly the Victoria Falls. The basin is also home to more than 35 protected areas, including part of the world’s largest Transfrontier Conservation Area (KAZA). These habitats safeguard a large number of species, including over 6000 plants, 700 birds, 165 freshwater fish, and 200 mammals from elephants to lechwe, hippos and lions. But the region’s growing population and economic development is driving ever-increasing demand for water, adding to pressures on water resources and ecosystems across the basin. Threats include alterations of natural flow regimes due to hydropower infrastructure; water pollution; unsustainable riverbank cultivation; deforestation of catchment areas and headwaters; invasive species; and overfishing. And climate change will worsen this scenario. But there’s hope to enhance the Zambezi’s health for the benefit of people and nature. Working with partners, WWF is playing an instrumental role in supporting KAZA as well as in developing and implementing the Upper Zambezi Project and the Blue Heart of Africa initiative

© Day's Edge Productions



Rising in the Rocky Mountains in the United States, this mighty river flows downstream, eventually forming a natural boundary between the US and Mexico. The Rio Grande, known as the Rio Bravo in Mexico, flows to the Gulf of Mexico, despite the many barriers it encounters along the way. It is the heart of the Chihuahuan Desert, one of the three most biodiverse deserts in the world. The Rio Grande/Bravo basin encompasses two global biodiversity hotspots, and it is a vital flyway for migrating birds and butterflies, and nearly half of all the fish species are endemic. It also provides freshwater to over 16 million people on both sides of the border, from indigenous peoples to ranchers and farmers - all depending on the river’s life-giving waters. Contributing billions of dollars to the economies of both countries, the river has been overallocated, overused, and dammed since the late 19th century, primarily due to irrigation for agriculture, followed by domestic use. The river basin health’s also faces growing threats, including climate change, pollution, and invasive species. Added to the complex and fragmented governance, the River nowadays dries up in many stretches – completely near El Paso in what is known as the “Forgotten Reach”- and it was declared one of the ten most water-stressed rivers globally by WRI in 2014. But there’s still hope for the Rio Grande. WWF projects support partners and stakeholders in identifying key conservation needs and solutions via scientific and technical expertise. Initiatives like those focused on improving corporate water stewardship can help mitigate impacts on the river and support restoration of critical flows and habitats.

© Weiyang Dou


#8 Yangtze

The Yangtze River is Asia's longest river and the world's third, flowing for more than 6300km from the Tanggula Mountains in Tibet towards the East China Sea. Its basin is one of the world's most biologically diverse ecoregions due to the climatic, geographical, and geomorphological diversity and complexity of river-lake relations. Known as the "Mother River" in China, the Yangtze is home to 459 million people, approximately one-third of China's total population. Cutting through 11 provinces, the river is central to China's past and future – providing water, food, and livelihoods for thousands of years. It has sustained much of the Chinese economy and social development – just in 2018, the GDP of the Yangtze River Economic Belt reached approximately 40% of the national GDP. The basin also safeguards incredible and ancient biodiversity like the Giant panda, Chinese sturgeon, and the world's only freshwater porpoise, the Yangtze finless porpoise. With over 400 species of fish swimming its waters, the basin has been featured as "the cradle of China's freshwater fishery" and "a treasure trove of fish genes". But the Yangtze is at risk - WWF's 2020 Yangtze Living Index report concluded that the overall health of the basin is declining fast and deteriorating as the river flows from source to sea. Driven by population growth, rapid industrial, agricultural, and fishery development, hydroelectricity development, and navigation, the river faces climate change, alterations to its flow, land-use change, pollution, overfishing, and invasive species. These pressures threaten water supplies and freshwater fisheries that feed millions. The Chinese government is quite aware - it established a 10-year fishing moratorium in January 2021. But as WWF's report shows, more can and should be done to save the Yangtze and all the benefits the "mother" river provides to humans & nature.

© Nicolas Axelrod / Ruom / WWF-Greater Mekong


#7 Mekong

One of the world’s great rivers, the Mekong flows nearly 5,000km from the Tibetan plateau to where its great delta meets the sea. Crossing through Laos, Thailand, Cambodia, and Viet Nam, the Lower Mekong supports the world’s most productive freshwater fisheries. Its fertile delta, nourished by the sediment carried downstream by the river’s natural cycles, is Viet Nam’s rice bowl, producing half of its total rice harvest. The Mekong basin is home to 70 million people who depend on a healthy, free-flowing river for water, irrigation, energy, transportation, and trade. Its waters also sustain thousands of species in one of the most biodiverse regions on Earth, including 89 Critically Endangered river dolphins and over 1000 fish species, including many of the world’s giant fish and the dazzling Siamese tiger perch. But all this life is under threat - hydropower dams and sand mining are stripping the famously muddy river of its sediment. The result: the Mekong delta is sinking and shrinking, putting people’s lands and livelihoods at risk. And Laos plans to build another four large hydropower dams across the main channel, which could slash the sediment supply to just 10% of its natural levels. Coupled with excessive groundwater abstraction and sea-level rise due to climate change, half of the Mekong delta could disappear under the waves by the end of the century. And the River basin also faces deforestation, industrial pollution, and overfishing. But another path is possible, as WWF’s 10 Rivers at Risk report enlightens - renewable alternatives, like solar and wind, are LowCx3 low carbon, low cost, and low conflict with rivers and communities. In 2020, the Cambodian government showed the way by imposing a 10-year moratorium on hydropower dams on Mekong’s mainstream, and encouraging investment in solar power. Keeping it free flowing is the best way to build resilience to climate change.

© Faouzi Maamouri


#6 Sebou

Flowing 500km from Morocco's Middle Atlas mountains to the Atlantic Ocean, the Sebou River is the largest North African river by volume. It is the main river of the Sebou basin, which is a water tower for Morocco. Although it represents only 6% of the country's land area, the basin is of crucial socio-economic importance – its 40,000 km2 is home to nearly 20% of the population. The livelihoods of 6.2 million depend on the basin, and its agricultural and industrial outcomes significantly contribute to the national economy. Morocco's most fertile region is located at Sebou rivers' mouth, being the country's most important agricultural region. The Sebou basin also has more than 10 large dams, one of which is the second largest dam in Africa. However, many of these infrastructure developments have negatively impacted the basin's remarkable ecosystems, which contain 39 important wetlands, 7 of which are Ramsar sites; 2 national parks; and 17 biological and ecological zones of interest. The basin also sustains many migratory birds and other rare and endangered endemic animal and plant species. But the Sebou and all the benefits it provides are threatened by: groundwater resources' overexploitation for agriculture; pollution from solid waste and industrial activities; hunting and poaching of birds and their eggs; and overexploitation of forests around lakes and overgrazing. Currently, only 25% of the basin drainage is covered with natural vegetation. Aiming to maintain and restore the quantity and quality of the Sebou's surface waters (lakes, streams, and wetlands) and recharge the aquifer, WWF launched the Sebou Water Fund in 2018. Water Funds are a sustainable financing mechanism based on payment for Ecosystem Services, where funds provided by the water beneficiaries are invested in improved watershed management.

© Jaime Rojo / WWF-US


#5 Paraguay

The Paraguay River is a major waterway in south-central South America. It meanders 2,600 km from its source in Brazil through Bolivia and Paraguay before joining the Paraná River and flowing into Argentina. The river is responsible for balancing an entire ecosystem, as it feeds the largest tropical wetland on the planet – the Pantanal. One of the most important regions in the world in terms of services provided to humanity, Pantanal’s annual cycles of floods and droughts dictate the lives of thousands of species. It sustains more than 10 million people living in the region and provides water to cities downstream. It also supports more than 4,000 species, including the threatened jaguar, the world’s largest concentration of caimans, and 23 migratory fish species critical to local fisheries. All this depends on the connectivity and natural flow of the Paraguay River, but plans for more hydropower projects threaten Pantanal’s lifeblood. And there are already over 50 plants in the basin. Most of them are small, but together they can have a big impact - the Brazilian Pantanal has lost 74% of its surface water over the past 30 years, partly due to dams infrastructure. Fishers reported that fish have disappeared as migratory routes have been cut. The region also faces agriculture expansion, unsustainable ranching, and engineering work for navigation. Unsurprisingly, wildfires have ravaged the drying Pantanal recently. WWF’s actions to protect the region include the Jornada da Água (Water’s Journey), the Pact in defense of the headwaters of Pantanal, and the Iconic Free Flowing Rivers initiative. But an additional 80 hydropower dams are still planned, closing off 11,000-12,000km of free-flowing river channels. But there is another path. Alternative renewables, like solar and wind, are LowCx3 - low carbon, low cost, and low conflict with rivers and communities - and could produce enough energy for the region while creating more jobs without destroying the rivers that give Pantanal life.

© WWF-Russia-E.Agryzkov


#4 Amu Darya

The Amu Darya is a major river in Central Asia, connecting Afghanistan, Tajikistan, Uzbekistan, and Turkmenistan. Formed by the merger of the Vakhsh and Panj rivers in the Tigrovaya Balka Nature Reserve, it flows down 2500km into the Aral Sea. People's livelihoods in the river basin (about 55 million in 2011) and the Aral Sea Basin depend on its waters, mainly allocated to agriculture – the region's key economic sector- hydropower generation, and industrial, domestic drinking needs. The river valley is composed of riparian forests known as Tugai – a floodplain jungle specific to Central Asia and a keystone aquatic ecosystem that used to be home to the extinct Caspian tiger. Together with the Syr Darya River, these floodplains harbour a remarkable amount of biomass and rich biodiversity, including more than 250 species of birds. But the Amu Darya is at risk. System of dams and canals for irrigation prevent natural floods and cause degradation of still existing riparian ecosystems. In the 20th century, agricultural fields replaced about 90% of the Tugai, and unsustainable irrigation used up to 95% of the river's water flow. Due to evaporation when the river flows through the Kyzylkum desert, the basin faces significant losses before reaching the Aral Sea. The Amu Darya is also under pressure from climate change - glaciers in the Himalayan region feed the river, where water flows are being reduced. WWF conservation efforts include the "Integrated river basin management and nature protection in the Tigrovaja Balka reserve" and the Bukhara deer conservation and restoration projects. WWF Russia also focuses on the critically endangered sturgeons in the Amu Darya and Tumnin rivers, together with our Sturgeon Initiative. In the long term, all the riparian countries must take action and use water efficiently, starting with developing the Amu Darya River Basin plan.

© WWF / Folke Wulf


#3 Kavango

The Kavango River (a.k.a Cubango in Angola and Okavango in Botswana) originates in Angola and flows for around 1200km to the south, where it joins the Cuito River. Together, they enter the flat basin of the Kalahari Desert in Botswana and spill into the Okavango Delta – the world’s largest inland delta. Regarded as one of Africa’s Seven Natural Wonders, this delta creates a dynamic wilderness unlike anything else on Earth. Its beautiful floodplains are rich in biodiversity and home to some of the most endangered large mammals in the world. A thriving nature-based tourism industry is key to the local and national economy, while freshwater fishes are crucial to local communities' food security and livelihoods. But the river that feeds the delta is at risk. The largest threat is the proposed hydropower dam at Mucundi in Angola, which would fragment the river and alter the natural flow of water, sediments, and nutrients that keep the delta healthy. The Kavango is already under pressure from the growing demand for water for agriculture and the impacts of climate change - a disruption of this free-flowing river would further undermine its resilience, and the delta would eventually succumb. But there are alternatives. Investments in renewables such as solar and wind promise a faster path to power generation and are LowCx3 energy sources - low carbon, low cost, and low conflict with rivers and communities. Sustainable development of the region is possible, but only by safeguarding the river that flows through its heart. The local inhabitants of Angola call Kavango's source waters "Fonte da Vida"- the Source of Life. By protecting these countries’ life source, we can power a better longer-term future for their people and nature. 

© W. Retter



The Isel is the last free-flowing glacial river in the European Alps. Its clear, cold waters flow almost 60km through gorges, gravel banks, and floodplain forests of Austria's East Tyrol region. Still in a near-natural state, it harbours many threatened species like the German tamarisk (Myricaria germanica) and draws tourists that power the local economy. But the future of the Isel is at risk. For years, developers have been trying to build new hydropower on the river and its tributaries, although over 1,000 hydropower plants are already in operation across Tyrol. And authorities appear unwilling to stop them, as six plants are planned, in the approval process, or under construction in the basin. These dams will alter the natural flow of water and sediment, threatening these free-flowing rivers' benefits. WWF's 10 Rivers at Risk report shows that these plants will produce negligible amounts of power at far from little cost, plus the high cost to nature and people – like the €30 million power plant which will provide electricity to only 1.100 local people, besides getting the municipality into debt to finance the project located at a site prone to landslides, floods, and avalanches. WWF and 43 groups, including prominent scientific voices, are calling for an end to all new hydropower development in the Isel and across the region. Renewable alternatives (e.g., solar and wind) offer a better path as they are LowCx3 - low carbon, low cost, and low conflict with rivers and communities. This way, authorities can protect one of Europe's last natural river systems to benefit nature and future generations. 

© Zig Koch / WWF-Brazil


#1 Tapajós

Brazil's Tapajós River is one of the largest, free-flowing tributaries of the Amazon, flowing for over 2000km through habitats ranging from the cerrado savanna to rainforests. It is also one of the few fast-flowing, clearwater rivers in the region, boasting extraordinarily rich biodiversity like the endangered river dolphin Tucuxi. Indigenous people and local communities also depend on Tapajós' natural flows and flood pulses – it supports fisheries, fertilizes fields, and provides clean water, sustaining livelihoods and cultures. But all these benefits are under threat, especially from hydropower dams. Regarded as one of the best remaining hydropower generation opportunities, there are 42 dams planned in the Tapajós River. WWF's 10 Rivers at Risk report  states that the region will suffer disastrous environmental and social consequences if these dams are built, such as flooding around 2,000km2 of Indigenous territories by reservoirs. It would also promote deforestation, which generates greenhouse gas emissions - hindering efforts to tackle the climate crisis. Thanks to the indigenous Munduruku tribe, who've fought years of court battles to protect their lands, the largest proposed dam at São Luiz do Tapajós was cancelled in 2016. But there are still many on the drawing board. Instead of pursuing 20th-century infrastructure solutions, Brazil should reassess the best energy mix by factoring in the plunging price of renewable alternatives, like solar and wind, and the full impact of these dams on communities, wildlife, and the climate. The hydropower plans on the Tapajós should be replaced by renewable energy that is LowCx3: low carbon, low cost, and low conflict with communities and rivers. 

© Zig Koch / WWF-Brazil

© Zig Koch / WWF-Brazil