The focus of ReNOKA is to support Lesotho in managing the transboundary Orange-Senqu River Basin collectively and more sustainably for the shared prosperity of all who live in it.

The Orange-Senqu River Basin – From source to sea

The Orange-Senqu River Basin has a vast footprint, covering nearly 1 million square kilometres and traversing four Southern African countries. From its mountain source in Lesotho, the Orange-Senqu River fans out like a network of life-giving arteries, supporting some of the most fragile and endemic biomes, including the Nama Karoo, Namaqua and the Richtersveld in South Africa, the Southern Kalahari of Botswana and the Namib Desert of Namibia.

There are a total of five wetlands of international importance registered with Ramsar, only one of which is located in Lesotho. Wetlands are typically biodiversity hotspots that support a large variety of birds and animals and sometimes host unique breeding sites for birds.

The Orange River is the most recognisable feature of the basin, changing its name from Senqu to Gariep depending on its location. It is highly engineered, with multiple dams and tunnels to move the water to where it is needed.

The Orange-Senqu River is such an important natural resource for Southern Africa that it directly impacts 15 million people who rely on it for water, farming and hydro power.

What is a basin?

A river basin is not just the rivers and dams that impound them, but all of the geographical features and landscapes surrounding those rivers, from where that water is collected. This is why a river basin is also known as a drainage basin or a catchment. River basins can be flat like the Okavango or very steep like the source of the Ganges in the Himalayas.

Since rivers do not recognise political borders, they represent shared resources that should be collectively and peacefully managed between neighbouring states. Many great world rivers like the Amazon, Nile, Zambezi, Yangtze and the Mekong all traverse political borders and therefore are transboundary in nature.

Managing the transboundary Orange-Senqu River Basin collectively

As the most important river in Southern Africa, shared between four countries, protecting the source of the Orange-Senqu River in the Mountain Kingdom of Lesotho is critical.



The water tower of Southern Africa

The Mountain Kingdom of Lesotho is the source of the Orange-Senqu River. From the cold blue peaks of Thabana Ntlenyana, the highest mountain in Southern Africa standing over 3 000 metres above sea level, where the Senqu River begins its journey; Lesotho is the water tower of Southern Africa.

The Maloti Mountains that dominate Lesotho’s landscape are part of the Drakensberg escarpment, both forming part of the Maloti-Drakensberg Transfrontier Conservation Area. This ancient mountain range can trace its birth back 180 million years when volcanic eruptions built the mountains from layers of hard basalt rock.

Lesotho’s terrain is so old that dinosaur footprints from some of the largest carnivores have been found there, alluding to a time when vegetation was abundant enough to support the therapod’s prey.

Millenia later when the Hunter-Gatherer Khoi-San occupied the sandstone caves close to the Mohokare River, rock art depicting great herds of eland, elephant and even crocodiles thriving in the area, prove that water and food supported a diversity of wildlife just 12 000 years ago.

From the diaries of European missionaries that came to “Basutoland” over two centuries ago, observations of vast acacia forests covering the slopes prove that deforestation is a recent phenomenon and human activity continues to alter the landscape.

Lesotho continues to enjoy high rainfall and snow with up to 1 500mm per year, supporting the unique Afro-Montane biome to survive with endemic flora and fauna such as the spiral aloe (Aloe polyphylla) and bearded vulture (Gypaetus barbatus).

The water mythologies of the traditional Basotho live on. Water and the animals that live in it are inextricably linked to life and the circle of life and death.

Lesotho contributes 40% of the total volume of the Orange-Senqu River Basin from a land base of just 3%

As droughts and floods become increasingly frequent as a result of climate change variability, ReNOKA aims to restore critical sub-catchments in Lesotho to support the most vulnerable communities and build a more climate-resilient Orange-Senqu River Basin.

Not only must Lesotho protect its water resources for its own domestic water, food and energy security, but also to meet its transboundary agreements with riparian states. In 1986, Lesotho and South Africa signed a treaty outlining the bulk water transfer agreement that underpins the Lesotho Highlands Water Project.

View ReNOKA’s StratEcon study for more on the importance of water to the interconnected economies of South Africa and Lesotho.

Lesotho’s sub-catchments

Lesotho has hundreds of rivers and streams that begin in the Maloti Mountains. The most recognisable of these are Senqu River that goes on to become the Orange as it flows west to South Africa. All the major rivers in Lesotho are tributaries of the Senqu River. These include the Mohokare that exits Lesotho at Bethulie to become the Caledon River flowing into the Gariep Dam, and the Malibamat’so River that feeds the Katse Dam. The Mokhotlong River joins the Senqu and the Senqunyane (meaning Little Orange) feeds the Mohale Dam.

Planning for the Integrated Catchment Management Action has divided Lesotho into 74 sub-catchments or smaller drainage basins, that will become the management units for ReNOKA. These sub-catchments fall within six larger management catchments, namely the Upper, Middle, and Lower Mohokare catchments, the Upper and Lower Senqu catchments, and the Makhaleng catchment.

ReNOKA has identified six sub-catchments that will be prioritised and rehabilitated during the Action:

Related sub-catchments

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    South Africa
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    South Africa hosts 64% of the Orange-Senqu River Basin but is heavily dependent on water from Lesotho for its industrial economy and heavily populated province of Gauteng.

    The Vaal River, which flows north-east out of the Orange River has been impounded several times since 1923 and the dam wall has been raised twice to increase its storage capacity.

    The city of Johannesburg remains the biggest user of the Orange-Senqu River Basin. Founded in 1886 after the discovery of gold, Johannesburg or eGoli is the only mega city in the world not built on a river. As a result, it is heavily dependent on water imports.

    The population of Johannesburg is highly contested as the official figure of 8 million people often excludes informal settlements populated with economic migrants. Some population figures include Soweto – bringing the population to 12 million. In 2011, residents of Johannesburg used 349 litres of water per day, almost double the usage of any other African city.

    The Lesotho Highlands Water Project (LHWP)

    LHWP is a highly engineered transfer scheme which moves water from the Lesotho Highlands to South Africa’s industrial hub of Gauteng, via the Ash River fallout. The entire project was conceived in four phases, envisioning 5 storage dams and 200 kilometres of transfer tunnels.

    The first phase, completed in 2004, resulted in the 185-metre-high Katse Dam and the 72-megawatt Muela Power Station, providing electricity to Maseru. The second phase included the Mohale Dam and another 32-kilometre transfer tunnel connecting Katse and Mohale.

    The Lesotho Highlands Water Project was awarded the ‘Most outstanding engineering achievement of the century’ by the South African Institute of Civil Engineering.

    While the dams generate revenue and energy security for Lesotho, however limited, they have also displaced thousands of households and reduced grazing and farm land by 2 000 – 5 000 hectares.

    Phase two is currently underway. It will result in the Polihali Dam, due for completion in 2026.

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    Botswana is a land of paradoxes with regards to water. It is host to the largest inland delta in the world, draining the Kavango River from Angola to form the Okavango Delta, which triples in size, from 6 000 to 15 000 square kilometres, during the floods. But in the south, Botswana is dominated by the Kalahari Desert and the Makgadikgadi Pans – the remnants of inland sea. After just a few inches of rain, the pans explode with algal blooms that attract large flocks of lesser flamingos, while supporting the largest zebra migration south of the Serengeti.

    Botswana, historically a British protectorate, was a deeply rural country depending on cattle farming for its economy before the discovery of diamonds in 1964. Despite tourism and mining revenue eclipsing beef exports as a GDP earner for the country, Botswana continues to farm beef mostly because of the country's pastoral culture and the historic Lomé Agreement that offered favourable subsidies to Botswana for its beef exports to Europe.

    Botswana is a member of three important transboundary river basins, including the Okavango, the Limpopo and the Orange-Senqu. But as a result of heavy industries such as mining and energy, water demands outstrip supply and the country may run out of water by 2025 unless new water is brought into the system.

    A plan to transfer water from Lesotho to Botswana is underway. The Lesotho-Botswana Water Transfer (L-BWT) Scheme will supply water to Botswana, Lesotho and South Africa from the Makhaleng Dam – part of the Lesotho Lowlands Water Supply Scheme – through a transfer tunnel extending for 700 km from Lesotho to Botswana.

    Botswana's Molopo River begins in Botswana but flows south west to join the Orange River at Mahikeng.

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    The lower Orange River is the last section of the Orange-Senqu River Basin, where it flows through the Northern Cape Province of South Africa and onto the Orange River Estuary at Oranjemund, before draining into the Atlantic Ocean.

    Namibia contributes just 7.9% of the Orange-Senqu River Basin.

    As a result of the many dams impounding the Orange River upstream, including the Gariep and the Vanderkloof Dam, the flows have been significantly reduced over time.

    The Orange River Mouth was recognized by Ramsar as a wetland of International importance in 1995, when its role in supporting the fish stocks on the Atlantic Coast, providing a habitat for breeding birds like flamingos and protecting the river from salt water intrusion became apparent.

    The Orange River Commission (ORASECOM) and the Benguela Current Commission (BCC) in Namibia are a good example of how regional cooperation can support integrated catchment management of the river. These two river commissions now ensure that the estuary is flooded every year by regulated releases.

    A further dam is proposed at Vioolsdrift that will help regulate floods for the lower Orange River and construction will begin in 2024.

    The Orange River in the Northern Cape province of South Africa nourishes the Namaqualand and Richtersveld biomes, each hosting unique plant and animal species that survive in harsh arid conditions. The quiver tree, for example, is a slow growing succulent with suede-like bark, named by the Khoi San who used the skin to hold their hunting arrows. The tree has since become an indicator species to track climate change as it offers a record of over 700 years in some examples.

    The Orange River splinters to form Namibia's Fish River, best known as the largest river canyon in Africa, which extends for 160 kilometres and is 550 metres deep at some points. The Fish River Canyon relies on significant rain events to flood and is mostly dry, but its size and depth does offer a glimpse into the past, when Namibia was certainly not a desert.