Cover Founder of the Great Spine of Africa series of expeditions and Rolex Perpetual Planet Initiative Partner Steve Boyes, pictured at sunset in Linyanti, Botswana
Founder of the Great Spine of Africa series of expeditions and Rolex Perpetual Planet Initiative Partner Steve Boyes, pictured at sunset in Linyanti, Botswana
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In Partnership With
Supported by the Rolex Perpetual Planet Initiative, conservationist and explorer Steve Boyes is reshaping our understanding of Africa’s vast water security by mapping and protecting the continent’s major river basins—a lifeline for more than 500 million people
Throughout Africa, where wilderness stretches far beyond the horizon and rivers trace the stories of nations, water is everything. Yet, as pressures from climate change and development intensify, Africa’s water security hangs in a delicate balance. South African conservationist and explorer Steve Boyes is determined to change that narrative.
Through his organisation, The Wilderness Project, Boyes is spearheading the Great Spine of Africa expeditions, a monumental effort supported by the Rolex Perpetual Planet Initiative. This mission, which began in mid‐2022 and aims to complete 200 expeditions, seeks to better understand and protect Africa’s critical waterways. The core work involves exploring and safeguarding the continent’s water towers—elevated regions such as the Angolan Highlands that act as essential natural reservoirs by storing and supplying fresh water downstream, often sustaining life even in dry season. Simultaneously, the team works to establish ecological and hydrological river baselines—the reference points that record the undisturbed flow patterns, water quality and biodiversity of a river system, providing a critical benchmark for measuring future change.
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Above Aerial view of the winding waterways of the Cuando River Basin in Botswana, which flows into the Zambezi
Aerial view of the winding waterways of the Cuando River Basin in Botswana, which flows into the Zambezi
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Heart of Resilience
The necessity of this work is evident when considering the Angolan Highlands water tower. Despite its relative obscurity, Boyes’s research reveals it to be a crucial source of resilience, releasing an estimated 423km3 of water annually—equivalent to nearly 10 times the yearly water usage of the entire state of California—and providing water security for millions of people.
This immense output is sustained by vast peatlands beneath its dense canopy that act like giant, natural sponges, holding up to 25 times their dry weight in water, ensuring a steady flow to the great rivers even during dry season. More than just water sources, these peatlands are essential carbon sinks, storing huge amounts of densely compacted carbon in their waterlogged soil.
To map and safeguard this vital system, the latest expedition focused on a key outflow: the Kasai River. This major tributary of the mighty Congo River winds through the Congo Basin, a remote equatorial rainforest so inaccessible that large sections have remained virtually uncharted. As Boyes explains, “our work is important for helping governments make informed decisions around water use, urban developments and infrastructure projects”.
Above Steve Boyes pictured at sunset in Linyanti, Botswana
Steve Boyes pictured at sunset in Linyanti, Botswana
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The discoveries from the Kasai expedition have been profound. Early on, the team found evidence suggesting that the river’s true source may have been misidentified for decades. Data gathered from the Munhango River, also originating in the Angolan Highlands, showed that it contributes nearly twice as much water as the previously credited source. This revelation means that the headwaters of the Kasai River may lie only about 20km from that of the Zambezi River, whose source is also in the Angolan Highlands water tower. The area of the Zambezi’s source is known locally as the Lisima Lya Mwono landscape.
Yet, charting this landscape is far from easy. For Boyes and his team, every kilometre travelled was hard‐earned. The expedition began on land, navigating through regions still scarred by Angola’s civil war, where unexploded landmines made every step precarious. “It’s almost a relief when you get on the river,” says Boyes, who shares that they had to travel in an armour‐plated truck for the first part of the journey. “But on the water, every day involves going into the unknown. No one navigates these rivers or knows what’s in them.”
Above Boyes making final adjustments to an acoustic doppler current profiler, a machine that measures the speed and direction of water flowing through a set point in a river
Boyes making final adjustments to an acoustic doppler current profiler, a machine that measures the speed and direction of water flowing through a set point in a river
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The Great Unknown
In the first 12 days, the team covered just 42km, as the upper reaches of the Kasai were so densely choked with vegetation that progress came only through relentless paddling and clearing by hand. Later, as the river widened, new challenges emerged in the form of treacherous rapids, lurking crocodiles and curious hippos. Yet, amid the hardship came some rare privileges, as the isolation meant that much of the local wildlife had never encountered humans. “It’s like being in Madagascar or New Zealand, where animals are not programmed to be scared of people,” says Boyes.
“It was extraordinary.” By meticulously recording these encounters, the team compiled one of the most comprehensive environmental baselines ever undertaken on an African river, and has discovered species new to science in the Angolan Highlands. Using aerial imagery, hydrological measurements, and environmental DNA sampling, it built a record that future generations of scientists can use to track ecological change and help governments make the right decisions.
Above Boyes and his team discovered that the Munhango River (pictured) might be the main source of the Kasai River, making the Angolan Highlands the primary source for one of the major tributaries of the Congo River
Boyes and his team discovered that the Munhango River (pictured) might be the main source of the Kasai River, making the Angolan Highlands the primary source for one of the major tributaries of the Congo River
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After years of intensive research, Boyes travelled to the 2025 Ramsar Convention in Zimbabwe, where he presented his findings on the Lisima Lya Mwono landscape, aiming to have it recognised as a Wetland of International Importance. This designation, known as a Ramsar Site, would ensure the area is protected by national and international conservation frameworks focusing on sustainable use and land management.
Having surveyed more than 30,000km of Africa’s wild rivers, Boyes is cautiously optimistic. Now, as he seeks to protect 1.2 million sq km of African watersheds, plateaus and rivers by 2035, the expeditions are expanding into the continent’s other major waterways, including the Congo and Nile Basins. The project has completed 20 expeditions this year, with plans to reach 25 next year, with Rolex’s support.
The Perpetual Planet Initiative represents Rolex’s long term commitment to support individuals and organisations that use science to understand and devise solutions to today’s environmental challenges. “It’s really inspiring, interacting with an organisation where you talk about big ideas, and it seems to want you to think even bigger than those ideas,” says Boyes. “The support from Rolex has changed my life.”
By championing pioneers such as Boyes, Rolex is helping to ensure that the vital resilience found in Africa’s hidden water towers is not just discovered, but also actively protected for generations to come.
Above The team approaching powerful rapids on the Kasai River
The team approaching powerful rapids on the Kasai River
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Under the Same Sky
Tatler believes that true luxury lies in preservation—in safeguarding the beauty of our world for generations to come. Guided by culture, community and creativity, Under the Same Sky shares the stories of those working tirelessly to preserve the health of our planet. These intrepid explorers, organisations and scientists and entrepreneurs are supported by the Rolex Perpetual Planet Initiative, and we are excited to share their innovations and ideas that will hopefully help sustain life on Earth. This is our shared commitment to ensure that the habitability of our planet endures—timeless, vital and everlasting.
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Annabel Tan is the Editor of Watches and Jewellery at Tatler Singapore, where she covers all things luxury timepieces and fine jewellery across both print and digital platforms. She is also the Editor of Tatler GMT Singapore, a role that deepens her fascination with the ever-evolving world of watchmaking. Outside of work, she’s usually on the hunt for her next favourite watch that she can’t afford, planning her next beach getaway, or catching up on the latest Formula 1 race.
