A Decade of Water Investment Strengthens Nairobi’s Water Security

Nairobi Kenya 

In Summary

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Ten years of sustained investment in the Upper Tana watershed have significantly strengthened water security for Nairobi, demonstrating how environmental restoration can serve as critical infrastructure for fast-growing cities.

The initiative, led by the Upper Tana-Nairobi Water Fund Trust, has focused on protecting water sources upstream through nature-based solutions that restore landscapes, improve soil management and stabilise river systems. The effort has reduced sediment flowing into rivers, improved water quality and increased the reliability of water supplies for millions of residents in Kenya’s capital.

The watershed, part of the wider Tana River Basin, supplies about 95 percent of the water consumed by Nairobi’s estimated 4.8 million residents. It also supports approximately five million additional people living within the basin, making its health critical to both urban and rural communities.

According to the Water Fund Trust, conservation and restoration efforts upstream have delivered tangible benefits to the city’s water system. Sedimentation levels in rivers have fallen by about 41 percent, significantly reducing the cost of water treatment for utilities while improving water quality for consumers. The programme has also added more than 27 million litres of water per day during the dry season, helping stabilise supply during periods of reduced rainfall.

Speaking during the tenth-anniversary commemoration in Nairobi, Festus K. Ng’eno, Principal Secretary in the State Department for Environment and Climate Change, described the initiative as one of Kenya’s most successful public-private partnerships for watershed restoration.

He noted that growing pressures on the country’s water towers—driven by population growth, land-use change and climate impacts—require sustained investment. According to him, the water fund model offers clear returns by lowering water treatment costs, improving water quality and strengthening long-term ecosystem resilience.

The programme’s impact extends far beyond the city’s water supply. Across the Upper Tana watershed, more than 470,000 acres of farms, forests and nearly 980 kilometres of rivers are now under improved sustainable management. Over 260,000 farmers have adopted climate-resilient land-management practices designed to reduce soil erosion, conserve water and improve agricultural productivity.

A key intervention has been the installation of more than 17,000 water pans that collectively harvest over two billion litres of rainwater annually. These small reservoirs help farmers store water during the rainy season and maintain productivity during dry periods, reducing pressure on rivers while strengthening rural resilience to climate variability.

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Tree-planting efforts have also played a central role in restoring degraded landscapes. Over the past decade, nearly 5.9 million trees have been planted across the watershed, helping stabilise soils, improve water retention and restore ecological balance in areas that previously experienced severe degradation. Adding to the pledges is the office of the First lady whereby through  representation today pledged provision of 2 million tree seedlings marking a milestone in kenyas afforestation efforts. 

The conservation programme has also generated socio-economic benefits for communities living in the watershed. More than 22,000 green jobs have been created through restoration activities and sustainable value chains. In addition, farmers have collectively earned an estimated 118 million US dollars in additional income through fruit, nut and livestock-feed production linked to sustainable land-use practices.

Eddy Njoroge, Trustee President of the Water Fund Trust, said the programme demonstrates the value of addressing water security challenges at their source rather than relying solely on downstream treatment infrastructure.

He noted that investing upstream—particularly in partnerships with farmers and communities—has proven to be a cost-effective way of safeguarding urban water supplies while supporting rural livelihoods.

The initiative was originally launched in 2015 by The Nature Conservancy as Africa’s first water-fund model designed to protect water at its source. Over time it has evolved into an independent public charitable trust that coordinates investment from government agencies, private companies, utilities and development partners.

Water-fund approaches are increasingly gaining global attention as cities face growing pressure on water resources. The model was first developed in Quito in 2000 and has since expanded to more than 30 cities worldwide, including 16 across Africa.

Kenya has emerged as one of the leading adopters of the approach, with similar initiatives established in areas such as the Eldoret-Iten watershed and the River Yala-Nyando basin. These programmes aim to replicate the success seen in Upper Tana by combining scientific planning, community engagement and sustainable financing.

As the anniversary event concluded, partners called for greater investment from both the private sector and development partners to expand the model to other cities and water towers across the country. With climate change increasing the frequency of droughts and extreme weather, safeguarding water sources is becoming an urgent priority for Kenya’s long-term urban resilience.

Experts say the lessons from Upper Tana highlight a critical reality: protecting ecosystems upstream can provide cities with one of the most effective and affordable strategies for ensuring reliable water supplies in a changing climate. 

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