Nairobi's flood crisis driven by poor planning, not just heavy rain

Nairobi's persistent flooding is being fueled by decades of poor urban planning, environmental degradation and weak governance, not just heavy rainfall, a new report by the World Resources Institute (WRI) has revealed.

The report, dubbed Flooding in Nairobi's Informal Settlements: Advancing Equitable and Resilient Solutions, warns that unless the city addresses the underlying causes of flooding, thousands of residents will continue to face displacement, disease and loss of livelihoods whenever heavy rains occur.

The report identifies several factors behind the city's worsening flood crisis, including unplanned development in flood-prone areas, inadequate drainage infrastructure, destruction of wetlands and green spaces, weak enforcement of land-use regulations, fragmented governance and limited investment in climate resilience. It also cites Nairobi's volcanic soils, which absorb water poorly, as a major contributor to surface flooding.

The findings come after a series of devastating flood events that exposed the city's vulnerability to climate shocks.

According to the report, nearly 21,000 families were displaced during the 2024 floods, more than 90 kilometers of roads and nine bridges were damaged, and over 147,000 cases of waterborne diseases were recorded. In March this year, flooding claimed 37 lives in less than three weeks, highlighting the growing human cost of extreme weather.

The report was based on flood modelling and mapping, as well as interviews with 98 households in Kibera, Mathare and Mukuru Viwandani. Residents reported losing homes, businesses and personal belongings while raising concerns over inadequate early warning systems, poor preparedness and limited involvement in flood risk management.

It also found that women, children, older persons and people living with disabilities are   disproportionately affected because they face greater challenges accessing information, evacuation support and recovery assistance.

Speaking during the launch, Wanjira Mathai, Managing Director for Africa and Global Partnerships at WRI, said Nairobi must shift from responding to disasters to investing in long-term resilience.

“The evidence from Nairobi's floods is clear: climate resilience cannot be separated from housing and basic services. Safer communities require risk-informed planning, reliable drainage and sanitation, healthy rivers and wetlands, and residents who are partners in designing and stewarding solutions,” she said.

Mathai said the initiative brings together scientific evidence, government leadership and local communities to support investments that protect both people and the environment.

To support that transition, WRI and the Nairobi Rivers Commission launched the Nairobi Rivers Nature-based Solutions Strategic Framework, a roadmap aimed at restoring river ecosystems while reducing flood risks through nature-based interventions.

The framework outlines measures such as restoring wetlands, rehabilitating river corridors and expanding green infrastructure to tackle flooding while addressing biodiversity loss, urban heat and air pollution.

Nairobi Rivers Commission Chairperson Margaret Wanjiru said the city needs coordinated action rather than isolated interventions to restore its rivers and reduce future disasters.

“Nairobi's rivers cannot be restored through isolated projects or short-term interventions. This framework provides an evidence-based roadmap to coordinate action, direct investment to priority areas and restore river corridors that reduce flood risk, improve public health and support livelihoods,” she said.

The launch also saw WRI sign Memoranda of Understanding with the Nairobi City County Government and the Kenya Forestry Research Institute to strengthen collaboration in climate research, restoration, nature-based solutions, capacity building and resource mobilization.

The report maintained that while climate change is increasing the intensity of rainfall, the devastating impacts seen in Nairobi are largely driven by poor urban development and weak planning systems.

It called for stronger enforcement of land-use regulations, investment in drainage infrastructure, restoration of wetlands and greater community participation in flood management.

With extreme weather events expected to become more frequent, WRI says Nairobi must move beyond emergency response and adopt long-term strategies that make the city more resilient while protecting lives, livelihoods and critical infrastructure.