Flooding in Nairobi’s informal settlements is not only a climate hazard; it is also a structural failure manifested through land-use, infrastructure, governance and equity challenges. This issue brief examines how the March–April–May 2024 floods exposed long-standing vulnerabilities in Nairobi’s urban development model, particularly in informal settlements located in low-lying floodplains and riparian corridors.

Drawing on literature and policy review, geospatial analysis, hydrodynamic flood modelling and exploratory household surveys with 98 households in Kibera, Mukuru Viwandani and Mathare, the brief identifies the environmental, socioeconomic and institutional factors that amplify flood risk. These include extreme rainfall, Nairobi’s west–east slope and river systems, soil compaction, encroachment on riparian zones and wetlands, poor drainage infrastructure, solid waste blockages, loss of green spaces, weak enforcement of land-use laws and fragmented disaster-risk governance.

The brief shows that the 2024 floods caused more than physical destruction. They disrupted health systems, sanitation, roads, bridges, schools, places of worship, public transport, food systems and livelihoods. The impacts fell hardest on women, children, persons with disabilities and low-income households, many of whom faced displacement, livelihood losses, exclusion from relief systems, increased exposure to violence and difficulty accessing safe shelters and services.

The paper recommends a shift from reactive disaster response toward proactive, inclusive and rights-based urban resilience. Key priorities include flood-resilient land-use planning, structured and humane resettlement for households in highest-risk zones, citywide adoption of green-grey infrastructure and nature-based solutions, advanced early warning systems, community-led disaster risk reduction structures, stronger institutional coordination and dedicated financing mechanisms such as FLLoCA and an Urban Resilience Fund.

Key Findings

  1. Nairobi’s flood risk is shaped by the interaction of hazard, exposure and vulnerability: extreme rainfall combines with settlements in floodplains, weak infrastructure and limited adaptive capacity.
  2. The MAM 2024 floods brought 400–660 mm of rainfall- 200mm above the seasonal average, displaced over 20,000 families and caused major damage to roads, bridges, homes and community infrastructure.
  3. Informal settlements are disproportionately exposed because many are located along the Nairobi, Ngong and Mathare river corridors, in low-lying floodplains, environmental fragile zones, and areas with limited drainage.
  4. Flood impacts are worsened by degraded wetlands and riparian buffers, expanding impervious surfaces, deforestation, soil compaction, blocked drains and poor solid waste management.
  5. The 2024 floods had major public health impacts, including increased waterborne disease risks linked to damaged sanitation infrastructure, stagnant water and contaminated water sources.
  6. Flooding disrupted livelihoods, public transport, schools, places of worship, informal businesses and food systems, deepening socioeconomic vulnerability.
  7. Women, children, older persons and persons with disabilities experienced disproportionate impacts, including barriers to evacuation, limited access to relief, heightened safety risks and psychological distress.
  8. Existing policy frameworks are relatively strong, but weak enforcement, fragmented mandates and limited inter-agency coordination continue to undermine flood-risk management.
  9. Nairobi’s disaster-risk financing remains too reactive, with greater investment needed in preparedness, resilient infrastructure, nature-based solutions and community-led resilience.
  10. Long-term resilience requires integrated action: risk-informed land use, green-grey infrastructure, early warning systems, community participation, rights-based resettlement and dedicated financing.

Executive Summary

Nairobi’s March–April–May (MAM) 2024 floods exposed how extreme rainfall can become a humanitarian, infrastructural and ecological crisis when rapid urbanization, floodplain encroachment, poor enforcement and weak resilience systems intersect. The season brought 400–660 millimetres of rainfall, displaced 20,968 families, caused at least 11 deaths and damaged roads and bridges, with informal settlements such as Mathare, Mukuru and Kibera among the hardest hit.

Drawing on literature review, geospatial analysis, hydrodynamic flood modelling and household surveys, this issue brief examines the environmental, socioeconomic and governance drivers that amplify flood risk in Nairobi. These include the city’s west–east slope, river systems, compacted soils, encroachment on riparian corridors, degraded wetlands, inadequate drainage, solid waste blockages, weak land-use enforcement and fragmented institutional coordination. The brief also documents the often-underreported impacts of flooding on health, livelihoods, education, transport, sanitation, ecosystems, gender and social cohesion, with disproportionate impacts on women, children, persons with disabilities and low-income households.

It argues that Nairobi must move beyond reactive disaster response toward proactive, inclusive and rights-based resilience. Key priorities include flood-resilient land-use planning, humane resettlement for households in highest-risk zones through Resettlement Action Plans, restoration of riparian buffers and wetlands, green-grey infrastructure, nature-based solutions, advanced early warning systems, stronger community participation, coordinated governance and dedicated financing mechanisms such as FLLoCA and an Urban Resilience Fund.