Expert: Nairobi's flood deaths trace back to lost green spaces, not rainfall
Nairobi
By
David Njaaga
| Mar 18, 2026
Lost green spaces and blocked drainage leave the city exposed, contributing to deaths in Nairobi’s March floods. [File,Standard]
For decades, Nairobi surrendered spaces designed to protect the city from floods. On March 6, 66 people paid with their lives, a soil scientist now charges.
Prof. Isaiah Wakindiki, a soil physicist and expert in hydrological systems, argues that the disaster exposed not a weather crisis but a generations-long failure to protect Nairobi's natural flood buffers.
His case is grounded in the science of infiltration zones, the green spaces where rain soaks into the ground rather than rushing across concrete and tarmac into homes.
In healthy soil, between 50 and 100 millimetres of rain per hour can be absorbed before flooding begins.
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On March 6, Nairobi received 160 millimetres in a single day. Much of the city had already lost the capacity to absorb even half that.
"We have permitted development that destroys soil infiltration capacity, neglects drainage systems and allows clogged culverts and channels to remain choked with sediment and litter. We have designed our own disasters and then blamed the weather," noted Wakindiki.
The floods that struck overnight on March 6 into 7 were among the deadliest in the city's recent history. The death toll rose to 66 in nine days, with Nairobi accounting for 33 of those fatalities and thousands of families still displaced as the rains continued.
Among the dead were 50 men, eight women and eight children, most of whom drowned or were electrocuted as floodwaters swept through homes, roads and low-lying areas.
A second wave of heavy rain struck the city on March 15, barely a week later.
The scale of the disaster has forced a reckoning about which parts of Nairobi are structurally vulnerable.
The Interior Ministry identified 37 flood-prone neighbourhoods through a mapping exercise conducted under the Nairobi Rivers Regeneration Programme.
The areas span the city from Mathare, Korogocho and Lucky Summer in the north to Kibera, South C and Mukuru Kwa Reuben in the south, and from Kawangware and Kangemi in the west to Dandora, Kariobangi and Kayole in the east.
Many of the flagged neighbourhoods are densely populated informal settlements where riverbanks and residential plots are, in practice, indistinguishable.
Wakindiki says that list is not an accident of geography. It is the consequence of decades of choices.
City Park is the starkest example. Established in 1921 and formally declared a public park in 1925, the park was conceived as one of Nairobi's original rainwater buffers.
It has since lost approximately 20 hectares to private development through squatting and illegal alienation beginning in the 1980s.
Karura Forest, a 1,041-hectare urban reserve north of the city, was similarly hollowed out before community-led restoration took hold in 2009, when politically connected individuals had illegally acquired large sections for housing development.
Portions of Uhuru Gardens are now paved and host a national monument complex.
Kenya's 1948 Nairobi Master Plan, designed for a city of 250,000 people, originally set aside 28 per cent of the city's land for public open space, precisely to manage stormwater.
That allocation has been steadily eroded as Nairobi's population swelled past four million, with each encroachment shrinking the city's capacity to absorb rain. Urban planners note the master plan's public space provisions carry no binding enforcement mechanism under current law, leaving green spaces exposed to political and commercial pressure.
"The lives we lost in floods did not die from rain. They died from poor choices. These choices can be unmade," noted Wakindiki.
He called for a three-part response: restoring soil function in urban areas, upgrading drainage infrastructure based on soil properties and enforcing development regulations to protect remaining infiltration zones.