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When it rains, it floods: The problem with Mombasa
When rain hits Mombasa, flooding often follows. Like clockwork, this week's downpour once again led to floods, exposing a deeper, more troubling reality for the city's residents.
According to the Kenya Red Cross Society, at least 103 households in Mombasa have were affected this time, with nine families displaced across Jomvu, Kisauni, Changamwe and Likoni sub-counties following days of intense rainfall.
The situation was further compounded by the inaccessibility of key health facilities, including Jomvu Model Hospital and Tudor Sub-County Health Facility, which were cut off by rising floodwaters.
This time, the floods were unusually intense. But beyond the immediate destruction, experts say the crisis reflects long-standing failures in urban planning, infrastructure development and governance.
For instance, at Inuka Police Station, officers were forced to climb onto desks as floodwater flowed into their offices. According to Mombasa County Executive for Transport and Infrastructure Dan Manyala, the incident is emblematic of historical planning mistakes.
The police station, he explained, sits in a swampy area in Ujamaa, similar to locations such as Maweni and Ziwa la Ng’ombe dispensaries. Over time, unregulated development around these areas has worsened the situation.
“Whenever it rains, all the water from surrounding areas drains to the lowest point, which is the police station,” said Mr Manyala.
He advised the Interior Ministry to work with the county government to construct vertical drainage systems into and out of the station as a long-term solution.
Vulnerable to flooding
Children play in stagnant rainwater at Ziwa la Ng'ombe area after heavy downpour in Mombasa on April 22, 2026.
Beyond Ujamaa, several parts of Mombasa remain highly vulnerable to flooding. In Dimbwini, Likoni Sub-county, a seasonal river frequently bursts its banks during heavy rains, sending water into homes and displacing families. Residents are often forced to move to higher ground when rainfall intensifies.
The problem is particularly structural in Old Town Mombasa, a heritage site recognised by Unesco. According to Mr Manyala, its drainage system, constructed centuries ago by the Portuguese, is now outdated and overwhelmed.
“The challenge with Old Town is that it is protected, so any intervention must preserve its heritage. But we are exploring ways to regenerate the area and improve drainage,” he said.
Other flood-prone areas include Ziwa la Ng’ombe, Kisumu Ndogo, Mwembe Legeza, Kalahari, Runyu and Junda. Both informal settlements and upmarket neighbourhoods such as Nyali, Bamburi, Kisauni and Kizingo are increasingly affected.
For urban planning experts, the floods are far from surprising. Dancan Odhiambo, a Coast-based architect and regional chair of the Architectural Association of Kenya, said the crisis is largely due to ignored planning regulations. Chief among these is the requirement that 20 to 50 percent of any development be left as permeable green space to absorb rainwater.
“Instead, many developments have maximised concrete coverage, leaving little room for water to soak into the ground. The result is rapid surface runoff that overwhelms drainage systems and pushes floodwaters into homes and streets,” he said.
Although the 2024 Building Code outlines clear stormwater management measures, including on-site drainage and sustainable urban systems, implementation remains weak.
“The issue is not the absence of policy, but the failure to enforce what already exists,” he added.
The situation is compounded by the lack of a comprehensive drainage master plan. Without a coordinated system to map drainage networks, guide expansion and ensure routine maintenance such as desilting, the city remains exposed to recurring floods.
Bad waste management
Solid waste management has further worsened the crisis. Blocked drains, clogged with improperly disposed garbage, significantly reduce drainage capacity during heavy rains.
“The waste comes from households. When it is dumped carelessly, it ends up in the drains and chokes the already limited infrastructure,” said Mr Manyala.
Illegal sewer connections have also contributed, with some households diverting wastewater into stormwater systems, further straining the network and posing public health risks.
Role of geography
Geography plays its part too. Mombasa’s highest point, Nguu Tatu, stands just 107 metres above sea level, leaving much of the island city flat and naturally prone to flooding.
Despite the challenges, Mr Manyala insists progress has been made.
He points to improved drainage maintenance, faster clearance of floodwaters and targeted infrastructure upgrades across the island. At the Kenya Railways Roundabout in Mombasa, for instance, upgrading the drainage system from a 600mm to a 900mm culvert has significantly improved water flow, allowing floodwaters to clear within minutes.
Previously flood-prone areas such as Marikiti, Tudor and Lasco have also benefited from interventions, including new drainage channels and land reclamation projects.
In Nyali, collaboration with the Kenya Urban Roads Authority has helped resolve persistent flooding near major commercial centres.
Still, major gaps remain, particularly in rapidly developing areas such as Utange, where land initially designated for agriculture was subdivided and developed without proper planning.
However, environmental expert Benson Wemali notes that the county still relies on outdated drainage infrastructure.
“The current drainage system is old and no longer functional. With increased population and construction, many drainage lines have been blocked or built over,” he said.
Mr Wemali called for a complete overhaul of the drainage system, including the construction of new drainage lines tailored to current population needs.
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