El Niño rains: Counties along Kenya’s rivers facing rising flood risk
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El Niño rains: Counties along Kenya’s rivers facing rising flood risk
Kenya is bracing for a potentially wetter-than-normal October–December season as a strengthening El Niño raises the risk of flooding along major rivers and in low-lying communities.
The Kenya Meteorological Service has warned of an 81 per cent chance of a strong El Niño during the October–December period, with a 97 per cent probability that its effects could continue into early 2027.
The government has identified 18 counties as high-risk areas, with flooding, landslides, disease outbreaks and infrastructure damage among the expected hazards.
For communities living along Kenya’s major river systems, the biggest concern is not simply the amount of rain expected but what happens when heavy rainfall upstream sends large volumes of water downstream.
Tana River threat
Tana River County remains one of the areas to watch as rainfall increases.
The Tana River cuts through a large section of the county before reaching the Indian Ocean, leaving communities around Garsen and Hola vulnerable when river levels rise.
The county experienced severe flooding during the 2023 El Niño season, when homes and farms were submerged. Additional heavy rainfall could again threaten homes, roads, crops and livestock.
The wider Tana basin also connects rainfall in upstream areas to communities downstream. Heavy rains far from the coast can therefore create flooding risks even when rainfall in Tana River County itself is limited.
Other coastal counties, including Kilifi, Lamu, Mombasa and Kwale, have also been identified among areas requiring heightened preparedness.
The Athi River
The Athi River is another major flood pathway to watch as El Niño rains intensify. Its catchment covers Nairobi, Kiambu, Machakos and Kitui, before the river continues towards the Coast where it becomes the Galana River.
Heavy rainfall in Nairobi and the upper Athi catchment can cause river levels to rise rapidly, threatening settlements, roads, bridges and farms downstream.
Nairobi is particularly exposed because several waterways drain into the Athi system. Flooding in the capital can therefore have consequences beyond the city, with increased water flows moving downstream towards Machakos and Kitui.
Machakos and Kitui also face flash-flood risks, particularly in low-lying areas and communities located close to river channels and seasonal streams.
Further downstream, the river becomes the Galana and flows through parts of Kilifi County, creating another potential flood pathway towards the Coast.
Lake Basin risks
The Lake Victoria Basin is another major area of concern, particularly around the Nyando River.
The river flows through parts of Kericho and Nandi before reaching Kisumu, with its lower basin around the Nyando plains repeatedly exposed to flooding.
Kisumu, Busia, Siaya, Homa Bay and Migori are among counties identified as vulnerable under El Niño preparedness plans.
Kisumu also faces an urban flood threat. Intense rainfall, swollen rivers and drainage pressure could disrupt transport and affect settlements in flood-prone areas.
The Nzoia River is another river to monitor across western Kenya. Its catchment covers parts of Nandi, Uasin Gishu, Kakamega and Bungoma before the river reaches Lake Victoria through Busia. Heavy rainfall upstream can increase water levels downstream, threatening farms, homes and roads.
Northern rivers
The Ewaso Ng’iro River is also expected to come under scrutiny as the rains intensify. Its basin covers areas including Laikipia, Samburu and Isiolo before extending towards northern and eastern Kenya.
Heavy rainfall in the upper catchment can increase river flows downstream, posing risks to settlements, livestock and agricultural land.
The Kerio River presents another concern across Elgeyo-Marakwet, Baringo and Turkana. Intense rainfall in the highlands can cause rapid rises in water levels and trigger flash floods in lower areas.
In West Pokot and Turkana, communities along the Turkwel River could also face flooding if heavy rains cause sudden increases in river flows.
Mara And Thwake
Narok County will also need to monitor the Mara River, which originates in the Kenyan highlands before flowing towards Tanzania.
Heavy rainfall in the river’s upper catchment can raise water levels and affect communities, farms and roads downstream. The river is also an important source of water for agriculture and livestock.
The Thwake River presents another risk in eastern Kenya, cutting across parts of Machakos, Makueni and Kitui.
These counties have previously experienced flash floods during periods of intense rainfall. While additional rain could replenish water sources and improve pasture, sudden downpours could destroy crops, damage roads and isolate communities.
The Athi River remains another major flood pathway. Nairobi forms part of its wider drainage system, meaning intense rainfall in the capital can contribute to dangerous river flows and flash flooding downstream.
Author
William Muthama
William Muthama is a digital journalist with a focus on entertainment, human interest, and current affairs. Share stories: [email protected]/ [email protected]
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Reporting originally appeared via K24 Digital. Read the full source for additional context.