Nairobi Dam Spillway Opened Ahead of El Niño Rains

By the 254.ke Newsroom.

The Nairobi Rivers Commission has opened the emergency spillway at Nairobi Dam, with water now flowing through it as the October to December short rains begin, according to a statement issued on Monday, October 19, 2026. Residents living downstream have been told to keep away from river channels and flowing water and to follow official advisories.

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Commission CEO Joseph Muracia described the move as part of “planned interventions” to improve the dam’s readiness for heavy rainfall, as reported by Capital FM. The work is being done with other government agencies and the Nairobi City County Government.

What did the Nairobi Rivers Commission say?

What happened: the emergency spillway at Nairobi Dam was opened and water is flowing through it.
Why: to prepare the dam for heavy rainfall, as part of a wider Nairobi Dam regeneration programme.
Who is involved: the Nairobi Rivers Commission, relevant government agencies and the Nairobi City County Government.
Advice to residents: stay calm, remain vigilant, keep away from flowing water and river channels, and rely on official communication for water levels and safety updates.

The commission cautioned that water levels and flow could change depending on rainfall. The statement did not give a flow rate or a list of affected neighbourhoods.

Why is the spillway being opened now?

The Kenya Meteorological Service says the short rains season has begun. Its seven-day forecast, valid from Tuesday, October 20 to Monday, October 26, expects rain in parts of 46 counties, including Nairobi, Kiambu, Machakos and Kajiado, according to The Star. Forecasters have linked the season to a strengthening El Niño. Pulse Kenya reported that the World Meteorological Organization projects Pacific Niño 3.4 anomalies of +3.7°C for October to December, above the 2015-2016 record of +2.6°C.

Opening a spillway before the heaviest rain is a way of controlling water movement early rather than leaving it to happen during a storm. The commission has not said how long the spillway will stay open.

What should people living downstream do?

Stay away from rivers, drainage channels and low-lying riverbanks, especially during and after rain.
Do not cross flowing water on foot or in a vehicle.
Check official channels for water-level updates rather than relying on social media forwards.
Report blocked drains or rising water to the county. Our Nairobi flood hotspots guide lists the 227 mapped areas and where to report.

What else is Nairobi doing to prepare?

The county earlier moved to waive building repair permits ahead of El Niño. For a regional breakdown of timing, see when the El Niño rains start, by region, and for the counties most at risk, Kenya’s 18 high-risk flood counties. Forecast bulletins are published by the Kenya Meteorological Department.

FAQ

Is Nairobi Dam going to overflow?

The commission has not said the dam is at risk of failure. It says the spillway was opened as a planned measure to prepare for heavy rain.

Which areas are downstream of Nairobi Dam?

The statement as reported did not list specific neighbourhoods. Residents near rivers and channels fed by the dam should follow official advisories.

When will the heaviest rains arrive?

The Met service says the season has started, with heavier rain expected at the Coast and in the northeast. A KMS official in Nyeri told KNA that much of the rain is expected from the second and third weeks of the season, running to January.

Reporting is based on Capital FM, The Star and Pulse Kenya as of October 23, 2026. We will update this report if the commission issues further advisories.

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