The emergency spillway at Nairobi Dam has been opened, with water now flowing through the structure as authorities prepare for the expected El Niño rains.
The Nairobi Rivers Commission (NRC) confirmed the development on Monday, October 19, saying the spillway was part of ongoing efforts to manage rising water volumes and reduce the risk of flooding around the dam.
In a statement, NRC Chief Executive Officer Brigadier (Rtd) Joseph Muracia said the commission was working with government agencies and Nairobi City County to prepare for the anticipated heavy rains.
The spillway is designed to provide an outlet for excess water, helping to control the dam's water levels and reduce the risk of water spilling over its embankment.
Construction and flood mitigation repairs began on October 13 as part of a joint effort involving the commission, the county government and other government agencies.
The work is also linked to the wider Nairobi Dam regeneration programme, which seeks to prepare the facility for comprehensive restoration.
Residents living downstream have been urged to remain alert now that water is flowing through the spillway. Those in Nyayo Highrise, Dam Estate, parts of Kibera, Nairobi West and Madaraka have been advised to keep away from river channels and avoid approaching flowing water.
Other areas further downstream, including South C, South B, the Industrial Area, Mukuru and the area around Strathmore University and T-Mall, could also face flooding risks depending on rainfall and river conditions.
The commission has cautioned residents against assuming that opening the spillway has removed the danger of flooding. Water levels may change as rainfall increases, making it important for people in affected areas to follow safety instructions from the relevant authorities.
The latest measures follow warnings issued during the March long rains, when the Water Resources Authority raised concerns about rising water levels that threatened the dam's embankment.
At the time, residents in several neighbourhoods, including Kibera, Nyayo Highrise, Dam Estate, Lang'ata, Nairobi West and Madaraka, were given 14 days to move to higher ground ahead of planned action targeting structures on riparian land and along river channels.
The preparations come as Kenya enters the October-to-December rainy season. The Kenya Meteorological Department has forecast a high likelihood of strong El Niño conditions extending into early 2027, according to the information provided by the authorities.
November is expected to receive particularly heavy rainfall, with some storms potentially bringing more than 50mm of rain within 24 hours.
Recent reports of storm damage in Kisumu and heavy rainfall in Nyeri have also highlighted the risks that intense rains can pose to homes, roads and other infrastructure.
Authorities are now urging residents in flood-prone areas to take the warnings seriously as preparations continue. While the spillway is expected to help manage excess water at Nairobi Dam, its effectiveness in reducing downstream flooding will depend partly on rainfall levels and conditions along the river basin.
