• Governor says emergency interventions are helping reduce flood risks in vulnerable neighbourhoods, with comprehensive rehabilitation of the dam planned after the rainy season.

Nairobi Governor Sakaja Johnson says ongoing spillway and embankment strengthening works at Nairobi Dam are helping reduce the risk of flooding in downstream neighbourhoods as the county intensifies preparations for the anticipated El Niño rains.

Speaking during an inspection of the works at the dam in Lang’ata, Sakaja said the interventions were aimed at protecting residents, businesses and infrastructure in areas vulnerable to flooding when water levels rise.

The dam overflowed during the March 2026 rains, raising concerns about the safety of communities downstream, including residents of Lang’ata, Madaraka, South C, South B and areas along Lang’ata and Mombasa roads.

“The dam, situated in an elevated area in Lang’ata, had posed a danger to people downstream, including residents in high-rise buildings and neighbourhoods such as Madaraka, South C, South B, as well as areas along Lang’ata and Mombasa roads,” Sakaja said.

He says teams had established a spillway channel to direct excess water towards the Ngong River, easing pressure on the dam and helping to minimise the impact of heavy rainfall.

According to the Governor, the intervention has included dredging, deepening sections of the watercourse, reclaiming riparian areas and removing walls in some South C estates to facilitate water flow through designated channels.

Sakaja said the works had helped reduce the potential impact of flooding from the dam, although further interventions would be necessary to address the underlying challenges.

“This is just an initial intervention. We have a plan underway to rehabilitate the entire dam, which will be undertaken after the El Niño rains,” he said.

The planned rehabilitation is expected to provide a more comprehensive response to longstanding concerns surrounding the dam’s condition, water management and environmental degradation.

Built in 1955 as part of the Ngong River flood attenuation system, Nairobi Dam was designed to help regulate floodwaters and protect downstream areas, including Nairobi West, South C and the Industrial Area.

Over the years, however, pollution, sediment accumulation and maintenance challenges have raised concerns about its capacity to manage rising water volumes during periods of heavy rainfall.

The ongoing spillway works form part of Nairobi County’s wider El Niño preparedness programme, which includes drainage clearance, river desilting, waterway rehabilitation and the removal of waste obstructing stormwater channels.

The county has also intensified clearance and rehabilitation works along the Nairobi, Mathare and Ngong rivers, with the Governor previously reporting that the interventions had reached 80 per cent completion.

These measures are intended to improve stormwater flow through the city’s drainage network and reduce the risk of flooding in residential and commercial areas.

Residents have also been urged to avoid dumping waste in drainage channels, keep their surroundings clean and support efforts to protect waterways.