Infrastructure

Thwake Dam Project Delayed Again Amid Setbacks

The government has so far spent over Sh36 billion on the project.

Updated on

May 9, 2025

AfDB officials visit the Thwake dam site on March 4, 2025. (Photo: Courtesy)

Completion of phase one of Thwake Dam in Ukambani, originally set for February 2024, has been pushed to October 30, 2025—extending a pattern of repeated delays.

According to Water and Irrigation Cabinet Secretary Eric Muuga, the delay has been caused by a combination of issues, including the Russia-Ukraine war and the Covid-19 pandemic.

Appearing before the Senate plenary recently, Muuga explained that the global crisis had led to a shortage of explosives in the country and a reduced labour force.

“I would like to inform the Senate that due to the war in Ukraine, access to explosives needed for blasting the rock bed foundation is limited, slowing construction,” he stated.

Muuga also added that the weak foundation of the riverbed required excessive excavation, with embankment settlement taking six to nine months.

“Without proper settlement, the concrete cracks, which results in a weak dam,” Muuga said.

In June 2024, then Water Cabinet Secretary Zachariah Njeru reported that civil works and related activities were 93.6% complete, slightly ahead of the 92.8% timeline.

“The dam is expected to be completed by early December after construction commenced on March 27, 2018. The Ministry expects the dam to be filled with water over approximately two normal rainy seasons,” Njeru said during a tour of the project.

The CS oversaw the completion of the embankment fill at the meeting point of the Thwake and Athi Rivers, located at the border of Makueni and Kitui counties.

“The filling of the embankment will now pave the way for the settlement of the dam and implementation of the bridge over the embankment, concrete face, installation of the gates and other downstream activities,” he said.

The project, whose contractual completion date was February 6, 2024, was expected to be finalised in December last year after the contractor, China Gezhouba Group Company (CGGC), applied for more time to complete phase one.

The contractor requested extra time to complete the project, citing various technical reasons, including the El Niño rains.

Over Sh36 billion has been spent on constructing the dam’s embankment.

On December 31, 2021, CGGC successfully diverted a section of the Athi River into two giant tunnels to facilitate on-site excavation.

The company said the tunnels, 700 metres long with diameters of 12 metres, would be used as substitute waterways where the Athi River would change course before later joining the original path to the Indian Ocean.

This would allow the construction of a rock-fill dam wall—87 metres high—and the installation of main and minor spillways for excess water flow.

“We have decided to alter the river course flow so that major excavation works can be allowed when the river base is dry,” CGGC general manager Frank Keeh said.

Thwake Dam, the second-largest in the country after the Masinga Dam on the border of Embu, Kitui, and Machakos counties, is jointly funded by the African Development Bank (AfDB) and the Government of Kenya.

It will be implemented in four phases.

688 million cubic metres

Phase one, which is underway, involves the construction of an 87 m-high dam wall with a 688 million cubic metres storage capacity, and preliminary works for the implementation of the subsequent three phases.

The second phase of the Thwake Multi-Purpose Dam project will involve the installation of a hydropower generation plant, while phase three comprises the installation of water supply, sanitation, and wastewater infrastructure.

The fourth phase will involve the development of the irrigation component.

The government will invest Sh59.95 billion through budgetary allocations, with AfDB contributing Sh21.94 billion.

Thwake Dam will provide water for domestic, irrigation, hydropower, and industrial activities, mainly serving Makueni County and parts of Kitui County.