The
announcement made on Thursday has raised hopes of millions of residents in the
water-scarce Lower Eastern region who are expected to benefit from improved water
supply, irrigation and electricity.
The
80.5-metre-high dam, being constructed at the confluence of the Thwake and Athi
rivers along the Makueni-Kitui border, was 94.2 per cent complete as of
Thursday.
The
latest funding follows an additional Sh10.6 billion financing package signed by
the AfDB to bridge a funding shortfall that had slowed construction.
In
June 2026, the lender announced approval of €68.4 million (Sh10 billion) in
additional financing for the dam’s first phase, alongside €15 million (Sh2.2
billion) in counterpart funding from the Kenyan government.
Speaking
during a site visit, AfDB director for Water and Sanitation, Mtchera Chirwa, said the bank was also discussing financing for the downstream infrastructure
needed to translate the dam’s completion into tangible economic benefits.
“As
a Bank, we will ensure the project reaches completion and achieves the
benefits. This means provision of water for food security; implementation of
the irrigation component, water supply and sanitation for residents and
hydropower for energy generation,” Chirwa said.
The
dam has a planned storage capacity of 688 million cubic metres, making it one
of Kenya’s largest water reservoirs.
It
covers approximately 9,217 acres, with a catchment area of about 10,276 square
kilometres, according to the programme’s official documentation.
Completing
the dam wall is only the first step towards delivering its full economic
potential.
The
wider programme is structured around four phases, including dam construction,
hydropower generation, water supply and sanitation, and irrigation development.
The downstream investments are expected to deliver up to 150,000 cubic metres of treated water daily to about 1.3 million people in Makueni and Kitui, as well as Konza Technopolis in neighbouring Machakos County
The project also envisages a 20-megawatt hydropower plant and an irrigation scheme designed to support up to 40,000 hectares, or approximately 100,000 acres, of farmland.
Water
Secretary Samuel Alima said construction had resumed after the funding gap was
addressed, with the remaining works focusing on the concrete face slab and a
bridge linking the two counties across the dam.
“The
contractor has resumed with the concrete face already having some panels, while
others are also under preparation. They have also started doing the bridge,”
Alima said.
The
Ministry is targeting water impoundment by the end of January 2027, followed by
commissioning in April, although the timeline will depend on the completion of
outstanding works.
The
project’s first phase has an estimated cost of Sh42.4 billion, according to
official project records, with the AfDB and the Kenyan government sharing the
financing burden.
The original design estimated the cost of the entire four-phase programme at 487 million units of account, an AfDB accounting unit whose value fluctuates with exchange rates.
Beyond addressing water scarcity, the dam is expected to help regulate flows along the Athi River, mitigating floods and supporting water availability during dry periods.
The
irrigation component could also reduce farmers’ dependence on unreliable
rainfall, strengthening food production in the semi-arid region.
Alima said parallel efforts to clean the Nairobi River system, including sewage collection, wastewater treatment and river widening, were underway to improve water quality.
