Thwake Multipurpose Water Development Project
Thwake multipurpose water development is a priority project in the Government of Kenya’s Vision 2030 strategy. It is the largest water conservation and hydropower project ever to be undertaken by the government of Kenya. The works will combine a new dam reservoir and hydropower facility with enhanced water supply and irrigation that will impact 1.3 million people.

Currently under construction, SMEC is leading the design and engineering of the dam, spillway, and powerhouse. SMEC is also undertaking investigations and developing designs for two new water treatment facilities and sanitation infrastructure for the projects later phases.


Integrated design and management


As part of the dam design, SMEC has delivered advanced hydraulic modelling to test and optimize flow rates across the 422km distribution network. The team also developed a miniature physical model of the site area to clearly articulate the interfacing components of the dam’s infrastructure.


Sedimentation of the dam was a major problem which was overcome using sediment modelling. Based on SMEC’s recommendations, a multi-agency government committee has been established to spearhead catchment protection and prevent buildup of sediment. This includes upgrading sewerage infrastructure in Nairobi City to control pollution to Athi River.


Late in December 2021, engineers successfully managed to divert the Athi river into the dam’s two mega tunnels, marking a significant milestone in the project’s implementation.

mega cubic m
water storage capacity
of irrigated land
of electricity to the national grid


Talk to one of our specialists about our role on the Thwake Dam Project.