Post-construction, the Thika Superhighway has been plagued with floods in seasons when the volume of rain has been greater than before. One factor that has contributed to this issue is the poor collection of garbage which finds itself in the drainage systems. In order to mitigate the impact of these floods, Minex Microtunneling was contracted to build flood control tunnels.
Minex constructed the tunnel alongside a bridge: the lowest section of the road which is a flood control zone. The two tunnels have a total length of 148 meters and an internal diameter of 1,200 mm. These tunnels have a flow capacity of 1.8 cubic meters per second. This tunnel will be effective in allowing water to flow through, limiting the likelihood of an overflow onto the road.