The 480m long diversion
tunnel was constructed by blasting
through solid granite using the controlled
drilling and blasting method. This
was done at the start of the construction
to divert the upstream stretch of
the Sungai Selangor River before the
construction of the main dam. The
tunnel is 7m diameter and of horseshoe
shape.
The long-term use of the diversion
tunnel is to house the twin 2200mm
diameter discharge pipes coming
out of the draw-off tower. The water
drawn from the dam via the draw-off
tower flows through these twin discharge
pipes for downstream release into
the Sungai Selangor River.
