and cement grout curtain during
construction are high.
The earthfill materials of
8.5 million m3 required for the
project is large. Shortage of
construction materials from the
project site will lead to import of
construction materials. Besides
higher construction cost, risk to
villagers and impact on traffic at
Bkt Mertajam will be high due to
the large number of construction
vehicles passing through.
MANAGING CONSTRUCTION
RISKS
During the course of
c on s t ru c t ion t here were
conditions which deviated from
original tender designs. The
major issues encountered were:●●
Impact of commercial
quarry operation on dam
construction
●●
Risk of leakage at left
abutment of new dam
due to rock mining at
quarry
●●
Impact of construction
activities on safety of
existing dam
●●
Potential shor tage
of earthfill and filter
materials
●●
Risk of Interruption to
raw water supply from
existing dam.
Figure 5: A View of Draw-off Tower Upstream of Draw-off Tunnel
Figure 6: Valve House Downstream of Draw-off Tunnel
Impact of Commercial
Quarry Operation
After construction of the new
dam commenced in 2012
ground movement s were
detected at the dam site due
to rock blasting activities at
the Weng Lee Quarry adjacent
the left abutment of dam (see
Figure 8). There was a serious
concern about damage to the
Figure 7: Raising Of Existing Dam
9