CONSTRUCTION of the Stamford Diversion Canal, dug to lower flood risk in the Orchard Road shopping belt, will enter its second phase next month.
National water agency PUB said yesterday that work for the second phase, between Grange Road and River Valley Road, will be done by Tiong Seng Contractors at a cost of $107.7 million.
The new 2km-long underground canal is meant to ease the load on the existing Stamford Canal, to help prevent a repeat of the flooding incidents in Orchard Road during heavy rains in 2010 and 2011.
To be ready by 2017, it will run from Tanglin to Kim Seng, connecting the upstream section of Stamford Canal with the Singapore River.
Together with an underground detention tank being built near the Singapore Botanic Gardens, it will divert rainwater from almost 40 per cent of the Stamford catchment area.
In Phase Two, a tunnelling method - not the conventional cut and cover method - will be used for a 1km stretch of Grange Road, to avoid the need for traffic diversions or removal of trees, said PUB's director of catchment and waterways, Mr Ridzuan Ismail.
"In terms of impact to residents and motorists, this (will be) minimised significantly," he said.
PUB has been collecting feedback from residents along Grange Road, he added.
Devices are being installed to monitor the impact of vibrations and noise from the work on surrounding buildings.
Barriers and enclosures will be set up to protect residents from excessive noise.
The PUB said it will also closely monitor the tunnelling works to guard against formation of sinkholes.
"We are very aware of the risks involved in tunnelling...
we will monitor the progress of the work and take necessary precautions," said Mr Hew Kit San, senior principal engineer at PUB.
Other Phase Two works in Hoot Kiam Road, Irwell Bank Road and River Valley Road are expected to cause traffic diversions in the middle of next year.
Work on Phase 1 of the diversion canal started in Tanglin and Kim Seng in July and will cost $50.6 million. Traffic diversions due to this may be put in place in January.
Meanwhile, PUB said it has drainage improvement projects under way or scheduled at 139 locations this year, with 58 already completed. It has scheduled new projects at 17 locations next year, including in Sunset Way, Mountbatten, Marina South, Bukit Timah, and Sungei Pandan Kechil.
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