<TABLE id=msgUN border=0 cellSpacing=3 cellPadding=0 width="100%"><TBODY><TR><TD id=msgUNsubj vAlign=top>
Coffeeshop Chit Chat - PUB: Barrage 'won't affect Orchard Rd'</TD><TD id=msgunetc noWrap align=right> </TD></TR></TBODY></TABLE><TABLE class=msgtable cellSpacing=0 cellPadding=0 width="96%"><TBODY><TR><TD class=msg vAlign=top><TABLE border=0 cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR class=msghead><TD class=msgbfr1 width="1%"> </TD><TD><TABLE border=0 cellSpacing=0 cellPadding=0><TBODY><TR class=msghead vAlign=top><TD class=msgF width="1%" noWrap align=right>From: </TD><TD class=msgFname width="68%" noWrap>kojakbt_89 <NOBR></NOBR> </TD><TD class=msgDate width="30%" noWrap align=right>1:08 am </TD></TR><TR class=msghead><TD class=msgT height=20 width="1%" noWrap align=right>To: </TD><TD class=msgTname width="68%" noWrap>ALL <NOBR></NOBR></TD><TD class=msgNum noWrap align=right> (1 of 5) </TD></TR></TBODY></TABLE></TD></TR><TR><TD class=msgleft rowSpan=4 width="1%"> </TD><TD class=wintiny noWrap align=right>36434.1 </TD></TR><TR><TD height=8></TD></TR><TR><TD class=msgtxt>Jul 21, 2010
Barrage 'won't affect Orchard Rd'
<!-- by line --><!-- end by line -->
<!-- end left side bar -->
The PUB said the Marina Barrage can prevent flooding only in low-lying areas and not in Orchard Road, which is far upstream and about 4m to 5m above sea level. -- PHOTO: PUB
<!-- story content : start -->
THE Marina Barrage can prevent flooding only in low-lying areas, and not in places such as Orchard Road, which lies above sea level.
So suggestions that it was somehow responsible for the flooding along Singapore's premier shopping street recently are off-base, national water agency PUB said yesterday.
Mr Tan Nguan Sen, PUB's director for catchment and waterways, said: 'Orchard Road is very far upstream and 4m or 5m above sea level, and it cannot be affected by the barrage, which prevents the Marina area from being flooded by keeping out the high tide.'
In response to media queries, he explained that the barrage did not affect the way rain drained into the canals, which are built to slope down towards the Marina Reservoir.
Before the barrier was built, low-lying areas such as Little India were more flood-prone when a high tide coincided with heavy rain.
Mr Tan said the barrage did what it was supposed to do very well last Saturday, when Singapore was lashed by a storm and widespread flash flooding occurred over the central and eastern parts of the island. Without the barrage, things would have been much worse, he said, as the storm occurred just as a high tide was receding.
Explaining how the barrage works, Mr Tan said the level of the Marina Reservoir is kept between that of the high and low tides.
The barrage's nine gates and its seven pumps are used only when the level of the reservoir rises to the higher end of this range.
The gates are used when the sea level is lower than that of the reservoir, and the pumps, when the sea level is higher than the reservoir's.
Last Saturday morning, the reservoir was at its usual level, PUB said yesterday, but the sea level was much higher as the tide was high.
The storm began at 4.30am that day, and about 20 minutes later, the National Environment Agency issued a heavy rain warning. These warnings are issued if rainfall is expected to exceed 50mm over at least 20 per cent of Singapore, up to a duration of two hours.
About 10 minutes after the warning was received, PUB staff began to partially open eight of the barrage's nine flood gates - the last one was undergoing maintenance at the time - as the reservoir level was rising. The process took about 15 minutes.
Thirty minutes later, the gates were opened fully as the tide had receded, and the seawater level fell to below that in the reservoir.
Mr Tan said that although the volume of water coming into the reservoir from the various canals is not measured, the fact that the water drained quickly from the reservoir meant it was not overwhelmed by the deluge.
</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
Barrage 'won't affect Orchard Rd'
<!-- by line --><!-- end by line -->
<!-- end left side bar -->
<!-- story content : start -->
THE Marina Barrage can prevent flooding only in low-lying areas, and not in places such as Orchard Road, which lies above sea level.
So suggestions that it was somehow responsible for the flooding along Singapore's premier shopping street recently are off-base, national water agency PUB said yesterday.
Mr Tan Nguan Sen, PUB's director for catchment and waterways, said: 'Orchard Road is very far upstream and 4m or 5m above sea level, and it cannot be affected by the barrage, which prevents the Marina area from being flooded by keeping out the high tide.'
In response to media queries, he explained that the barrage did not affect the way rain drained into the canals, which are built to slope down towards the Marina Reservoir.
Before the barrier was built, low-lying areas such as Little India were more flood-prone when a high tide coincided with heavy rain.
Mr Tan said the barrage did what it was supposed to do very well last Saturday, when Singapore was lashed by a storm and widespread flash flooding occurred over the central and eastern parts of the island. Without the barrage, things would have been much worse, he said, as the storm occurred just as a high tide was receding.
Explaining how the barrage works, Mr Tan said the level of the Marina Reservoir is kept between that of the high and low tides.
The barrage's nine gates and its seven pumps are used only when the level of the reservoir rises to the higher end of this range.
The gates are used when the sea level is lower than that of the reservoir, and the pumps, when the sea level is higher than the reservoir's.
Last Saturday morning, the reservoir was at its usual level, PUB said yesterday, but the sea level was much higher as the tide was high.
The storm began at 4.30am that day, and about 20 minutes later, the National Environment Agency issued a heavy rain warning. These warnings are issued if rainfall is expected to exceed 50mm over at least 20 per cent of Singapore, up to a duration of two hours.
About 10 minutes after the warning was received, PUB staff began to partially open eight of the barrage's nine flood gates - the last one was undergoing maintenance at the time - as the reservoir level was rising. The process took about 15 minutes.
Thirty minutes later, the gates were opened fully as the tide had receded, and the seawater level fell to below that in the reservoir.
Mr Tan said that although the volume of water coming into the reservoir from the various canals is not measured, the fact that the water drained quickly from the reservoir meant it was not overwhelmed by the deluge.
</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
