Flooding in Singapore: Stamford Canal gets new debris traps

5 gratings placed at key spots to prevent Orchard Road area from flooding again
Grace Chua Straits Times 25 Jun 10;

THE PUB is spending $25,000 to install five debris- trap gratings at the Stamford Canal to prevent the Orchard Road area from flooding again.

All five will be in place by today.

The gratings were lowered just days after massive floods hit the Orchard Road shopping belt last week, costing many shops and restaurants there millions in damage. Some of the shops are still closed.

The cause of the floods was later traced to a clogged drain at the canal, which is meant to clear rainwater away from Orchard Road.

The national water agency said in the aftermath that it would install more of these gratings along Stamford Canal and step up maintenance checks at the canal to once a month, from once every three to six months.

The PUB is spending $150 million a year for the next five years to upgrade drainage infrastructure, it said last week.

Gratings are placed in strategic areas picked by PUB engineers who model the water flow in canals.

The five new zig-zag gratings, which catch debris without stopping water flow, are in open drains for easy maintenance in Camp Road, Napier Road near Minden Road, Nassim Road, Grange Road and Tanglin Road.

They add to the Marina Reservoir catchment's 100 existing gratings and 26 float booms - to catch flotsam - at the mouths of canals.

In addition, the PUB has been talking to the owners of Lucky Plaza on ways to upgrade the building to deal with flooding. As the shopping mall was built before 1984, it does not conform to PUB guidelines that entrances be 1m above the highest known flood level.

Building experts have also suggested adding raised platforms to places such as Liat Towers and Lucky Plaza, where water spilled into the lower levels and flooded shops.

Last week, Environment and Water Resources Minister Yaacob Ibrahim said that all major canals would come under review. The review includes how often they are inspected and cleaned.

The PUB is also adding one new sensor to the current four in the Stamford Canal. There are 32 of these sensors in canals islandwide.

These sensors do not prevent floods, but they help alert the water agency to potential floods and it can then send contractors and officers to a potential flood site to manage the damage.

Over the years, such measures have cut the number of flood-prone hot spots from 90 in 2008 to 58 last year and 54 this year, including Orchard Road, the PUB said.

To handle more frequent maintenance checks and cleaning work, cleaning contractor Lian Shing Construction will be hiring 20 more workers on top of its 120 existing cleaning staff, said director Seah Siew Seng yesterday at a press briefing.

The additional workers will not change the cost of its cleaning contract with the PUB because the hiring of more workers is written into the 'performance-based' contract, which specifies a minimum cleaning frequency but allows contractors to decide how many workers and what tools are needed.

The PUB's three cleaning contracts began in January.

The agency said the five-year contract with Lian Shing, which handles cleaning for the central watershed's drains and canals - spanning Bukit Timah, Little India, the Singapore River, Geylang and Orchard Road - is worth $4.3 million a year.

Besides Lian Shing, the PUB's other contractors are Neo Lian Poh Construction, which cleans drains in the eastern watershed, and Kim Bock Contractor for the western catchment.

In total, maintaining PUB's 7,000km of drains and canals around the country costs $23 million a year, a figure that has doubled over the past three years.

Asked whether the new maintenance requirements would raise the cost of the firm's operations, Mr Seah said the company had no choice. 'We need to do the job well, and we need enough manpower to do that,' he said.

During its over two decades in the industry, the family business has also mechanised. Where workers used to simply dig out silt and debris, they now use machines like the Bobcat mini excavator to clear canals.

Debris-trapping gratings for Stamford Canal
Evelyn Lam/Lynda Hong Channel NewsAsia 24 Jun 10;

SINGAPORE: The PUB has stepped up efforts to prevent flooding, following the massive flooding on Orchard Road. It is installing gratings in the drains linked to the Stamford Canal drainage system.

PUB is paying special attention to the drains after it surfaced that trapped debris at a culvert had caused floodwater to overflow onto Orchard Road last week.

It is installing zig zag gratings to trap debris while allowing water to flow smoothly.

PUB is spending S$25,000 on the gratings in five drains along Grange Road, Holland Road, Camp Road, Nassim Road and behind Tanglin Shopping Centre.

Maintenance of the drains in the central catchment areas will also be stepped up - from once every three months to once a month.

To do this, the contractor will increase the number of people for the job - from 120 to 140.

Mini dredgers, which can do the job of 20 workers, will be increasingly used to remove debris quickly. And to be alerted faster if water reaches alarming levels, a water sensor will be installed in a drain near Grange and Orchard roads by this week.

- CNA/i

Flood prevention measures
Lynda Hong Ee Lyn Today Online 25 Jun 10;

Work is in progress to prevent the Stamford Canal drainage system from being blocked again. 'Z'-shaped gratings were installed in drains along Holland Road yesterday. The gratings will trap debris while allowing water to flow.

PUB's assistant director of Catchment and Waterways, Mr Choy Yai Kwong, said more will be installed in drains along Grange Road, Camp Road, Nassim Road and behind Tanglin Shopping Centre. A blocked culvert was the cause of the recent floods in Orchard Road.

PUB is also installing a sensor in the drain near Grange and Orchard Roads to monitor water levels. SIM YI JIN