Stormwater Management and Road Tunnel (SMART)
Malaysia (2003 - 2007)

One of our most distinctive and challenging engineering projects we undertook was the Stormwater Management and Road Tunnel (SMART) project – conceived after a series of devastating flash floods washed the heart of Kuala Lumpur city centre and accumulated losses rose to billions of ringgit.

Conceived with an innovative and never-before-attempted concept to tackle the crippling floods and snarling traffic jams that plaque the Southern Gateway of Kuala Lumpur, SMART captured the attention of the international engineering community with its ingenuity and functional capability.

Employing two Slurry Mix-Shield Tunnel Boring Machines (TBMs) measuring 13.26m in outer diameter, the largest in Sought-East Asia then, we tunnelled under live traffic that began from the old Public Works Department football fields at Jalan Chan Sow Lin, at the central of the alignment, and moved outwards towards their respective ends.

Altogether, the TBMs – named Tuah and Gemilang (literally “Luck” and “Splendid” in English terms) – traversed a combined distance of 9.7km beneath federal-owned owned roads and the city centre’s highly unstable tropical karstic limestone and alluvium geology that included loose silt sand, peats, cliffs, pinnacles, cavities, collapsed cavities and sinkholes.

In the process, our engineering team achieved a world record and record-breaking time of building 66 rings in a week and 13 rings in 24 hours of operation for a large-diameter TBM.

The 9.7km stormwater tunnel in SMART helps divert excess floodwater from Sungai Klang and Sungai Ampang saving the Financial District of Kuala Lumpur, in the surrounding area of Masjid Jamek, from future floods. The 3km motorway tunnel incorporated into SMART acts as an efficient alternative route from the Southern Gateway of KL-Seremban Highway, Federal Highway, Besraya and East-West Link from entering and exiting the city centre.

This iconic project assembled the best of Malaysian engineering expertise and won the Group international accolades from the most prestigious builders’ award, the British Construction Industry Award (BCIA) for Best International Project.

Locally, SMART won double honours from the Construction Industry Development Board of Malaysia for Excellence in Innovation and Environmental Protection, and a year later as the top builder in the country.

Three-mode operation: The SMART system works on a three-mode principle based on the level of flood discharge.

Mode 1
Motorway tunnel operates as usual when there is no storm and excess floodwater

Mode 2
In the event of a moderate storm, the SMART system will be activated and excess rainwater will be diverted through the stormwater bypass tunnel, in the lower channel of the motorway tunnel. The motorway tunnel is open to motorists

Mode 3
During severe storm or heavy inundation, the monitoring stations will issue an alert of the need to close the motorway tunnel from motorists. Sufficient time will be allocated to allow the last vehicle to exit the motorway safely before the automated water-tight gates are opened to allow floodwater to pass through to the storage pond and subsequently to Sungai Kerayong. The motorway tunnel will be re-opened to traffic within 48 hours after closure


Client Government of Malaysia
Concessionaire Syarikat Mengurus Air Banjir & Terowong Sdn Bhd
Turnkey Contractor MMC–Gamuda Joint Venture
Scope of Works
  • Design
  • Construction
  • Maintenance
  • Supervision
  • Commissioning
Stormwater Tunnel
Length: 9.7km
Diameter: 13.2m (outer diameter)
Tunnelling Method: Tunnel Boring Machine (TBM)
TBM Type: Slurry Mix-Shield – Largest in South East Asia and the second largest in Asia
Other Features of
Safety System in the Motorway Tunnel:
  • Automated Flood Control Gates
  • Cross Passage between decks at 250m intervals
  • Ventilation/ escape shafts at 1km intervals
  • Radio Re-Broadcasting Services
  • 38 sets of Air Quality Monitoring Equipment (AQME) monitoring carbon monoxide (CO), nitrogen monoxide (NO) and particulate
  • 24-hour SCADA Monitoring & Surveillance
  • Equipped with firefighting equipment, telecommunication and surveillance system at 1km intervals along the motorway tunnel
  • 9.7km stormwater by-pass tunnel
  • 3km double-deck motorway within stormwater tunnel
  • 11.5km inclusive of ingress and egress connections to the motorway tunnel linking the southern gateway to the city centre
  • Holding basin complete with diversion and tunnel intake structures
  • Storage reservoir and a twin-box culvert to release flood discharge
  • State-of-the-art operations control room equipped with the latest operations management, surveillance and maintenance systems