The Tunner That Is So SMART

I attended The Highway Concessionaire Conference 2005 which was held at Sunway Lagoon Resort Hotel on 29th November 2005 till 30th November 2005. The conference was launched by Yang Berbahagia Dato’ Seri S. Samy Vellu, the Minister of Works Malaysia. The main highlight of the conference was a visit to the SMART Tunnel project area which had got me really excited.

What is so smart about SMART Tunnel?

SMART is an acronym for Storm Management and Road Tunnel, a project under the Federal Government initiated to alleviate the flood problem in the city center of Kuala Lumpur. The project is implemented through a joint venture pact between MMC Berhad (Malaysian Mining Corporation) and Gamuda Berhad, with the Department of Irrigation and Drainage Malaysia and the Malaysian Highway Authority as the executing government agencies. Studies had indicated that the critical stretch Sg. Klang between Sg. Klang / Sg. Ampang confluence and Sg. Gombak / Sg. Klang confluence to be flood prone areas. The river is further constrained by the low height of the Jalan Tun Perak Bridge (near Masjid Jamek), resulting in frequent flash floods in the surrounding areas. 

Objectives and Benefits of SMART Tunnel

Construction on the riverbanks made it impossible to widen the flood plains, hence, the only feasible method of flood control is to tap water upstream and divert part of the water before it enters the critical area. The solution is to build a large tunnel to store and divert the floodwater. The floodwater is diverted at the confluence of the Sg. Klang and Sg. Ampang into a holding pond. From there, the water flows through the 11.8m inner diameter, 9.7km long tunnel into a storage reservoir at Taman Desa before discharging into Sg. Kerayong. Once completed, the SMART system will be able to divert large volumes of floodwater from entering this critical stretch via a holding pond, bypass tunnel and storage reservoir. This will reduce the floodwater level at the Jalan Tun Perak Bridge, preventing spill-over.

Special Features of SMART Tunnel 

A central 3km long section of the water tunnel would be used as 2 x 2 lane road tunnel when the flood diversion is not in operation to ease the congestion of the southern road arteries of the city. The firms proposed to build the road tunnel section at a cost to be recovered by toll collection concession from the government.

As stormwater tunnel:

·         to divert floodwater away and bypass the city center

·         to regulate and keep the water level in Sg. Klang manageable throughout the year

·         to improve the efficiency of the hinterland drainage within the city

As motorway tunnel:

·         provide traffic relief on the main Southern gateway to the city center from the South (KL-Seremban Highway) and the West (Federal Highway)

·         provide an alternative traffic dispersal system for this area

·         reduce traveling time

The unique feature of this project is the 3km double deck motorway within the stormwater tunnel. The operation of the SMART system works on the three-principle mode of operation based on the flood discharge of Sg. Klang / Sg. Ampang confluence and the operation status of the motorway. 

Operation of Combined Tunnel

Mode 1

The monitoring system of the catchment area pre -warns the occurrence of floods. Under normal condition, where there is no storm or low rainfall, no floodwater will be diverted into the system.

Mode II

During moderate storms, the system will be activated and floodwater is diverted into the bypass tunnel in the lower channel of the motorway. Up to this stage, the motorway section is still open to traffic.

Mode III

During major storms, the system is activated and the motorway will be closed to traffic. Sufficient time will be allocated to allow the last vehicle to exit the motorway before the automated watertight gates are opened for flood water to pass through. In this event, the full cross section of the tunnel is available for water storage and diversion. The motorway will be re-opened to traffic within 48 hours after the closure.

Method of Construction

Due to the nature of the soil condition, a construction method that would have minimal negative impact on the geological condition of the soil is selected. In Europe, tunnel construction using tunnel boring machines (TBM) is the most advanced and cost effective method used. As Kuala Lumpur city sits on karstic limestone geology with high ground water table. After much research, study and survey, the Slurry Shield TBM was chosen and the machine is designed to overcome problems of underground water drawdown. Two Slurry Shield TBM are used, both starting from the JKR field area in Jalan Chan Sow Lin. The first machine, the Heroic TUAH heads north under Jalan Tun Razak and Jalan Desa Pandan before terminating at the pond at Ampang, behind Gleneagles Hospital. The Magnificent GEMILANG, the second machine, heads south under Jalan Chan Sow Lin and the KL-Seremban Highway next to Sg. Besi airfield before terminating at the existing pond in Taman Desa. 

Period and Cost of Construction
The SMART Project was commenced on 1st January 2003 and is expected to be completed by 31st December 2006 with a total cost of RM2 billion.

Extracted from SMART Tunnel brochure