Located in the foothills of eastern Pahang, Sungai Lembing is a town with a deep industrial heritage. Established as a tin mining settlement in the late 1800s, it grew into one of the most important mining centres in British Malaya. By the early 1900s, operations had been formalised under Pahang Consolidated Company Limited (PCCL), which managed what was then the largest and deepest underground tin mine in the world.
At its peak, Sungai Lembing had electricity, schools, petrol stations, a hospital and even a cinema. This level of infrastructure was exceptionally advanced for rural Southeast Asia at the time. Although the mining industry declined following the global collapse of tin prices in the 1980s, the town remains a symbol of Malaysia’s industrial past. Today, Sungai Lembing attracts a steady stream of weekend tourists drawn by its historical charm, nature and mining heritage sites.
In recent years, Sungai Lembing has faced a new challenge in the form of recurring flash floods. These events are driven by a combination of upstream sedimentation due to deforestation, steep terrain that accelerates runoff, and backstream effect where Sungai Kenau meets larger Sungai Kuantan during heavy rain. To address this, the Department of Irrigation and Drainage (DID) initiated the Sungai Lembing Town Flood Mitigation Project. Bridgex Sdn Bhd was appointed as the Design and Build contractor, with Asia Infrastructure Solutions (AIS) engaged as the lead consulting engineer responsible for designing a flood mitigation scheme to protect the town from events with a 200-year Average Recurrence Interval (ARI).
This project presented several technical challenges. Years of sedimentation had reduced parts of the river to less than 0.5 meters deep, significantly limiting its capacity to convey floodwater. AIS proposed several engineering solutions, beginning with river deepening and desilting to restore flow capacity and reduce the frequency of overbank flooding.
Flood protection measures formed the core of the scheme. Levees and floodwalls were designed along both riverbanks, with profiles developed through detailed hydraulic modelling and adjusted to suit soil and foundation conditions on site. To manage peak runoff, AIS designed three pump stations at strategic locations along the riverbanks. These were supported by detention ponds that temporarily store excess stormwater and control downstream discharge during high flow events.
AIS also introduced strategic upgrades to the local internal drainage network within the town to ensure surface runoff is effectively collected and channelled into the pump system. A rock weir was incorporated upstream to reduce flow velocity and trap sediment before it reaches more sensitive downstream sections. This improves overall system performance and extends its operational lifespan.
Geotechnical conditions added further complexity. The riverbanks consist primarily of sandy and gravelly soils, which are susceptible to seepage and internal erosion during rapid flood rise and drawdown. AIS conducted detailed assessments to evaluate seepage risks and embankment stability, and considered the introduction of sheet piles as cutoff walls in areas with higher seepage potential. Land acquisition was also necessary in certain areas to enable construction of the levees, particularly where houses were located close to the river edge.
As of writing, construction is underway and approximately 17 percent complete. The Sungai Kenau Flood Mitigation Project reflects AIS’s commitment to delivering practical, site-specific engineering solutions that safeguard homes, local businesses and heritage assets. In a location where terrain, hydrology and history intersect, a standardised design is unlikely to be enough. AIS continues to work closely with project stakeholders to ensure that each phase is delivered safely, responsibly and with the long-term needs of the community in mind.
About the Author
Ir. Ts. Azam Syariff Zahar,
Technical Director
Azam brings over 25 years of experience in civil and geotechnical engineering, leading and delivering complex infrastructure and ground engineering solutions in Malaysia and internationally.
A senior technical and delivery leader, Azam is recognised for providing clear technical direction and aligning teams to deliver practical, buildable outcomes that safeguard schedule, cost, and safety. He brings a strong blend of client advisory and project management capability, with a proven ability to take projects from concept and design through construction and completion under demanding timelines.
Azam holds a Bachelor of Civil Engineering from Nagoya Institute of Technology in Japan and is registered as a Professional Engineer with the Board of Engineers Malaysia. He is also an ASEAN Chartered Professional Engineer and a registered Professional Technologist with the Malaysia Board of Technologists.
