KUALA LUMPUR, Feb 4 — From a little-known nerve centre in the city, a small team of just 43 people works around the clock, making the critical real-time decisions that stand between the city's 2.1 million residents and devastating floods.

Situated beside the Batu flood retention pond near Batu Metropolitan Park, the Sungai Klang Basin Office (PLSK) functions as Kuala Lumpur’s flood-control nerve centre.

It is responsible for overseeing river-level monitoring, reservoir release management, diversion system activation, and issuing early flood warnings across all rainfall conditions, playing a pivotal and often unseen role in protecting the capital.

Their effectiveness was proven on November 24 last year.

As relentless and heavy rain caused widespread flooding across several other states, the PLSK team successfully diverted up to five million cubic metres of floodwater over a 14-hour period, preventing any river-overflow flooding downstream in the city centre.

Small team with a big role

With just 43 staff , PLSK manages and directly oversees three key flood retention infrastructures across the city: the Batu and Jinjang flood retention ponds and the Batu Dam located further up north.

Monitoring is a continuous, 24/7 operation. A network of water-level telemetry stations across Kuala Lumpur streams real-time data from the Batu, Keroh, and Gombak rivers, allowing the team to follow rising waters second-by-second and make critical, time-sensitive decisions.

During intense rainfall, the team channels excess river water into the massive Batu and Jinjang flood retention ponds, which are capable of holding 4.5 million cubic metres (MCM) and 2.5 MCM of water, respectively, keeping the city centre safe from direct flooding.

Beyond flood management, PLSK also maintains the city’s 3.4km-long Gombak and 2.2km-long Keroh river diversions.

These vital arteries are triggered according to strict standard operating procedures, which take into account downstream river levels near Hospital PUSRAWI and the World Trade Centre KL, upstream levels along the Gombak and Keroh rivers, and rainfall exceeding 40mm within an hour.

Battling man-made and natural challenges

Despite their success, the team faces a constant battle against a range of challenges, from sudden shifts in weather to the consequences of human mismanagement.

Uncontrolled land use upstream, for example, has led to heavy sediment buildup in the flood retention ponds and diversion channels, which indirectly reduces their critical water storage capacity over time.

Unmanaged solid waste and debris also continue to clog and weaken flood structures. 

Although mitigation systems like log booms, trash rakes, and trash screens are in place to filter waste, their effectiveness is limited without the active involvement of local authorities and the public in comprehensive waste management.

Climate change adds another layer of unpredictability.

The team must sometimes halt a scheduled release of water from the retention ponds if it coincides with another bout of continuous, heavy rain. 

This decision, necessary to prevent overwhelming downstream rivers, in turn limits the ponds’ ability to handle subsequent downpours.

Future upgrades and a collective responsibility

To address these challenges, a RM70 million project to upgrade the capacity of the Batu flood retention pond and enhance the Gombak diversion is currently underway.

The project, led by the Department of Irrigation and Drainage’s Flood Management Division, is slated for completion in 2028.

Ultimately, PLSK stressed that flood management is a shared responsibility between the government and the community.

They said active public participation and close cooperation with emergency agencies are crucial to ensuring all flood-control measures remain effective.

During periods of heavy rainfall, the team advises the public to stay alert, follow official flood warnings, and, crucially, avoid sharing unverified information that could trigger widespread panic and hinder effective response efforts.