The deluge that never ends

After decades of spending and planning for flood mitigation, Klang Valley residents are still waiting for solutions that match the scale of the problem

“BANJIR kilat melanda Lembah Klang” ... This is a phrase you will be hearing or reading with increasing frequency in the next few months.

On Monday afternoon, the skies opened over the Klang Valley and torrential downpours and thunderstorms turned roads into ­rivers. The Federal Highway near Amcorp Mall snarled into gridlock. Both directions of the NKVE between Shah Alam and Setia Alam (KM9.1-KM9.4) were closed after floodwaters rendered the stretch impassable.

In Denai Alam, TTDI, Bukit Jalil and Subang, cars crawled through brown water or stalled. In Kampung Melayu Subang, 116.5mm of rain (roughly three days’ worth), fell in about an hour. Sungai Damansara rose to 18.77m, more than a metre above the danger level, inundating some 92 homes with water up to a metre deep. Residents waded through chest-high floods; furniture and appliances floated or were ruined.

The northeast monsoon officially began on Oct 27 and is forecast to run until March 2027. MetMalaysia has warned of continuous heavy rain between three and five days in the initial phase through January. Commuters already know the drill: check the Selangor Irrigation and Drainage Department’s Infobanjir portal or Malaysian Highway Authority updates before travelling in low-lying routes.

Warnings help, but they do not stop the floods. We do not need to be reminded of the frequency of floods nor of “low lying areas and areas which flood frequently”.

It happens all too often, like clockwork. The same stretches of road and the same neighbourhoods flood year after year. Traffic comes to a standstill, schools are disrupted, productivity shrinks, and households absorb the cost of damaged goods and lost workdays.

What has changed is the scale of the response and the stubborn persistence of the problem. Millions have been spent and more has been promised. In Budget 2027, the government allocated RM100mil for retention ponds and river maintenance, specifically to tackle Klang Valley flash floods.

The federal and Selangor governments agreed on measures that include reassessing the capacity of Batu Dam and Klang Gates Dam for the next 30 years.

Selangor is receiving more than RM4bil in federal flood-mitigation projects, in various stages of completion, others still in the planning stage. The Sungai Buloh and Sungai Damansara projects alone carry a combined allocation of nearly RM700mil and are expected to be completed by 2029 (currently 30-60% done).

The Prime Minister visited Kampung Melayu Subang relief centre the day after the latest floods and ordered the work expedited, including river widening, additional retention ponds and dredging.

Short-term “quick-win” measures – on-site detention ponds, flap gates, drainage upgrades – have been rolled out across the state. River deepening along stretches of Sungai Klang has increased capacity and reduced some incidents.

Major infrastructure such as the SMART Tunnel has demonstrably prevented catastrophic monsoonal flooding in central Kuala Lumpur on multiple occasions. That is real progress.

Yet localised flash floods continue unabated. Experts point out structural reasons. Much of the drainage network was designed using rainfall data from the 1970s and 1980s. Today’s short, intense “cloudbursts” – often exceeding 60mm in two hours, routinely overwhelm those thresholds.

Unrestrained urban development has contributed to this. Construction sites themselves often temporarily worsen drainage. Silt, rubbish and sediment clog drains and reduce runoff capacity. The result is that even moderate storms can generate more water than the downstream drains and rivers can handle.

We know that land once earmarked for retention ponds in parts of Kuala Lumpur were transferred to developers, shrinking flood-storage capacity. Auditor-General reports in the past have documented these missteps but still development approvals continue even as existing systems struggle.

It is true that climate change is amplifying the extremes – more intense rain events interspersed with longer dry spells – but this only paints a partial picture.

The core problems are outdated design standards, planning that has not kept pace with growth, weak enforcement of green-space and drainage requirements, and a reactive rather than preventive culture.

There are tough questions that beg answers. If billions have been allocated and major works are under way, why do the same places still flood after an hour of heavy rain? Why are temporary ponds and emergency desilting still the go-to response years into these expensive initiatives? Why does the loss of flood-storage land to development keep occurring?

Monitoring portals and sirens are useful, but they are symptoms of a system that still treats flooding as an inevitable seasonal inconvenience rather than a failure of urban management.

The monsoon is here to stay, at least until March 2027. The next intense downpour is not a surprise. The continuing disruption to lives, traffic, schools and productivity is the part that should no longer be accepted as normal.

After decades of spending and planning, Klang Valley residents are still waiting for the solution that matches the scale of the problem.