‘Flash flooding in USJ neighbourhoods yesterday due to extreme rainfall’

‘Flash flooding in USJ neighbourhoods yesterday due to extreme rainfall’

SUBANG JAYA: Extreme rainfall triggered localised flash floods in several USJ neighbourhoods yesterday, mirroring river level patterns seen during the major 2019 flood along Persiaran Kewajipan in Subang Jaya.

In a joint statement, Subang Jaya assemblyman Michelle Ng and Zone 3 councillor EJ Christopher said the USJ1 monitoring station in the Sungai Klang river catchment recorded 113.5mm of rainfall on Oct 17 – the highest reading in Selangor that day.

By comparison, maximum readings in Kuala Lumpur reached 59.5mm, while Petaling district stations recorded from 34.5m to 90.5mm.

Under Drainage and Irrigation Department (DID) standards, rainfall exceeding 60mm is classified as a “very heavy downpour”.

At nearly double that threshold, the statement explained that the torrential rain caused water levels to surge in both the Sungai Klang at USJ1 and its primary storm drains.

This temporarily overwhelmed downstream discharge capacity, causing flash floods in low-lying pockets of USJ1, USJ9 and USJ12.

DISYORKAN UNTUK ANDA :

RSN Rayer Jangan Cetus Persepsi Buruk Terhadap Institusi Kehakiman

However, they said that recent infrastructure upgrades prevented a repetition of the inundation seen in 2019, as floodwaters on Saturday receded within 15 minutes.

When contacted, Christopher said floodwaters did not enter residential homes and traffic was able to move along main thoroughfares.

“While this demonstrates better water flow, the absence of a repeat of the 2019 incident does not mean that the current situation is acceptable.

“Residents deserve infrastructure that provides a greater level of protection against flooding and we must continue working towards that objective,” he said.

The joint statement highlighted that the RM756,100 on-site detention (OSD) facility at the Persiaran Kewajipan–Persiaran Perpaduan junction operated at maximum capacity during the storm.

DISYORKAN UNTUK ANDA :

Raudhatul Ummah: JABHAH Manifestasi Komitmen Berterusan UMNO Memperkasa Islam

Together with weirs installed at the monsoon drains along Persiaran Tujuan, USJ18 to Persiaran Kewajipan and the OSD pond in the USJ1 industrial area, the system successfully retained peak stormwater run-off as designed.

According to the statement, the investments fulfilled their immediate containment role and averted severe property damage.

However, extreme rainfall of this magnitude underscored the urgent need to expand total retention capacity across the wider drainage network.

Ng and Christopher added that they were evaluating several technical interventions with relevant authorities.

These include installing more hydraulic weirs at key drainage channels as a short-term measure to regulate downstream discharge rates without increasing upstream risk.

For the medium-term, they proposed an additional OSD facility at strategic commercial or high-risk locations, similar to Petaling Jaya City Council’s Taman Medan underground facility.

For the long term, they noted that a feasibility study is needed for a major drainage connection between storm drains in USJ13 and USJ14 (Persiaran Mulia), alongside structural assessments near LRT support infrastructure.