The Selangor irrigation and drainage department has installed additional pumps and upgraded existing ones at Jalan Resak and Desa Subang Perantau in Kampung Melayu Subang, among the worst flood-hit areas in the Klang Valley recently.
The department said the pump at Jalan Resak had been replaced with a new, higher-capacity unit of 280 litres per second, double the previous 140 litres per second, while the original pump had been moved to Desa Subang Perantau, giving that area two pumps to discharge water into Sungai Pelempas.
It said an assessment after the floods on Nov 2 and Nov 4 found that Desa Subang Perantau, which lies downstream, needed more high-capacity pumps because of the higher risk of backwater overflow from the Kampung Baru Subang bridge. Jalan Resak recorded 116.5mm of rain on Nov 2 and Desa Subang Perantau 91.5mm on Nov 4.
The department said the high water level in Sungai Pelempas made it difficult for water from internal drains to flow into the river, while the affected areas were low-lying with limited and poorly organised drainage systems.
The pumps are a short-term measure pending the Sungai Pelempas project, which involves raising low-lying sections of the riverbank by 0.5m to 1m. The department has also installed flap gates at drainage outlets to stop river water from flowing back into internal drains, and identified sites for urgent floodwalls along Sungai Pelumut as well as for retention ponds and river widening along Sungai Pelempas.
It added that the downstream stretch of Sungai Damansara will be widened and deepened under the Sungai Damansara flood mitigation project.
The Selangor government has also said it will review development approvals to ensure flood mitigation measures are carried out, and has halted all development work in Puncak Alam pending a flood review.