KUALA LUMPUR: The Drainage and Irrigation Department (DID) has implemented a new strategy, building underground reservoirs to mitigate flash floods in the Klang Valley.
This initiative aims to minimise the impact of flooding on residential areas, especially given the limited space available for constructing flood reservoirs.
Currently, a construction project for an underground reservoir is underway at the Police Training Centre (Pulapol), and another reservoir is in the planning stage at Sungai Kuyuh, Seri Kembangan.
The Pulapol project has an estimated cost of RM30 million.
Once completed and operational next year, it will help reduce the effects of flash floods caused by overflowing rivers in the Klang Valley, especially by managing excess water from Sungai Bunus.
Similar to surface tanks, the reservoir will collect rainwater before it flows into the river as part of standard operating procedures (SOP).
DID deputy general director (Business Sector) Amiruddin Alaldin said another project employing the same technique is planned for Sungai Kuyuh, Seri Kembangan.
The Pulapol reservoir will have a storage capacity of 109,000 cubic metres and a footprint of 943.4 square metres.
Amiruddin said: "We used this approach when building the SMART Tunnel in 2007, this project is the result of collaboration among local experts."
He said the purpose of the reservoir system and pumps is to reduce the peak levels and heights of floods.
In addition to disrupting several areas in the Klang Valley, recent flash floods had caused landslides in Taman Melawati and resulted in the temporary closure of the SMART Tunnel as part of flood preparedness measures.
Areas affected by the floods included key locations in Kuala Lumpur, such as Jalan Parlimen to Bukit Aman, Jalan Duta, Jalan Sultan Abdul Halim, the Universiti Malaysia campus, Wisma Central, and Sekolah Kebangsaan Padang Jawa in Shah Alam.
Amiruddin said reservoirs play a crucial role in flood management.
He said these tanks can reduce river or rainwater inflows by 40 per cent during heavy rain.
"Putrajaya is a model, developed with a modern urban approach that integrates various water-storing lakes, ponds and parks, making it less susceptible to flooding.
"However, in the Klang Valley, available space for constructing above-ground tanks is diminishing.
"Thus, the strategic focus has shifted to building more underground water reservoirs."
Currently, there are 33 flood tanks in the Klang Valley, 18 are maintained by DID, while 15 are overseen by the Kuala Lumpur City Hall.
Amiruddin added that constructing underground tanks is a more effective solution than widening existing rivers to address flooding issues in the region.
In June 2022, the then Kuala Lumpur Mayor Datuk Seri Mahadi Che Ngah, had announced City Hall's plans to build an underground reservoir as part of long-term preparations to address extreme weather conditions over the next decade.
This plan serves as an alternative to existing surface reservoirs, which often reach maximum capacity during prolonged heavy rains.
On Oct 15, during a flash flood that affected the capital, DID had successfully channeled over four million litres of water away from the Klang Valley.
Three water systems during that time managed to handle this volume, including reservoirs at Lencongan Gombak and Lencongan Keroh, which manage streams from Sungai Gombak and Sungai Keroh.
Amiruddin saidon that day, the SMART Tunnel also stored approximately 2.45 million litres of water."If more than 4 million litres of water had not been diverted, the Klang Valley would have experienced flooding similar to other severe incidents prior to the SMART Tunnel's operation in 2007," he said.