Prime Infra’s Upper Wawa Dam cited for containing typhoon-induced flood

MANILA, Philippines — The water supply dam developed by Prime Infra-led WawaJVCo Inc. was cited by government officials as a key factor in reducing the impact of the flooding caused by Super Typhoon Carina.

WawaJVCo Inc. is the developer and operator of the Wawa Bulk Water Supply Project. Phase 2 of the infrastructure project is the Upper Wawa Dam, which began impounding its reservoir on July 10.

While designed as a water supply dam, the project can also help mitigate flooding in downstream communities, particularly low-lying areas in Rizal province and the eastern district of Metro Manila.

During the situation briefing on the impact of Carina and the enhanced southwest monsoon in Rizal province last Friday, Rizal Governor Nina Ynares informed President Marcos that without the Upper Wawa Dam, flooding in certain areas of the province could have been significantly worse.

Ynares noted that the Upper Wawa Dam’s reservoir needed six months to fully impound water. However, due to the heavy rainfall from Carina, the reservoir was nearly filled in just two days.

“The Upper Wawa Dam project by WawaJVCo has significantly reduced the effects of flooding in comparison to previous occurrences,” the provincial government highlighted in its presentation to the President.

The Upper Wawa Dam features a reservoir of about 450 hectares, approximately twice the size of Bonifacio Global City, and can store up to 120 million cubic meters of water. It is the largest dam to be built in over 50 years, with the critical objective of addressing water supply security in Metro Manila and the province of Rizal.

Based on measurements conducted throughout July 24, Wednesday, the floodwater entering the dam’s reservoir peaked at approximately 2,100 cubic meters per second (m3/s). The controlled impoundment successfully managed the discharge downstream to approximately 200 m3/s, significantly lessening the impact of the floods by a factor of 10.

The Upper Wawa Dam reservoir accumulated over 90 million cubic meters of water during the typhoon. This helped to mitigate downstream flooding, contributing to the protection of lives and property.