Huge Rizal dam cited as one of factors that reduced Carina’s flood impact

Aerial shots of the Upper Wawa Dam reservoir during and after typhoon Carina. (Photos from PRIME INFRA)

WawaJVCo Inc., a unit of Razon-led Prime Infrastructure Capital Inc., said its P26-billion Upper Wawa Dam in Rizal helped mitigate flooding in the province and nearby cities caused by typhoon Carina.

Citing a report of Rizal Governor Nina Ynares, the water supply dam reduced further widespread flooding, particularly in low-lying areas in Rizal province and the eastern district of Metro Manila.

“Mr. President, some time this month, we were together during the inauguration of (Upper) Wawa Dam. We saw it was empty and (they said) it would take six months for them to fill it up… ” the governor told President Ferdinand Marcos Jr. during a situation briefing on Friday.

“If without it, I feel that, most likely, San Mateo and Montalban would be down; and definitely, Marikina and parts of Quezon City and even Pasig would be affected,” he said.

“The Upper Wawa Dam project by WawaJVCo has significantly reduced the effects of flooding in comparison to previous occurrences,” the governor added.

Meanwhile, according to the company, the floodwater entering the dam’s reservoir peaked at approximately 2,100 cubic meters per second (m³/s).

Then, the dam managed to control the discharge downstream to about 200 m³/s, “significantly lessening the impact of the floods,” the firm said.

WawaJVCo Inc., the developer and operator of the Wawa Bulk Water Supply Project, began the impounding process for the Upper Wawa Dam on July 10.

The Upper Wawa Dam, known to be the largest dam built in more than five decades, has a reservoir of about 450 hectares.

This is approximately twice the size of Bonifacio Global City.

The dam can store up to 120 million cubic meters of water.

It is expected to start supplying bulk water by the latter part of 2025.