The newly operational Upper Wawa Dam demonstrated its indispensable role in flood mitigation during the recent onslaught of Typhoon Uwan, reducing downstream flooding by an estimated 99.5% and safeguarding communities in Rizal province.
Operated by WawaJVCo, a subsidiary of Manila Water, the dam’s primary function is to augment Metro Manila’s water supply. However, during the 30-hour period as Uwan traversed the region, it captured a massive 33.7 million cubic meters of stormwater. The dam’s reservoir level rose by 10 meters as it recorded 110 mm of rainfall at the site, preventing that volume from cascading into vulnerable areas.
This direct action significantly minimized flood impacts in downstream local government units, including Montalban, San Mateo, and Antipolo City. Joe Costales, General Manager of WawaJVCo, emphasized the dual purpose of the infrastructure: “The Upper Wawa Dam is more than just a water source but a lifeline for communities downstream. Its engineering design ensures that even during extreme weather events, we can protect lives and property.”
Beyond flood control, the dam is a cornerstone of regional water security. As the largest new water source in over 50 years, it has a year-round supply capacity of up to 710 million liters per day (MLD), set to benefit over 700,000 households or approximately 3.5 million Filipinos in Metro Manila and nearby provinces.
The dam’s flood mitigation capability is rooted in its robust design. With a 262-square-kilometer watershed catchment area and a 120-million-cubic-meter reservoir volume, it incorporates features like a stepped chute and stilling basin to dissipate water energy and ensure controlled flow. Its design adheres to stringent international standards from the International Commission on Large Dams (ICOLD) and the U.S. Army Corps of Engineers (USACE) for stability during extreme events.
Local officials have hailed the dam’s performance. Montalban Mayor Ronnie Evangelista stated, “The Upper Wawa Dam is a game-changer for Rizal. It not only secures water for our growing population but also provides a strong defense against flooding. This is a testament to how infrastructure can serve both development and disaster resilience.”
The Provincial Government of Rizal has formally recognized the dam’s continued contribution, underscoring its vital dual role in ensuring sustainable water supply and enhancing community resilience against climate-driven disasters.#
