Upper Wawa Dam reiterates its critical role in reducing flooding

In addition to its primary goal of supplying a dependable water supply for the present and securing water for the future, the Upper Wawa Dam, a water supply dam run by Manila Water subsidiary WawaJVCo, has once again demonstrated its crucial role in flood prevention.

The Upper Wawa Dam is a historic infrastructure effort planned to enhance Metro Manila’s raw water supply and strengthen water security in Metro Manila and nearby provinces. As the largest new water source in over five decades, it would have a yearlong supply capacity of up to 710 million liters of water per day (MLD), helping more than 700,000 homes or nearly 3.5 million Filipinos.

During the onslaught of Typhoon Uwan, the dam significantly reduced flooding impacts in downstream communities in the Province of Rizal, including the local government units of Montalban, San Mateo, and Antipolo City.

According to WawaJVCo, in just 30 hours from Typhoon Uwan traversing Metro Manila and Rizal, the reservoir level in the Upper Wawa Dam rose by 10 meters, of which 110 mm of rainfall was recorded at the dam site.

Despite this, the Upper Wawa Dam successfully mitigated downstream flooding by 99.5%, effectively minimizing the impact in the communities surrounding the dam and storing an impressive 33.7 million cubic meters of water during the typhoon.

“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 while continuing to secure water for Metro Manila and Rizal.” said Joe Costales, General Manager of WawaJVCo.

With a watershed catchment area of 262 square kilometers (26,200 hectares) and a reservoir volume of 120 million cubic meters, the dam features innovative engineering solutions such as a stepped chute and stilling basin. These structures dissipate water energy and reduce turbulence, ensuring controlled flow downstream. By minimizing the force of released water, this design significantly lowers the risk of erosion and flooding in surrounding communities.

The Upper Wawa Dam was built in accordance with globally accepted guidelines, including those of the International Commission on Large Dams (ICOLD) and the U.S. Army Corps of Engineers (USACE), ensuring its structural strength and reliability even under extreme conditions like floods, earthquakes, and other natural hazards.

The Provincial Government of Rizal has once again acknowledged the ongoing contributions of the Upper Wawa Dam, with Montalban Mayor Ronnie Evangelista highlighting its essential role in strengthening water security and reducing flood risks.

“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.” Evangelista shared.