The local government of Rizal Province acknowledged over the weekend the important role the Wawa Dam played in managing floodwaters caused by super typhoon Carina.
Rizal Governor Nina Ynares said that without the project, the flood in certain areas of the province would have been significantly worse, particularly in low-lying areas and the eastern district of Metro Manila.
The dam is composed of the Wawa bulk water supply project alongside its second phase, the Upper Wawa Dam which began impounding water at the reservoir on 10 July.
Ynares said the Upper Wawa Dam reservoir requires six months to fully impound water but was nearly filled in only two days with heavy rainfall from super typhoon Carina.
“Without it, San Mateo and Montalban would have drowned and definitely, Marikina and parts of Quezon City and even Pasig would have been (severely) affected,” Ynares said, in a report to President Marcos.
The Upper Wawa Dam features a reservoir of some 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 built in over 50 years with the objective of addressing water supply security in Metro Manila and the province of Rizal.
Dam measurements conducted throughout 24 July, floodwaters entering the 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 reducing the impact of the floods.
The Upper Wawa Dam reservoir also accumulated over 90 million m³ of water during the super typhoon.
The facility is set to begin supplying bulk water next year under the WawaJVCo Inc., a subsidiary of Prime Infrastructure Holdings Inc.
The dam’s 710 million liters per day capacity will reduce Metro Manila’s reliance on the Angat-Ipo System.
WawaJVCo has a 30-year offtake agreement to supply Manila Water with 518 MLD.
