NIA Central Office – The National Irrigation Administration (NIA) reaffirms that the recent flooding in Cagayan Valley is not wholly attributed to Magat Dam located in the Municipality of Ramon, Isabela.
During the onslaught of Typhoon Ulysses (Vamco) in Luzon on November 11-12, 2020, Magat Dam was pinpointed as the culprit in the widespread flooding within the Cagayan Valley Region, especially, in Central Isabela and in the entire stretch of lower Cagayan River System down to Aparri, Cagayan. However, based on the Flood Bulletin No. 3 Cagayan River Basin of the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) Northern Luzon Regional Services Division, these areas were identified as low-lying and flood prone areas in the Region.
Cagayan River Basin is subdivided into three parts: Upper Cagayan River Basin (Ganano and Magat), Middle Cagayan River Basin (Siffu-Mallig, Pinacanauan Rivers of Ilagan, Tumaini, and San Pablo), and Lower Cagayan River Basin (Pinacanauan de Tuguegarao, Chico Pared, and Dummun).
Magat River Basin is only one of the 20 river systems within the Cagayan River Basin. Studies showed that Magat Dam contributes only 15% of the river basin’s total water storage capacity and 21% if the considered control point will be in Buntun Bridge, Tuguegarao City.