The number of gates releasing excess water from Magat Dam has been reduced amid the slow recession of water level in the middle and lower Cagayan River Saturday.
Based on the monitoring of the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA), the number of gates spilling excess water from the Magat Dam reservoir was reduced to two gates from seven gates.
Each gate has an opening of four meters, discharging 5,073 cubic meters per second of water.
Magat Dam's water level remains near the 193-meter spilling level at 192.18 meters as of 9 a.m. Saturday but it is slightly lower than the 192.70 meters Friday morning.
PAGASA has issued Flood Bulletin No. 12 for the Cagayan River basin due to the continuous threat of flooding in many areas in Isabela and Cagayan.
The Tumauini Station (Tumauini, Isabela) in the middle Cagayan River and Buntun Station (Tuguegarao, Cagayan) in the lower Cagayan River have monitored "slow recession on water level" but remain "above critical."
PAGASA said widespread flooding may persist.
Those in Tumauini, Delfin Albano, Sto. Tomas, Cabagan, Sta. Maria, and San Pablo in Isabela and Peñablanca, Tuguegarao City, Enrile, Solana, Iguig, Amulung, Alcala, Baggao, Lasam, Gattaran, Lallo, Camalaniugan, and Aparri in Cagayan were asked to remain vigilant.
Meanwhile, upper Cagayan River's monitoring stations in Pangal (Echague, Isabela), and Maris (Ramon, Isabela), as well as middle Cagayan River's monitoring station in Gamu (Gamu, Isabela) have recorded "continuous recession on water level" but remains "above alarm" as flooding still persists.
Residents living in the low-lying areas of San Agustin, Jones, Echague, Alicia, Angadanan, Cauayan City, Naguilian, Reina Mercedes, San Mateo, Cabatuan, Aurora, Luna, Gamu, Ilagan City, and San Mariano in Isabela were asked to take precautionary measures.
Ninoy Aquino Bridge Station (Tuao, Cagayan) in the lower Cagayan River also monitored slow recession on water level but still above alarm, which means flooding still persists.
Low-lying communities in Tuao, Piat, and Sto. Niño were also advised to take necessary actions.
With a total cost of P3.4 billion when it was approved in 1975, Magat Dam is one of Asia's biggest dams, according to the National Irrigation Administration.
It was constructed in 1978 and started operations in 1983.
The dam is part of the Magat River Multipurpose Project, which aimed to improve the existing Magat River Irrigation System and the Siffu River Irrigation System and increase the production of rice in the Cagayan River basin.
During the months of January to May which are normally dry months, water release for irrigation normally exceeds the river flow resulting to reservoir drawdown, however, during the months of June to November, river flow normally exceeds the irrigation requirement and the reservoir re-fills.