The operator of the Magat River Integrated Irrigation System Dam and Reservoir (Magat Dam) in Isabela province issued an advisory that it would release water starting this April 20, 2021, as a “precautionary measure” with the arrival of ‘Typhoon Bising.’
In an advisory to the Philippine weather bureau, PAGASA (Philippine Atmospheric, Geophysical and Astronomical Services Administration), water would be released starting at 6:00 am from one of the dam’s “spillway gates” (Radial Gate No. 4) with a one-meter opening.
This translates to an estimated 200 cubic meters per second of water in anticipation of the expected heavy rain water inflow due to the typhoon that already made landing in the Bicol region last April 18, 2021.
As of 6:00 am on April 19, 2021, water level at the dam has been placed at 190.42 meters or just 2.58 meters short of its 193-meters spilling level.
In the aftermath of massive flooding that hit Cagayan Valley and nearby provinces last November 2020 due to ‘Typhoon Ulysses’ (international code name, ‘Vamco’) and for which the National Irrigation Administration (NIA) was erroneously blamed by some quarters, NIA administrator Ricardo Visaya announced the revision of the Magat Dam protocol in dam discharge and flood warning last February 2021.
Visaya, former Armed Forces chief of staff, in a report to Congress a month before, said he immediately formed a dam crisis management task force dedicated to review the existing protocols and address concerns on dam management crisis following the flooding incident in Cagayan Valley.
Under the revised ‘Magat Dam Protocol on Dam Discharge and Flood Warning Operation,’ Visaya said this involved “improved coordination with PAGASA” and that warning stations are now mandated to issue warning 24 hours before the preemptive release of water from the Magat Dam.
Public advisory shall also be completed thru text messaging “blasting” while local government units (LGUs) should acknowledge receipt of public announcement of the preemptive release.
The NDRRMC Operation Center will also be asked to issue Emergency Alert and Warning Messages aside from information dissemination through the media.
Meanwhile, preemptive release will be done when the dam reaches 190 meters above sea level (MASL) and when a typhoon is expected to make landfall within 3 to 4 days in the Cordillera Autonomous Region and Regions 1, 2 and 3.