EXPLAINER: How PAGASA monitors river basins to prepare for floods

As the Southwest Monsoon or Habagat brings heavy rain in many parts of the Philippines, the weather bureau PAGASA’s monitoring of the country’s river basins becomes even more important.

According to GMA News Feed, PAGASA hydrologist Jayson Bausa, keeping a close watch on the river basins is crucial because heavy rain, runoff from the ground, and the rising water level in rivers may worsen flooding especially in low-lying areas.

How does PAGASA monitor the country’s river basins and warn the public of impending floods?

The agency’s Flood Forecasting and Warning Section collects data, rainfall observation, rainfall forecast, satellite monitoring, radar, and observed rainfall from rain gauges at the country’s river basins.

A river basin is a vast area of land where rainwater accumulates and flows toward a main river, lake, or other body of water.

There are 18 river basins in the country. These are:

1. Pampanga,
2. Abra,
3. Agusan,
4. Cagayan,
5. NCR/Pasig-Marikina-Laguna de Bay,
6. Agno,
7. Cagayan de Oro,
8. Ilog-Hilabangan,
9. Jalaur,
10. Panay,
11. Tagum-Libuganon,
12. Apayao-Abulug,
13. Bicol,
14. Agus,
15. Buayan-Malungon,
16. Davao,
17. Mindanao, and
18. Tagoloan.

Bausa said river basins are the areas where water is accumulated, and it is important that these areas are closely watched, especially amid heavy rain, ground runoff, and rising water levels in the rivers.

He said having all three conditions happening simultaneously would have a grave impact on the low-lying areas of the river basins.

With its hydrological forecast and flood bulletins, PAGASA gives information on which areas will have high water levels and their impact on the community. –NB, GMA News