01 · The problem
What is happening
The Philippines lies in one of the most active tropical cyclone basins in the world. Metro Manila is built on low-lying land between Manila Bay and Laguna de Bay, and extreme rainfall events such as Tropical Storm Ketsana (Ondoy) in 2009 caused extensive flooding. Land subsidence in parts of the metropolitan area, linked to groundwater extraction, and waterway encroachment add to flood risk.
High severity. Serious, widespread effects requiring sustained action. Severity is descriptive editorial metadata summarising documented effects. It is not a measured index or a score.
02 · Causes
Why it is happening
- 01
Tropical cyclones and monsoon rain
Typhoons and enhanced southwest monsoon rains can deliver extreme rainfall.
- 02
Low-lying terrain
Parts of the metro area lie close to sea level and around a large lake.
- 03
Encroachment and blocked drainage
Settlements and waste in waterways reduce drainage capacity.
- 04
Land subsidence
Groundwater extraction has contributed to sinking in some coastal areas.
03 · Impacts
Who and what it affects
- 01
Loss of life and displacement
Major floods displace large numbers of residents, especially in informal settlements.
- 02
Economic disruption
Businesses, transport and schools are disrupted during floods.
- 03
Post-flood disease
Leptospirosis and other diseases increase after flood exposure.
04 · Solutions
Documented approaches
Metro Manila Flood Management Project
Modernising pumping stations and improving drainage with World Bank support.
Expected effectReduces flood duration and depth in served areas.
Forecasting and early warning
PAGASA forecasts and warning systems with local disaster response.
Expected effectImproves evacuation and preparedness.
Resettlement from high-risk waterways
Relocating families from danger zones with attention to livelihoods.
Expected effectReduces exposure when done with community participation.
05 · Key indicators
What can be measured
No reliable quantitative indicator is included for this issue. TerraLens shows figures only where a credible source supports them — consult the sources below for current data.
06 · Sources
Where this comes from
- [1]Philippine Atmospheric, Geophysical and Astronomical Services AdministrationPAGASApagasa.dost.gov.ph(opens in a new tab)
- [2]World Bank in the PhilippinesWorld Bankworldbank.org(opens in a new tab)
Links open the publishing organisation's site. Some point to the publisher's main page, where the named report or dataset can be found.