Many areas within the region are vulnerable to flooding. This vulnerability is a result
of a combination of several factors which include its location within the tropical
monsoon region, being a flood plain of generally low elevation, intensive urbanization
which increases runoff intensity, and inadequate drainage.
About 20% of the more than 20 typhoons frequenting the country each year pass
though the Region. Associated heavy downpour during typhoons inundate about 20
percent of the region particularly in the eastern, south-eastern, and southern parts,
particularly those areas bounded by the Laguna Lake which includes Taguig and
Muntinlupa. There is a positive correlation between the extent of flood prone areas
and the cities and municipalities with larger proportions of low-income residents.