HOW CAN WE SOLVE THE FLOODING PROBLEM?
A study of flood vulnerability of cities and municipalities in the Greater Metropolitan Manila Area (GMMA)
Recurrent flooding has been a problem, not only in major cities but across the country. When there is a typhoon about to make landfall, residents of affected areas are already expecting floods, especially in low-lying areas.
In Metropolitan Manila, many motorists and pedestrians have complained of being stranded or stuck in traffic due to flooding.
There have been several projects funded by the government to address the issue of flooding, since when Metro Manila was heavily flooded due to Typhoon Ondoy.
Despite these efforts, the residents of Metro Manila and surrounding provinces still face the issue of flooding yearly.
Before we can provide any solution, we must understand the condition that we are in.
Flood vulnerability refers to the likelihood of people or communities to be affected by flood phenomena considering the socio-economic, environmental, and physical components.
VULNERABILITY INDICATOR 1:
POPULATION DENSITY
The areas of higher population density represent higher exposure to a hazard and areas where evacuation may be more difficult, so they are very vulnerable.
GMMA Population Density
VULNERABILITY INDICATOR 2:
ESTIMATED ECONOMIC LOSS
The loss to an individual is estimated to be equivalent to 5 percent of their income (approximated using the GRDP)
GMMA Estimated Economic Loss
VULNERABILITY INDICATOR 3:
SLOPE
Steep slopes tend to reduce the amount of infiltration of water into the ground, and this water can then flow quickly down to rivers as overland flow. The western area of the map has a more flat slope
GMMA Slope Classification
VULNERABILITY INDICATOR 4:
ELEVATION
Low-level areas are prone to massive flooding, especially if there are adjacent to areas with high elevation. There is a significant area that has low elevation.
GMMA Elevation
VULNERABILITY INDICATOR 5:
RAINFALL
Areas with a high amount of annual rain have a higher risk of flooding if proper urban planning and flood control management is not in place.
GMMA Average Annual Rainfall
VULNERABILITY INDICATOR 6:
LAND COVER
Land cover describes how the area’s land is used. The land cover type can describe the influence on the rainwater runoff for a decision on what kind of crop is suitable for a given area. This decision substantially affects the impact of future floods as crops affect soil quality.
GMMA Land Cover
IF WE COMBINE ALL THESE FACTORS, ARE WE ON THE RIGHT TRACK ON OUR SOLUTIONS OR DO WE NEED TO RE-THINK?
GMMA Flood Vulnerability Study
Highly urbanized areas have the highest vulnerability in terms of exposure and susceptibility, while municipalities far away from the business districts have a low vulnerability.
Arable lands have very high record of rainfall which is conducive to farming but not exempted to flooding due to low elevation and level slope
Though high areas (high elevation) have a low vulnerability to flooding, rains flowing down from these areas can aggravate the flooding conditions in the low-lying areas.
Areas surrounding Laguna Lake have moderate to high vulnerability, notably those households within 1 kilometer from the lake’s shores.
RECOMMENDATION
The country needs to ramp up spending to mitigate loss, economically, socially, environmentally, and physically.
The government must still periodically revisit the conditions of cities and municipalities surrounding the big cities.
Extended the review to a countrywide focus to distribute resources to other provinces and regions.
Additional factors may be added in the study, such as soil quality and drainage capacity flow.
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