Urban flooding

Ruffy Magbanua

THERE’s a buzzword in social media these days that is circulating fast and, well, furious enough and that is urban flooding.

Flooding in urban areas can be caused by flash floods such as the recent disaster that hit Cagayan de Oro, or coastal floods, or river floods, but there is also a specific flood type that is called urban flooding.

What is urban flooding? Urban flooding is the inundation of land or property in a developed environment, particularly in more densely populated areas like Cagayan de Oro. Basically, it is caused by massive rainfall overwhelming the capacity of drainage systems, such as storm sewers.

Urban flooding is specific in the fact that the cause is simply the lack of adequate drainage in an urban area and Cagayan de Oro is no exception to that.

Last Monday’s high-intensity rainfall had caused the flooding of low-lying areas  of the city, and the absence of a dedicated sewage system and drainage canals had forced large amounts of rain to swell into the city’s open spaces including streets, hallways parks and even malls.

Flood waters may enter existing sewage system but then it get deposited somewhere else in the city particularly on the streets. And most often than not, drain covers dance freely, indicating that the city’s drainage is undersized and more so, inadequate.

Elsewhere in developed and developing countries, urban flooding may happen frequently and surprisingly. The same sort of thing can happen in rural areas and is then called ponding.

Urban floods are a great disturbance and therefore, it dislocates people and destroys properties, including vehicles.   Case in point: some 50 vehicles, most of which were top-of-the-line cars, SUVs and commuter vans were seen half-submerged in highways, city streets and even inside shopping malls.

Roads can be blocked, people can’t go to work or to schools. The economic damages are high but the number of casualties is usually very limited, because of the nature of the flood.

Such in the case of the floodwaters that hit Cagayan de Oro where it only claimed at least five persons, displaced some 5,000 city dwellers and damaged properties worth millions of pesos.

Urban floods are floods that happen in a relatively short period of time and can inundate an area with rampaging waters in minutes, or even in seconds. As areas become “urbanized” or go through the process of urbanization, increased flood risks go with it as well.

Further, the problem with urban flooding is the fact that they occur in highly in populated urban centers, seldom in sparsely populated areas.

As more and more land areas are converted into residential and industrial zones, the amount of surface area available for water infiltration into the soils decreases.

Clearly enough, a city with no urban planning, urban flooding takes over.

E-mail: ruffy44_ph2000@yahoo.com