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Monday, August 13, 2012

Solution to Manila flooding may involve more of living with it than protecting against it

August 12, 2012

Metro Manila is, by its very nature, a city vulnerable to flooding. Yet it has grown and developed into a monstrous megalopolis that, today, teeters on the brink of catastrophic failure. Manila is bisected by the Pasig River into which connect a system of natural waterways that both feed into it and absorb excess water in times of heavy water flow (say, brought about by heavy rains). The following 1898 map of Manila shows how these waterways weave through much of the city in the immediate vicinities of the Pasig…

[Following two photos courtesy Erick Quinto]

Many of these natural waterways don’t seem to be visible in the following modern aerial photo of the same area in Manila. They may have been built over or been narrowed to the standard width of a street and therefore obscured from view.

Much of the forests that once covered highlands from which water that feeds Manila’s river systems originates once served as the lowlands’ first line of protection from torrential water flow into the low-lying rivers and waterway systems. With that forest cover gone, Manila would have benefited greatly had its natural river system channels still been intact today — perhaps, had city planners applied a bit of foresight, these might even have been enhanced and even turned into key features of the city.

A city the size of Manila therefore cannot be protected against flooding but could be designed to live with it. This, in fact, is the thesis of a group of innovative architecture firms who propose applying a ‘soft architecture’ approach to protect New York City from the next big storm (NB: the following two images are sourced from that article)…

“In lieu of a literal wall around lower Manhattan, which would cost millions of dollars but would only perform in a flood, we proposed an ecological infrastructure that would allow water in and out of lower Manhattan,” [Adam Yarinsky, principle of the Architecture Research Office (ARO)] says. “We’re thinking about a continuum of land and water.”

In order to do this, islands and marshes would be constructed along the edges of the city to diminish the force of storm surges, and streets would have porous pavement which would prevent the city from shutting down in the event of a flood. Gas, electric, sewage, water infrastructure would be relocated to waterproof vaults beneath the sidewalk. Roads and buildings would be renovated in order to have more greenery for absorbing and storing rainwater.

At the moment, the challenges that face Manila residents’ efforts to see permanent solutions to flooding and an acceptable state of preparedness for disasters implemented within their lifetimes are formidable. Among these are the obvious vulnerability of inhabitants (many of them “informal settlers”) of residential areas built on flood plains and low-lying coastal areas…

[Photo courtesy AlertNet.]

…and the rather laissez-faire attitude Manila residents apply to garbage disposal which came back to bite with a vengeance…

[Photo courtesy MacauDailyTimes.com.mo.]

Suffice to say, politics Pinoy-style, will likely be more of a hindrance than a catalyst for the rolling out of solutions across what is really a a broad and profound system of factors that contribute to flooding that Metro Manila desperately requires. For now, Filipinos can only pray.

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