DPWH storm drain system, a ‘permanent solution’ to Metro floods

The widespread floods in Metro Manila brought about by recent cyclones Pedring and Quiel has the Department of Public Works and Highways (DPWH) convinced that unconventional urban constructions like catchment basins for storm drains are the way to go in solving Metro Manila’s floodwater woes. “Storm drain" systems are networks of gutters, channels, and subterranean pipes designed to take away excess water accumulating on roads, parking lots and sidewalks after a large downpour of rain. Large amounts of excess water are first collected in “catchment basins" that are basically large underground tanks or cisterns. The collected excess water then gets released to creeks and other bodies of water only after rainfall has subsided, so as to prevent subsequent flooding resulting from otherwise simultaneously raising levels in those waterways.

“Water czar" and DPWH Secretary Rogelio Singson said that starting next year, catchment basins like those found in cities in other countries will be built as a “permanent solution" to the National Capital Region’s flood problems. He pointed out that in Fort Bonifacio, such a catchment basin was built in the storm drain system of the Padre Burgos Circle. At an Oct. 14 press conference, Singson lamented that despite a budget of between P8-P12 billion for flood control, it appeared the government could not find a permanent solution – which was why he cited the use in foreign cities of catchment basins for their storm drains. Singson cited the stretch of España Boulevard in Manila as a prime example of where to build such a storm drain system. He said that a catchment basin can be constructed under the adjacent University of Santo Tomas football field in order to prevent the road from flooding. In an interview that aired over the weekend on GMA News TV’s “Balitanghali" and GMA News “Saksi", architect Jun Palafox said he was glad that the government would finally implement what he had recommended during the Arroyo administration, which was to build catchment basins. He added that homeowners themselves could help by building smaller catchbasins in their homes. The world’s largest constructed catchment basin is the cavernous Saitama storm sewer system in Japan. It is composed of giant concrete silos 65 meters tall and 32 meters wide, connected by 6.4 kilometers of underground tunnels 50 meters below the surface. It also has a giant tank that is 25.4 meters tall, 177 meters long and 78 meters wide, with 59 concrete columns. — with a report from Jun Veneracion and Marlon Anthony Tonson/KBK, GMA News