MANILA, Philippines - The Department of Public Works and Highways (DPWH) plans to put up retention tanks in at least nine different locations in Metro Manila to address the problem of heavy flooding spawned by heavy rains.
DPWH Secretary Rogelio Singson yesterday said the construction of retention tanks or retarding basins is one of the doable flood control projects that the DPWH could undertake.
The DPWH earlier proposed to officials of the University of Sto. Tomas, the construction of a retention tank beneath its football field. A similar project is being planned along Mother Ignacia street in Quezon City.
Singson said the DPWH is identifying the other flood-prone areas with the help of the Metropolitan Manila Development Authority. He said those that are near waterways will be given priority.
“We want to do a permanent solution and the permanent solution is to put the excess water during height of heavy rains underneath. As of now the city drainage system could not contain the inflows from all the drainage pipes,” Singson said.
“There is a high peak flow of rainwater. We have to retard that peak flow, to reduce the peak flow so that it would not be added to the rainfall,” he added.
Singson said they are still finalizing the design of the retention tanks and will be consulting the affected residents and institutions. He said he hopes to start working on the retention tanks by next year.
He said funding for the project will come from the flood control budget of the agency.
The DPWH secretary said the usefulness of the basin has been proven in Fort Bonifacio, where a retention tank with a diameter of 72 meters is placed under the Burgos Circle.
“You hold it (water) there and pump it out based on the capacity of the creek. Otherwise, if all the water in the drainage pipe are released to the creek, it would flood EDSA and Kalayaan Avenue,” Singson said.
Singson said that there is also a retarding basin along Magallanes Avenue that measures seven hectares. But he said the basin has not been used to its full capacity because there are illegal occupants in the area.
However, Singson, said the retention tank is not a generic solution for all. He said pumping stations are needed to address flooding in low-lying areas in the Caloocan-Malabon-Navotas-Valenzuela area.