Will Metro Manila be flood-free? No, says DPWH
MANILA, Philippines - Even if the government invests in a P351-billion worth flood control master plan for Metro Manila, the Department of Public Works and Highways (DPWH) said flooding will still continue in several parts of the megacity.
Speaking at the Management Association of the Philippines (MAP) General Assembly Meeting on Friday, September 21, DPWH Secretary Rogelio Singson said the master plan, which will be implemented until 2030, will be able to reduce flooding in Metro Manila by over 70%.
"Now, if you ask me, will Metro Manila be flood-free? My answer is no because there are many catchment, natural catchments in Metro Manila. What we can only do is minimize the impact or mitigate the damage," Singson said.
Singson said these natural catchment areas include San Juan, España, Araneta avenue, Boni, and Rotonda areas. These areas experience flooding even with little rainfall.
He said to be able to alleviate flooding in these areas, the government must employ different strategies such as the repair or creation of new drainage.
"There can be more than 70% reduction in flooding in Metro Manila. There are isolated areas that are really flood-prone. What we will do, because of (increased) pumping capacity, instead of several hours, you reduce it (flooding) significantly," Singson explained.
Clearing, upgrading waterways
In reducing flooding in Metro Manila, Singson said the first order of business for the government is to clear waterways of garbage, reduce siltation and relocate illegal settlers.
Singson said this will be financed by P5-billion funds granted to the DPWH to start the initial works for the flood master plan. This stage will take 15 to 18 months. It has already begun.
The DPWH official said Metro Manila's waterways now only have 30% water carrying capacity due to heavy siltation. But he said silt cannot be removed by simply dredging the waterways. He said it will require the removal of illegal settlers.
Singson said there are 120,000 families living on waterways across Metro Manila. He said this translates to 1.17 million people who are living in high-risk areas that experience flooding even with little rainfall.
"Our program for relocating them would be a 3-5 year program but as I said we are starting at the mouths of the river systems so that at least we can clear up, the mouths can start discharging water. So it has to be in a river system, it cannot be Quezon City starting first, it has to be San Juan... because the San Juan river goes all the way to Quezon City," Singson said.
He added that the waterways are also being improved. Singson said the DPWH will be using coconets, cocolumber, and vegetation as riprap on these waterways instead of concrete.
Singson explained that using concrete in waterways prevents any kind of absorption and somehow increases the velocity of water running on the waterways. Increased velocity of water also increases the amount of silt, he said.
Upgrading pumping stations
Singson also said that the DPWH, during this 15- to 18-month period will also upgrade Metro Manila's 15 pumping stations.
He said that while the plan to upgrade the city's 30-year-old pumps have been recommended as far back as 2005, it has not actually been done.
The DPWH Secretary said the pumps need to be upgraded badly because they are old and no longer have spare parts. He said the agency is closely coordinating with the Metro Manila Development Authority, which operates the pumping stations for the project.
The flood master plan will include some 11 major projects such as the rehabilitation of dikes, strengthening of seawalls, river dredging, and construction of river control works, among others. - Rappler.com