UP resilience expert: Restoring forest cover is effective flood control

A geologist and resilience expert of the University of the Philippines urged the restoration of the forest cover and other measures to help mitigate the perennial floods during typhoon season, instead of building more dikes.

In Ian Cruz’s report in “24 Oras” on Thursday, UP Resilience Institute and NOAH Center executive director Mahar Lagmay said the forest cover that vanished in the past two decades must be restored. 

He added that there must be a retention basin, as well as flow-through or mini dams that could help control floods.

He also suggested the conduct of rain water harvesting and the establishment of pumping stations to expel the water out to the sea. 

Lagmay stressed that the construction of dikes must be the last option.

“Ang dike na ‘yun mas magiging epektibo pa kasi nabawasan na yung baha. So yung ngayon na palaging dike, mas malaki na yung baha, ay aapaw,” he said. 

(That dike will be even more effective because the flood has already been reduced. So, the current practice of always building dikes when the floods are high will just cause the dikes to overflow.)

“Pero kapag in-exhaust mo muna, ginamitan mo muna ng paraan, naglagay ka ng mga iba-ibang solusyon, patong-patong na solusyon, at saka ka magi-isip ng dike para maging epektibo siya, mas mura, at mas sustainable,” he added.    

(But when you have exhausted other measures first, when you put various solutions together and then you add a dike, it will be more effective, cheaper, and more sustainable.) 

On Wednesday, Department of Public Works and Highways (DPWH) Secretary Vince Dizon visited Talisay City and Mandaue City in Cebu, which were among those heavily flooded at the height of Typhoon Tino.

Dizon said the dikes and revetments in the said cities were not able to hold the large volumes of rainwater dumped by the typhoon.

“Dalawang rivers ang talagang umapaw ng todo-todo. ‘Yung Mananga River na nag-o-originate sa mga bundok sa Cebu City pababa ng Talisay,” the DPWH chief said.

(Two rivers really overflowed completely. The Mananga River, which originates from the mountains in Cebu City, going down to Talisay.) 

“At yung Butuanon River na nanggagaling din sa bundok sa Cebu City pababa naman papuntang Mandaue. ‘Yung mga nakita nating mga grabeng pinsalang dinulot doon sa dalawang ilog na malalaking ‘yun.”

(And the Butuanon River, which also comes from the mountains in Cebu City, going down to Mandaue. Those were the severely damaged areas we saw caused, by those two large rivers.) 

Cebu has P26.7 billion worth of flood control projects. According to data from the Sumbong sa Pangulo website, there are 19 flood control projects in Mananga River worth P2 billion and there are 17 flood control projects amounting to P1.4 billion. 

“Ang dike can only take you so much. Ibig sabihin ‘pag normal na baha o normal na ulan, okay, kaya ng dike. Pero ‘yung mga ganitong klase na once in 20 years na bagyo, hindi kaya ‘yan,” said Dizon. 

(The dike can only take you so much. Meaning, during a normal flood or normal rain, okay, the dike can handle it. But these kinds of once-in-20-years typhoons, it cannot handle that.) 

“Ang isa sa mga pinaka-importanteng flood control, ay ‘yung pagko-control ng daloy ng tubig na nanggagaling sa upstream ng isang ilog pababa, ‘yun ang wala.” 

(One of the most important flood control measures, which is missing, is controlling the water flow from upstream, going down the river.) — Vince Angelo Ferreras/JMA, GMA Integrated News