MMDA wages war on water hyacinths

The Metropolitan Manila Development Authority (MMDA) has started using a locally developed “water hyacinth harvester” to speed up the removal of the fast-growing aquatic plant, a river-choking nuisance partly blamed for flooding in the metropolis.

MMDA General Manager Corazon Jimenez said the boat-mounted harvester, developed by engineers from the Department of Science and Technology (DOST), could be used in major rivers in the capital to clear these of water hyacinths daily.

“I think we can use this machine on a daily basis, say, for the Pasig River,” she told reporters during the inaugural operation of the machine at the MMDA Pumping Station in Barangay Wawa, Taguig City, on Wednesday.

“Think of it as a street sweeper which travels through the river, clearing water hyacinths on a daily basis,” she added.

According to engineers Lemuel Apusaga and Jorge Garcia, the machine, which resembles a steamroller because it has two water wheels that propel it on both sides, can harvest 200 kilos of water hyacinths in one go.

The machine cuts through water hyacinth beds and sends the chopped-up vegetation down a conveyor belt and into a collecting boat.

“If it needs to clear one hectare of hyacinths, it can do it at around 20 days if the machine is operated eight hours a day. We can spend some P6,000 worth of diesel for the operation, which is quite (efficient),” he said.

Jimenez said they can use the machine in several locations in Metro Manila where residents often complain of heavy water hyacinth growth, which could double in size in a week.

“We are hoping we could get one for the Manggahan floodway in Pasig. The local government there always asks us to clear the area of water hyacinths,” she said.

Other areas like Las Piñas, Taguig, and the Camanava (Caloocan, Malabon, Navotas, and Valenzuela) areas could also use the machine, MMDA official added.

Jimenez believes that the harvester is more cost-efficient compared to the backhoes mounted on barges which the MMDA currently uses.

DOST Secretary Mario Montejo said the machine, conceptualized in the aftermath of the Cotabato floods last year which were largely blamed on water hyacinths clogging Rio Grande de Mindanao, can be built on a bigger or smaller scale depending on the needs of the local governments.

“We are looking at building 10 more of these this year. It is fully customizable,” Montejo said.

Jimenez described the water hyacinth as the “most damaging plant worldwide,” citing infestations on major  waterways in North and South America, Africa and in other Southeast Asian countries.

Montejo said the plant spreads quickly in any weather condition in the Philippines, especially in dirty water.

Aside from causing floods, thick hyacinth beds also prevent sunlight from penetrating deep into the water, killing underwater plants and eventually the fish and other aquatic life forms that depend on them.