LAGUNA, Philippines-- Laguna Lake Development Authority (LLDA) general manager Rodrigo E. Cabrera welcomed Friday the move to “rainforest” the Marikina Watershed.

“Rainforestation” means the replanting of forested areas with indigenous tree species, in contrast to other projects that emphasize quick-growing commercial trees.

Cabrera said the watershed needs to have a forest cover of about 54 percent to ensure that the watershed, now estimated at only 16,574 hectares, will continue to provide groundwater reserves.

Technically, a watershed is an area that drains to a common body of water, such as a river, lake, estuary, wetland, aquifer, or even the ocean.

In Executive Order 33 of 1904, the Marikina Watershed Reservation was declared a protected area since it was the water source of Manila and covered 28,410 hectares in Antipolo, Montalban, Baras and Tanay.

The surface water from Boso-Boso and Tayabasan Rivers flows to the Marikina River and down to Marikina, Pasig and Cainta.

Cabrera said the watershed has been the source of silt that eventually ends up at the Pasig River and down to the Laguna de Bay.

No less than 4.5 million metric tons of silt come from the watershed and contribute to the further shallowing of the Laguna de Bay, the country’s biggest lake at 94,900 hectares.

Ramon Isberto of the Philippine Disaster Recovery Foundation (PDRF) has raised the ante on the rainforestation bid for the Marikina Watershed by mounting a 12-mall tour of the exhibit on the need to reforest the area.

Baggerwerken Decloedt en Zoon (BDC), the Belgian company contracted by the Department of Environment and Natural Resources (DENR) to undertake the dredging of the Laguna de Bay, also supported the rainforestation program and agreed to support it.

Dimitry Detilleux, BDC North Asia area manager, said watershed protection is required to reduce the silting of Laguna de Bay and check the incursion of millions of tons silt that would wreak havoc on the country’s biggest lake.

However, Detilleux said the quickest way to reduce siltation in Laguna de Bay was to establish silt traps that are deep enough to catch the silt that would otherwise settle at the lake.

This is an immediate need, he added, since trees take a long time to grow while the traps can work in at least three points of the lake from the three rivers that empty into Laguna de Bay.

Nonetheless, these silt traps may no longer be created since the Philippine government is adamant in canceling the Laguna Lake Rehabilitation Project (LLRP) that his company had proposed.

This month, BDC is bringing an arbitration case against the Philippine government before the International Center for the Settlement of Investment Disputes (ICSID) in Washington, D.C.

Laguna de Bay is also a big source of water for Maynilad Water, and reports say the company will be harvesting up to 600 million liters per day from the lake to provide potable water for residents in areas south of Manila.