Drought-resistant crop to replace rice once Isabela’s Magat Dam shuts down

SAN MATEO, Isabela — If the national government continues to ignore Magat Dam’s continuing degradation, soon, this province may shift to a drought-resistant crop once Luzon’s vital source of irrigation shuts down due to massive siltation.

This early, the local government is already considering transforming the vast rice fields here into a munggo plantation as the Magat Hydro-electric Dam in neighboring Ramon town is feared to cease operation in about 15 years if siltation, which has been clogging the dam’s waterways, cannot be stopped.

Mayor Roberto Agcaoli yesterday said that munggo could be the most potent crop suited for droughts in case the dam shuts down as a result of siltation as well as illegal cutting of trees within and near the dam’s periphery.

Cultivation of munggo, he said, is one of the province’s alternative measures to replace rice as a major crop once the 22-year-old Magat Dam’s projected lifespan is shortened.

Earlier, officials of the National Irrigation Administration (NIA) predicted that the lifespan of Southeast Asia’s first biggest multi-purpose dam has been radically reduced to 36 years due to siltation, slash-and-burn farming, fish caging and illegal tree-cutting.

The dam’s original lifespan was 50 years, but the 1990 earthquake that hit Northern Luzon caused a lot of landslides that heavily silted all major and minor tributaries of the Magat River’s networks.

Agcaoili said that he foresees the catastrophic end of the dam sooner than designed if rehabilitation measures are not implemented immediately.

Engineer Vicente Galvez, NIA director for Cagayan Valley, said the government has to spend millions of pesos to have the dam desilted. Massive reforestation is also necessary as well as banning of farm activities, especially kaingin in the immediate vicinity of the dam’s watershed.

But while the government has yet to act on it, Agcaoili said that the local government of Isabela is now considering alternative crops. "While the catastrophic end of the dam as predicted is alarming, we are now preparing to face such realities. Once our rice farms will no longer be irrigated, we can transform them into munggo plantations.

A high-value crop, munggo, or balatong in the local term, is drought-resistant. This crop is also said to be one of the riches sources of protein, calcium and iron.

This town has at least 7,000 hectares of munggo plantations. Agcaoili said that all the province’s farmlands could be converted to such plantations once the Magat dam cease supplying irrigation waters.

"Cultivating the drought-resistant crop also enhances and preserves the fertility of the soil because of the nitrogen fixing bacteria that dwell in its root system," he said.

Save Magat project

Last month, in an effort to save the Magat dam from its projected shortened lifespan, the San Mateo local government and other concerned agencies, including the Department of Environment and Natural Resources (DENR) and the National Irrigation Administration-Dam and River Division (NIA-DRD) forged a partnership for a 25-year rehabilitation of the dam.

NIA-DRD has allocated 50 hectares within the Magat River watershed for immediate rehabilitation while the Department of Environment and Natural Resources (DENR) shall assist the local government in planning and implementation of development activities, particularly nursery operations, plantation establishment, maintenance and protection.

The local government will also provide funds and manage directly the implementation of the reforestation project.

Besides Ramon and Santa Mateo towns, which are the dam’s major impact area, there are at least 20 other major rice-producing towns benefiting from the irrigation waters provided by the dam.