Super El Niño: NIA-6 to rotate water, shrink irrigated areas

By Rjay Zuriaga Castor

ILOILO CITY — The National Irrigation Administration 6 (NIA-6) may put water deliveries to Western Visayas farmlands on a rotational schedule and reduce irrigated areas as it prepares for a forecasted super El Niño.

Engr. Andres Bonie Tuala, section chief of the NIA-6 Operation and Maintenance Section, said the adjustments will be based on water availability, hydrological data, and forecasts from the state weather bureau.

Tuala said the El Niño is expected to affect Western Visayas from late 2026 through the first quarter of 2027.

El Niño is a climate pattern marked by warmer-than-normal sea surface temperatures in the central and eastern equatorial Pacific. In the Philippines, it typically brings below-normal rainfall and increases the risk of drought in many areas.

Tuala said NIA-6 will retain its cropping calendar but reduce the areas programmed for irrigation in drought-vulnerable locations.

The first dry-season cropping period normally runs from September to December, with harvesting beginning in January. The second dry-season cropping period runs from December through April or May.

The wet-season cropping period generally starts in May or June, with harvesting around October.

For the upcoming dry season, however, NIA-6 will adjust the programmed areas based on available water and weather forecasts.

“If we program a regular 1,000 hectares and we have a vulnerable area of 300 hectares, what we program for the first dry season or the next cropping is 700 hectares. That could be the scenario. That is the reduction in areas that we explain to farmers,” Tuala told Daily Guardian.

Under that scenario, NIA-6 would irrigate 700 of the 1,000 programmed hectares.

Rotational irrigation and water-saving practices

NIA-6 will also implement rotational irrigation, in which water is distributed to different areas by turns instead of being supplied continuously to all farmlands.

Tuala said the measure is intended to maximize available water supplies and allow irrigation services to reach more agricultural areas amid the expected dry conditions.

He added that NIA-6 is also promoting water-saving measures, including alternate wetting and drying (AWD).

In AWD, farmers allow surface water to disappear and the field to dry to a controlled level before irrigating again, instead of keeping paddies continuously flooded.

Rice research institutions, including the International Rice Research Institute, promote the technique as a way to reduce irrigation water use.

“Our irrigators’ associations are well informed so that they would have the option on what to do so that we can cope with the devastation and damages of the impending super El Niño,” Tuala added.

Drought-vulnerable areas

NIA-6 has also submitted to its central office a list of areas identified as vulnerable to drought, along with proposed mitigation measures, including pumps and shallow tube wells, Tuala said.

He said the proposals are under evaluation to determine whether the planned facilities are properly located in the vulnerable areas and whether the number of shallow tube wells should be increased or reduced.

Tuala said downstream portions of irrigation systems are expected to face greater challenges because water can be delivered more easily to upstream areas.

“Basically, what we are seeing to have extreme effects are the downstream portions because the upstream can be easily delivered with water, but the end-of-the-line farms would have a challenge,” Tuala said.

NIA-6 is also ramping up the desilting of irrigation canals to improve water delivery efficiency.

Water levels remain stable

Tuala said water levels in the dams monitored by the agency remain stable for now, with the effects of El Niño not yet strongly felt in Western Visayas.

“So far, the water level has only slightly decreased, and we are currently in the harvesting season. But in the coming months, we may already see reports of reduced irrigated areas and begin to feel the impact of El Niño,” he said.

NIA-6 manages about 45,000 hectares under its national irrigation systems, including areas in Negros Occidental, while its communal irrigation systems cover more than 32,000 hectares.