Thousands of farmers in Bulacan and Pampanga are losing much-needed irrigation water during the past 40 years due to the diversion of water from Angat Dam to supply Metro Manila and adjacent provinces.

This admission was made in a press briefing by Arthur de la Cruz of the operations department of the National Irrigation Administration.

The National Water Resources Board stressed that officially, NIA had been allocated 36 cubic meters per second (CMS) from Angat Dam daily, but it only uses 21 CMS at the minimum and 28 CMS at the maximum.

The NWRB, the only agency that can allocate water nationwide and is mandated to grant water rights for utilities, said the Metropolitan Waterworks and Sewerage System gets 15 CMS from Angat daily.

As a result of this diversion, the NIA could only supply its irrigation systems in Bulacan and Pampanga with water to serve 89 percent of the 33,000 hectares it was supposed to cover, meaning that 3,630 hectares are left to rely on rainfall.

All told, NIA said, a total of 6,335 tons of palay are lost per harvest, or 3,167 tons of rice. Using 25 kilos per sack, the total grain production not realized by farmers would be 126,680 sacks per harvest. Rice farms in Central Luzon ordinarily have two cropping seasons per year.

Once Angat Dam is privatized by the Public Sector Assets and Liabilities Management Corp. (PSALM), Metro Manila would most likely lose the water diverted to irrigation since the turbines through which the irrigation water passes can produce 200 megawatts (MW) of power.

On the other hand, the turbines through which the water destined for Metro Manila pass could only generate 67 MW of electricity.

Thus, whoever wins ownership of Angat Dam would have to reduce or cut the supply to MWSS altogether to secure the maximum output of power. Angat Dam is owned by the National Power Corp.

Thousands of farmers in Central Luzon had been badgering Napocor to restore the diverted irrigation water in order for them to maximize rice production and thus strengthen the country’s food security.

Angat Dam is the only source of potable water for Metro Manila, says MWSS administrator Diosdado Jose Allado, and its privatization would result in reduced water supply for the national capital region.

MWSS deputy administrator Isaias Bongar Jr. said this is the principal reason why another water source has to be developed soonest because by 2015, when the population of Metro Manila shall have grown to 15 million, an acute water shortage would hit the region.