NORZAGARAY, Bulacan?Gene Briones was busy with just one task on Tuesday: Spot clouds.

The cloud-seeding operation that she and her team will do in the next two months will help decide if Bulacan and Pampanga farmers can irrigate 30,000 hectares of farms or if 10 million Metro Manila residents can enjoy enough drinking water.

The success of the operation will also determine if the National Power Corp. (Napocor) can produce electricity from the water?s outflow.

The Thailand-trained Briones said the job was difficult, given the wind pattern in this part of the Sierra Madre mountains.

?Cloud identifier?

The first round of cloud seeding ended on July 22 but the water rose from 157 meters above sea level (masl) in April to only 169 masl on Tuesday, said Briones, a ?cloud identifier? of the Bureau of Soils and Water Management (BSWM).

But the rains hardly helped, said Rodolfo German, general manager of Angat River Hydroelectric Power Plant (Arhepp), a facility run by the Napocor in Angat Dam.

?[The 169 masl] is not sufficient. We can?t release [water] for irrigation,? German said.

That level, which is several meters from the ideal 180 masl, is part of the continuing effect of El Niño in 2009, he said. This abnormal rise in the temperature of the surface of the Pacific Ocean leads to, among other things, a long dry spell.

1967 dam

The dam, which opened for multiple uses (power, irrigation, drinking water and flood forecasting) in 1967, experienced low water levels in 1992, 1998 and 2003, said German.

?We need nonstop rains that will last for a week. We need strong southwest monsoons and tropical cyclones,? he said.

Angat Dam, covering 23 square kilometers, is now fed through a tunnel by the Umiray River in the boundaries of Aurora and Quezon provinces on the other side of the Sierra Madre.

Backed by a team sent by BSWM Director Silvino Tejada in Plaridel, Bulacan, Briones scans for clouds that can be filled with vacuum-dried iodized salt to produce rain.

The task was contracted by the Metropolitan Waterworks and Sewerage System for its concessionaires, Maynilad Water Services Inc. and Manila Water.

?We?re doing this to produce water for drinking and irrigation,? Briones said.

In July, operators of the dam shut down the power-generating facility for three days to avoid equipment damage.

The Angat plant has been producing at least 10 megawatts of electricity that contribute daily power to the Luzon grid.