La Mesa Dam level returns to normal

La Mesa Dam. (File photo by JOAN BONDOC / Philippine Daily Inquirer)

The water level of the La Mesa Dam, part of the system that supplies most of Metro Manila’s water for households, is now back to normal, after it dipped to “code red” status on Thursday.

The dam’s reservoir water level was at 79.38 meters as of 6 a.m. on Saturday – up by nearly a meter from Friday and Thursday’s 78.4 meters.

The normal water level of the La Mesa reservoir is from 79 to 80 meters. Anything below or above this range would merit a “code red” status, state hydrologist Richard Orendain said in a phone interview on Saturday.

Orendain works at the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa).

The increase might have been caused by the approval of a requested “inflow” from Ipo Dam, which in turn, got an inflow from Angat Dam, Orendain said.

The hydrologist noted it was the first time he observed a “critical” low level at La Mesa Dam, though decreasing water levels in dams is normal during the summer season.

Orendain credited the dip to stronger consumption of water during the dry season, which at the La Mesa Dam reached 100 cubic meters a day.

Last weekend, Pagasa appealed to the public to start conserving water, since water levels in dams would start to dip with the onset of the dry season.

Orendain said critically low levels at the Angat Dam – that is, below 180 meters – -may occur by mid-June. But that would happen if it would not rain from now until then, which is unlikely, since rains are expected in May, Orendain said.

Dams are expected to “recover” normal water levels in May.

When reservoir water levels in dams are critical, they can no longer supply water for all functions such as for irrigation, power generation, and domestic use.

If Angat Dam should reach a critically low level, the water supply for irrigation would automatically be cut, Orendain explained. /atm