News update Water in Angat Dam dips to critical level

The water level in Angat Dam dipped Sunday to 159.87 meters, lower than the allowable elevation of the reservoir to fully supply 97 percent of Metro Manila's domestic water needs.

Due to the declining water level in the dam, the plant operations will be temporarily be stopped from July 7 to 9 to protect its turbines from breakage.

The water level dropped to 159.87 meters from 160.12 meters last Saturday, reflecting a deficit of 21.78 meters from Angat Dam's its normal operating level.

In a report over radio station DZBB last Saturday, Angat Dam plant manager Engineer Rodolfo German said the dam will temporarily stop its operations from July 7 to 9 to protect the Angat Dam's turbines from breakage.

This is in light of the continuous drop in the Angat Dam's elevation.

The dam has been designed to keep its elevation to more than 160 meters because an elevation below that mark could cause ''cavitation'' or collapse in the rubber plates of the turbines.

However, German assured that the domestic water supply of Metro Manila residents will not be affected by the three-day suspension on the Dam's operation.

The dam is also the source of irrigation for 27,000 hectares of agricultural land in Bulacan and Pampanga.

Metro Manila will likely source additional water supply from Ipo Dam in Bulacan (with an elevation of 100 meters) or from La Mesa Dam (78.26 meters) in Quezon City.

Water is normally transmitted from Angat Dam through tunnels down to Ipo Dam, which serves as ''an intermediate intake,'' passing through another set of tunnels and further goes down to the La Mesa Dam.

Metro Manila's current water allocation is 35 cubic meters per second (cm) or 3.045 million liters per day (MLD).

Due to the decreasing water in Angat Dam, the present allocation has been reduced 24 percent from the normal 46 cms to 35 cms earlier this year.

The National Water Resources Board (NRWB), the lead government agency that regulates the country's water resources, aimed to prevent the dam's elevation from falling below 160 meters by the end of last June because the water outlet going to Metro Manila operates above a 160-meter level.

Data from the NWRB show that the Dam's lowest level recorded in history was in July, 1998, with 158 meters.

Dr. Susan Espinueva, Philippine Atmospheric, Geophysical, and Astronomical Services Administration's (PAGASA) chief hydrometeorologist, said at least 600 millimeters of rainfall, equivalent to two storms, will be needed to achieve Angat Dam's normal level.

''Although the daily rate of Angat Dam is at 20 centimeters, which is lower than the 50-centimeter per day decline in April and May, the water decrease is still significant,'' Espinueva had earlier pointed out.

The PAGASA official said Angat Dam's water level is expected to normalize in August with the expected arrival of strong typhoons.

''The situation is similar to a dry spell in May, 2007, that caused a summer-like condition in the country. It was only in August, 2007, when storms arrived and brought significant increase in the reservoir. One storm caused about eight-meter increase in the dam's level during that time,'' she explained.

Espinueva noted that the average rainfall during August is from 200 to 300 millimeters.