Siltation threatens Pantabangan, Angat water supply

CABANATUAN CITY , Philippines  – The water supply of some nine million people in Central Luzon is seriously being threatened because of siltation caused by degradation of surrounding watersheds in the Pantabangan and Angat Dams, the Department of Environment and Natural Resources said yesterday.

Perla Collado, DENR regional public affairs chief, told The STAR that the twin dams are the only major sources of freshwater for domestic use, irrigation and hydro-electric power generation in the region but siltation is taking its toll on its operations. She said each of the nine million people needs about 400 liters of freshwater a day for drinking, cooking and washing.

Pantabangan and Angat Dams, considered the country’s largest and third largest irrigation systems, irrigates 100,000 hectares and 26,000 hectares of farmlands in Central Luzon, respectively.

Collado said that public vigilance and cooperation is needed to stave off the impacts of water shortage amid the worsening conditions of major water systems in the region.

She said that years of public indifference and indiscriminate dumping of garbage and untreated industrial wastes also compound the problem.

According to the DENR, the 55-km. Marilao-Meycauayan-Obando river system in Bulacan which has been listed in Black Smith Institute’s “World’s 30 Dirtiest” receives at least 133,000 cubic meters of untreated wastewater each day.

Antonio Principe, DENR regional executive director, said about one million people from seven towns and cities in Bulacan and Metro Manila dispose at least 400 tons of garbage into the river system daily, further contributing to its biochemical oxygen demand loading of 57,000 kilograms a day.

BOD is the amount of dissolved oxygen consumed by microorganisms and aquatic life in a body of water. The higher the BOD level, the lower the available dissolved oxy­gen needed to support life.