Magat Dam is a large rock-fill dam on the island of Luzon in the Philippines. The dam is located on Magat River, a major tributary of Cagayan River. Construction of the dam started in 1975 and completed in 1982. Magat Dam is one of the largest dams in the Philippines and has two primary purposes: as a source of irrigation water and as a provider of hydroelectric power.

Source:  http://en.wikipedia.org/wiki/Magat_Dam