Pantabangan Dam

Pantabangan Dam is an earth-fill embankment dam on the Pampanga River located in Pantabangan in Nueva Ecija province of the Philippines. The multi-purpose dam provides water for irrigation and hydroelectric power generation while its reservoir, Pantabangan Lake, affords flood control. The reservoir is considered one of the largest in Southeast Asia and also one of the cleanest in the Philippines. Construction on the dam began in 1971 and it was completed in 1974.
History.
In May 1969, the Congress of the Philippines authorized the development of the Pampanga Basin with Republic Act No. 5499. In October of that year, detailed studies of the Pantabangan site were carried out and lasted two years. By June 11, 1971, Pantabangan was an old town of around 300 years old. President Ferdinand Marcos and many others arrived for a ground breaking ceremony in Palayupay, Pantabangan, Nueva Ecija, to signal the beginning of the construction of Pantabangan Dam. The dam went into operation in February 1977 and was completed later in May. Approximately 1,300 people were relocated from the dam's reservoir zone.
Design.
The dam is a tall and long embankment-type with of homogeneous earth-fill and an impervious core. The crest of the dam is wide while the widest part of its base is . The dam's crest sits at an elevation of and is composed of three sections: the main dam, a saddle dam, and an auxiliary dam located with the spillway. The spillway is a chute-type controlled by three radial gates but equipped with an overflow section as well. The design discharge of the spillway is . The dam's reservoir has a gross capacity of and of that volume is active (or useful) for irrigation and power. The dam sits at the head of a catchment area known as the Pantabangan–Carranglan Watershed Forest Reserve and its reservoir has a surface area of and elevation of when at its maximum level. The reservoir's life is estimated at 107 years due to silt from denudation. The dam was designed to withstand an intensity 8 earthquake.
The power house is located at the base of the main dam and contains two 60 MW Francis turbine-generators for an installed capacity of 120 MW. Each turbine receives water via a diameter penstock. When the water is discharged, it is released into a long tailrace channel where it re-enters the river.