Magat Dam is a large rock-fill

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...

in the island of

Luzon Luzon ( , ) is the largest and most populous List of islands in the Philippines, island in the Philippines. Located in the northern portion of the List of islands of the Philippines, Philippine archipelago, it is the economic and political ce ...

in the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

. The dam is located along the

Magat River The Magat River is a river in the Philippine island of Luzon with a total length of . It originates in the Nueva Vizcaya municipality of Aritao, where the Santa Fe River joins the Marang. It is the largest tributary of the Cagayan River by ...

, a major tributary of the

Cagayan River The Cagayan River, also known as the Río Grande de Cagayán, is the longest river and the largest river by discharge volume of water in the Philippines. It has a total length of approximately and a drainage basin covering . It is located in ...

. The construction of the dam started in 1975 and was completed in 1982. It is one of the largest dams in the Philippines. It is a multi-purpose dam which is used primarily for irrigating about of agricultural lands,

flood control Flood management or flood control are methods used to reduce or prevent the detrimental effects of flood waters. Flooding can be caused by a mix of both natural processes, such as extreme weather upstream, and human changes to waterbodies and ru ...

, and power generation through the Magat Hydroelectric Power Plant. The water stored in the reservoir is enough to supply about two months of normal energy requirements.

History

The construction and appurtenant structures were authorized by Presidential Decree No/ 693 signed on May 7, 1975, by then President

Ferdinand E. Marcos Ferdinand Emmanuel Edralin Marcos Sr. (September 11, 1917 – September 28, 1989) was a Filipino lawyer, politician, dictator, and kleptocrat who served as the tenth president of the Philippines from 1965 to 1986. He ruled the country under ...

. The Magat Dam was constructed in 1978, inaugurated by Marcos on October 27, 1982, and started operations in 1983. Implementation of this multipurpose project was based on the preliminary study conducted in 1973 by the

National Irrigation Administration The National Irrigation Administration (NIA; ) is a government-owned and controlled corporation of the Philippine government responsible for irrigation development and management in the Philippines. History NIA was created under Republic Act ( ...

(NIA) with the assistance of the

United States Bureau of Reclamation The Bureau of Reclamation, formerly the United States Reclamation Service, is a federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it applies to the oversight and operatio ...

(USBR) and the

United States Agency for International Development The United States Agency for International Development (USAID) is an agency of the United States government that has been responsible for administering civilian foreign aid and development assistance. Established in 1961 and reorganized in 1998 ...

(USAID). Subsequent detailed and extensive dam site investigation and engineering studies further confirmed the feasibility of what is now known as NIA's most daring infrastructure project and one of Asia's biggest dams today. It was

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

's first large multipurpose dam. The dam is part of the Magat River Multipurpose Project (MRMP) which was financed by the

World Bank The World Bank is an international financial institution that provides loans and Grant (money), grants to the governments of Least developed countries, low- and Developing country, middle-income countries for the purposes of economic development ...

and whose purpose is to improve on the existing Magat River Irrigation System (MARIS) and to triple the production of rice in the

basin. The project was jointly financed by the

Philippine Government The government of the Philippines () has three interdependent branches: the legislative, executive, and judicial branches. The Philippines is governed as a unitary state under a presidential representative and democratic constitutional repub ...

and the

which extended a US$150M loan to finance the foreign exchange requirement. In addition, a US$9M loan from

Bahrain Bahrain, officially the Kingdom of Bahrain, is an island country in West Asia. Situated on the Persian Gulf, it comprises a small archipelago of 50 natural islands and an additional 33 artificial islands, centered on Bahrain Island, which mak ...

was obtained for the purchase of other equipment for the diversion tunnel, soil laboratory and model testing. The total project cost is US$3.4B (yr. 1975). The dam was constructed to last for 50 years but increased

siltation Siltation is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary o ...

and

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to th ...

in the reservoir,

slash-and-burn Slash-and-burn agriculture is a form of shifting cultivation that involves the cutting and burning of plants in a forest or woodland to create a Field (agriculture), field called a swidden. The method begins by cutting down the trees and woody p ...

farming,

illegal logging Illegal logging is the harvest, transportation, purchase, or sale of timber in violation of laws. The harvesting procedure itself may be illegal, including using corrupt means to gain access to forests; extraction without permission, or from a p ...

and fish-caging resulted in the deterioration of the dam's watershed. The

1990 Luzon earthquake The 1990 Luzon earthquake occurred on July 16 at 4:26 p.m. (Daylight saving time in the Philippines, PDT) or 3:26 p.m. (Philippine Standard Time, PST) on the densely populated island of Luzon in the Philippines. The shock had a surfac ...

also contributed to the increased siltation in the Magat River system. Because of this, in January 2006, then President

Gloria Macapagal Arroyo Maria Gloria Macaraeg Macapagal-Arroyo (; born April 5, 1947), often referred to as PGMA or GMA, is a Filipino academic and politician who served as the 14th president of the Philippines from Presidency of Gloria Macapagal-Arroyo, 2001 to 2010 ...

instructed various government agencies to create a rehabilitation plan to improve the lifespan of the dam system. The non-power components such as the dam, reservoir, and intake gates are owned, operated, and managed by the

(NIA). The hydroelectric plant was formerly owned by the

National Power Corporation The National Power Corporation (, also known as NAPOCOR, NPC or National Power) is a Philippine government-owned and controlled corporation that is mandated to provide electricity to all rural areas of the Philippines by 2025 (known as "mission ...

(NAPOCOR). Under the Electric Power Industry Reform Act of 2001 (

Republic Act This article contains a partial list of Philippine laws. Sources of Philippine laws ;Notes : *Customs may be considered as supplementary source of law, however, customs which are contrary to law, public order or public policy shall not ...

No. 9136), the Magat hydroelectric power plant underwent a

privatization Privatization (rendered privatisation in British English) can mean several different things, most commonly referring to moving something from the public sector into the private sector. It is also sometimes used as a synonym for deregulation w ...

process. As a result, the plant's ownership and operation was turned over to SN Aboitiz Power-Magat, Inc. (SNAP-Magat), a joint venture of a local company,

Aboitiz Power Corporation Aboitiz Power Corporation also known as AboitizPower (AP), a subsidiary of Aboitiz Equity Ventures (AEV), is a holding company engaged in power distribution, generation and retail electricity services. Background Aboitiz Power Corporation w ...

(AP), and a Norwegian firm SN Power in April 2007. SNAP won the bidding in 2006.

Geography

The dam is located within the boundaries of Namillangan,

Alfonso Lista Alfonso Lista, formerly known as Potia, officially the Municipality of Lista is a municipality in the province of Ifugao, Philippines. According to the 2020 census, it has a population of 34,061 people. History Potia was created as the municip ...

Ifugao Ifugao, officially the Province of Ifugao (; ), is a landlocked province of the Philippines in the Cordillera Administrative Region in Luzon. Its capital is Lagawe and it borders Benguet to the west, Mountain Province to the north, Isabela t ...

and Ramon, Isabela, approximately north of

Metro Manila Metropolitan Manila ( ), commonly shortened to Metro Manila and formally the National Capital Region (NCR; ), is the capital region and largest List of metropolitan areas in the Philippines, metropolitan area of the Philippines. Located ...

Magat River

The Magat Dam is on the

, which is the largest tributary of the

on the island of

.The Cagayan River Basin
– PAGASA. ''Accessed on April 21, 2008.'' Cagayan is the longest river in the Philippines. The Magat River has an estimated yearly water discharge of 9,808 million cubic metres and has an approximate crest length of with its headwaters in the province of

Nueva Vizcaya Nueva Vizcaya, officially the Province of Nueva Vizcaya (; ; Pangasinan: ''Luyag/Probinsia na Nueva Vizcaya''; ), is a landlocked province in the Philippines located in the Cagayan Valley region in Luzon. Its capital and largest town is Bayo ...

and its confluence with the Cagayan River in the province of Isabela.

Features

Spillway

* Length: * Width: * Discharge capacity: 30,600 cubic meters * Radial Gates: 7 sets * Orifice Gates: 2 sets

Diversion tunnels

* Number: 2 * Diameter: * Average length:

Reservoir

* Storage Capacity at Full Supply Level (FSL): 1.08 billion cubic meters * Elevation at FSL: 193 masl * Minimum Supply Level: 160 masl * Maximum Flood Level: 193 masl

Power

* Installed capacity: 360

MegaWatts The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named in honor o ...

* Turbine: 4 units, Francis vertical shaft * Generator: 4 units x 90 MW, vertical synchronous

Access

It is connected by an all-weather road to San Mateo–Santiago Road at Oscariz, Ramon, Isabela some north of Metro Manila.

Magat Hydro

The Magat

hydroelectric power Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

plant is a four-unit powerhouse with an installed capacity of 360

megawatt The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...

s.Magat Hydro: Environmental & Social Review Summary
– International Finance Corporation (World Bank) It is designed to accommodate two more units that will allow it to generate up to 540 megawatts. The hydroelectric plant is a

peaking power plant Peaking power plants, also known as peaker plants, and occasionally just "peakers", are power plants that generally run only when there is a high demand, known as peak demand, for electricity. Because they supply power only occasionally, the powe ...

, which means that it only operates when there is a high demand for electricity in the Luzon power grid, to which the plant is connected. It is capable of providing

ancillary services Ancillary services are the services necessary to support the transmission of electric power from power plant, generators to consumers given the obligations of control areas and transmission utilities within those control areas to maintain reliable ...

for the stability of the grid, and was augmented by a 24 MW

battery Battery or batterie most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source * Battery indicator, a device whic ...

in 2024. SN Aboitiz Power-Magat, Inc. completed the half-life refurbishment of the Magat Hydroelectric Power Plant in 2014. Refurbishment began in 2009 and was completed in June 2014. Half-life refurbishment ensures that the power plant facility remains available throughout its life span.

Discharge-induced floods

In November 2020, Typhoon Vamco (locally known in the Philippines as Typhoon Ulysses) crossed the country, dams from all around Luzon neared their spilling points, forcing them to release large amounts of water into their impounds including Magat Dam. The dam opened all of its 7 gates at , releasing over 5,037 cubic metres (1,331,000 US gal) of water into the Cagayan River flooding numerous riverside towns. Waters under the Buntun Bridge went up as high as , flooding the nearby barangays up to the roofs of houses. Prior to the flooding, the National Irrigation Administration (NIA) said Sunday it had already warned residents of Cagayan and Isabela of Magat Dam's water release two days prior to Typhoon Ulysses' landfall on November 11. As a result of the catastrophe, the NIA said that it will review its protocols regarding the release of water in Magat Dam and improve its watershed.

References

External links

* {{Dams in the Philippines Dams completed in 1983 Dams in the Philippines Hydroelectric power plants in the Philippines Buildings and structures in Isabela (province) Tourist attractions in Isabela (province) Establishments by Philippine presidential decree