The Pulangi IV Hydroelectric Power Plant, also known as the Pulangi Dam, is located on the

Pulangi River The Pulangi River ( Cebuano pronunciation IPA uˈlaŋi, also spelled Pulangui, is one of the major tributaries of the Rio Grande de Mindanao, an extensive river system in Mindanao, Philippines. With a length of , it is the longest river in Buk ...

near

Maramag Maramag, officially the Municipality of Maramag ( ceb, Lungsod sa Maramag; tl, Bayan ng Maramag), is a 1st class municipality of the Philippines, municipality in the Philippine Province, province of Bukidnon, Philippines. According to the 2020 ...

Bukidnon Bukidnon(), officially the Province of Bukidnon ( ceb, Lalawigan sa Bukidnon; fil, Lalawigan ng Bukidnon; hil, Kapuroan sang Bukidnon; Binukid and Higaonon: ''Probinsya ta Bukidnon''), is a landlocked province in the Philippines located in the ...

province on the island of

Mindanao Mindanao ( ) ( Jawi: مينداناو) is the second-largest island in the Philippines, after Luzon, and seventh-most populous island in the world. Located in the southern region of the archipelago, the island is part of an island group of ...

in the Philippines. It uses two reservoirs, produced by

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, a ...

ming the Pulangi River, to supply water to a

run-of-the-river Run-of-river hydroelectricity (ROR) or run-of-the-river hydroelectricity is a type of hydroelectric generation plant whereby little or no water storage is provided. Run-of-the-river power plants may have no water storage at all or a limited amou ...

hydroelectric Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...

power plant; the power plant is capable of generating of power. Construction began in 1982; the first two generators became operational in December 1985, with the last generator being commissioned in 1986. The upper (

pondage Pondage usually refers to the comparably small water storage behind the weir of a run-of-the-river hydroelectric power plant. Such a power plant has considerably less storage than the reservoirs of large dams and conventional hydroelectric stations ...

) reservoir located at diverts water into a power channel which parallels the river until it reaches the lower reservoir (surge pool) at , to the south. At the lower reservoir, water is fed to each of the three

Francis turbine The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency. The proces ...

-generators via a

penstock A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydro turbines and sewerage systems. The term is inherited from the earlier technology of mill ponds and watermills. H ...

. The Pulangi IV power plant provides 23% of the hydroelectric power generated on Mindanao. Since operation, the reservoirs associated with the power plant have received an estimated of sediment annually. Of the reservoir's combined active capacity, has been filled with silt. The siltation rate was almost 1 meter annually and caused the dam's reservoir to work at 50% capacity. The unexpected

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 or ...

threatens safe operation of the dams and power generation, in addition to drastically shortening the predicted operational lifespan of the dam. At first, the minimum and maximum water levels were raised and, in 2007,

dredging Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing da ...

work was performed around the head work of the upper reservoir's head. Selective dredging in the upper reservoir began in 2010, and continues as of 2011. The

artificial lake A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

created by the reservoir proper is called the Pulangi Lake or the Maramag.

References

{{Dams in the Philippines Energy infrastructure completed in 1986 Hydroelectric power plants in the Philippines Run-of-the-river power stations Buildings and structures in Bukidnon 1986 establishments in the Philippines