The Bhumibol Dam is a concrete arch dam

Arch dam

An arch dam is a type of dam that is curved and commonly built with concrete. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes...

 on the Ping River

Ping River

The Ping River , along with the Nan River, is one of the two main contributaries of Chao Phraya River. It originates at Doi Chiang Dao in Chiang Dao district, Chiang Mai Province. After passing Chiang Mai town, it flows though the provinces Lamphun, Tak, and Kamphaeng Phet...

, a tributary of the Chao Phraya River

Chao Phraya River

The Chao Phraya is a major river in Thailand, with its low alluvial plain forming the centre of the country. It runs through Bangkok, the capital city, and then empties into the Gulf of Thailand.-Etymology:...

, in Amphoe Sam Ngao

Amphoe Sam Ngao

Sam Ngao is the northernmost district of Tak Province, northern Thailand.-History:The minor district was established in 1930 as a subordinate of Ban Tak district. Originally named Tha Pui , it was renamed to Sam Ngao in 1939...

 district of Tak Province

Tak Province

Tak is one of the northern provinces of Thailand. Neighboring provinces are Mae Hong Son, Chiang Mai, Lamphun, Lampang, Sukhothai, Kamphaeng Phet, Nakhon Sawan, Uthai Thani and Kanchanaburi...

, Thailand

Thailand

Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...

. It is located about 480 km (298 mi) north of Bangkok and was built for the purposes of water storage, hydroelectric power production, flood control, fisheries and saltwater intrusion

Saltwater intrusion

Saltwater intrusion is the movement of saline water into freshwater aquifers. Most often, it is caused by ground-water pumping from coastal wells, or from construction of navigation channels or oil field canals. The channels and canals provide conduits for salt water to be brought into fresh...

 management. The dam was named after King Bhumibol Adulyadej and was Thailand's first multi-purpose project.

Background

The Bhumibol Dam among others in the Chao Phraya basin were constructed beginning in the 1950s to exploit the agricultural and hydroelectric potential of the basin. Construction on the dam began in 1958 and was finished in 1964 while the reservoir was completely filled in 1970. The first two generators were commissioned in 1964. In 1972, the Sirikit Dam

Sirikit Dam

The Queen Sirikit Dam is an embankment dam on the Nan River, a tributary of the Chao Phraya River, in Uttaradit Province, Thailand. The dam was built for the purpose of irrigation, flood control and hydroelectric power production...

 was completed on the Nan River

Nan River

The Nan River is a river in Thailand. It is one of the most important tributaries of the Chao Phraya River.-Geography:The Nan River originates in Nan Province. The provinces along the river after Nan Province are Uttaradit, Phitsanulok and Phichit. The Yom River joins the Nan River at Chum Saeng...

, one of two major tributaries of the Chao Phraya including the Ping. The Bhumibol and Sirkit Dams control 22% of the Chao Phraya's annual runoff combined. Both dams also help provide for the irrigation of 1200000 ha (4,633 sq mi) in the wet season and 480000 ha (1,853 sq mi) in the dry season. The dam's power house underwent extensive upgrades and renovations in the 1990s. In 1991, the Lower Mae Ping Dam (17°14′31"N 99°00′58"E) was constructed 5 km (3 mi) downstream to create a lower reservoir for the one pumped-storage turbine that was installed. When constructed, the Bhumibol Dam contributed 22% of Thailand's power generation and in 2003 that number was 2%.

During the 2011 Thailand floods

2011 Thailand floods

Major floods are occurring during the 2011 monsoon season in Thailand, most severely in the Chao Phraya but also in the Mekong River basin. Beginning in late July and continuing for over three months, the floods have caused 602 reported deaths by early November, affected over 2.3 million people,...

, rainfall for March 2011 over the area of northern Thailand

Northern Thailand

Thailand's northern region is geographically characterised by multiple mountain ranges which continue from the Shan Hills in bordering Myanmar and Laos, and the river valleys which cut through them...

 was an extraordinary 344% above normal. Bhumibol Dam in particular got 242.8 mm of rain, 224.7 mm above the mean

Mean

In statistics, mean has two related meanings:* the arithmetic mean .* the expected value of a random variable, which is also called the population mean....

 of 25.2 mm; and since 1 January had accumulated 245.9 mm, 216.0 mm or 186% above normal.

Design

The dam is an arch-gravity type and is 154 m (505 ft) tall, 486 m (1,594 ft) long and 8 m (26 ft) wide at its crest. It withholds a reservoir of 13462000000 cubic metre of which 9762000000 cubic metre is active or "useful" storage. The dam's catchment area is 26400 km² (10,193 sq mi)
while its surface area is 300 km² (116 sq mi). Its power plant contains eight different turbines for an installed capacity of 749 MW. Of the eight, six are 76.5 MW Francis-type

Francis turbine

The Francis turbine is a type of water turbine that was developed by James B. Francis in Lowell, Massachusetts. It is an inward-flow reaction turbine that combines radial and axial flow concepts....

, one is a 115 MW Pelton turbine and one is a 175 MW Francis pump-turbine. The Lower Mae Ping Dam is 8 m (26 ft) high, 300 m (984 ft) long and has a storage capacity of 5000000 cubic metre. In off-peak hours, the one pump-turbine returns water back into the Bhumibol (upper) reservoir and when demand is high, the pump serves as a generator for power production.

External links

• Bhumibol Dam at Electricity Generating Authority of Thailand