Bhumibol Dam

Conceived and approved in 1951 as the Yanhee project, with preparatory work from 1952, it was renamed "Bhumibol Dam" by King Bhumibol on 25 July 1957.

Most sources date the start of construction to 1958 (some say 1957, likely the naming or preparatory year). The King laid the foundation stone on 24 June 1961, and the dam was formally inaugurated on 17 May 1964 with its first two generators, at a cost of about 3.5 billion baht. The King and Queen visited the dam in 1964.

A 1963 World Bank report says the first loan, 175-TH for US$66 million, was signed in November 1957, on condition that the Yanhee Electricity Authority be created, which it was in September 1957. Construction began late in 1958 and the first power was sold in March 1961; the first phase cost about US$100 million, and later loans paid for units 3–4. Two sources say King Bhumibol opened the dam in person on 17 May 1964.

Filling the reservoir displaced about 2,400 households from 21 villages in the Doi Tao and Hot area to plots along the Mae Tuen–Doi Tao–Hot road, with compensation of 400 baht per rai (less in practice), and a self-help settlement gave 5 rai each to 1,711 families, according to a single Thai Post report (2018).

It is a concrete arch-gravity dam 154 m high with a 486 m crest — Thailand's tallest dam and its only concrete arch dam. The reservoir holds 13,462 million m³ (about 9,762 million usable), covers some 300 km² and stretches over 200 km to Hot district in Chiang Mai. It first filled in 1970.

The power station has eight units: units 1–6 installed 1964–69 and uprated to 76.3 MW each, unit 7 of 115 MW in 1982 and unit 8, a 171 MW pump-turbine, in 1996 — about 743.8 MW in total per IEA's technical report (Wikipedia gives 779.2 MW). In 1965 it supplied about 73.66% of the nation's electricity, falling to about 2% by 2003.

In 1991 the Lower Mae Ping dam was built 5.5 km downstream as the lower pond for pumped storage. With Sirikit Dam it irrigates about 10 million rai and holds back an average of some 2,050 million m³ of floodwater a year, and its spillway was used in the great flood of 2011. As for floating solar, Thansettakij reported in July 2026 that 158 MW (expandable to 205.4 MW) had been contracted for about 4,092 million baht, but it still awaited Cabinet approval and the commercial start date had slipped.

Water levels swing widely: about 43.4% on 24 August 2024 and about 8,247 million m³ (61%) on 30 September 2024; about 89.8% on 7 October 2025, rising to about 97% on 4–6 November 2025 — the highest since 2011, under Typhoon Kalmaegi — before peaking at 13,406 million m³ (99.59%) on 13 November with no spillway needed; and about 8,512 million m³ (63%) on 28 September 2026. Raft and boat routes depend on the level.

Visitors can walk the dam crest and viewpoints, stay in EGAT guesthouses with a pool and bicycle hire, eat northern food at Heun Phu Kaew on a hilltop, play the public 18-hole golf course, and camp.

On the reservoir, towed raft houses and boats visit Phra Phutthabat Khao Nam, Valentine Island with a sandy swimming beach, Doi Chao Pho Luang and the Kaeng Soi archaeological site. Doi Khao Nam is an island hill with a Buddha footprint on top, found in 1947, about 5 km or 30 minutes by boat. Boats to Doi Tao run only on some routes depending on water levels, so charter and agree the fare first.

Other stops include the Luang Pho Chet Kasat statue on a hill, the Lower Mae Ping dam, the Ping Phiphat Bridge, the Namjai garden, a teak tree planted by King Bhumibol in 1970 and the 50-Year Bridge. EGAT also hosts an international mountain-bike race.

From Tak take Highway 1 to the junction at km 566+600, turn left onto Highway 1357 and continue to about km 15 for the dam entrance. There is no direct public transport. The grounds open about 08:00–17:00 and are free. November to February is best — cool, with the reservoir usually full after the rains — while April is very hot, with a record of 43.7 °C.