Khwae Noi Bamrung Daen Dam

It is a royally initiated project: on 4 December 1995 King Bhumibol voiced concern about floods and droughts in the lower Khwae Noi basin. First called the Khwae Noi Royal Initiative Dam, it was later given the name Khwae Noi Bamrung Daen by the King, one of the projects he named himself.

Feasibility studies were finished around 1997 and the Cabinet approved construction on 21 January 2003, with a budget of about 6,780 million baht. Sources give 2003 or 2005 for the start and 2008–2009 for the main dam's completion and first impounding; EGAT gives full completion in 2011. On 26 November 2008 Princess Sirindhorn presided over the ceremony to begin storing water.

On 7 July 2012 King Bhumibol opened the dam together with four other RID projects from the RID pier at Samsen in Bangkok, with Princess Sirindhorn attending — not at the dam itself. Two days later the reservoir held only about 210 million m³.

The project has three dams. The main dam is a concrete-faced rockfill dam 75 m high and 681 m long per EGAT, its crest at +133.5 m above mean sea level; there are also the Santakhian dam, about 1,270 m long, and a saddle dam about 640 m long. The spillway has six radial gates.

The reservoir holds 769 million m³ at the normal level of +130 m, with a surface of about 29,000 rai and a catchment of about 4,254 km². It irrigates about 155,000 rai in the project zone and about 250,000 rai in the Chao Phraya zone in the dry season, and helps with flood relief and water supply. The 769 million m³ figure is the original design; later storage reports use a capacity of about 939 million m³ — the reservoir was full at about 937 million on 27 October 2016, held only 28% on 30 April 2012, about 46% during Typhoon Kajiki in August 2025 and about 90% during Typhoon Bualoi on 30 September 2025.

The dam crest has a viewpoint over the reservoir and hills. Below the dam, the Nang Phae Lae Nam play area with bamboo rafts runs 1 March–30 April while water is released for dry-season rice, organised by the Khan Chong subdistrict; before COVID it drew about a million visitors in two months. Since 2023 raft numbers are limited and stakes may not be driven into the riverbed. No evidence of permanent floating restaurants on the reservoir was found.

Visiting the dam is free, though rafts, tubes and life jackets below the dam are charged. No fixed opening hours are published, so call the project on 055-316542 first. From Phitsanulok drive to Wat Bot district and on to Khan Chong, about 50–70 km, by private car. Nearby are Khwae Noi National Park, with seas of mist over the reservoir in the cool season, and Ban Nam Chon, where wood from the flooded forest is carved. Do not swim in the reservoir or near the spillway.