Phumirak Thamachat Centre

Phumirak Thamachat Centre sits about 200 metres behind Khun Dan Prakan Chon Dam in Ban Tha Dan, Nakhon Nayok. The Chaipattana Foundation and the Vajiravudh College Alumni Association built it under royal patronage on a modest plot — 14 rai, 2 ngan, 18 square wah — granted specifically to demonstrate King Bhumibol’s self-sufficiency development concepts on the ground, not just in theory. Entry to walk the grounds is free; only organised group courses carry a fee.

The centre organises its exhibits around four management themes: soil, water, forest, and human resources. The clearest of these is the Monkey’s Cheek (Kaem Ling) water-retention model — physical demonstration ponds showing how the theory that shaped Bangkok’s flood-management system actually works at small scale. Nearby, vetiver-grass plots show the erosion-control planting used across royal projects nationwide, and a New Theory farming plot lays out the land-division model used to teach smallholder rice farmers. An outdoor energy zone and a light-and-sound museum building cover artificial rain-making, the Chaipattana aerator (the paddlewheel device used to treat Bangkok’s Bueng Makkasan wastewater), and other royally-initiated inventions.

Insider Tip: Ask at the welcome building for the terrace-gardening display — it’s built around growing vegetables in stacked containers on a condo balcony, a rare practical angle for anyone living in a Thai high-rise rather than farmland.

Household-scale projects round out the site: displays on producing your own liquid cleaning enzyme (“Khon Mi Namya”), the Hom Din soil-fermentation method, and a bamboo-house exhibit with a bamboo slide that’s popular with visiting school groups. The centre runs hands-on courses lasting half a day, a full day, or five days and four nights, covering earth-house building, DIY crafts, and paddy rice cultivation — these are the fee-based activities, aimed at school trips and study groups rather than casual visitors.

Watch out: This is a working demonstration farm, not a manicured garden — expect a functional, slightly dusty rural-project feel rather than polished landscaping. Shade is limited in the open demonstration plots, so visit in the morning if you’re touring in hot season.

The site works well paired with the dam itself, which most visitors see first — walk the reservoir viewpoint, then drop down to the centre for an hour of hands-on rural-development context that the dam alone doesn’t provide. Bring cash for the small on-site shop selling vetiver-grass products and local produce.