Khun Dan Prakan Chon Dam

Khun Dan Prakan Chon was completed in 2005 on the Nakhon Nayok river below the Khao Yai massif, built to control flooding and store irrigation water for the province, and it is claimed as the longest roller-compacted concrete dam in the world - about 2,600 metres of crest and around ninety metres high. It is a working water-management structure rather than an attraction, but the reservoir behind it, held between forested hills on the edge of Khao Yai National Park, has become a weekend destination: kayaks and pedal boats are hired on the water, the crest road is cycled and driven for the view down the valley, and camping and rafthouses operate along the shore. The dam was contested during construction over the flooding of forest and settlement. It is a straightforward two-hour drive from Bangkok and gets almost no foreign visitors, which makes it noticeably quieter than the Khao Yai side of the same hills.

What you actually see

• The crest - about 2,600 metres of dam wall with a road along it.
• The reservoir - held between forested hills below Khao Yai.
• The kayaking - boats hired on the water at the shore.
• The scale claim - the longest roller-compacted concrete dam built.

When to go

November to February. Water levels are highest at the end of the rains and drop through the dry season. Weekends bring Thai visitors; weekdays are empty.

Honest expectations

It is a working dam - a large concrete structure, and the appeal is the reservoir rather than the engineering. Little shade on the crest. Kayak hire is informal. Almost no English.

Nearby

Nakhon Nayok and its waterfalls are south; Khao Yai National Park is north.