The current was swift, the water foaming over the occasional rocks that protruded or lay under its surface. The prow of the long tail boat crunched softly onto the sloping sandy beach and I stepped off on an island full of creeks and pools, a Harry Potter-like landscape of old trees with roots exposed and bent and folded in one direction, and of trees with bits of other trees suspended high in their branches, 10 to 15m above my head.
Two wild ducks flew up from a pond as I waded across a rivulet, the cool water swirling around my ankles, my toes sinking into the soft sand. There were no other footprints.
There were numerous sandbanks to choose from, to sit at and have our packed lunch, while unseen birds called from the green canopies of twisted trees, the wind down the valley sighing through their leaves.
Among the creeks and rivulets in the patches of dense brush, a bird took wing - a brief flash of white in the shadows. This is the home of the incredibly rare whiteshouldered ibis; I did not get to see one but, am told that with some effort, you can.
The agency owner from whom I had rented the Lexus in Phnom Penh to drive here had seemed rather dismissive of Stung Treng. "People go to Kratie," he said. "Not many go to Stung Treng. Maybe if they want to have good fish to eat. Stung Treng is good for fish."
Kratie is one of the few places left where you can see the Irrawaddy dolphin. I intended to go there but my real objective was Stung Treng.
Stung Treng, a "Wetland of National and International Significance" under the Ramsar Convention, an international treaty that conserves wetlands, is storied for its flooded forests - whole forests submerged every monsoon, then left to emerge when the swollen Mekong subsides.
The trees and bushes remain gnarled and twisted in the direction of the water flow, surrounded by contoured dunes of fine sand in a vast expanse of rolling water.
Initially I was overwhelmed to be hiring a Lexus. But it is a common SUV in Phnom Penh, a city where the gap between the wealthy and well-connected and the rest is a wide one. And there is no doubt one needs a four-wheel drive vehicle for the trip; the alternative was a car or van in which the going would be rougher and take longer, or a public taxi van, crammed with passengers and with an extraordinary amount of heavy goods strapped to its rear end, extending it by a metre and many kilos.
This Lexus turned out to be a 15-year-old vehicle, and in good shape, given what it must have been through in Cambodia. The price with the English- speaking driver - another huge advantage - was US$100 (S$126) a day, including fuel.
I was grateful for the sealed-off interior because the road to Kratie from Phnom Penh began with choking red dust, vehicles churning through kilometres of red gravelly earth on a half-made road under construction. After about half an hour of this though, the road improved and the rest of the five-hour journey was smooth.
In particular, the driver Meas Savan drove at a gentlemanly pace. It is always better to have a driver who trundles rather than one who drives fast and takes risks, especially in a country where the highways are busy with people and animals.
At Kratie - where I would return later - Mr Savan and I had a good lunch at Heng Heng restaurant on the riverside, overlooking the broad Mekong.
Then we set off for Stung Treng, a two-hour journey on a road that made the previous one out of Phnom Penh seem smooth by comparison. It was impossible to drive faster than 35kmh on stretches of broken road. The Lexus had to slow to a crawl at some places, pitching and rolling like a boat in heavy waves as we forged ahead.
I checked into the best hotel in Stung Treng, the Gold River. It is occasionally known as the Golden River, the woman at the counter said with a smile. The room cost US$20, was very clean, and came with a piping hot shower and an electric kettle, plus an empty fridge. There is a VIP room - much bigger - to be had for US$35, but it was booked when I reached. The hotel has Wi-Fi in all the rooms.
There is no restaurant in the hotel. During a quick recce of the town, I discovered a good pharmacy behind the smiling fish statue on the riverfront. I also found a Vietnamese restaurant called Hoa Mai (with Wi-Fi too) by the dusty market which arranges itself around the square at the centre of the small town; the food there was easily the best I managed to find.
The market is a useful place to buy essentials. Shops around it include a bakery with freshly baked French loaves and more.
I set out at about 6.30am the next day, hiring a boat for US$75 for the whole day. I planned to explore the lower half of the Ramsar site. We puttered out into the main stream, swinging around a bend and passing a lone woman standing on a tiny boat in the middle of the vast expanse of water, poling silently to shore while dawn broke in the east.
In perhaps 20 minutes or so, we were in the famed flooded forests. It was an extraordinary, constantly shifting landscape, with a refreshing breeze, soft sand beaches, a vast expanse of water with hardly any people except the odd fisherman and, on shore, the occasional local villagers with a couple of buffalos. We had entered a zone where the borders of the river dissolve and the flooded forests stand on water-sculpted islands in a vast lake-like body of water.
On the way back, I stopped by Kratie for a night to break the strenuous journey and also to see the almost legendary Irrawaddy dolphin. For US$9, you can book a seat on a boat for an hour scouring the deep pools of the Mekong and waiting in silence for the telltale sound of a dolphin surfacing, and then actually seeing it.
It is very difficult to get a picture especially of the round face of this unique dolphin. Binoculars are recommended.
I saw several dolphins. At one point, I was bobbing in the boat with the engine cut, surrounded by them.
The sigh of the Irrawaddy dolphin as it surfaces to breathe is one of the soundtracks of the Mekong. Already one of the most endangered species in the world, it may soon fade into distant memory as dams spring up along the river, disrupting its supply of fish.
"No fish, no dolphins," said the World Wildlife Fund's local man in Kratie, Mr Saber Masoomi.
I left Stung Treng resolved to return for a longer trip - to go to the top of the Ramsar site near the Lao border to see the falls on the Mekong and, from there, to drift down in a kayak for five days, with supplies in a boat, camping under the stars on the beaches.
And perhaps I will, one night, hear the dolphins sigh again.
This is part of a series on off-the-beaten path places to explore around Asia and beyond.
Making your way around Stung Treng
Fly to Phnom Penh. From there, transport starts at US$20 (S$25) for a seat in a bus or van; there are regular services to Kratie, if not Stung Treng, and from Kratie it is easy to get a bus or local transport for the bumpy and dusty two-hour ride to Stung Treng.
Or you can fly to Siem Reap; bus services have recently started between Siem Reap and Stung Treng. The journey is five hours, slightly shorter than from Phnom Penh.
One company which runs this route is Asia Van Transfer (tel: +855-63-9638-53). Another, Makara Taxi, which has a range of vehicles, can be booked in advance via firstname.lastname@example.org, or call the company on +855-88-7777-327.
You pay more to rent a vehicle for yourself, but prices are still reasonable. I rented a 15-year-old Toyota Lexus SUV with a driver - including his overnight stay - and fuel for US$100 a day for the trip to Stung Treng from Phnom Penh.
It is faster, more reliable and more comfortable than a bus or van - and it is good to have the driver around. Many speak enough English to get by so they double up as guides, which is useful when hunting for a hotel or restaurant.
My driver, the unflappable Mr Meas Savan, can be contacted on +855-92-6800-03 or +855-97-6800-03.
Where to eat
The Hoa Mai restaurant was my choice on two occasions in Stung Treng. It offers fairly good, tasty Chinese and Vietnamese food. A good meal for two at this restaurant costs about US$5.
It is in front of mobile phone shop Metfone, right by the central market. Just ask a local for directions, everyone knows where Metfone is.
The restaurant is referred to as both Hoa Mai and My Hoa.
Wi-Fi is available at the restaurant. In fact, Wi-Fi is available in many places in Stung Treng and Kratie.
The market which is in the central square in Stung Treng can be a bit dusty and dismal, but offers fresh fruit and fresh bread.
Hoa Mai is one of many restaurants and guest houses clustered around the square.
Where to stay
In Stung Treng, I stayed at the Golden River, where my spacious air-conditioned room with a fridge and Wi-Fi cost US$20 a night.
Another place to stay is Le Tonle, a wooden house with no air-conditioning but is done up more tastefully. The enterprise is run by a non-government organisation that sponsors local students and trains locals for the tourist industry.
Le Tonle in Stung Treng has four rooms, all impeccably clean with mosquito nets in the old style, for US$8 for a double room. The four rooms share two bathrooms (also immaculately clean).
There is a family room which sleeps more, for between US$8 and US$10, depending on the number of occupants. There is a kitchen, where you can learn to cook some local dishes; a cooking class costs US$5.
Le Tonle has a unit in Kratie. It is also a wooden house, slightly bigger than the unit in Stung Treng. I stayed for the same price as I did at Stung Treng, in a nicely decorated room - this time with air-conditioning (and the standard Wi-Fi). There is a shared bathroom.
Staying in that traditional wooden house was a pleasure, and the kitchen's mango shake was divine.
You can book the Le Tonle guest houses at the website letonle.org.
What to do
I hired a boat (you can do this at the main pier, which you will see when you walk to the waterfront from the market) for US$75 for a whole day's travel, but only up to the halfway point of the Stung Treng Ramsar site.
You could hire a boat for a longer day, going all the way to the Laos border, and returning in time for dinner, for US$110.
But next time, I would hire a car to take me to the northern end of the Ramsar site at the Laos border and, from there, drift downstream over about five days, camping on the islands. You can also do some sections by bicycle.
The agency to contact in Stung Treng is Xplore Asia, which runs van, boat and bicycle tours of the Ramsar site. Its website is at www.xplore-cambodia.com.
Its operation in Krabi in Thailand can set up the whole tour, complete with kayaks and cycles. Contact them on +855-11-4338-36 or +855-74-9734-56, or e-mail email@example.com.