A Lake Freely Expands and Contracts: Lake Tonle Sap in Cambodia
Everything from Houses, Schools, to Hospitals are on Ships
Most of the passengers on the airplane from Phnom Penh, the capital of Cambodia, to Siem Reap are tourists heading to Angkor Wat. During the rainy season, the land seen from the window of the aircraft is full of water.
The area around Phnom Penh is a lowland where the Mekong from China and the Tonle Sap meet. The Tonle Sap swells from Kampong Cham, which is 100 km (ca. 60 mi) upstream of this meeting point, to Siem Reap. This is called Lake Tonle Sap.
If you strain your eyes, you'll see houses, roads and banks under the water, so you'll notice it was originally land. But there are fixed fishing nets where it should originally have been land. It's not certain anymore if the place was originally land, a river, or a lake. The incline of the downstream of the Mekong is quite slight; measuring about 1m (ca. 40 in) every 100 km (ca. 60 mi).
When the rainy season starts, the water level of the main stream of the Mekong rises. But water flows back to Lake Tonle Sap and only a little water goes to the estuary. The water level of Lake Tonle Sap is 9 m (ca. 30 ft) higher in the rainy season than in the dry season, and the lake area becomes 10000 km2 (ca. 4000 mi2), though the area is only 3000 km2 (ca. 1000 mi2) during the dry season. However, the water level rises to more than 10 m (ca. 30 ft) during the rainy season, though in the dry season it's only 1 m (ca. 3 ft).
There is a town called Phnom Krom ('phnom' means mountain) in the south of Siem Reap. Phnom Krom village at the foot of this mountain has a port for high-speed vessels. This village is an interesting village, because it moves according to the movement of the lake shoreline. Large vessels can reach the very foot of the mountain during the rainy season, whereas even small boats can reach only 10 km away from the foot of the mountain during the dry season.
Each school, hospital, and public office is on a ship, and the ship moves as the water level moves. Of course, most houses are on ships; in other words, these ships are a type of houseboat. It's not only residents who live lives that change according to the movement of the water level; the stem of a rice plant also grows as the water level becomes higher. This variety of rice is called floating rice.
Lake Tonle Sap is a treasury of fish. People sell fresh fish and dried fish in the markets of Siem Reap. There is a dried fish which looks like a halfbeak, and is good for eating with beer.
Many Vietnamese fishermen came to Tonle Sap to catch this fish during the civil war in Cambodia. Cambodians and Vietnamese are long-time enemies, so even now they still sometimes fire machine-guns at each other, for intimidation.
Lake Tonle Sap
Gulf of Thailand
From the left: a school ship, a hospital ship, and a public office ship
Fixed fishing net
In the front is the Tonle Sap, and in the back, the Mekong. When the water level of the Mekong rises, water flows back to the Tonle Sap.
Lake Tonle Sap seen from Phnom Krom during the rainy season. You can see a warship of the Cambodian navy.
Vietnamese fishermen. They usually fish in peace with the Cambodians, but sometimes there is conflict.
Dried fish being sold in the market of Siem Reap. Both fresh fish and dried fish are sold there.