Son La Reservoir

A boat sits on a wide sheet of water, with mountains on every side. There is no seashore, no salty waves, no smell of the sea. Yet in every direction there is only water and mountains, stretching so far that it is hard to tell where they end.

This is the Sơn La hydropower reservoir. People in the area often call it Biển hồ Tây Bắc, the Sea Lake of the Northwest. That is a popular name used for tourism, not an administrative name, but it captures exactly how it feels to sit in the middle of this lake. The lake covers 224 square kilometers. It stretches for more than 120 kilometers and holds more than 9 billion cubic meters of water. A concrete dam holds all that water back. It is 138 meters high and more than 960 meters long. The Sơn La hydropower plant stands at the dam. Work on it began in 2005, and it was inaugurated in 2012, three years ahead of schedule. At the time, it was the largest hydropower plant in Vietnam and in Southeast Asia. Its six generating units make more than 10 billion kilowatt-hours of electricity in an average year.

But before its beauty comes the story of what had to happen for this lake to exist.

To fill the reservoir, more than 93,000 people had to leave their homeland. They came from three provinces. Besides Sơn La, they were Điện Biên and Lai Châu. It was one of the largest resettlements in Vietnam in peacetime. In Sơn La province alone, more than 58,000 people had to move. Their homes lay in 169 villages across three districts of that time. Two were Quỳnh Nhai and Thuận Châu. The third was Mường La. They were moved to new resettlement areas. Most of them were Thái. The Thái are one of Vietnam's ethnic groups, and Sơn La is one of the provinces where they mainly live.

Houses, rice fields, gardens, temples and ancestral graves all lie under the water below the boat. Before the reservoir was filled, the Vietnam Institute of Archaeology carried out urgent excavations at many sites, to keep whatever could be kept. One temple was saved in another way. It is the Linh Sơn Thủy Từ Temple, where the Thái honor the spirits of the river and the mountains. Its origins go back to before the 17th century. It was moved and rebuilt on a high hill, and it was inaugurated in May 2012.

Somewhere beneath the boat lie the old villages of the Quỳnh Nhai area. The calmer the water, the more it brings to mind everything that lies down below.

This is not told to sadden the trip. It is told because the beauty of this lake cannot be fully understood without the story that made it.

Ahead now is the great Pá Uôn Bridge. From down on the water, it can be felt more fully than from any other viewpoint. The bridge is 1,418 meters long. Its tallest pier reaches almost 99 meters, about the height of a 30-story building. No other bridge in Vietnam has a taller pier, a record confirmed by the Vietnam Records Organization. The bridge carries National Highway 279 across the reservoir on the Đà River. It links this province with Lai Châu and Điện Biên.

Upstream, more than 10 kilometers from the bridge, lies Đảo Trái Tim, Heart Island. That is a local tourism name for a hill. When the reservoir filled, the body of the hill went under, and only its top stayed above the water. Seen from above, that top has the shape of a heart. The island covers about 1.3 hectares and is green with trees.

Another spot on the lake is Uy Phong Bay. It lies at Khoang village, in Mường Giôn commune. The bay has a floating restaurant and an area of fish cages. It is a good place for a lunch of fresh fish from the Đà River, right in the middle of the lake. There is cá trắm and common carp. There are also two river fish, cá leo and cá lăng, specialties of these waters.

Speaking of fish, the Sơn La reservoir is also home to farmed sturgeon. A few years after the reservoir filled, the first sturgeon cages were set out on the lake as a trial, and the farming has slowly grown since. The sturgeon has long been a specialty of Russia and Europe, and now it swims in this lake of the Northwest.

One more place is worth a stop, a pair of temples on a hill that looks down over the lake at Quỳnh Nhai. One of them is the Linh Sơn Thủy Từ Temple, which honors the spirits of the river and the mountains. The story of how it was moved and rebuilt is bound up with the story of the whole region. When the people had to leave their homeland, they took their gods with them.

The other is the Nàng Han Temple. It honors a heroine from a legend of the Thái. In the legend, she dressed as a man to lead the villagers against foreign invaders. It is a folk legend, but the temple itself is real, and it is the center of the community's faith.

Beneath its calm surface, this lake keeps an unfinished record of the people who lived here before the water rose.

The boat drifts, and the wind moves across the wide lake. Somewhere down below, the old homes and fields lie still in the green shadow of the water. This lake is deep, not only in meters of water, but in memory.