| Búng Bình Thiên | |
| Location: | An Phú District, An Giang Province, Vietnam |
| Coordinates: | 10.9167°N 109°W |
| Type: | Lake |
| Pushpin Map: | Vietnam |
| Pushpin Map Alt: | Location of the lake in Vietnam. |
Búng Bình Thiên or Nước Trời Lake is a fresh water lake in the Mekong Delta in Vietnam.[1] The name that the lake is most often referred to, Búng Bình Thiên, means '[the] lake from the sky', referring to the stillness of the lake's surface and blue color it retains year-round.[2] Located in the An Giang province, about 35km (22miles) from the province's capital, Chau Doc, within the An Phú District. Búng Bình Thiên links three communes, namely Khánh Bình, Nhơn Hội, and Quốc Thái. It also links the Bình Di River and the Hậu River. [3]
The lake's water surface area is 200 hectares and is 4m (13feet) deep in the dry season.[4] During the rainy season, the influx of water from the Mekong River causes the surface area to expand to 800 hectares with the depth rising to up to 8m (26feet).[5]
The lake is still year-round. Large amounts of algae, kelp, and aquatic plants such as water hyacinth, lotus, and water lily contribute to, and maintain clarity of the water of Búng Bình Thiên in times of Mekong Delta floods via filtering silt, oxygenating water, and roots preventing agitation of the lakebed.[6] [7]
In the 18th century, a Tây Sơn dynasty general chose the place where the lake now sits to train soldiers and store food; at the time, the area was very dry and barren, and so a ritual was held to ask the gods for rain and a source of water.[8] Legend states that after this ritual was held, the general thrust his sword into the ground, creating a wellspring from which the lake appeared.[9]
This legend holds a similarity to that of Gia Long Well, in Phú Quốc, in which the well was created by Gia Long's sword slashing into the earth to find water.[10]
The area around Búng Bình Thiên is home to many ethnic Cham people who live around the lake and in the villages of Khánh Bình, Nhơn Hội and Quốc Thái. In modern times, the local Cham engage in the modern world, developing businesses and participating in cultural and artistic activities.