No water has been available to irrigate crops in the Son Tho Lake in Huong Tho Commune, Huong Tra Town, for two months.
The lake spans 28 hectares (around 69 acres) and serves as an irrigation source for 80 hectares (197.68 acres) of rice and vegetables.
Locals have turned the lakebed into pasture land for cattle.
Vo Dai My, 59, Huong Tho Commune resident, said: "Over the past 10 years, this is the first time I have seen Son Tho irrigation lake as dry as this."
My has to rent a pump to draw water from ponds in the lake to irrigate his rice fields and fill his fish ponds.
Nguyen Van Quy, chairman of Huong Tho Commune, said more than 20 hectares (49.42 acres) of crops for the summer-autumn season face the risk of withering due to the lack of water.
The Hoa My irrigation lake in Phong My Commune of Phong Dien District has also run dry. Locals said the lake's water level is at the lowest in 15 years.
The lake is the irrigation source for 320 hectares (790.74 acres) of crops in three communes.
A dead fish dies on the lake's arid soil.
Temperatures in Thua Thien-Hue, home to the former Imperial Citadel in Hue which is a popular tourist attraction, were often between 36-38 degrees Celsius (96.8-100.4 degrees Fahrenheit) in June and July.
The boats, which locals used to get across the lake, is now sunbathing 20 meters away from it.
At Huong Xuan Ward in Huong Tra Town, the water level in the Tho Son irrigation lake has plunged to the minimum level, meaning residents are no longer allowed to use it.
Many rice fields in Thua Thien-Hue Province are bare now.