Lugu Lake, located at the junction of Yanyuan County, Sichuan Province and ninglang county, Yunnan Province, is slightly northwest-southeast, with an area of 50 1 km2 and a storage capacity of 2.252 billion cubic meters. Qionghai Lake is the second largest freshwater lake in Sichuan Province, with a water area of about 30 square kilometers.
Although the water area of Lugu Lake is small, it is the third largest deep-water lake in China due to its water depth (average water depth is 40.3m, the deepest is 93.5m [1]) and huge water body, with a reserve of over 2 billion cubic meters, several times larger than that of Dianchi Lake in Kunming.
The water body of Lugu Lake is crystal clear and very clean. The naked eye can look directly at the depth of underwater 12 meters. Such water quality is rare in Yunnan and even the whole country. It belongs to the first-class drinking water quality in China, and it is also an alpine deep-water lake with extremely low pollution in China. Because it is located on the plateau and high mountains, the temperature of the lake is very low, but it is not frozen all year round. The edge of the lake basin is complex and steep. Although the lake is clean and soft, swimming is still considered taboo.
Extended data
Hydrological characteristics of Lugu Lake
I. Flood season
The flow of Lugu Lake reaches 3-5m3/s in flood season. After June 65438+ 10, the flow is very small, and the lake basically does not leak from June 65438+ 10 to May every year.
Second, there is no ice age.
The surface water temperature of the lake is greatly influenced by external climatic factors. The water temperature changed obviously in July and June, with the range of 17. 1-22.0℃. In the deep water layer (below 40 meters), it is basically unchanged all year round, at 9.5- 10℃, and there is no ice age.
Throughout the year, the surface water temperature in the north of Lugu Lake is lower than that in the south. In spring, summer and autumn, there is thermal stratification in the north and south of Lugu Lake, especially in summer and autumn.
Third, water quality.
The maximum transparency of lake water is 12m, the PH value is between 7.7 and 8.6, the salinity is 0.54mg/L, and the total hardness of fresh water is 5.5, so it belongs to soft water. [9]? . The water quality of the lake meets the first-class national standard for surface water.