Lake-Qinghai Lake

Qinghai Lake

Source: Ministry of Water Resources website

     Qinghai Lake, the Tibetan name is "Tsaowenbu" (meaning "blue sea"). Located in the northeast of Qinghai-Tibet Plateau and Qinghai Province, China's largest inland lake and saltwater lake. It was formed by the fault subsidence between Datong Mountain, Riyueshan Mountain and Nanshan Mountain of Qinghai. Cause of formation: The tectonic faulted lake of Qinghai Lake, the edge of the lake basin is mostly connected with the surrounding mountains by faults. At the early stage of lake formation 200-2 million years ago, it was a large freshwater lake, which was connected with the Yellow River. At that time, the climate was mild and rainy, and the lake water discharged into the Yellow River through the backward flow river in the southeast, which was an outflow lake. Up to 130,000 years ago, due to neotectonic movement, the surrounding mountainous areas were strongly uplifted. From the end of Pliocene, Riyueshan and Bison Mountain in the eastern part of the lake rose rapidly, which blocked the back-flow river that originally flowed into the Yellow River and forced it to flow into Qinghai Lake from east to west, resulting in the emergence of Gahai and Erhai lakes, and then separated from Haiyan Lake and Shadao Lake.

     Territory change. Due to the blockage of the outlet passage, Qinghai Lake has evolved into a blocked lake. With the dry climate, Qinghai Lake has gradually changed from freshwater lake to saltwater lake. In the Northern Wei Dynasty, the perimeter of Qinghai Lake was called Qianli, 400 kilometers in the Tang Dynasty, and 350 kilometers in the Qianlong Period of the Qing Dynasty. There are ancient lake embankment sites about 20 kilometers in the front of Buha River Delta, and Cha Seoul (built in Han Dynasty) 25 kilometers away from the East Bank of the lake. The East and West have retreated 25 km and 20 km respectively, and the water level has dropped by about 100 meters. Qinghai Lake is oval with a circumference of more than 300 kilometers.

     In 1908, Russian Kozlov speculated that the lake level was 3205 meters and the lake area was 4800 square kilometers. Surveying and mapping data in the 1950s showed that the water area of Qinghai Lake was more than 4568 square kilometers. The topographic map published in the 1970s measured the lake level around 3195 meters. In 1988, the water level was 3193.59 meters and the lake area was 4282 square kilometers. In 2000, based on remote sensing satellite data analysis, the area of Qinghai Lake was 4256.04 square kilometers. In August 2013, the area of Qinghai Lake was 4337.48 square kilometers. The water volume of the lake is 73.9 billion cubic meters, the longest is about 104 kilometers, the widest is about 62 kilometers, the maximum water depth is 31.4 meters, the average salinity of the lake level is 12.32 grams/liter, and the salt content is 1.25%.