There are 4 Caohai Lakes (Grass Lakes) of varying sizes in the Caohai Scenic Area of Lugu Lake , which are dotted around the mother lake - Lugu Lake. The scenic is mainly distributed in the north and northeast of Lugu Lake, and there are 2 Caohai Lakes in Sichuan and 2 Caohai Lakes Yunnan.
The Caohai Lakes in Yunnan Province is very small, while it is very large in Sichuan Province with an area of about 10 square kilometers. The Caohai which people says normally is the big one in Sichuan. These 2 Caohai in Sichuan are also divided into different sizes. The large one is 10 square kilometers and the small one is only two square kilometers. They are distributed on both sides of Lugu Lake Town in Yanyuan County, Sichuan Province.
"Caohai" refers to the grassy plateau lake, which is very distinctive on this plateau more than 2,000 meters above sea level. It is a sub-lake of Lugu Lake, and the water of Lugu Lake is connected to it.
China Tours Including Lugu Lake in West Sichuan and Northeast Yunnan
https://www.tibet-tours.com/829-Rental-Car-Tour-to-Discover-the-Mythos-of-Shangri-La.html
https://www.tibet-tours.com/1314-Discovery-Tour-in-Tibetan-Areas-Kham-Amdo-1