Changhai is Jiuzhaigou high altitude, the lake is wider sea, the sea water is ink blue, the water source from the alpine snow melt, strangely, the lake is more than 100 meters deep, the S line is spread, Haizi surrounded by forests, the peaks are snowy all year round. There is no water outlet around the long sea, single summer rainy season, water does not overflow the embankment, winter and summer long drought, not dry, so Changhai is known as "packing dissatisfied, leaking treasure gourd". In the middle of winter, the long sea ice layer is up to 60 cm thick, which is an ideal place for ice sports.