Long Lake (Changhai) is crescent-shaped and is the highest, largest and deepest lake in Jiuzhaigou, measuring 8 km in length and up to average 44.57 m in depth. Covering an area of 930,000 square meters, it reportedly has no outgoing waterways, getting its water from snowmelt and losing it from seepage. The lakes is at an elevation of 3,060 meters.