ERHAI is a plateau lake, belonging to the Lancang River - Mekong River system, with a watershed area of 2565 square kilometers. When the lake level is at an elevation of 1966 meters, ERHAI's capacity reaches 2.959 billion cubic meters, covering an area of 252 square kilometers. It is a crucial source of drinking water for the local area, as well as an important source of domestic, industrial, and agricultural water.

DEEPINFAR, utilizing the Hetun IV-A, conducted investigations and studies on the environmental conditions of ERHAI Lake, including aquatic plants and benthic animals. The underwater data collected provides valuable support for subsequent environmental protection efforts.