Nakdong River, which starts from Taeback of Gangwon Province, runs down around 525 km towards south, drenches graceful mountains & fertile fields and creates back marshes such as Upo Swamp and Junam Reservoir. Splitting largely into two main streams: West Nakdong River and original main stream at Daedong-Myeon in Kimhae and Hwamyeong-Dong in Busan, Nakdong River forms the vast plain and sand islands at the point of meeting the south sea. The place where Nakdong River meets the sea, that is the Nakdong River Estuary.

The Nakdong River Estuary has well-formed small &

large sized deltas such as Eulsukdo, ILwoongdo, Daemideung, Jangjado , Shinjado, Jinwoodo, Baekhapdeung, Doyodeung, etc, and along with these deltas, the tidal flat and the forest of rank reeds around the estuary have been good habitats for migratory birds. The peripheral area of the estuary where the sea water meets the river water and the shallow tidal flat is widely formed, thus lots of planktons, fishes, shellfishes and aquatic insects propagate provides migratory birds with abundant prey.
The Nakdong River Estuary, has been well known from old times as the production place of diverse marine products see weeds, oysters and corbiculas were representative one among the major products . At present, however, the shape and utilization of it is changed and the remains of the past can not be found in the remaining names of those places.

The Nakdong River Estuary is now being used as the habitats for migratory birds designated as the Precious National Treasure No. 179 (designated 1966), the visiting place of migratory birds even though the number of head has been greatly reduced compared with the past, and has been kept under control since it was designated as the Natural Environment Preservation Area in 1988, the Ecological Landscape Preservation Area in 1989, the Marsh Preservation Area in 1999, the Special Management Water Region of Busan Coast in 2000.

Therefore, it is regarded as the very thing only Busan can be proud of to see a great number of migratory birds visiting throughout the whole seasons, and overspreading the estuary with the enormous population.