It is a large-scale artificial reservoir that was created to supply water for agricultural purposes as part of the foundation for safe farming in the Cheorwon Plain, and is also called an all-weather candidate. Located on the entrance road to the 2nd Tunnel, the center of Cheorwon security tourism, it forms a beautiful lakescape and serves as a sleeping place for migratory birds during the winter. The sight of a flock of geese flying in unison at dawn (around 7 o'clock) in winter is a sight to behold among bird watchers. It is also a place that evokes. Dongsong Reservoir, also called Gangsan Reservoir, is an artificial reservoir built by storing water resources flowing in from Boyang Lake and Gagok in Hakjeon-ri. The total length of the embankment is 2km, making it the longest in Korea.