Passing through Gangtaedeung, the streams rising from 'Tteunbongsaem Spring', the source of Geumgang (Riv), has created Gangtaedeunggol Valley, containing the first streamlet of Geumgang (Riv). The original Subuncheon flows 1.5km from Gangtaedeunggol Valley and lead to Subuncheon, joining with neighboring streamlets, and flowing about 395km, or 1000 Li through seventeen cities and guns.

The origin of Tteunbongsaem Spring has the following story;
『The first king, Yi Seong-gye, who established Joseon, built an altar on the hillside of Sinmusan Mountain to start praying for 100 days in order to receive a revelation from the mountain gods of the national Yeongsan so that he could gain a country. On the dawn of the hundredth day, a rainbow rose from the valley a short distance from the altar, and a colorful phoenix rode the rainbow and left to the sky. Hearing the heavenly revelation from the air where the phoenix was leaving, he heard “Open a new country,” Yi Seong-gye built the Sangiam Hermitage beside the altar and made sacrificial food with the spring water to serve a ritual for the worship of the heavenly gods. The phoenix emerged from the spring and the name of this place was became Tteunbongsaem Spring.』