Yishuitu Introduction
The spillway is used to discharge excess water from Sun Moon Lake to Shuili Creek, and local residents refer to it as the "Sky Well." The spillway has a circular tower shape, as circular outflows allow for the fastest water discharge. The circular tower spillway is designed with a fixed water level; when the water level is normal, the lake water does not flow into the tower. Once it exceeds the full water level, it automatically flows into the spillway for discharge. The spillway has a diameter of 24.39 meters and is funnel-shaped, tapering downwards, connecting to a tunnel with an inner diameter of 3.48 meters, with a total length of 219.93 meters. To adapt to the complex terrain, the tunnel and channels take on many shapes, which is also one reason why it was considered the "largest hydraulic engineering project in the East" at the time, and it remains a spectacular attraction to this day. Visitors walking the Sun Moon Lake Shushe to Xiangshan Trail should not forget to stop and take a look.
