Yishuitu Introduction
The spillway is used to discharge excess water from Sun Moon Lake to Shuili Creek, and the local residents refer to it as the "Sky Well." The spillway has a circular tower shape, as circular outlets allow for the fastest water flow; the cylindrical spillway is designed with a fixed water level. When the water level is at a normal value, water from the lake does not flow into the tower, but when it exceeds the full water level, it automatically flows into the spillway for discharge. The spillway has a funnel shape with a diameter of 24.39 meters, gradually narrowing from top to bottom, 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 various shapes, which is one reason it was regarded as the "largest hydraulic engineering project in the East" at the time, and it remains a remarkable scenic spot to this day. When visitors walk from Shuishe to Xiangshan Trail, don't forget to stop and take a look.
