Yishuitu Introduction
The overflow spillway is used to discharge excess water from Sun Moon Lake to the Shui Li Creek, and nearby residents refer to it as the "Tianjing." The spillway has a circular tower shape, as circular water flow is the fastest; it is designed with a fixed water level. When the water level is at normal, the lake water does not flow into the tower, but once it exceeds the full water level, it automatically flows into the spillway for discharge. The overflow spillway is a funnel-shaped structure with a diameter of 24.39 meters, gradually narrowing from top to bottom, connected to a 3.48-meter diameter tunnel, with a total length of 219.93 meters. To accommodate the complex terrain, the tunnel and channel have many shapes, which is one of the reasons why this is considered part of the Sun Moon Lake hydropower project, once regarded as the "largest hydropower project in the East." It remains a marvel to this day. Visitors walking along the Water Society to Xiangshan Trail should also take a moment to stop and take a look.
