The spillway features a funnel-shaped design with a diameter of 24.39 meters at the top, gradually narrowing as it descends. It connects to a tunnel with an inner diameter of 3.48 meters and a length of 219.93 meters. To adapt to the complex terrain and topography of Sun Moon Lake, these tunnels and channels were constructed in various shapes, making the Sun Moon Lake Hydropower Project one of the most remarkable feats of engineering in the region. At the time, it was hailed as the largest hydroelectric project in the East, and even today, it remains an awe-inspiring spectacle.
Located near the Shuishe to Xiangshan Trail, this spillway features a unique 12-sided polygonal structure, resembling a mysterious passage leading to the Earth's core. Locals have nicknamed it "Tianjing" (Heaven’s Well) due to its intriguing appearance. Its primary function is to regulate the water level of Sun Moon Lake and prevent flooding. When the lake's water level exceeds the designated height, the spillway directs the excess water into the nearby Shuili River, ensuring the lake's stability and protecting the surrounding area. During overflow events, the spectacular sight of cascading water creates a breathtaking natural phenomenon.
