"The Xiuguluan River originates in the Central Mountain Range, flows along the East Rift Valley through Rei Shui, turns east, cuts through the coastal range and empties into the Pacific Ocean at Da Gangkou. At 104 km long, it is the longest river in eastern Taiwan and the only river that cuts through the Coastal Mountain Range. It's a great classroom for geology and topography.The Xiuguluan River from Rei Shui to Da Gangkou is known as the Xiuguluan River Canyon. Here, the river has over twenty sets of rapids and is a popular spot for river-rafting."