The Dongshan River is the fifth largest river in Yilan, flowing through three townships including Luodong, Dongshan and Wujie. In the 24-kilometer-long Dongshan River Basin, it is divided into riverside recreation areas with multiple functions of sports, recreation and leisure. The upper, middle and lower sections of the forest each present different recreational features, and are expected to become an "outdoor water museum".

Being close to the water is the most important tourist and leisure base of Dongshan River. In order to rebuild the natural ethics of man and water, the built landscape was modified and integrated into the colors of Lanyang Park, such as the water stage, five conical pebble hills and the sea-curved Guishan Island. , inadvertently introducing Lanyang landmarks into the garden.

It is said that the Dongshan River has green dragons and yellow dragons protecting its banks since ancient times. Therefore, an undulating and curved dragon slope was built with pebbles on the riverside. It was inlaid with green, blue, yellow, and orange pottery pieces. On the steps of the dragon slope, there is an interesting mosaic. , is a collage masterpiece made by children from Yilan.