沿山河是杭州市境内的一条界河，有800多年的历史。河的北面是西溪湿地，南面是天目山路，它将湿地与城市，闲适与嘈杂隔离开来。沿山河发源于余杭区闲林街道与富阳区银湖街道交界的板照山麓，经留下，沿天目山路一路向东至古荡，在保俶路八字桥大拐弯后向北，改称西溪河，过文一路后并入余杭塘河，最终注入大运河。
在天目山路和西溪路中间，夹着一条幽静的游步道，绿树成荫，不但是钓鱼的好地方，也是寻宝的好地方。宝藏是一个圆形的小盒子，藏在石墙的间隙中。
Yanshan River is a boundary river in Hangzhou with over 800 years of history. To the north of the river lies Xixi Wetland, and to the south is Tianmushan Road. The river separates the wetland from the city, creating a divide between tranquility and urban noise. Yanshan River originates at the foot of Banzhao Mountain, at the junction of Xianlin Subdistrict in Yuhang District and Yinhu Subdistrict in Fuyang District. It flows eastward through Liuxia, along Tianmushan Road, reaching Gudang. After a sharp turn at Bazi Bridge on Baoshu Road, it changes its name to Xixi River. It then merges into Yuhang Tang River after passing Wenyi Road and ultimately flows into the Grand Canal.
Between Tianmu Road and Xixi Road lies a tranquil walkway, shaded by green trees. It is not only a great place for fishing but also an ideal spot for cache hunting. The cache is a small, round box hidden in the crevices of a stone wall.