mountain river; mountain stream
Refers to a river or stream flowing through mountains, often with a connotation of clear, fast-flowing water in a natural setting.
The murmur of the mountain stream is pleasant.
この山川にはイワナが棲んでいる。
Char live in this mountain river.
Compound of 山 (mountain) and 川 (river). The reading やまがわ is a straightforward kun'yomi combination.