The main branch of this white water river runs for a course of 53 kilometers. Upstream it has almost 10 tributaries. It flows between steep mountains, and its two banks are primarily made up of easily collapsing sandstone and shale. Hence its waters are good for crops and rich with minerals.
主流長五十三公里，上游有近十條支流齊匯，一路山勢陡峻，兩岸岩質又多為鬆散易崩碎的砂岩、頁岩，因此溪水肥沃富含礦物質，日常無風無雨也呈微濁，下游的閩南人士遂稱它為樂樂（濁濁）溪。