The Columbia Encyclopedia, Sixth Edition. 2001-07.
Yuan
(yüän) (KEY) , river, 540 mi (869 km) long, rising in S Guizhou prov. and flowing generally NE to Donting lake, Hunan prov., SE China. Navigation above Changde is limited by rapids to small craft. The Yuan valley, a major north-south trade route, yields tungsten, iron ore, and tung yu (wood oil).