River systems of Thailand divides into two major branches, the " Tiền Giang" (Front River) and "Hậu Giang" (Back River). These in turn enter the South China Sea through nine estuaries. The following are the principal tributaries of Mekong River which flow through Thailand (tributaries entirely outside the Thai border not shown). The Mekong drains a considerable portion of northeast Thailand. In terms of Thai territory drained, it is second only to the Chao Phraya system. The Salawin River rises in Tibet (Tibetan: རྒྱལ་མོ་རྔུལ་ཆུ།) after which it flows through Yunnan, where it is known as the "Nujiang" River (), although either name can be
River Yeo (tributary of the Creedy) Road at Whiddon Down. Since January 1997, a flood gauge at Yeoford measures the river height, which is normally below . The site base level is The highest recorded level is on 25 November 2012. South of Crediton the River Yeo forms part of the boundary between Crediton Civil Parish and Crediton Hamlets Civil Parish. Southwest of Yeoford the River Yeo forms the boundary between Colebrook Civil Parish and Crediton Hamlets Civil Parish. Further to the southwest it forms the boundary between Hittisleigh CP and Cheriton Bishop CP. Places along the river include Downs Crediton Golf Club, Fordton Mill, Salmonhutch,