"Reach 3: Vientiane and Nong Khai to Pakse". The boundary between Reach 2 and 3 is where the Mekong hydrology starts to change. Reach 2 is dominated in both wet and dry seasons by the Yunnan Component. Reach 3 is increasingly influenced by contributions from the large left bank tributaries in Laos, namely the Nam Ngum, Nam Theun, Nam Hinboun, Se Bang Fai, Se Bang Hieng, and Se Done Rivers. The Mun-Chi river system from the right bank in Thailand enters the mainstream within this reach.