1. The Ganga Plain is drained by the river Ganga and its tributaries.
2. The Upper Ganga Plain has a very low gradient and slopes towards the southeast. So the Ganga and its Himalayan tributaries Yamuna, Ramganga, Ghaghara, Kali and Gomati flow gently making meanders and ox-bow lakes in the plain. The Chambal flowing in the Plain is a tributary of the Yamuna. It originates in the Peninsula.
3. The middle Ganga Plain is drained mainly by the Ganga, Ghaghara, Kosi and son. The sons, Kosi Ghaghara are notorious for floods and frequent changes in their courses. The son, originating in the Peninsula, is a major tributary of the Ganga.
4. The lower Ganga Plain is drained by the rivers Ganga, Brahmaputra and Subarnarekha. The Damodar meets the Ganga-Hugli in the deltaic region.
