➤ It includes those rivers which originate from Peninsular Plateau and flow towards North direction and finally meet with the Ganga river as south bank tributary.
➤ Important Peninsular Plateau rivers are Son, Punpun, Phalgu, Karmanasa, Sakri, Ajay, Chandan and Kiul rivers.
Karamnasa
- The Karamnasa rises near Sarodag on the northern face of the Kaimur range about 29 km west of Rohtasgarh in Mirzapur district of UP at an elevation of 350 m and forms a boundary between Bihar and UP from the point River Gurwat joins Karamnasa.
- Then it flows through Varanasi district in UP and finally falls in Ganga near Chausa. Its important tributaries are the Durgawati, the Gurwat and Chandraprabha.The Total geographical area of the basin is 5127 sq km.
- The total length of the river is 192 km of which 92 km lies in UP, 24 km in Bihar and balance 76 km forms the common-boundary between Bihar and UP.
- Its other tributaries are Lorse, Kumda, Geria, Dharmawati etc.
Punpun
➤ It originates from Chauraha hill in Palamu district in Jharkhand and meets the Ganga near Fatuha in Patna.
It is the second most important river of South Bihar.
➤ It enters Bihar in Gaya district. Dordha, Butane, Madar and Morhar, Ramrekha, Baraki, Yamuni, Bilro are its tributaries.
➤ It is 200 km long but flows 182 km only in Bihar. The catchment covers the districts of Patna, Jahanabad, Gaya, Aurangabad.
Phalgu
➤ It originates from the Northern part of Chota Nagpur plateau in the form of many streams. Its main stream is known as ‘Niranjana’ (Lilajan) which meets with Mohana stream near Bodhgaya and forms Phalgu river.
➤ It is said that at Bodhgaya on the banks of Niranjana river, Gautama Buddha obtained enlightenment.
➤ At the banks of Phalgu river in Gaya, people offer ‘Pind Daan’ for the souls of their ancestors. Thus, Phalgu river is the holy river not only in Bihar but all over the country.
➤ It divides into two streams near Barabar hill (Jehanabad district) and again divides into many streams after some distance (Dhohar, Dhanruji, Khuri, Lokain, and so on).
➤ At the confluence of Lilajan and Mohana rivers, Phalgu becomes a subject of heavy floods during monsoon season while in other seasons it dwindles into different streams and flows through sandy region.
Ajay
➤ It originates from Batpad place of Jamui district. It flows in the East and South direction and enters Jharkhand then West Bengal and finally meets the Ganga river.
➤ Its length in Bihar is 202 km. This river is also known as ‘Ajyabati’ or ‘Ajmati’.
Kiul
➤ It originates from Hazaribag plateau and enters Bihar in Jamui district through a narrow gorge near the Satpahari hill. Its total length in Bihar is 111 km.
➤ Its important tributaries are Harohar, Anjan, Barnar and Ulan. It meets the Ganges in Surajgarha village in Lakhisarai.