Key Highlights
- The Ganga, entering at Chausa, is the backbone of agriculture, transport and worship in Bihar.
- Tributaries such as the Kosi, Son and Ghaghra shape the state’s hydrological and cultural landscapes.
- Major dam and barrage projects – Mahatma Gandhi Setu, Gandak Barrage, Kosi Barrage – regulate floods and supply irrigation.
- Rivers double as religious arteries; Chhath Puja, Pind Daan and other rituals are performed on their banks.
Detailed Insights
Ganga River enters Bihar at Chausa and traverses Patna, Bhagalpur and Munger before emptying into the Bay of Bengal. Its major tributaries are the Son, Gandak, Kosi, Bagmati, Punpun and Karmanasa. The Mahatma Gandhi Setu bridges the northern and southern banks, underscoring the river’s logistical significance.
Ghaghra (Saryu) River originates from Nepal’s Nampa region, joins the Ganga at Chhapra, and nourishes the northern plains with fertile alluvium while holding sacred status for Hindus and Buddhists alike.
Gandak River – known as Narayani in Nepal – flows north‑south through Champaran, Muzaffarpur and Saran, framing the Bihar‑Uttar Pradesh frontier and supporting the Triveni Canal Irrigation system. The Gandak Barrage at Valmikinagar manages floodwaters and regulates irrigation.
Burhi Gandak River rises from Someshwar Hills, parallels the Gandak before merging with the Ganga at Khagaria. It remains a vital water source for the arable lands of West and East Champaran, Muzaffarpur and Samastipur.
Bagmati River originates in the Shivpuri Hills, flows through Sitamarhi, Muzaffarpur and Darbhanga, and ultimately meets the Kosi at Badlaghat. It is perennial, supported by major tributaries Lalbakeya and Lakhandei, and is revered by both religious communities.
Kamla River springs from the Mahabharat Hills, enters at Jainagar, passes through Mithila, and merges with the Kosi. The Kamla Barrage near Jainagar assists in irrigation and flood control.
Mahananda River rises in Sikkim, traverses Purnia and Katihar, and marks a linguistic boundary in its upper reaches before joining the Ganga in Bangladesh. It supplies water to eastern agricultural belts and commercial routes.
Son River embarks from Amarkantak Hills, joins the Ganga at Maner, and flows through Aurangabad, Rohtas, and Patna. The Dehri Anicut and Indrapuri Barrage regulate its floodplain for irrigation purposes.
Kosi River – the ‘Sorrow of Bihar’ – originates in Nepal, is also called Saptakoshi due to its seven headstreams, and regularly floods the fertile plains of Katihar and Kursela, yet delivers rich silt to farmers. The Kosi Barrage mitigates its destructive potential.
Punpun River begins on the Hazaribagh Plateau, travels through Aurangabad, Gaya and Patna, and drains into the Ganga at Fatuha. Ancient texts such as Vayu Purana note its spiritual importance along Buddhist and Hindu traditions.
Phalgu River – alternatively the Niranjana – is formed by the confluence of Lilajan and Mohana near Gaya. It is considered auspicious for performing Pind Daan and is revered in Buddhist lore.
Karmanasa River rises on the Rohtas Plateau, follows the Bihar‑Uttar Pradesh border, and joins the Ganga at Chausa. Its tributaries Durgavati, Chandraprabha and Khajuri enhance its scenic and historical significance.
Key Concepts
- Tributary – a river or stream that flows into a larger one.
- Floodplain – the flat area adjacent to a river prone to flooding, rich in silt.
- Irrigation Barrage – a low dam built across a river to divert water for agriculture.
- Saptakoshi – name given to the Kosi River highlighting its seven contributing tributaries.
- Chhath Puja – a major Bihar festival honoring the Sun God on riverbanks.