The total geographical area of Bihar is about 94 thousand Sq. Km., out of which about 54 thousand Sq. Km belongs to North-Bihar and remaining 40 thousand Sq. Km belongs to South Bihar. Both the two parts of Bihar is divided by the ganga river, which passes through almost middle of Bihar. Besides the Ganga, many other rivers are in the state in Both the parts. Rivers in North Bihar are perennial (flows all year) while rivers in South Bihar are non-perennial (flows during rainy season mainly and remain almost dry in summer season).
Classification of Rivers in Bihar
Rivers in Bihar can be classified into two categories:-
- Rivers in North Bihar
- Rivers in South Bihar
1. Rivers in North-Bihar
Almost every rivers of North Bihar originate from Himalayas and flow towards south and South-East direction and finally converge into Ganga.
Important rivers of North Bihar are:-
- Ghaghra (Saryu)
- Burhi Gandak
2. Rivers in South Bihar
Important rivers in South Bihar are given below:-
- North Koyal
Major rivers in Bihar
1. The Ganga
The ganga river flows in middle of Bihar and serves as the sink for all rivers of both the parts of Bihar. It originates from Gangotri glacier in Uttarkashi district in Uttarakhand at about 5611 metre above the sea level. the it enter in Bihar at Chausa (Buxar district). Ganga in Bihar runs for 445 Km, out of 2525 Km (third longest part of the Ganga after Uttar Pradesh and West bengal).It ultimately draw out 90% of river water of Bihar in to Bay of Bengal.
- In Bihar this river causes floods nearby it's banks on both sides due to overloading of water brought by rivers from both parts of Bihar.
- In every parts fo Bihar, Ganga is navigable, hence it can be utilised as cheap transportation network in Bihar.
Ghaghara originates from Nampa region of Nepal. It passes through Uttar Pradesh and enters into Bihar Siwan and passes through Saran and finally submerges into the Ganga nearby Chhapra (Bihar). This river is also known as Ayodhya (Uttar Pradesh).
- This river causes flood in Uttar Pradesh, but in Bihar it does not cause floods.
This is one of the very important rivers in Bihar. It originates from central Himalayan region in Nepal, where it is also known as Narayani. It enters into Bihar at the Valmiki Nagar and passes through West & East Champaran , Gopalganj, Muzaffarpur, Saran and Vaishali and finally submerges into the Ganga at Pahleja Ghat (near Patna).
- Earlier it was a reason for flooding in Bihar, but after the construction of Bhaisalotan Project (in which Triveni Canal was constructed) in Valmiki Nagar region , this river turned as an important sources of irrigation and does not cause flooding in Bihar.
The Kosi river originates from Tibet region in form of multiple channels. And flow through Mahabharat ranges of Himalaya in Nepal. At Triveni in Nepal, it's three major tributaries converge to form one river the Kosi.The three major tributaries are Tamur, Arun and Sun Kosi rivers.
Besides these, tributaries of Sun Koshi river i.e. Dudh Kosi, Likhukhola, Tama Kosi, Bhote Kosi and Indravati are also contribute to the Kosi river system.
After passing the Chatra gorge water of the Kosi is controlled by Kosi Barrage, from where it enters into Bihar. In Bihar it flows in Multiple channel through Supaul, Saharsa, Madhepura and submerges into Ganga in Khagaria dn Purnea in form of multiple distributaries.
- During it's coarse in Bihar, Kosi receives many tributaries like Kamala, Bagmati and Burhi Gandak.
Kosi in Bihar causes flood almost every year despite the formation of Rajpur on Kosi river river it causes floods in Bihar almost every year. That's why Kosi is often referred as the "Sorrow of Bihar"
- Kosi is the longest North-bank tributary (120 Km) of the Ganga river in Bihar.
- Kosi is important for irrigation in Supaul, Saharsa, Madhepura, Khagaria etc. as well as floods caused by Kosi spread more fertile newer alluvium in the plains of North Bihar, which enhances the fertility of soil.
The Mahananda river originates from Mahabharat ranges in Nepal and enters into Bihar in Kishanganj and passes through Purnea and finally converges into the Ganga river in North-Western region of Katihar district.
- This is an important source of irrigation in it's basin region in Kishanganj, Purnea and Katihar districts. In it's river basin Jute, rice, wheat etc. are cultivated at very large scale.
Son is the most important river in South Bihar. It originates from Amarkantaka Hills in Madhya Pradesh and passes through Jharkhand and enters into Bihar between Rohtas and Aurangabad districts and finally converges into the Ganga near Danapur (Patna). It is the longest South Bank tributary (760Km) of the Ganga.
- In between 1869-74, the British government constructed son canal system on the Son river. Since then it serves as one of the prime sources fo irrigation in Kaimur, Rohtas, Buxar, Bhojpur, Aurangabad, Arwal and Patna districts in South Bihar.
Punpun is the second most important river in South Bihar. It originates from Chhotanagpur Plateau region of Palamu district in Jharkhand and enters into Bihar in Aurangabad and glows through Arwal and Patna and finally converges into the Ganga at Fatwah (Patna).
It originates from Chhotanagpur Plateau region in Jharkhand in form of Lilanjan (alos called as Niranjana) and enters into Bihar in Gaya and at Bodhgaya, it's tributary Mohana converges into it and Known as Phalgu and acquires very wide coarse of more than 820 metre and then passes through Jehanabad, and Nalanda and finally converges into the Ganga in Tal region (Patna).
It has very important religious significance for both Hindus and Buddhists. Two important religious tourist spots i.e. Mahabodhi Temple and Vishnupad Mandir are located near the bank of Phalgu river. Besides these Phalgu finds an special mention as Niranjana river in many sacred epics of Hinduism.
The Karmanasa river originates from Kaimur Range (an extension of Vindhyachal range) near Sarodag in Kaimur district (Bihar). In it's course, it passes through Varanasi and Ghazipur districts of Uttar Pradesh and again enters in Bihar at Chausa Buxar and submerged here into the ganga river.
- Karmanasa forms boundary between Uttar Pradesh and Bihar for a very long distance.
- Karmanasa is considered as unholy river according to Hindu mythology and believed that bathing in the river will destroy all religious merits of a person.
The Kiul river originates from Tisri Hill range in Giridih district of Jharkhand. After that it enters into Bihar through a gorge in Satpahari hill in Jamui district, then it passes through Lakhisarai and at Rahuaghat, Harohar river (a continuation of Sakari river, coming from Nawada via Sheikhpura) converges into it and finally submerges into Ganga near Surajgarh (Lakhisarai).
- Kiul-Harohar river System forms the famous Tal region in Bihar along Southern bank of the Ganga river.
The Ajay river originates from Chakai block of Jamui (Bihar) and flows through Jharkhand and West bengal and finally converges into Bhagirthi river near Katwa Town (West Bengal).