Bihar: Rivers, lakes and dams

Bihar's rivers include the Ganga, the Gandak, Burhi Gandak, Bagmati, Kosi and Mahananda in the north and the Son, Punpun and Phalgu in the south. Bihar also has lakes, waterfalls and hot springs of religious and ecological note. The Water Resources Department handles irrigation, flood protection and inter-state water sharing.

The Ganga

• The Ganga is a 2,525 km trans-boundary river of India and Bangladesh, rising in Uttarakhand.
• After entering West Bengal it divides into the Hooghly and the Padma.
• It is the third largest river in the world by discharge.
• Capitals such as Pataliputra, Patna, Hajipur, Munger and Bhagalpur stood on its banks.
• Small rivers meeting it directly in Bihar form the Ganga stem basin: Karmnasha (near Chausa), Kao-Thora, Dharmawati, Gangi and Gerua from the right; Mahi (near Sonepur) and Baya (near Bachhwara) from the left.

North Bihar Rivers

• Gandak: rises at 7,620 m north of Dhaulagiri in Tibet; forms the Uttar Pradesh–Bihar boundary; joins the Ganga at Hajipur.
• Burhi Gandak: rises at Chautarwa chaur near Bisambharpur (West Champaran); joins the Ganga near Khagaria; catchment 12,021 sq km, of which 9,601 sq km in Bihar.
• Bagmati: a perennial river; rises in the Shivpuri hills of Nepal; about 589 km long, 394 km in Bihar; falls into the Kosi at Badlaghat.
• Kosi: rises above 7,000 m; Mount Everest and Kanchenjunga lie in its catchment; called Sapta Kosi in Nepal.
• The Kosi enters India near Hanuman Nagar and joins the Ganga near Kursela (Katihar).
• Kosi catchment: 74,030 sq km, of which only 11,410 sq km in India.
• Mahananda: rises in the Darjeeling hills at 2,100 m; drainage area 20,600 sq km (11,530 sq km in India); joins the Ganga at Godagari Ghat in Bangladesh.
• Adhwara group: rises in Nepal's foothills and falls into the Darbhanga–Bagmati at Ekmighat.

South Bihar Rivers

• Son: principal southern tributary of the Ganga; rises in Madhya Pradesh; cuts through the Kaimur Range and joins the Ganga above Patna after 784 km.
• The headworks of the Son canal system are at Dehri.
• Punpun: rises in the Chottanagpur hills (Palamau); 200 km long; joins the Ganga at Fatuha, about 25 km downstream of Patna.
• Punpun catchment is about 8,530 sq km; it often causes flood damage on the eastern side of Patna.
• Phalgu: flows by Gaya; called the Niranjana in ancient texts; its water flows below the sandy bed.
• Karmanasha rises in Kaimur; the Ghaghra rises near Manas Sarovar in Tibet.

Lakes

• Kanwar Lake (Begusarai): draws migratory birds from Central Asia in winter; more than 106 species of resident birds.
• Muchalinda Lake (Bodhgaya): where the Buddha meditated in the sixth week, during a severe thunderstorm.
• Saraiya Man (near Bettiah): its water is held good for digestion because of Jamun fruit falling into it.
• Kharagpur Lake (Munger): improved by a reservoir built by the Maharaja of Darbhanga.
• Moti Jheel (Motihari), Pandu Pokhar and Ghorakatora (Rajgir) are other lakes.

Waterfalls and Springs

• Kakolat Falls (Nawada): water falls from 160 feet.
• Telhar Kund (Kaimur): near the origin of the Durgavati River, 32 km from Bhabua.
• Karkat Waterfall (Kaimur): near the Kaimur Wildlife Sanctuary.
• Tutla Bhawani (Rohtas): a fall of 200 m, with a rock edict of Nayak Pratap Dhawal dated 1158 AD.
• Dhua Kund (Sasaram): a pair of falls used for hydroelectricity (50–100 MW capacity).
• Rajgir hot springs: at the foot of Vaibhava Hill; the hottest, Brahmakund, is 45 °C.
• Sita Kund (Sitamarhi): 5 km west of Sitamarhi; honoured as the birthplace of Sita.

Water Resources Department

• Formerly the Irrigation Department; protects the state's rights in inter-state river water.
• Builds and runs major and medium irrigation schemes, embankments and flood works, and drains waterlogged areas.
• Works to mitigate floods in 29 districts.

Interlinking of Rivers

• NWDA proposed 30 river link canals; cost about ₹5,60,000 crore at 2002 prices.
• Six Himalayan links concern Bihar: Kosi-Mechi, Kosi-Ghaghara, Chunar-Sone Barrage, Sone Dam-Southern tributaries of Ganga, MSTG, and (partly) Gandak-Ganga.
• A Kosi high dam at Barahkshetra (Nepal): 9,370 MCM storage, 3,000 MW.
• Kosi-Mechi canal: 112.55 km; irrigates 4.74 lakh ha, of which 2.99 lakh ha in Bihar.
• Kosi-Ghaghara canal: 428.76 km; benefits 10.58 lakh ha, including 8.17 lakh ha in North Bihar.