BPSC 70th CCE Prelims General Studies · Question 126 of 143

Correct — B, Ghagra. The Ghaghara rises on the northern slopes of the Himalaya in Tibet, in the Mapchachungo glaciers at about 3,962 metres, where it is called Mapcha Tsangpo; it runs 507 km through Nepal as the Karnali, that country's longest river; it enters India and crosses eastern Uttar Pradesh, where its lower course through Awadh is known as the Sarayu and gives Ayodhya its river; and it finally joins the Ganga at Revelganj, a little upstream of Chhapra in Saran district, Bihar. Its whole length is about 1,080 km, and it is the largest tributary of the Ganga by volume of water and the second longest after the Yamuna. Because that confluence lies inside Bihar, the river's last stretch and the low-lying country of Saran and Siwan on either side of it are part of Bihar's drainage — which is exactly what the question asks. The other three never touch the state. Bihar is drained almost wholly by the Ganga system, which enters the state near Chausa in Buxar district and cuts across it from west to east. The Himalayan rivers come in from Nepal to the north — Ghaghara, Gandak, Burhi Gandak, Bagmati, Kamla Balan, Kosi and Mahananda — and the peninsular rivers rise on the Chhotanagpur side to the south — Sone, Punpun, Falgu and Kiul. The Ghaghara is the westernmost of the northern group.

• (a)Mahanadi — The Mahanadi rises in the highlands of Chhattisgarh, crosses the Chhattisgarh plain past the Hirakud reservoir and flows through Odisha to the Bay of Bengal. Its basin lies entirely south of the Chhotanagpur plateau, which forms Bihar's southern watershed, so no part of Bihar drains into it.
• (c)Narmada — The Narmada rises at Amarkantak in Madhya Pradesh and flows west through the rift valley between the Vindhya and Satpura ranges into the Gulf of Khambhat. It is one of India's few major west-flowing rivers and drains the opposite side of the subcontinent from Bihar.
• (d)Yamuna — The most tempting wrong answer, because the Yamuna is a Ganga tributary and Bihar is Ganga country. But the Yamuna merges with the Ganga at Prayagraj in Uttar Pradesh — hundreds of kilometres upstream of Bihar's western border — so it delivers its water to the Ganga before the Ganga ever reaches the state, and no Bihar land lies in the Yamuna's own basin.

Bihar's drainage is a three-part story arranged around the Ganga. The Ganga enters near Chausa in Buxar district and flows east across the middle of the state, splitting it into a north Bihar plain and a south Bihar plain. From the north come the Himalayan rivers, which rise in Nepal or Tibet, carry enormous silt loads out of young mountains, shift their channels and flood — the Ghaghara, Gandak (also called Narayani), Burhi Gandak, Bagmati, Kamla Balan, Kosi and Mahananda. From the south come the peninsular rivers off the old, hard rock of the Chhotanagpur plateau — Sone, Punpun, Falgu, Kiul — which are seasonal, carry less silt and have stable beds. The northern rivers are the reason Bihar is India's most flood-prone state; the Kosi, notorious for wandering westward across the plain, has long been called the Sorrow of Bihar. Note that a river 'drains' a state if that state's land sheds water into it, so a river's basin matters more than the length of channel visible on a map.

Do not test the options by asking 'is this river famous in India' — all four are. Ask instead where each one's basin lies relative to Bihar's two watersheds. The Chhotanagpur plateau on the south is the divide beyond which water goes to the Mahanadi and the Subarnarekha, not to the Ganga in Bihar; the Vindhya-Satpura rift far to the west sends the Narmada into the Arabian Sea. That disposes of Mahanadi and Narmada in one step. The Yamuna is the genuinely tricky one, and the discriminating fact is the location of its mouth: it ends at the Prayagraj confluence in Uttar Pradesh, so its water reaches Bihar only after it has stopped being the Yamuna. The Ghaghara, by contrast, is still the Ghaghara when it enters Bihar and only ends at Revelganj near Chhapra. That single confluence point decides the question.

• The Ghaghara rises in the Mapchachungo glaciers in Tibet at about 3,962 m as the Mapcha Tsangpo, is the Karnali in Nepal (507 km, Nepal's longest river) and runs about 1,080 km in all
• It joins the Ganga at Revelganj, a little upstream of Chhapra in Saran district, Bihar — the confluence that makes it a Bihar river
• It is the largest tributary of the Ganga by volume of water and the second longest after the Yamuna; its Awadh course is known as the Sarayu, the river of Ayodhya
• Bihar's northern, Himalayan tributaries of the Ganga: Ghaghara, Gandak (Narayani), Burhi Gandak, Bagmati, Kamla Balan, Kosi and Mahananda; the southern, peninsular ones: Sone, Punpun, Falgu and Kiul
• The Yamuna's basin ends at Prayagraj in Uttar Pradesh, the Mahanadi drains Chhattisgarh and Odisha, and the Narmada flows west from Amarkantak to the Gulf of Khambhat — none of the three has any catchment in Bihar

• Assuming any Ganga tributary drains Bihar — the Yamuna, Gomati and Chambal all end their courses well upstream of the state
• Confusing the Gandak with the Burhi Gandak, or the Ghaghara with the Gomati; they are separate rivers with separate confluences
• Forgetting that the Ghaghara is called Karnali in Nepal and Sarayu in Awadh, so the same river appears under three names in different questions

BPSC asks Bihar geography as direct single-fact recall — which river drains the state, where a named river rises, what a river's other name is, which districts a link project serves — and expects district-level precision. UPSC asks the same rivers as a sequencing or statement problem: arrange the Himalayan tributaries joining the Ganga from west to east, or judge whether a named river formed a named lake. Learn the confluences in order and both styles are covered.

• practice — not a real PYQ

  The Ghaghara river joins the Ganga near which town of Bihar ?

  • (a)Sonpur
  • (b)Revelganj (near Chhapra)
  • (c)Maner
  • (d)Kahalgaon

  Answer(b) Revelganj (near Chhapra) — the confluence lies in Saran district, a little upstream of Chhapra; Sonpur is the Gandak confluence and Maner is near where the Sone joins.

• practice — not a real PYQ

  Which of the following rivers of Bihar rises in the Chhotanagpur plateau and joins the Ganga from the south ?

  • (a)Bagmati
  • (b)Kamla Balan
  • (c)Punpun
  • (d)Mahananda

  Answer(c) Punpun — a south-bank, peninsular tributary rising on the Chhotanagpur side; Bagmati, Kamla Balan and Mahananda are all Himalayan rivers entering north Bihar from Nepal.