Indian Drainage and Water Resources

The question asks for causes, not merely for true statements, and it defeats two of the three items on two different grounds.

• Statement 1 is correct and is causal. The Narmada occupies a linear trough of tectonic origin, a rift or graben bounded by parallel faults along the Narmada Son lineament. A stream confined between faulted blocks is constrained to follow the axis of the trough rather than the regional slope, which is why it does not join the Bay of Bengal drainage, and the same structure explains why it enters the sea by an estuary rather than building a delta, a rift valley river discharging into a subsiding coast.
• Statement 3 is incorrect, and this is the item that decides the question. The peninsular block is tilted eastward, the Western Ghats forming the high western edge and the land falling gently towards the east, which is exactly why the Mahanadi, the Godavari, the Krishna and the Kaveri all drain to the Bay of Bengal. Central India does not slope west. The Narmada and the Tapi flow west in spite of the regional gradient, not because of it, and it is the rift structure that overrides the regional slope. A candidate who accepts statement 3 has inverted the very fact that makes the Narmada anomalous and that the stem itself points to when it says most other large peninsular rivers flow to the east.
• Statement 2 is factually true, the Narmada does flow between the Vindhya range to the north and the Satpura range to the south, but it fails as an answer to why. It describes position, not cause. A river in a corridor between two ranges could in principle flow either way along that corridor; what fixes the direction is the structure.
• Statement 2 is in any case a restatement of statement 1, since the two ranges are the uplifted shoulders of the same rift. With statements 2 and 3 both out, the official answer is (a), one only. The elimination route is the stem: it tells the candidate that westward flow is the exception, so any statement asserting a general westward slope must be false.

Thermal power generation is by a wide margin the largest industrial water user in India, and the reason is the physics of the steam cycle rather than anything about the fuel. A thermal station must condense the exhaust steam leaving the turbine back to water, and it does so by rejecting the latent heat of condensation to cooling water; once through systems draw very large volumes and return them warmed, and even closed cycle systems with cooling towers consume substantial quantities through evaporation and blowdown. Cooling accounts for the overwhelming share, with smaller quantities going to ash handling, which in Indian plants is significant because of the high ash content of the coal, and to boiler make up and flue gas treatment. Studies of industrial water withdrawal in India consistently place thermal power at a large multiple of any other user, which is why plant siting is governed by water availability and why droughts have forced generating units to shut down.

• Option (d) is correct.
• Options (b) and (c) are the strong distractors and are correctly identified as water intensive per unit of output, paper and pulp requiring large volumes for pulping, washing and bleaching and textiles for dyeing, bleaching and finishing, but the question asks for the maximum consumer in aggregate, and neither industry approaches the scale of the power sector.
• Option (a), engineering, is the least water intensive of the four. The governing distinction, and the elimination route, is between intensity per unit of output and total volume consumed nationally.

• Statements 1, 3 and 4 are correct and statement 2 is incorrect, so the official answer is (c). A watershed is a drainage unit, the area from which runoff drains to a common outlet, and watershed development works on that unit as a whole through a ridge-to-valley sequence of treatments.
• Statement 1 is correct: contour bunding, trenching, gully plugging and check dams reduce the velocity and concentration of overland flow and therefore the detachment and transport of soil.
• Statement 3 is correct: the same structures detain runoff and increase the time available for infiltration, which is exactly how percolation tanks and check dams recharge the water table, and this is often the most visible benefit in hard-rock areas.
• Statement 4 is correct: afforestation, closure to grazing and soil moisture improvement together allow natural vegetation to re-establish, and vegetative measures are an integral part of the treatment rather than an incidental effect.
• Statement 2 is incorrect and belongs to an entirely different proposal, the interlinking of rivers, which operates at the scale of river basins and involves inter-basin transfer through link canals; it has no connection with watershed treatment, which is local and works within a single small catchment. The item is decided on statement 2 alone, and (c) is the only option that omits it.

The Godavari and the Krishna were linked through the Pattiseema lift irrigation scheme, commissioned by Andhra Pradesh in September 2015, which lifts water from the Godavari at Pattiseema in West Godavari district into the Polavaram right main canal and thence to the Krishna at Prakasam barrage. Its significance was that it was presented as the first river link of the national interlinking programme actually to be executed, delivering Godavari surplus to the Krishna delta ahead of the completion of the Polavaram project itself. Hence (b).

• Option (a) is wrong: no Cauvery-Tungabhadra link has been executed, and the Tungabhadra is in any case a Krishna tributary.
• Option (c) is wrong: the Mahanadi-Godavari link is a proposal under the peninsular component and Sone is a Ganga tributary.
• Option (d) is wrong: the Par-Tapi-Narmada link remained a proposal and has since faced sustained opposition. The elimination route is that three options name links that exist only on the National Water Development Agency's map, and only one names a scheme that had actually delivered water.

• Statement 1 is incorrect. The Teesta rises in the Pauhunri and Cho Lhamu region of North Sikkim, conventionally traced to Cho Lhamu lake, whereas the Brahmaputra rises as the Yarlung Tsangpo from the Chemayungdung and Angsi glacier region near Mount Kailash and Lake Mansarovar in Tibet. Two rivers of very different orders, separated by the main Himalayan axis, cannot share a source.
• Statement 2 is correct. The Rangeet rises in West Sikkim below Kanchenjunga, flows south and joins the Teesta near Melli on the Sikkim and West Bengal boundary; it is the principal tributary of the Teesta.
• Statement 3 is incorrect and is the more instructive error. The Teesta does not reach the sea at all as an independent river. It enters Bangladesh below Jalpaiguri and joins the Brahmaputra, in its Jamuna course, near Chilmari, so its waters reach the Bay of Bengal only through the Brahmaputra and Meghna system. Rejecting statement 1 eliminates (a) and (d); statement 3 then eliminates (c), leaving (b). Governing principle: for any Himalayan river, fix the source with reference to the main range and fix the mouth by identifying the trunk stream it joins, since a tributary that merges before the coast never has a mouth of its own.

• Option (a) is correct. The lake at Kodaikanal in the Palani hills is man made, created in 1863 when Sir Vere Henry Levinge dammed a hollow in the hills and stocked it with fish, and it forms the centre of a hill station laid out by Europeans in the nineteenth century.
• Option (b) is wrong. Kolleru is a natural shallow freshwater lake lying between the deltas of the Krishna and the Godavari, functioning as a natural flood balancing reservoir between the two river systems; it is a Ramsar site and was declared a wildlife sanctuary.
• Option (c) is wrong. Nainital is a natural lake of tectonic origin, occupying a depression formed along a fault in the Kumaon hills, and its crescent shape follows that structural line.
• Option (d) is wrong. Renuka is the largest natural lake in Himachal Pradesh, also a Ramsar site, and is associated in tradition with the mother of Parashurama, its outline being said to resemble a reclining woman. Governing principle for this recurring question type: hill station lakes in the peninsular hills are very often engineered, because the Palanis and the Nilgiris have no natural lake basins of any size, whereas lakes in the Himalaya and the sub Himalaya are commonly tectonic or glacial, and the large lakes of the coastal plains are lagoons or deltaic depressions. Since three of the four options are recognised natural water bodies with Ramsar or sanctuary status, the odd one out is the constructed one.

Hence (a).

• Pair 1 is correct. Pandharpur in Solapur district of Maharashtra, the seat of the Vithoba temple and the destination of the Varkari pilgrimage, stands on the Bhima, which is locally called the Chandrabhaga at Pandharpur because of the crescent shape of its bend there.
• Pair 2 is correct. Tiruchirappalli in Tamil Nadu stands on the Cauvery, at the point where the river divides around Srirangam island between the Cauvery and the Coleroon.
• Pair 3 is incorrect. Hampi, the Vijayanagara capital in Karnataka, stands on the Tungabhadra. The Malaprabha is a different Krishna tributary and is associated with Aihole, Badami and Pattadakal, the early Chalukyan sites. Since pairs 1 and 2 hold and pair 3 fails, the official answer (a) follows. The elimination route is Hampi and the Tungabhadra, which is standard knowledge and removes options (b), (c) and (d) at a stroke, so the item is decided by one fact even though it appears to demand three.

• Pair 1 is correct. The Yamunotri glacier lies on the Bandarpunch massif in Uttarkashi district and feeds the Yamuna.
• Pair 2 is correct. The Bara Shigri glacier in the Lahaul valley of Himachal Pradesh drains to the Chandra, which joins the Bhaga at Tandi to form the Chandrabhaga or Chenab.
• Pair 3 is incorrect. The Milam glacier in the Pithoragarh district of Kumaon feeds the Goriganga, a tributary of the Kali or Sharda. The Mandakini rises from the Chorabari glacier near Kedarnath, which is the association the pair displaces.
• Pair 4 is correct. The Siachen glacier in the eastern Karakoram feeds the Nubra, a tributary of the Shyok and thus of the Indus.
• Pair 5 is incorrect. The Zemu glacier in Sikkim, on the eastern flank of Kangchenjunga, feeds the Teesta. The Manas rises in Bhutan and Tibet and is a Brahmaputra tributary, unconnected to Zemu. Since pairs 1, 2 and 4 hold, the official answer (a) follows. The reliable elimination is Zemu and the Teesta, which is standard and removes options (c) and (d), after which the Milam pairing alone decides between (a) and (b).

All three are reservoirs behind dams, so (d) is correct. Aliyar is a reservoir in the Anaimalai foothills of Coimbatore district in Tamil Nadu, part of the Parambikulam Aliyar project. Isapur is a dam on the Penganga, a Godavari tributary, in Yavatmal district of Maharashtra. Kangsabati is a reservoir on the Kangsabati river in Bankura district of West Bengal, serving one of the largest irrigation commands in the State.

• Option (a) is wrong because India's uranium is associated with Jaduguda and the Singhbhum thrust belt in Jharkhand, Tummalapalle in Andhra Pradesh and Lambapur Peddagattu in Telangana, none of which are these.
• Option (b) is wrong because Indian tropical rain forest is confined to the Western Ghats, the north east and the Andamans as a contiguous biome, and three scattered locations across Tamil Nadu, Maharashtra and West Bengal cannot share it.
• Option (c) is wrong because India's notable cave systems are the Meghalaya limestone caves, Borra in Andhra Pradesh and Belum in Kurnool. The elimination route is the geographical spread itself, since the three names lie in three widely separated States with nothing geological or ecological in common, which leaves an engineered feature, and among the four options only a reservoir is engineered.

• Statement 2 is correct. The Central Ground Water Authority was constituted in 1997 under section 3 of the Environment Protection Act of 1986, on the direction of the Supreme Court, and it draws its regulatory power to notify and restrict extraction from that statute rather than from any dedicated groundwater law.
• Statement 3 is correct. India irrigates more land from groundwater than any other country, ahead of China and the United States, the tubewell having displaced canal and tank irrigation since the green revolution.
• Statement 1 is treated as incorrect. Assessment is carried out by unit, that is by block, taluka or mandal rather than by district, and the proportion falling in the overexploited and critical categories is materially lower than thirty six per cent, though it rises if the semi critical category is added. The answer is 2 and 3, giving (b).

All four are salt lakes of the Nagaur and Sikar belt of Rajasthan, part of the same inland drainage system as the much better known Sambhar Lake, where evaporation in an arid basin with no outlet concentrates dissolved salts and supports commercial salt extraction.

• Option (a) is wrong because Indian glaciers carry Himalayan names such as Siachen, Gangotri and Zemu.
• Option (b) is wrong because mangroves occur on the deltaic and tidal coasts, Sundarbans, Bhitarkanika, Pichavaram, not in interior Rajasthan.
• Option (c) is wrong because although Sambhar itself is a Ramsar site, these four are not designated as such. Hence (d). The unifying logic is aridity plus internal drainage, which is the standard setting for saline lake formation and is worth teaching as a process rather than as a list.

The gorge at Gandikota lies in the Kadapa district of Andhra Pradesh, where the Pennar, or Penna, has incised a deep canyon through the quartzite of the Erramala hills, the feature that gives the site its popular description as the Grand Canyon of India and its name, which refers to the narrow gap beside the fort.

• Option (a) is wrong because the Cauvery rises in Karnataka and drains through Tamil Nadu to the Bay of Bengal well to the south, its notable gorge features being at Hogenakkal and Shivanasamudra.
• Option (b) is wrong because the Manjira is a tributary of the Godavari flowing through Telangana and does not reach the Kadapa region.
• Option (d) is wrong because the Tungabhadra, a Krishna tributary, flows to the north of this tract through the Hampi region.

Hence (c).

Note first that the question asks how many pairs are not correctly matched, an inversion that costs candidates marks even when they know the geography.

• Pair 1 is wrongly matched: the Ghataprabha is a tributary of the Krishna and its reservoir lies in Karnataka, in Belagavi district, not in Telangana.
• Pair 2 is correctly matched: Gandhi Sagar is on the Chambal in Madhya Pradesh, the uppermost of the Chambal valley project dams.
• Pair 3 is wrongly matched: the Indira Sagar reservoir is on the Narmada in Khandwa district of Madhya Pradesh, and is among the largest reservoirs in the country by storage.
• Pair 4 is wrongly matched: the Maithon dam is on the Barakar, a tributary of the Damodar, within the Damodar Valley Corporation system, and lies in Jharkhand rather than Chhattisgarh. Three pairs are therefore incorrect, giving (c).
• Options (a) and (b) undercount, and (d) would require Gandhi Sagar to be misplaced as well.

• Statement 1 is correct. The Jhelum flows into and out of Wular Lake in Kashmir, which acts as a natural flood absorption basin for the river.
• Statement 2 is incorrect. Kolleru Lake lies between the Krishna and Godavari deltas and is fed principally by the Budameru and Tammileru streams, with only seasonal spill connection to the deltas. The Krishna does not directly feed it.
• Statement 3 is the decisive one. Kanwar Taal, also written Kabartal, in Begusarai district of Bihar is an oxbow lake formed by the meandering of the Burhi Gandak, which is a separate river from the Gandak. On that reading only statement 1 is correct, giving (a).
• Option (b) would follow if the examiner treated Gandak and Burhi Gandak as interchangeable, (c) is ruled out by the Kolleru error, and (d) is ruled out because the Jhelum and Wular relationship is textbook.

• Statement I is correct. India is the largest extractor of groundwater in the world, accounting for roughly a quarter or more of global withdrawal, more than the United States and China combined.
• Statement II is incorrect, and the error is in the stated purpose rather than in the quantity. Around eighty to ninety per cent of India's groundwater extraction goes to irrigation, not to drinking water and sanitation, a pattern driven by tubewell expansion, subsidised or free power for pumping and the cropping choices encouraged by procurement. Domestic and industrial use together account for a small fraction. The scale of extraction is therefore explained by agriculture, and the drinking water justification offered in Statement II does not hold.
• Statement I correct and Statement II false gives (c).
• Options (a) and (b) require the domestic use explanation to be accepted, and (d) denies the reported extraction share.

Moving downstream from Prayagraj, that is west to east, the confluences occur in this order. The Gomati joins the Ganga near Saidpur in Ghazipur district of Uttar Pradesh. The Ghaghara joins further east near Chhapra in Bihar. The Gandak joins at Patna. The Kosi joins furthest east near Kursela in Katihar district. Hence Gomati, Ghaghara, Gandak, Kosi, which is (b).

• Options (a) and (c) place the Ghaghara before the Gomati, which reverses the true order since the Gomati confluence lies upstream.
• Options (c) and (d) place the Kosi before the Gandak, which is wrong because the Kosi is the easternmost of the four. Note that the Gomati is strictly a Himalayan foothill river rising from the Fulhaar jheel, which the question treats as Himalayan.

Only item 3 can serve as a basis, so (d) is correct. Freshwater river dolphins of the genus Platanista occur as closely related populations in both the Indus system and the Ganga system, and since these animals cannot cross salt water or watersheds, a shared ancestry implies that the two systems were once physically connected. That biogeographic argument is precisely the kind of independent evidence a Pleistocene drainage rearrangement requires.

• Item 1 fails on chronology, because the Nadi Sukta is a Rigvedic hymn of the second millennium BCE that lists rivers of the period and can bear on Holocene channel changes such as the Sarasvati question, but it cannot testify to the Pleistocene, which ended more than ten thousand years earlier.
• Item 2 fails on fact, since Robert Bruce Foote's field work is associated with prehistoric stone tool discoveries in peninsular India, notably at Pallavaram, rather than with a survey of Sutlej and Yamuna palaeochannels. (a), (b) and (c) all rest on one or both of these unsound items.