Select the correct pair of river basins separated by the Dudhatoli Mountain Range.
- (a)Bhagirathi and Bhilangana basins
- (b)Nayar and Aglar basins
- (c)Pindar and Ramganga basins
- (d)Bhilangana and Mandakini basins
Correct — C, Pindar and Ramganga basins.
Dudhatoli is a Lesser (middle) Himalayan range in Garhwal that runs roughly north-south for about 25 km, from near Thalisain tehsil of Pauri Garhwal, with Gairsain in Chamoli district at its western limit; its high point, Musa ka Kotha, is about 3,114 m and the Dudhatoli Danda averages roughly 2,900-3,000 m.
Its importance is hydrological rather than scenic: it is a water divide, and the way to place it is to ask which rivers rise on which of its flanks.
The Ramganga (West) rises on the southern slopes of Dudhatoli, its source lying in Gairsain tehsil of Chamoli, from where it runs south-east into Almora district, crosses the Corbett landscape, leaves the hills at Kalagarh on the Uttarakhand-UP border and enters the plains in Bijnor district, eventually joining the Ganga far downstream in Hardoi district of Uttar Pradesh.
On the other side, the ground falling away to the north of the range drains into the Pindar, which comes off the Pindari glacier in Bageshwar district and flows west to meet the Alaknanda at Karnaprayag.
So the two basins that actually abut along this range are the Pindar's, feeding the Ganga high up through the Alaknanda, and the Ramganga's, reaching the Ganga only after crossing the whole of western Uttar Pradesh. That is option (c), and it is the keyed answer.
The idea to carry away is that a named Himalayan range is usually best remembered as a boundary, not as a lump of rock: fix the rivers that rise on either side of it and the range locates itself.
It is also worth carrying away the contrast in character — the Pindar is glacier-fed, while Dudhatoli's own streams are non-glacial perennial rivers supplied by rain, snowmelt and springs.
- (a)Bhagirathi and Bhilangana basins — These are two genuinely adjacent valleys, but they lie in Tehri district on the Bhagirathi side of the state, west of the Alaknanda and well away from Dudhatoli.
The Bhilangana rises at the foot of the Khatling glacier and joins the Bhagirathi at Old Tehri, the site of the Tehri dam, so the ground that separates them is the ridge running down between those two headwater valleys to that confluence.
The pair is the right answer to a question about the divide inside the upper Bhagirathi system; it has nothing to do with a range whose western limit is Gairsain in Chamoli.
- (b)Nayar and Aglar basins — This option is tempting because the Nayar half is true — the East Nayar and the West Nayar both rise on this range and merge at Satpuli before the Nayar goes on to join the Ganga at Vyasghat, below Devprayag.
The Aglar ruins it. The Aglar drains in Tehri Garhwal and joins the Yamuna near Yamuna Bridge, so to get from the Aglar's basin to Dudhatoli you would cross the Bhagirathi and then the Alaknanda.
Two basins on opposite sides of two intervening river systems cannot be separated by one middle-Himalayan range.
- (d)Bhilangana and Mandakini basins — The Bhilangana (Tehri) and the Mandakini (Rudraprayag, joining the Alaknanda at Rudraprayag) are also a real neighbouring pair, and they are separated by the high ridge crossed on the Ghuttu-to-Triyuginarayan route over the Panwali Kantha meadows.
That is a different divide, some way west and north of Dudhatoli.
Picking it means answering the question 'name a pair of basins separated by some ridge' rather than the question actually asked, which names Dudhatoli.
A mountain range in the Himalaya usually doubles as a water divide: rain and snowmelt landing on one flank leave by one river system, and what lands on the other flank leaves by another. Identifying a range therefore means identifying the drainage on each side of its crest.
Dudhatoli is a compact middle-Himalayan range in Garhwal, below the permanent snowline, and it works exactly this way — the northern fall goes to the Pindar, which is a headwater tributary of the Alaknanda, while the southern fall gives birth to the Ramganga (West) and to the two Nayars.
Because the range is not glaciated, the rivers it originates are non-glacial perennial streams fed by monsoon rain and springs, which is a different regime from a glacier-fed river like the Pindar even though the two basins meet along the same crest.
Uttarakhand's physical geography is organised around a handful of these divides.
Water leaving Dudhatoli's northern flank joins the Alaknanda network and reaches the Ganga inside the hills; the southern flank sends the Ramganga (West) out of the mountains to reach the Ganga deep in the plains, while the Nayars from the same flank join the Ganga at Vyasghat, a little below Devprayag.
Getting these boundaries right is what lets you place districts, dams and towns without memorising each one separately — Karnaprayag on the Pindar-Alaknanda confluence, Gairsain at the head of the Ramganga, Satpuli where the two Nayars meet, Kalagarh where the Ramganga leaves the hills.
- Dudhatoli is a middle-Himalayan range extending roughly 25 km north-south, beginning near Thalisain tehsil in Pauri Garhwal district, with Gairsain in Chamoli district as its western limit.
- Its highest point, Musa ka Kotha, is about 3,114 m (10,217 ft); the Dudhatoli Danda averages roughly 2,900-3,000 m.
- The Ramganga (West) rises on the southern slopes of Dudhatoli, with its source in Gairsain tehsil of Chamoli district.
- The Ramganga (West) enters Almora district through a deep valley, passes through the Corbett landscape, leaves the hills at Kalagarh (Ramganga Dam, Pauri Garhwal district, on the Uttarakhand-UP border), enters the plains in Bijnor district and joins the Ganga in Hardoi district of Uttar Pradesh.
- The Pindar rises at the Pindari glacier in Bageshwar district, flows through Bageshwar and Chamoli districts, and joins the Alaknanda at Karnaprayag.
- Dudhatoli also feeds the East Nayar and the West Nayar, which merge with each other at Satpuli — so the range is not a tidy two-basin divide; it sends water into more than one southern system as well.
- Dudhatoli's rivers are described as non-glacial perennial rivers, in contrast with the glacier-fed Pindar on the far side of the divide.
- The Aglar flows in Tehri Garhwal and meets the Yamuna near Yamuna Bridge.
- The Bhilangana rises at the foot of the Khatling glacier and joins the Bhagirathi at Old Tehri, the Tehri dam site.
Read the range by its drainage: Pindar to the north into the Alaknanda, Ramganga (West) to the south into the plains. The other three options name real basins that are separated by other ridges.
- Recognising Dudhatoli only as 'the range where the Nayar rises' and stopping there. Option (b) opens with Nayar, which is true, and a candidate who reads the first word and commits has lost the mark before reaching Aglar.
- Treating any two neighbouring Uttarakhand rivers as an acceptable answer. Bhagirathi-Bhilangana and Bhilangana-Mandakini are both real adjacent pairs; they are simply divided by other ridges, in a different part of the state. The question names one range, so the test is which pair meets along that range.
- Assuming a range divides exactly two basins. Dudhatoli feeds the Ramganga (West) and both Nayars on its southern side, so the honest picture is messier than the four neat pairs suggest; the option to choose is the pair that the range genuinely stands between, not the only water it touches.
- Confusing the Ramganga of this question, the western one rising in Chamoli, with the eastern Ramganga of the Kumaon hills. Mixing them moves the divide to the wrong part of the state and makes option (c) look implausible.
- Forgetting that the Pindar is only a tributary. If you remember it as reaching the plains on its own you will not see how a Pindar basin can sit against a Ramganga basin; it ends at Karnaprayag, in the Alaknanda.
The form used here is a pairing: a named range on one side and candidate basins on the other, where the discrimination is purely locational and no reasoning about relief or climate substitutes for knowing which water leaves which flank.
The same map knowledge answers other forms, and it is worth being able to produce it in each of them. Asked as a source question — which range or district a river rises in — Dudhatoli is the answer for the Ramganga (West) and for the Nayars.
Asked as a confluence question, naming a town and wanting the two rivers that meet there, this card has already given you Karnaprayag, Rudraprayag, Devprayag and Old Tehri to hold.
In each case the underlying work is the same: hold a mental map of which water goes where, and the specific fact falls out of it.
UKPSC_2012_MAINS_PaperIV_Q22012Same underlying vocabulary, tested from the opposite end. The 2012 Mains item asks the candidate to define the difference between a mountain ridge and a mountain range in the abstract; this 2024 Prelims item supplies one named Garhwal range and asks what its crest divides. What is shared is the idea that a range is a line with drainage on either side of it. What differs is the form and the demand: the Mains question wants a written distinction with no options and no place names, while this one is a single locational recall with four fixed pairs, and no definition of 'range' will get you to the Pindar and the Ramganga without knowing where Dudhatoli sits.
UPPSC_2022_PRE_GSI_Q1302022Both items test whether a named hill or range can be placed on a map rather than merely recognised. The UPPSC matching item pairs four hills and ranges with Indian states — Haryana, Manipur, Bihar and Karnataka — so the discrimination there is entirely at the scale of Indian states. The UKPSC item works at a much finer scale, inside one state, and asks not where the range is but which two river basins meet along it, so a candidate who can locate Dudhatoli in Uttarakhand still has to know the drainage on each flank to answer it.
UPSC_2012_GS1_Q482012The link is structural rather than factual. The UPSC item asks which field observations are evidence that the Himalaya are young fold mountains, and parallel mountain ranges are among the features listed; that parallel arrangement is precisely what produces divides such as Dudhatoli, with a separate river system in the trough on each side. The difference is that UPSC asks for the cause-and-evidence reasoning at the scale of the whole mountain belt, while UKPSC asks for one specific consequence of it in Garhwal, and gets there with named rivers instead of landform descriptions.
- practice — not a real PYQ
The Ramganga (West) rises on the slopes of which range, and its source lies in which district of Uttarakhand?
- (a)Dudhatoli range; Chamoli district
- (b)Nag Tibba range; Tehri Garhwal district
- (c)Mussoorie range; Dehradun district
- (d)Pindari glacier area; Bageshwar district
Answera — The Ramganga (West) rises on the southern slopes of Dudhatoli, its source lying in Gairsain tehsil of Chamoli district.(b) fails because Nag Tibba is a separate Lesser Himalayan range in Tehri Garhwal, on the Yamuna-Bhagirathi side of the state, and the Ramganga does not begin there. (c) fails for the same reason and is further west still, above Dehradun.
(d) names the source of the Pindar, not of the Ramganga, and Bageshwar lies in Kumaon on the far side of the divide.
- practice — not a real PYQ
The Pindar river merges with which river, and at which town?
- (a)Bhagirathi, at Devprayag
- (b)Alaknanda, at Karnaprayag
- (c)Alaknanda, at Rudraprayag
- (d)Alaknanda, at Nandprayag
Answerb — The Pindar comes off the Pindari glacier in Bageshwar district and joins the Alaknanda at Karnaprayag.(a) is wrong on both counts: Devprayag is where the Alaknanda and Bhagirathi unite to form the Ganga, and the Pindar is not part of that meeting. (c) names the confluence of the Mandakini with the Alaknanda. (d) names the confluence of the Nandakini with the Alaknanda.
- practice — not a real PYQ
Which one of the following rivers does NOT originate on the Dudhatoli range?
- (a)Ramganga (West)
- (b)East Nayar
- (c)West Nayar
- (d)Aglar
Answerd — The Aglar drains in Tehri Garhwal and joins the Yamuna near Yamuna Bridge; it is separated from Dudhatoli by the Alaknanda and Bhagirathi valleys.(a) is wrong as an answer because the Ramganga (West) does rise on Dudhatoli's southern slopes. (b) and (c) are wrong as answers because the East Nayar and West Nayar both rise on this range and merge with each other at Satpuli.
- practice — not a real PYQ
The Bhilangana river joins the Bhagirathi at which place?
- (a)Devprayag
- (b)Old Tehri
- (c)Karnaprayag
- (d)Rudraprayag
Answerb — The Bhilangana rises at the foot of the Khatling glacier and flows into the Bhagirathi at Old Tehri, the site of the Tehri dam.(a) is the Alaknanda-Bhagirathi confluence that forms the Ganga, not a Bhilangana confluence. (c) is on the Alaknanda, where the Pindar joins. (d) is also on the Alaknanda, where the Mandakini joins; none of the three lies on the Bhilangana.