Grand Canyon of U.S.A. is formed by which of the following rivers?
- (a)St. Lawrence
- (b)Missouri
- (c)Ohio
- (d)Colorado
Correct — D, Colorado.
The Grand Canyon is cut into the Colorado Plateau of northern Arizona, and the river running along its floor is the Colorado. It rises in the Rocky Mountains and reaches the plateau after a long upland course.
The plateau was slowly uplifted while the river went on sawing downward. Because that downcutting ran far ahead of the widening of the valley sides, the walls stayed near-vertical instead of being worn back into a gentle V.
The pairing is worth carrying away with its mechanism: a canyon is a river landform, made by vertical erosion into rising, resistant, dry ground. In a dry climate the walls are weathered back only slowly, so the trench stays narrow and steep.
- (a)St. Lawrence — The St. Lawrence is the right answer to which river carries the Great Lakes eastward to the Atlantic, flowing past Montreal and Quebec City into the Gulf of St. Lawrence.
It works through humid, glacially shaped lowland in north-eastern North America, and it widens into a broad estuary near its mouth rather than cutting a deep rock-walled trench across a plateau.
- (b)Missouri — The Missouri is the right answer to the longest river in the United States; it rises in the northern Rockies and joins the Mississippi near St. Louis, feeding the Gulf of Mexico.
Length is the trap. Canyon cutting depends on uplift, resistant flat-lying rock and a dry climate, not on a river's size, and the Missouri's long middle course crosses the Great Plains in a broad valley.
- (c)Ohio — The Ohio is the right answer to the river formed at Pittsburgh where the Allegheny meets the Monongahela; it then flows south-west and joins the Mississippi at Cairo, Illinois.
It drains a humid, well-vegetated interior region east of the Mississippi. The Grand Canyon lies far to the west, in the arid plateau country that the Colorado crosses.
A canyon is a deep, narrow valley with near-vertical rock walls, cut by a river that erodes downward much faster than its sides are worn back.
Three conditions usually work together. Land is being uplifted, so the river keeps a steep gradient and goes on incising.
The rock is resistant and horizontally bedded, so it holds a sheer face. And the climate is dry, so weathering and slope wash do little to soften the walls.
A gorge is the same idea at a smaller scale. Because the agent at work is running water, a canyon is classed as a fluvial landform.
Canyons belong to the erosional side of fluvial geomorphology, beside gorges, waterfalls, rapids and V-shaped valleys — the landforms of a river in its downcutting stage.
The Grand Canyon is the standard worked example because the relationship is visible in one view: an uplifted plateau, flat-lying strata of many ages exposed in the walls, and a single river on the floor doing the cutting.
Holding the river–landform pair also anchors the Colorado's wider role in the arid American south-west, where it is heavily dammed and diverted for water supply and power.
- The Grand Canyon lies in northern Arizona, largely within Grand Canyon National Park.
- Grand Canyon National Park was inscribed on the UNESCO World Heritage List in 1979.
- The canyon runs roughly 446 km (277 river miles) and is over 1.6 km deep at its deepest.
- The Colorado River rises in the Rocky Mountains and crosses the uplifted Colorado Plateau before entering the canyon.
- Glen Canyon Dam, holding Lake Powell, lies upstream of the Grand Canyon; Hoover Dam, holding Lake Mead, lies downstream.
- The Colorado's lower course heads for the Gulf of California, though diversion often leaves little flow reaching the delta.
- In India, the Pennar river has cut the Gandikota gorge in Andhra Pradesh.
Each option is a real North American river; the Grand Canyon belongs to the one crossing the uplifted, arid Colorado Plateau.
- Reading 'Colorado' as the state and rejecting it because the canyon is in Arizona — the river rises in the state of Colorado and flows on into Arizona.
- Assuming the largest canyon must belong to the largest or longest river, which pushes the guess towards the Missouri or the Mississippi system.
- Filing a canyon under ice or wind action; the pairing to hold is canyon and river.
- Swapping the two Colorado dams: Glen Canyon Dam with Lake Powell above the canyon, Hoover Dam with Lake Mead below it.
- Placing the Grand Canyon in a humid setting; the dryness is part of why the walls stay steep rather than worn back.
The pairing turns up as a direct one-liner — name the river that cut a named canyon — and it is also reversed, naming the river and asking which landform it made.
The same idea appears inside matching sets that put landforms against countries, or against the agent that shaped them, where 'Canyon – River' is the pair being checked.
A third form asks which listed feature is not fluvial, placing a canyon among gorges and braids so that the classification itself is the test.
UPSC_2022_GS1_Q242022The same device and the same answer type: a named canyon is given and the river that cut it must be supplied. What differs is the setting — Gandikota is a gorge on the Pennar in Andhra Pradesh, against a plateau canyon in the U.S.A. here.
UPSC_2009_GS1_Q392009The Grand Canyon appears again, but inside a matching set where the pairing wanted is the country, U.S.A. This question works one level finer, asking for the river rather than the location.
MPPSC_2017_PRE_PaperI_Q892017Tests the same link in the abstract — 'Canyon – River' as a landform-and-agent pair set beside wind and glacial landforms. Here that general rule is tested through one concrete example instead.
CDS_GK_2020_II_Q652020Also rests on a canyon being a fluvial landform, asking which listed feature is not one. It stops at classification, while this question asks for the specific river behind one named canyon.
- practice — not a real PYQ
The Grand Canyon lies mainly in which State of the U.S.A.?
- (a)Nevada
- (b)Arizona
- (c)Utah
- (d)Colorado
Answerb — The Grand Canyon is cut across northern Arizona, and most of it lies within Grand Canyon National Park.Colorado is where the river rises, not where the canyon is. Utah lies upstream along the Colorado's plateau course. Nevada lies to the west, sharing Lake Mead with Arizona, downstream of the canyon.
- practice — not a real PYQ
Hoover Dam, on the Colorado River, impounds which of the following?
- (a)Lake Powell
- (b)Lake Mead
- (c)Lake Winnipeg
- (d)Lake Okeechobee
Answerb — Hoover Dam stands on the Colorado downstream of the Grand Canyon and impounds Lake Mead.Lake Powell is the reservoir of Glen Canyon Dam, upstream of the canyon. Lake Winnipeg is a natural lake in Manitoba, Canada, and Lake Okeechobee is a natural lake in Florida; neither is a Colorado River reservoir.
- practice — not a real PYQ
A canyon-type valley develops most readily where
- (a)vertical downcutting runs well ahead of valley widening in uplifted, resistant, arid terrain
- (b)a river spreads its load across a gently sloping plain
- (c)moving ice scours out a broad trough
- (d)waves undercut a rocky coastline
Answera — Steep walls survive where the river incises far faster than the sides are worn back, which uplift, resistant flat-lying rock and a dry climate together allow.Option b describes deposition, which builds floodplains and deltas. Option c is glacial erosion, giving a U-shaped valley. Option d is marine erosion, giving cliffs and stacks. Each names a different agent from the one that makes a canyon.
- practice — not a real PYQ
Which one of the following rivers carries the water of the Great Lakes to the Atlantic Ocean?
- (a)Ohio
- (b)Missouri
- (c)St. Lawrence
- (d)Colorado
Answerc — The St. Lawrence leaves Lake Ontario and flows north-east past Montreal and Quebec City into the Gulf of St. Lawrence, on the Atlantic.The Ohio joins the Mississippi at Cairo, Illinois. The Missouri also joins the Mississippi, so both drain to the Gulf of Mexico. The Colorado flows south-west towards the Gulf of California.