River Landscapes

Question 1

What is the source?

Answer 1

the starting point of a river often a spring or lake

Question 2

What are tributaries?

Answer 2

a smaller river that joins the main one

Question 3

What is the mouth?

Answer 3

where a river flows into a lake or sea

Question 4

What is the watershed?

Answer 4

the boundary between two drainage basins usually highland such as hills or a ridge

Question 5

What is the drainage basin?

Answer 5

the area of land that is drained by a river and its tributaries

Question 6

What is the river channel?

Answer 6

the place in which the river flows

Question 7

What is the floodplain?

Answer 7

land that gets flooded when a river overflows

Question 8

What is a confluence?

Answer 8

a point where two streams or rivers meet

Question 9

from source to mouth the gradient of a river …

Answer 9

…decreases

Question 10

from source to mouth sediment size becomes…

Answer 10

…more rounded and smaller

Question 11

What are the three ways in which water gets into a river?

Answer 11

surface runoff
through flow (from infiltration)
ground water flow (due to impermeable rock)

Question 12

What are the types of erosion that can affect rivers?

Answer 12

hydraulic action
attrition
abrasion
solution (corrosion)

Question 13

Describe the features of a river in its upper course

Answer 13

near the source - steeper gradient
slow flowing (friction)
narrow and shallow
overall load is low so very clean water
large angular sediment
vertical erosion -valleys and waterfalls

Question 14

Describe the features of a river in its middle course

Answer 14

less steep gradient
increasing velocity (less friction)
wider and deeper
rounded and angular rocks
load increases so less clean water
meanders develop
floodplain develops

Question 15

Describe the features of a river in its lower course

Answer 15

near the mouth-almost flat land
very fast flowing-less friction
wide and deep channel
small suspended sediment, load is high
leeves
wide flood plain
deltas or estuary at the mouth

Question 16

V-shaped valley:

Where and how does it form?

Answer 16

Upper course
river erodes vertically, deepening the valley
banks become less stable
after heavy rain, due to gravity, they collapse creating a v-shaped valley

Question 17

Interlocking Spurs:

Where and how do they form?

Answer 17

Upper course
lots of vertical erosion in valley
river is forced to swing from side to side around more resistant rock (spurs)
little energy for lateral erosion -cuts down vertically
winds and bends to avoid areas of hard rock
creating interlocking spurs

Question 18

Waterfall:

Where and how does it form?

Answer 18

Upper course
forms when a river flows over softer rock after flowing over hard, resistant rock
1. the soft rock is easy to erode and a ledge forms
2.the water erodes the soft rock, forming a plunge pool
3.in time, the ledge falls into the plunge pool
4.the water retreats upstream, carving out a gorge