Chapter 8- Rivers Flashcards

1
Q

What is the source?

A

Where the river begins

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2
Q

What is the course?

A

The path of the river from source to mouth

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3
Q

What are tributaries?

A

Small rivers that join a larger river

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4
Q

What is the watershed?

A

A line dividing the waters of a river basin from the waters of another river basin

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5
Q

What is a delta?

A

Land that forms at the mouth of a river due to deposition

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6
Q

What is the mouth?

A

Where the river enters the sea or lake

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7
Q

What is the basin?

A

The area drained by the river from source to mouth

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8
Q

What is a confluence?

A

The pace where a tributary joins the main river

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9
Q

What is an estuary?

A

The tidal mouth of a river

Transition between river and sea, affected by the tide

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10
Q

What are distributaries?

A

Smaller rivers that break food from the main river

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11
Q

What is the material transported by a river called?

A

Load

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12
Q

What are the 4 methods of river erosion?

A

Hydraulic action
Abrasion
Attrition
Solution

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13
Q

What is hydraulic action?

A

The force of moving water eroding the bed and the banks

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14
Q

What is abrasion?

A

The load hitting of the bed and the banks wearing them away

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15
Q

What is attrition?

A

The load hitting off itself, wearing itself down

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16
Q

What is solution?

A

Rock minerals dissolve in a river and are carried away

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17
Q

What are the four methods of river transport?

A

Solution
Suspension
Saltation
Traction

18
Q

What is suspension?

A

Light material e.g. Silt is transported in the water

19
Q

What is saltation?

A

Small stones are bounced along river bed

20
Q

What is traction?

A

Large rocks ate rolled along riverbed

21
Q

What is deposition?

A

When a river slows down, it loses energy so it deposits some of its load

22
Q

What are the 3 stages of a river?

A

Youthful
Mature
Old-age

23
Q

What are th characteristics of the youthful stage?

A

Steep slope
Fast moving
V-shaped valley: steep sides, narrow floor

24
Q

What are the characteristics of the mature stage?

A

Slower moving
Wider
Gentle slope
Mature valley: gentle sides, wide floor

25
What are the characteristics of the old age stage?
Slow Meandering Almost flat slope Plain: little/no valley
26
What stage is river erosion most active?
Youthful
27
What is vertical erosion?
Wearing away of river bed
28
Name 2 landforms of the youthful stage of a river
V-shaped valley | Waterfalls
29
How are v-shaped valleys formed?
River wears down valley floor Weathering wears back slopes of valley Gravity causes regolith on valley sides to move downslope
30
What are interlocking spurs?
When sides of a belly jut into each other | -created when youthful river avoids hard rocks
31
When do waterfalls occur?
When a river falls from a height
32
How are waterfalls formed?
A band of hard rock lies next to a band of softer rock River erodes soft rock faster, creating waterfall Plunge pool develops at base- caused by hydraulic action and abrasion River undercuts harder rock creating overhang Rock over head collapses Waterfall retreats up stream
33
Name an example of a waterfall
Powerscourt Waterfall, Co. Wicklow
34
Name 2 landforms of the mature stage
Floodplain | Meander
35
What is a floodplain?
A flat area along the river corse that is flooded by the river As the river floods it lays down alluvium on the valley floor
36
What is alluvium?
Mixture of clay, silt, sand, gravel and other material
37
What are meanders?
Bends in the river in the mature and old age stages
38
How are meanders formed?
*when river wears away on its outer bend and deposits on its inner bend 1. Water flows faster on outer bend- erodes bank by undercutting causing it to collapse 2. Water flows slower on inner bend- deposits load here This continues and meander becomes more prominent
39
Name three landforms of the old-age stage
Ox-bow lakes Levees Deltas
40
What is an ox-bow lake?
A curved shape of water formed when a meander in a river is cut off leaving the river to straighten its course
41
How are ox-bow lakes formed?
1. River forms a meander 2. River erodes land on outer bends 3. River deposits on inner bends 4. During a flood, river breaks through to straighten course 5. Meander is cut off from river ti form ox-bow lake Eventually lake will dry out, leaving the shape in the landscape
42
What is a levee?
A raised bank of earth running along the sides of a river