Changing Landscapes Of The Uk - Rivers Flashcards

1
Q

Mass movement

A

The movement of rocks and soil downslope due to gravity

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2
Q

Soil creep

A

Individual particles of soil move slowly down a slope

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3
Q

Sliding

A

Material moving rapidly down a slope in one go e.g landslide

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4
Q

Flows

A

Masses of rocks moving downslope as they mix with water and flow like a liquid

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5
Q

Deposition

A

When a river no longer has enough energy to carry its load (material) so drops the material the process of material being dropped by the river

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6
Q

Transportation

A

A river picks up and carries material as it flows downstream

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7
Q

Hydraulic action

A

Air is forced into cracks in rocks in the river,forcing rocks apart

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8
Q

Attrition

A

Rocks and pebbles in the river crash into each other, causing the rocks to become smoother and smaller

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9
Q

Abrasion

A

Rocks in the river crash into river banks and are dragged along the river bed causing erosion like sand paper

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10
Q

Solution

A

Acidity in the river dissolves soft rock

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11
Q

Weathering

A

The breakdown of rocks at or near the surface by natural processes (usually on the river valley sides)

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12
Q

Biological weathering

A

Living things, such as the roots of trees,breaking soil and rocks apart

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13
Q

Chemical weathering

A

Rainfall is slightly acidic therefore it dissolves softer rocks

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14
Q

Mechanical weathering (Freeze-thaw)

A

Water that’s has seeped into the cracks of rocks as it freezes it expands in volume by 9% in volume cracking and forcing the rock apart it is repeated until the rock splits in two

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15
Q

Saltation

A

Small rocks are bounced along the river bed

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16
Q

Suspension

A

Small sediments are carried in the river (held up) downstream

17
Q

Solution (transportation)

A

Small grains of sediment are dissolved and carried down the river downstream

18
Q

Traction

A

Large boulders being rolled along the river bed downstream

19
Q

point bars

A

Point bars are made up of the deposited material that accumulates on the inside bend of a river meander.
They are crescent-shaped, are very gently sloping and found below the slip-off slope.
They are made of alluvium.

20
Q

levees

A

Levees are piles of sediment that form at the side of river channels after repeated flooding.

21
Q

mouth

A

the end point of a river where it meets the sea or ocean

22
Q

levee

A

a raised bank of sediment along the side of a river

23
Q

waterfall

A

a flow of water falling from a height into a plunge pool

24
Q

source

A

the starting point of a river

25
confluence
the point where two rivers meet
26
gorge
a steep narrow valley with rocky sides
27
meander
a bend in a river caused by erosion and depostition
28
tributary
a small stream or river that joins a larger one
29
drainage basin
A drainage basin is the area of land around the river that is drained by the river and its tributaries.
30
oxbow lake
A horse-shoe shaped lake left after the necks of meanders meet
31
floodplain
the flat fertile land in a valley next to a river that often floods
32
watershed
the boundary between the drainage basins
33
interlocking spurs
Pieces of land that over lap , they are hills that a river meander around in a V shaped valley. When viewed from downstream these spurs appear to be locked together
34
How are meander formed and oxbow lakes
Outside of a river flows at high velocity, causing lateral erosion, inside slower so material deposits forming a point par. Literalersonion eveuntially becomes curved process continues creating a meander Oxbow lake During flooding the river takes a straight past From neck of mender this eroded material eventually. Creating a slight line . This forms an oxbow lake
35
How are waterfalls formed?
Band of Gand rock positioned above exposed soft rock, less resistant rock is eroded creating and over a hand. After more erosion over hang falls forming a plunge pool A steep suedes gauge is formed at side and a waterfall where it originally was
36
River dee and its long profile
Located in snow Donna wales flows east into England its mouth is located in Chester Upper - steepest - waterfalls etc Middle - widens, menders Lower- flood plains , levee How is the river Dee important Import t water source for newly 3 million people Provides habitats for. Range of animals Flows through areas f natural bath Physical changes to river Dee- Drought Climate through the yer is variable in UK, and rainfall influences river flows. During drought, river flows are low, however , when rainfall is high , river flows r high. This causes erosion to church
37
Causes and effects of flooding
Flooding first of all is when a river bank bursts and overflows onto the nearby land What causes flooding Heavy rainfall Narrow shallow rivers Blocked drain Building houses on Floodplains Roads impeable water rushes Ito river Physical Causes Duration of rainfall Intense rainfall Rocks- imprarmable Relief- water reaches river channel much faster where stopes are steeper as water travels faster Snow melt- in high altitude areas, snow falls during inter. When temp rise in summer, this snow melts and causes rivers to flood Human Deforestation- trees and plant intercept water Urbanisation- more concrete Tamra Climate change- extreme weather more common. So more storms and rainfall Impacts- Cumbria flood in Workington Social 1 death- PC Bill Barker 50 people had to be rescued from their homes 25 bridges destroyed or loses due to damage 1300 homes flooded in Cocker-mouth and Workington Economic- Cockermouth high street was completely flooded, forcing businesses to close 3057 businesses were affected in some way Total cost was over £270 million Environmental- river derwents course was changed by erosion
38
Flood Defences
Soft Enineering Washlands- areas on flood plain that are allowed to flood Pros Give safe place fo floodwater to go Improves rivers natural sedimentation processes Cons Allowing land to flood limits usage of the land River restoration Restoring the rivers original course Pros Slows river down Natural rivers are more attractive Cons Some flood banks are often still needed Floodplain zoning Locating more areas of land to different uses, according to their level of old risk Pros Flood risk management aims to recent homes and businesses and high risk zone. Such as open space for leisure Cons May not be best places of activities in terms of public access Italy Flood plains are attractive places to build on Hard engineering Embankments(levees)- high banks built on river banks Pros St pater from spreading into areas where it could cause problems- such as housing They can be earth and gras banks which blend in with the environment Cons Flood may still go over to- water can be trapped behind them Can burst under pressure, possibly causing even greater damage River Channelisation Deepening or strengthening the river Pros This allows more water to floe Cons - Water taken ownstream may put ther places at risk Does not look natural Flood relief channels- extra channels built next to the river- Can accommodate high flow of water Cons May not be needed often May be unsightly Dams and reservoirs Long lasting ad can also be used to produce hep Cons expensive and can cause displacement of people
39
What is river discharge
the volume of water flowing through a river channel; measured at any given point in cubic metres per second.