Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
41 Cards in this Set
- Front
- Back
|
What is mechanical (freeze thaw) weathering |
Water fills a crack or joint in a rock. Water freezes and the crack expands. This process repeats until the rock breaks away |
|
|
What is chemical (acid rain) weathering |
Rainwater is slightly acidic. The acid reacts with minerals in the rocks and dissolves them. |
|
|
What is biological weathering |
Roots grow into rock cracks and split them apart |
|
|
What is mass movement |
The sides of a river valley becoming less steep as material is moved from the top to the bottom |
|
|
What is sliding |
When gravity pulls a weakened material downwards |
|
|
What is slumping |
Where the river eroded the bottom of the valley slope, making it steeper. Material above then slides down as a consequence |
|
|
What is traction |
Large boulders being rolled along the river bed |
|
|
What is saltation |
Smaller pebbles being bounced along the river bed. |
|
|
What is Suspension |
Finer sand particles are carried along in the flow |
|
|
What is Solution |
Some minerals such as chalk are dissolved in the water and carried along in the flow |
|
|
Whatβs the gradient like in the upper course and why |
Steeper. Because the river eroded vertically |
|
|
How do interlocking spurs form? |
The river at the source is small and has limited energy. This causes the river to naturally flow from side to side, around ridges in the valley, called spurs |
|
|
How do waterfalls form? |
They form in the upper course where there is an increase in vertical erosion. They form where there is a layer of hard resistant rock overlying a softer, less resistant rock |
|
|
How are gorges formed |
Over a long time, the process of undercutting and collapse is repeated, and the waterfall retreats, forming a steep-sided gorge |
|
|
What is a floodplain |
A wide, flat area of land either side of a river which experiences flooding when the river tops its banks |
|
|
How much sediment does the lower course carry and why |
A huge amount of sediment because itβs nearing the sea |
|
|
How does flooding form a floodplain? |
Flooding causes the river which is carrying sediment to overflow and lose its velocity and deposit the sediment |
|
|
What are levΓ©es and how are they formed |
The deposition process, which takes place during flooding, continues until eventually embankments, made of larger, heavier sediment, are created besides the river |
|
|
Where do meanders form? |
Usually in the middle but sometimes lower course |
|
|
How does a meander form? |
In the middle course the width, depth, and velocity of the river all increases. This causes the river to erode sideways which starts to form bends. These bends get bigger and wider and eventually develop into a horseshoe shape |
|
|
Give the five step process of the formation of an Ox-bow lake |
1.) narrow neck of meander is gradually being eroded 2.) water now takes the quickest route 3.) deposition then takes place which seals off the old meander 4.) meander neck has been cut through completely 5.) Ox-bow lake left behind when meander is completely cut off |
|
|
How does urbanisation cause more flooding? |
Leads to less permeable surfaces |
|
|
How does agriculture effect flooding? |
Moves water into streams and rivers faster |
|
|
How does agriculture effect flooding? |
Moves water into streams and rivers faster |
|
|
How does rainfall intensity effect flooding |
A lot of rainfall over a short period of time prevents soil infiltration |
|
|
How does geology effect flooding |
Rocks like granite are impermeable so water is unable to percolate from the thin soil above |
|
|
How does snow melting effect flooding |
At spring time warmer temperatures will melt snow creating more water |
|
|
How does drainage basin effect flooding |
Steep-sided valleys or a lot of tributaries means the water enters the river system quicker |
|
|
How does drainage basin effect flooding |
Steep-sided valleys or a lot of tributaries means the water enters the river system quicker |
|
|
All these four factors lead to what thing that effects flooding? |
Excess water flows towards the river as surface run off |
|
|
How does drainage basin effect flooding |
Steep-sided valleys or a lot of tributaries means the water enters the river system quicker |
|
|
All these four factors lead to what thing that effects flooding? |
Excess water flows towards the river as surface run off |
|
|
Name two pros and two cons of Dams and reservoirs (hard engineering) |
ππ»store large volumes of water until needed ππ»long-lasting; can be used to generate hydro-electric power ππ»expensive to build ππ»sediment can build up in reservoirs |
|
|
Name a pro and two cons of channelisation |
ππ»allows water to flow more quickly away from areas of flood risk ππ»visually unattractive ππ»more water is taken downstream, increasing the flood risk to other settlements |
|
|
What is the landscape impact of dams and reservoirs |
The natural river valley landscape is flooded |
|
|
What is the landscape impact of channelisation |
Replaces the natural meanders and floodplain with an artificial channel |
|
|
Give two pros and a con of floodplain zoning (soft engineering) |
ππ»reduces number of homes at risk of flooding ππ»allows infiltration to reduced surface run-off and flooding is reduced ππ»restricts the growth of settlements |
|
|
Give two pros and a con of washlands (soft engineering) |
ππ»create an area for floodwater to go ππ»allow natural river processes such as deposition ππ»might limit the use of land |
|
|
Describe the landscape impact of floodplain zoning |
Preserves the natural floodplain |
|
|
Describe the landscape impact of floodplain zoning |
Preserves the natural floodplain |
|
|
Describe a landscape impact of washlands |
Preserves the natural floodplain landscapes in the mid and lower river courses |
