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;
40 Cards in this Set
- Front
- Back
|
What are the processes of erosion? |
Hydraulic Action - Sheer weight of water in river channel |
|
|
What are they key features of ANY river? |
River Channel - Where the water flows River Bed - Bottom of the channel River Banks - Sides of the River channel |
|
|
What is meant by Discharge? |
The amount of water passing a specific point at any given time, measured in cubic meters per second (m³/s) and depends on river volume and velocity |
|
|
What is meant by Velocity? |
The speed of the water - determined by the amount of friction on the bank and bed. Deeper rivers flow faster |
|
|
What are the words to describe the start and end of a river and the stages of the river? |
Starts at its source, flows through upper, middle and lower courses until it reaches the mouth, where it meets the sea. |
|
|
What changes occur to a river as it goes from Source to Mouth? |
Lesser gradient, Wider river, Deeper river, Faster river, more water flowing, smaller load, more lateral erosion than vertical erosion. |
|
|
What do Drainage basin, tributary, watershed and confluence mean? |
Drainage basin - The area that drains into that river Tributary - A small river that joins a larger one Watershed - The boundary between drainage basins Confluence - The point where two rivers join to make a bigger one |
|
|
What are the features of the upper course? |
V-Shaped valleys, interlocking spurs and waterfalls |
|
|
What are V-shaped valleys and interlocking spurs and how are they formed? |
A sharp valley with bands of rock which the river winds around. Because there is a lot of friction, the majority of the river's energy is used to erode downward, forming narrow V-Shaped valleys. As the river winds around bands of hard rock, SPURS form that interlock |
|
|
How and when do waterfalls form? |
They form when there is a band of hard rock on top of a band of Soft Rock. 1) Soft rock is eroded by splashing water that falls of the hard rock (hydraul + corras) 2) Hard rock is undercut and unsupported .
|
|
|
What are the processes of river transportation? |
Traction - Heavy rocks are rolled along the river bed Saltation - Sand sized particles 'bounce' along the river bed Suspension - Clay sized particles float in the water Solution - Some minerals dissolve in the water |
|
|
What are the features of the middle course? |
Straight river channels, River meanders, Ox-bow lakes |
|
|
What are the relative flow speeds of a river at any given point, and how does that affect the shape of the river? |
The fastest flow is in the middle, meaning it erodes the most there, as there is least friction, eroding down. The slowest flow is at the river banks where there is the most friction, so deposition occurs |
|
|
|
|
|
|
|
|
How is an oxbow lake formed? |
1) The fastest current is on the inside of a meander bend, eroding fastest 2) This continues, narrowing the neck between the bends 3) The two sides then join, cutting through the neck of land 4) The river now flows on, depositing near the meander bend, forming an ∩ shaped river |
|
|
What are the features of the Lower course? |
Flood plains, Levees |
|
|
How are Floodplains and Levees formed? |
1) Rivers carry lots of material and when the river floods, this is spread out over surrounding land. .. 2) The material flows over the land. Every time it floods, this adds another layer, providing a flat fertile floodplain.
|
|
|
What is a Floodplain and a Levee? |
A floodplain is flat fertile land found either side of a river. A Levee is raised land on the sides of a river, often artificially enhanced. |
|
|
What is a Delta and how are they formed? (generally) |
An area of low flat land that is found at the mouth of a river and formed by deposition. They are formed when a river loses energy as it flows to the mouth and becomes part of the sea |
|
|
What is an Arcuate Delta and how is it formed? |
A triangle shaped delta, formed of course sediment. The course sediment causes the river to deposit its load easily, forming MANY new channels for the water to get to the sea, called 'Distributary Channels' |
|
|
What are some Human causes of River flooding? |
1) Ploughing DOWN slopes allows water to run down easier 2) Dams may burst releasing lots of excess water ...
|
|
|
What are some Physical causes for flooding? |
1) Impermeable rock means water is not absorbed and runs faster into the river 2) Rises in temperature can cause a sudden thaw, releasing water rivers cannot cope with 3) Long periods of dry water hardens the land allowing the water to run off it easier ....
|
|
|
Give some examples of Global effects of flooding: |
Sudan 2007 - River Nile flooded, putting three and a half million at risk from water born diseases such as cholera. 89 were killed. 73,000 houses were destroyed Brazil 2007 - Rio Grande flooded (Amazon tributary). 343,000 people were affected, 100,000 left homeless. Many roads in Santa cruz were blocked by mud slides |
|
|
What are the organisations that deal with the forecasting and education of how to deal with river floods? |
Met Office - Predicts likelyhood of flooding, including news flashes. Gives advice on what to do before and during a flood. Environment Agency - Provides information on likelyhood of flooding, series of weather warnings, what to expect, how to prepare .....
|
|
|
How can you flood proof a building, why would you do it, and how much does it cost? |
Costs between £3000 and £10,000, therefore they only really protect it after it has been flooded, BUT all new houses have to be flood resilient if they are built in a flood area. - Moving sockets up the wall - Concrete floors (do not rot)
|
|
|
What are the two types of river flooding defences and what is the difference? |
Hard engineering (involves large building to protect) or Soft engineering (Working with nature to protect the river) |
|
|
What are Embankments, what type of engineering is it and what are the pros/cons? |
Raised banks along the river (hard) Pros - Can be used as a path - Concrete embankments are VERY effective. Cons - Look unnatural/ugly - Banks are often not built high enough |
|
|
What is Channelisation, what type of engineering is it and what are the pros/cons? |
Artificially widening, deepening or straightening a river (hard) Pros - Long lasting ,Provides protection for immediate area Cons - Increases chance of flooding downstream, Unnatural and ugly |
|
|
What is a Flood Relief Channel, what type of engineering is it and what are the pros/cons? |
Diverting a river course so it avoids settlements (hard) Pros - Lowers risk of flooding in the village - Can be used for water sports Cons - Lots of land needed - Extremely expensive |
|
|
What are Dams, what type of engineering is it and what are the pros/cons? |
Large structures that change the flow of water from the dam (hard) Pros - Large amount of water can generate hydroelectricity Cons - Ridiculously expensive, Land needs to be flooded to build the dam, maybe including settlements |
|
|
What are Flood Walls, what type of engineering is it and what are the pros/cons? |
Vertical barrier on river sides made of concrete (hard) Pros - Can be used in areas with little space - Easily and quickly erected Cons - They need to be assembled very carefully to not allow water through the joins |
|
|
What are Storage areas, what type of engineering is it and what are the pros/cons? |
Depression near a river which fills when river floods (hard) Pros - Looks natural - Doesn't damage the environment. Cons - Needs lots of unused land - Only useful during a flood. |
|
|
What is floodplain zoning, what type of engineering is it and what are the pros/cons? |
Introduction of areas near rivers where no building is allowed (soft) Pros - very cheap - Sustainable Cons - Difficult in places with lack of housing - Hard to do in LICs |
|
|
What are Washlands, what type of engineering is it and what are the pros/cons? |
River is allowed to flood wasteland areas to stop flooding later on (soft) Pros - Provides habitats for birds - Very cost effective Cons - Large areas of land are taken over - Productive land is turned into a marsh |
|
|
What are Warning Systems, what type of engineering is it and what are the pros/cons? |
A series of alarms to let people know of flooding (soft) Pros - Very Cheap - Gives people time to prepare Cons - Sirens can be vandalised - Might not provide enough warning |
|
|
What is Afforestation what type of engineering is it and what are the pros/cons? |
Planting trees on River banks to slow the water (soft) Pros - Very Sustainable - Improves environment quality Cons - Increases fire risk - Soil is made more acidic |
|
|
3) Hard rock collapses and the rocks fall into the plunge pool, making it deeper 4) Waterfall retreats upstream 5) Steep-sided gorge is left as waterfall retreats
. |
3) The course material is deposited first, forming a natural embankement, a levee 4) When a levee is artificially enhanced, then it is called an embankment.
.. |
|
|
3) Removing vegetation means less INTERCEPTION, so the water moves more quickly ... 4) Towns on flood plains' storm drains allow water to move into river at a greater speed |
4) Steep valley slopes allow water to run of more rapidly 5) Lots of rain can cause saturation of the land so flows quicker into the river 6) Silted river beds are smaller so need less water to flood .... |
|
|
The Government - Give advice on how to prepare and protect their homes, information on specific rivers DEFRA - Choose where the money goes ..... |
. |
