Section C :rivers Flashcards
What is attrition?
Rocks knock against each other and become smaller and rounder
What is solution?
The water dissolve certain types of rocks
What is abrasion?
Pebbles grind along the river banks like sandpaper
What is a Hydroalic action?
Water are smashing against riverbanks and cracks rocks
What is traction?
Rocks are rolled along the river bed
What is saltation?
Rocks are bounce along the riverbed
What is suspension?
Lighter sediment is carried within the water
What do you find in the upper course of a river?
V shaped valleys and interlocking spurs. These spurs are formed as a result of the river, trying to find the fastest way down towards the sea, the land then forms around the waterways, which is why there is spurs around the river. It erodes vertically.
Explain the process involved in the formation of a landform
The resistant rock where the river flows over. Beneath the resistant rock that is softer less resistant rock. Through hydraulic action and abrasion, the softer rock erodes causing an undercut. The gravitational potential energy erodes the base of the waterfall to get a deep plunge pool. Eventually, the resistant rock will collapse, causing an over hang.
Describe a flashy hydrograph
Has short leg time and high peak discharge
Steep slopes-water moves faster into the river from The Hills
High density-lots of streams will help rainfall get to the river more quickly
Urbanisation
Impermeable rock-encourage rapid overland flow
Very thin, soil
Thin Grassmoor land
Describe other hydrographs
Long lag time and lower peak discharge
Gentle slopes-what are move slower into the river from The Hills
Low density-leads to slow transfer
Forest-trees will catch intercept water and use it for growth which reduces the amount of rain reaching the river
Permeable rock-slow transfer by ground water flow
Deep soil
Rural area
Dams and reservoirs
How it works: during her reign for water can be stored, and then rainfall is low. It is released.
Pros: effective in regulating waterflow
Cons: cost huge amounts of money, floods, large areas of land, people have to be moved from houses.
Channel straightening
How it works: cutting through meanders to create Straight channel
Pros: speeds up river flow, prevents banks from collapsing
Cons: flood risk upstream, unattractive an unnatural
Embankments
How it works: a raised riverbank, which allows river channel to hold more water before flooding occurs. Includes concrete walls.
Pros: cheaper, most of stainable, looks more natural
Cons: nothing
Flood relief channels
How it works: man-made river channel constructed to bypass urban areas.
Pros: reduces threat of flooding
Describe the gradient of different parts of rivers
Lower-very gentle gradient
Middle-gentle
Upper-steep gradient
Name, five ways of soft engineering for Rivers
Planting trees, wetlands+ Flood storage areas, floodplain, zoning, river, restoration, preparing for floods
How do you Levees work?
Levees and naturally raised riverbanks, found on the side of a river channel that is prone to flooding. They formed after flood deposit sediment on the floodplain close to the river-is the water is spilling out across the land.Its velocity is reduced because of it fit friction which leads to deposition
what does a long profile show
shows you a cross-section, taken sideways, of a river channel and/or valley at certain points in the rivers course
Which stage of a river does lateral erosion take over from vertical erosion as the predominant type of erosion?
middle
where does the majority of a rivers load come from?
The majority of a rivers load comes from Weatherred material that has ended the river Channel
where is deposition most likely to occur
Shallow water due to energy levels being lower
deposition occurs whenever a river loses energy and velocity falls. When will this not happen?
Deposition does not typically occur on the outside bend of meander because of velocity is high

What can be formed when a meander bend is cut of
Oxbow Lake
where can slip off slopes be found?
 inside bend of meander
what is the name of the complex corkscrewlike motion of velocity within a river known as?
helicoidal flow
 where are interlocking spores found along the course of a river?
upper 
where is the velocity of a river greatest when it travels around meaner
Outside of the bend
explain how an oxbow Lake Forms overtime
1 A meander neck is eroded over many years, until it becomes very narrow and then flood occurs
2 extra erosive power enables water from the main channel to break through the meander neck
3 flooding subsides , but most water in the river now follows the new shorter channel
4 deposition occurs at the side of the New channel, reducing flow around the old meander
5 overtime, further deposition cuts off the old meander completely ;create an oxbow lake 
Give two advantages of hard engineering to manage the risk of river flooding
recreational or tourist value eg dams create reservoir
Protection of property creates economic savings
Give two disadvantages of hard engineering to manage the risk of river flooding
expensive to install and maintain
Environmental damage; appearance may be unpopular; may create problems downstream
“ the benefits of hard engineering strategies to minimise the risk of folding outweigh the cost”
Flood occurs every year across the UK, causing huge amounts of damage to property, making people temporarily homeless and closing businesses. Installing hard engineering methods such as flood in bank, the capacity of the river increases therefore flooding is less likely. People may argue that these are unattractive to look at, but they save millions of pounds in the repairs and insurance payouts, and also reduced the number of people who lose their homes.
Hard engineering is building dams, which control the flow of the water so less water reaches downstream, stopping flooding from a caring. However, land behind the dam is flooded creating as reservoir, meaning that some people could be displaced. Dams are incredibly expensive to construct but the reservoir created can provide a water supply to homes and businesses as well as creating a leisure amenity, which would provide jobs.
in conclusion I strongly agree that hard engineering is the best way to minimise the risk of flooding, and although there cost, these are outweigh by the social and economic benefits 
