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
