Rivers and Valleys Flashcards
What are the 5 stages of River Landscapes?
Source
Mouth
Course
Discharge
Tributary
What is the Source Stage?
The start of the River.
What is the Mouth Stage?
Where it goes into the sea.
What is the Course Stage?
River follows a path (its “course”) from source to mouth.
What is the Discharge Stage?
Where the river meets the sea (flow of the water).
What is the Tributary Stage?
When it joins together with a larger river.
What is a Drainage Basin?
A Drainage Basin is like a catchment area for a river. It is an area of land drained by a main river and all of its tributaries. The Drainage Basin system works like the water gets stored into a pond and then flows out and leaves the drainage system.
What is the description of a Waterfall?
When a river flows over bands of hard and soft rock, the soft rock is less resistant so it gets eroded more quickly.
This ‘different erosion’ fine by abrasion/hydraulic actions.This makes a ledge which the water flows down.
The erosion of the soft rock undercuts the hard rock, creating a hollow plunge pool with overhanging hard rock.
The water flows over the overhang, causing more erosion in the plunge pool through hydraulic action.
Eventually the overhang collapses. The process keeps going and the the waterfall retreats back upstream. Overtime, this leaves a steep sided george.
What are the Features of the Middle/Lower Course-Meander?
In the Middle and Lower course, the land becomes flatter. On flatter land, rivers flow from side to side instead of in straight lines.
The river begins to meander which results in areas of faster and slower movement.
Rivers flow faster in the outside bend where the river has more energy to erode (abrasion/hydraulic action), creating a river cliff.
There is a slower flow on the inside bend where the river has less energy to transport material, so it depends it to form a river beach.
Over time, erosion on the outside bend and deposition on the inside bend forms a wider meander.
What is a Ox-Bow Lake?
The remains of the bend of the river. Water does not flow into or out or them.
What is a Levee?
Natural embankments of deposited material at the banks of the river.
What are the Features of a Levee?
In the lower course, the river flows over flat flood plains, which are covered during floods.
When a river has access water, the water level will rise until it bursts its bank.
We the water spreads over the flood plain, it is slowed down due to friction and can no longer transport its load.
The water deposits heavy material forts, close to the river, so that it can keep moving. Over repeated floods, natural embankments called levees build up.
Levees allow the river to flow at a higher level, protecting the land from further flooding.
What is Abrasion?
Fine material in the river hits off the bed and banks, wearing it away like sandpaper?
What is Corrosion?
Acids in the water slowly dissolve the bed and banks.
What is some of the points of a formation of a V-Shape Valley?
A river in its upper course flows downhill, eroding the landscape vertically.
The vertical erosion deepened the base of the river, using the processes of hydraulic action, abrasion and corrosion (explain features).
The rocks that fell into the river aid abrasion, causing further erosion.
