Geography-Rivers and Coasts Flashcards
What are the three different parts to the hydrological cycle?
The sea, the land and the atmosphere
What does the hydrological cycle show?
How water moves around
What sort of system is the hydrological system?
A closed system, there are no inputs or outputs (water going in/out), the water just flows around the cycle
What is the first stage of the hydrological cycle?
Water evaporates from the sea and the land
What is evaporation?
When water is heated by the sun and turns into water vapour
What is transpiration?
The evaporation of water from plants
What is evapotranspiration?
Evaporation and transpiration happening together
What is the second part of the hydrological cycle?
Water vapour is moved inland by winds
What is the third stage of the hydrological cycle?
The water vapour condenses to form clouds and then falls over the land as precipitation
What is the fourth part of the hydrological cycle?
Water moves from one place to another (flows or transfers)
What are the different ways that water moves around in the hydrological cycle?
Infiltration (water soaks into soil), percolation (water moves vertically down through soil and rock), through flow (water in the soil flows downhill), groundwater flow (water in rocks flows downhill), surface runoff (water flows overground), channel flow (flow of water in a river) and also the movement of water vapour by wind
What else happens in the fourth part of the hydrological cycle?
Water can be held on the land in stores
What are the different types of water stores?
Channel storage (water held in a river), groundwater storage (water stored underground in soil and rock(aquifer eg chalk)), interception storage (when water lands in things like plant leaves and doesn’t hit the ground), surface storage (water is held in things like lakes, reservoirs and puddles)
What is a drainage basin?
The area of land drained by a river
What part of the hydrological cycle involves drainage basins?
The part the happens on land
What sort of system are drainage basins?
Open systems, there are inputs and outputs
What is the input for drainage basins?
Precipitation
What are the flows in drainage basins?
Surface runoff, channel flow, infiltration, through flow, groundwater flow and percolation
What are the stores in drainage basins?
Channel storage, groundwater storage, interception storage and surface storage
What are the outputs in drainage basins?
Evaporation, transpiration and river flow into the sea
What are drainage basins separated by?
A boundary called a watershed (ridges of high land, water falling either side of these ridges will go into different drainage basins)
What are the key features of a drainage basins?
A tributary (smaller river eg stream that joins a main river), the source (where a river starts, unusually in an upland area eg mountains), a confluence (a point where two rivers join) and the mouth (where a river flows into the sea or a lake
What happens to rocks in a drainage basin?
They are broken down by weathering
What is weathering?
The breakdown of rocks where they are (the material created doesn’t get taken away like with erosion)
What are the three types of weathering?
Mechanical weathering, chemical weathering and biological weathering
What is mechanical weathering?
The breakdown of rock without changing its chemical composition. Freeze thaw weathering is a type of mechanical weathering that happens in drainage basins
How does freeze thaw weathering work?
Happens when the temperature alternates above and below 0 degrees c. Water gets into rock that has cracks eg granite. When the water freezes freezes it expands which adds pressure on the rock, when the water thaws it contracts which releases the pressure on the rock. When this repeats, the cracks widen and the rock breaks up
What is chemical weathering?
The breakdown of rock by changing its chemical composition. An example is carbonate weathering which happens in warm and wet conditions.
How does carbonation weathering work?
Rainwater has carbon dioxide dissolved in it which makes it a weak carbonic acid. Carbonic acid reacts with rock that contains calcium carbonate eg limestone so the rocks are dissolved by the rainwater
What is biological weathering?
The breakdown of rocks by living things eg plant roots break down rocks by growing k to cracks on their surfaces and pushing them apart
What is a rivers course p?
The path of a river as it flows downhill
What sort of courses do rivers have?
An upper course, middle course and lower course
Where do rivers flow?
In channels, in valleys
What do the rivers do to the landscape?
They erode the landscape-wear it down then transport the material to somewhere else where its deposited
Why does the shape of the valley and channel change along the river?
It changes depending on whether the erosion or deposition is having the most impact
What does the long profile of w river show you?
How the gradient change over the different courses
What does the cross profile of a river show you?
What a cross section of the river looks like
What is the upper course of a river like?
Steep gradient. v shaped valley, steep sides. Narrow, shallow channel
What is the middle course of a river like?
Medium gradient. Gently sloping valley sides. Wider, deeper channel
What are meanders?
Large bends in a river
What are meanders?
Large bends in a river
What is the lower course of a river like?
Gentle gradient. Very wide almost flat valley. Very wide, deep channel
Where do meanders develop?
In a rivers middle and lower couses
Where do meanders develop?
In a rivers middle and lower couses
How do meanders develop?
The current is faster on outside of bend (river channel is deeper there as there is less friction to slow the water) more erosion takes place on outside of bend forming river cliffs. Current slower on inside as channel is shallower, more friction, slowing water. Eroded material is deposited on inside of bend forming slip-off slopes
How do meanders develop?
The current is faster on outside of bend (river channel is deeper there as there is less friction to slow the water) more erosion takes place on outside of bend forming river cliffs. Current slower on inside as channel is shallower, more friction, slowing water. Eroded material is deposited on inside of bend forming slip-off slopes
What are ox-bow lakes?
They are formed by meanders that get larger and eventually separating from the rest of the river
What are ox-bow lakes?
They are formed by meanders that get larger and eventually separating from the rest of the river
What is the process of an ox-bow lake forming?
Erosion causes outside bends to get closer until small bit of land left called a neck between the bends, river breaks through this land usually in a flood and the river flows along the shorter course. Deposition cuts off meander-forming an ox-bow lake
What is the process of an ox-bow lake forming?
Erosion causes outside bends to get closer until small bit of land left called a neck between the bends, river breaks through this land usually in a flood and the river flows along the shorter course. Deposition cuts off meander-forming an ox-bow lake
What are flood plains?
Flat areas of land that flood
What are flood plains?
Flat areas of land that flood
Where are flood plains usually located?
The wide valley floor on either side of a river which occasionally get flooded
Where are flood plains usually located?
The wide valley floor on either side of a river which occasionally get flooded
What happens when a river floods onto the flood plain?
The water slows down and deposits the eroded material that its transporting, this builds up the flood plain-makes it higher
What happens when a river floods onto the flood plain?
The water slows down and deposits the eroded material that its transporting, this builds up the flood plain-makes it higher
How else can flood plains be built up?
Meanders migrate across the flood plain making it wider, the deposition that happens on the slip-off slopes of meanders build up the flood plain
How else can flood plains be built up?
Meanders migrate across the flood plain making it wider, the deposition that happens on the slip-off slopes of meanders build up the flood plain
What are levees?
Natural embankments along the edges of a river channel. During a flood, eroded material is deposited over flood plain, heaviest material is deposited closest to river channel as its dropped first when river slows down. Over time the deposited material builds up creating levees along the edges of the channel
What are levees?
Natural embankments along the edges of a river channel. During a flood, eroded material is deposited over flood plain, heaviest material is deposited closest to river channel as its dropped first when river slows down. Over time the deposited material builds up creating levees along the edges of the channel
What are deltas?
Low-lying ayes where a river meets the sea or a lake
What are deltas?
Low-lying ayes where a river meets the sea or a lake
What happens when rivers are forced to slow down when they meet the sea or a lake?
They deposit the material that they’re carrying
What happens when rivers are forced to slow down when they meet the sea or a lake?
They deposit the material that they’re carrying
What happens if the sea doesn’t away the deposited material?
it builds up and the channel gets blocked, this forces the channel to split up into lots of small rivers called distributaries. Eventually the material builds up so much that low lying areas of land called deltas are formed
What happens if the sea doesn’t away the deposited material?
it builds up and the channel gets blocked, this forces the channel to split up into lots of small rivers called distributaries. Eventually the material builds up so much that low lying areas of land called deltas are formed
What are the three types of deltas?
Arcuate, Cuspate and Bird’s foot
What are the three types of deltas?
Arcuate, Cuspate and Bird’s foot
What are arcuate deltas?
Rounded shape and lots of distributaries eg the Nile delta
What are arcuate deltas?
Rounded shape and lots of distributaries eg the Nile delta
What are cuspate deltas?
Triangular shape and few distributaries eg the Tiger delta
What are cuspate deltas?
Triangular shape and few distributaries eg the Tiger delta
What are bird’s foot deltas?
Shaped like a bird’s foot eg the Mississippi delta
What are bird’s foot deltas?
Shaped like a bird’s foot eg the Mississippi delta
What do contour lines tell you about a river?
The height and steepness of land by how close the lines are, so you can tell the direction of the river because they can’t uphill
What do contour lines tell you about a river?
The height and steepness of land by how close the lines are, so you can tell the direction of the river because they can’t uphill
What do contour lines look like on a map?
Orange lines
What do contour lines look like on a map?
Orange lines
How can you identify a river’s upper course on map?
Blue line representing a river and close contour lines showing steepness
How can you identify a river’s upper course on map?
Blue line representing a river and close contour lines showing steepness
How can you identify a waterfall on a map?
Black block lines that symbolise a cliff and close contour lines
How can you identify a waterfall on a map?
Black block lines that symbolise a cliff and close contour lines
How can you identify a river’s lower course?
Low land, if the river only crosses one contour line showing only a gentle slope, if it joins a sea or a lake, if it has large meanders, if there is a thick blue line showing a wide river
How can you identify a river’s lower course?
Low land, if the river only crosses one contour line showing only a gentle slope, if it joins a sea or a lake, if it has large meanders, if there is a thick blue line showing a wide river
What are the four processes of erosion?
Hydraulic action (force of water breaks rock particles away from river channel), Corrasion (Eroded rocks picked up by river scrape/rub against channel wearing it away-most common), Attrition (Eroded rocks picked up by river smash into each other, break into smaller fragments, edges get rounded) and Corrosion (River water dissolves some types of rock eg chalk and limestone)
What is transportation?
The movement of eroded material
There are four processes of transportation, what is traction?
Large particles like boulders are pushed along the river bed by the force of the water
What is saltation?
Pebble-sized particles are bounced along the river bed by the force of the water
What is suspension?
Small particles like silt and clay are carried along by the water
What is solution?
Soluble materials dissolve in the water and are carried along
What is deposition?
When a river drops eroded material, when the river slows down
What are he reasons why a river can slow down?
Volume of water in the river falls, the amount of eroded material in the water increases, the water is shallower eg inside of the bend And the river reaches it’s mouth
What part of a river are waterfalls and gorges found in?
The upper course of a river
When do waterfalls form?
Where a river flows over an area of hard rock followed by an area of softer rock, softer rock erodes more than hard rock making a step in the river, water goes over step, eroding it more, steep drop is eventually created which is a waterfall
How are gorges formed?
Hard rock is eventually undercut by erosion, becomes unsupported and collapses, collapsed rocks swirl around foot of waterfall where they erode the softer rock by corrasion creating steep plunge pool, over time, more undercutting = more collapses, waterfall will retreat living behind a steep-sided gorge
How are steep sided, v-shaped valleys formed?
In the upper course of a river most of the erosion is vertically downwards, creating these valleys
How do interlocking spurs then occur?
The river aren’t powerful enough to erode laterally they have to wind around the high hillsides that stick out onto their path either side. The hillsides that interlock with each other as the river winds around them are called interlocking spurs
What is river discharge?
The volume of water that flows in a river per second. It’s measured in cumecs (cubic meters per second)
What do hydrographs show?
How the discharge at a certain point in a river changes over time
What do Storm hydrographs show?
The changes in river discharge around the time of a storm