Distinctive Landscapes ✅

this topic may send me into a coma

What is a landscape

An area of land with a particular appearance

Difference between built and natural landscapes

• The built landscape is created by people for human activity

• such as a town / city

• Whereas the natural landscape is formed from natural processes

Where are upland, lowland, glaciated landscapes distributed in the UK

• Upland areas are found in Wales, Scotland and the north of England (above Manchester)

• Lowland areas are found south of Manchester and stretch all the way down to places like Cornwall

• Glaciated areas are found in Wales Scotland, and parts of England (anything north of London)

Characteristics of upland landscapes

Glaciated upland

• Formed through glaciation, where glaciers erode the surface of the land

• U-shaped valleys

Non glaciated upland

• Formed through river erosion and weathering

• Predominantly areas of limestone and sandstone as these are prone to river erosion

• V-shaped valleys

Characteristics of lowland landscapes

Glaciated lowland

• Ancient glaciers have created fertile plains and a rolling landscape

• Opportunities for farming and settlements

Non glaciated lowland

• Flat land, mostly formed by deposition

• Often marshland and near the coast

What are the three types of weathering

Mechanical, chemical, biological

What is mechanical weathering

• Freeze thaw

• Water seeps into cracks in rocks

• When water freezes, it expands, wedging the rock apart

• With repeated freeze thaw cycles, rock breaks off

What is chemical weathering

Rain is naturally acidic, causing chemical weathering in rocks

What is biological weathering

• Mix of physical and chemical

• More example when roots extend (physical) and leaves decompose (chemical)

What are the two types of mass movement

Sliding, slumping

What is sliding

Sudden movement of rock and soil along a zone of saturated soil

What is slumping

• Movement of permeable rock and soil that is lying on top of impermeable material

• Due to heavy saturation

What are the four types of erosion

• Abrasion

• Hydraulic action

• Attrition

• Solution

What is abrasion

When waves pick up rocks and smash them against the coast

What is hydraulic action

• When water enters cracks in the cliff

• Causing the crack to expand

What is attrition

When rocks hit each other, becoming smaller and rounder

What is solution (erosion)

When rocks slowly dissolve in the water

What are the four types of transport

• Traction

• Saltation

• Suspension

• Solution

What is traction

When boulders roll along the sea bed

What is saltation

When pebbles bounce along the sea bed

What is suspension

When particles float and are carried along

What is solution (transport)

When particles dissolve in water

What is deposition

• The dropping of materials onto land when the water does not have enough energy to carry it

• Heavier sediments drop first

How are headlands and bays formed

• Headlands and bays form at discordant coastlines

• Hard rock erodes slowly, forming headlands

• Soft rock erodes quickly, forming bays

How is a cave formed

• Crack in the rock is opened up by hydraulic action and abrasion

• The crack grows into a cave by hydraulic action

How is an arch formed

When water breaks through the headland it forms an arch

How is a stack formed

• When the arch erodes more, chemical weathering causes it to collapse and form a stack

• Further weathering and erosion leaves a stump

Example of stack/stump?

Old Harry Rocks, Dorset

How is a beach formed

• Strong swash pushes beach sediment up the beach at an angle, in the same direction of the waves

• Then the weaker backwash brings some materials straight

• This continues along the shore and the sediment forms a beach

How is a wave cut platform formed

• Chemical weathering weakens top of the cliff

• The sea erodes the base of the cliff, forming a wave-cut notch

• The notch increases in size, causing the cliff to collapse

• The backwash carries the rubble towards the sea, forming a wave cut platform

How is a spit formed

• Longshore drift moves the material along a coastline

• When the coastline changes direction, the material is deposited

• The deposited material builds up, formed a long ridge called a spit

How is a waterfall formed

• A waterfall forms when resistant hard rock lies on top of non-resistant soft rock

• Water erodes the non-resistant rock by hydraulic action and abrasion, forming an undercut and a plunge pool

• The resistant rock doesn't get eroded, so as time goes on, an overhang develops

• Eventually the overhang collapses into the plunge pool

• The process repeats and the water gradually retreats upstream to form a gorge

How is a gorge formed

• A gorge can be formed as a waterfall retreats up a valley.

• This happens when a river flows over a band of hard rock that lies over the top of the softer, less resistant rock.

• The river erodes the softer rock faster, through hydraulic action and abrasion.

• This erosion leads to the undercutting of the softer rock.

• Over time an overhang of hard rock forms.

• Eventually, the overhang collapses as it cannot support itself.

• This process repeats causing the waterfall to retreat upstream, leaving behind a steep and narrow gorge.

How is a v-shaped valley formed

• Due to gravity rivers can erode landscapes

• A v-shaped valley forms when a river vertically erodes into the land

• Over time, the steep sides on either side of the river weaken due to weathering, causing the rock to break apart and tumble into the river channel

• The river then transports the eroded rock downstream

How is a floodplain formed

• Floodplains are located in the middle and lower course of a river

• Floodplains form due to erosion and deposition.

• Erosion removes any interlocking spurs, creating a wide, flat area on either side of the river.

• During a flood, the material being carried by the river is deposited (as the river loses its speed and energy to transport material).

• Over time, the height of the floodplain increases as the material is deposited on either side of the river.

How is a levee formed

1. When rivers overflow their banks, they deposit transported sediment due to increased friction with the floodplain.

2. As the velocity of the water decreases due to the increased friction, its ability to to transport material is rapidly reduced.

3. Larger sediment is deposited first, often along the edge of the river channel.

4. Whereas finer sediments are transported further across the floodplain.

5. This results in a higher ridge of material next to the river channel, known as a levee.

How is a meander formed

• Meanders are bends in a river found in the middle course

• As water flowers through the channel it moves fastest on the outside of the bend, and slowest on the inside

• Where water moves fastest, it erodes

• Where it moves slowest, it deposits

• Over time, small bends get bigger, eventually leading to meanders

How is an oxbow lake formed

• Oxbow lakes are still, curved bodies of water near rivers

• They are found in the middle course

• Over time a meander changes shape so a bend ends up joining

• But the water takes the easiest, shortest route

• This eventually cuts off the bend and leaves an oxbow lake

Which landforms have been created by geomorphic processes on the Jurassic Coast

• Lulworth Cove

• Old Harry Rocks

Describe Lulworth Cove

• A concordant coastline has the same type of rock along its length

• The alternating bands of hard and soft rock run parallel to the coast

• Lulworth Cove is situated on the south coast of England on a concordant coastline

• The entrance to the cove is narrow where the waves have cut through weaknesses in the limestone

• Then the cove widens where the softer clays have been more easily eroded

• At the back of the cove is a band of more resistant chalk so erosion is slower here

Describe Old Harry Rocks

• Old Harry is two miles northeast of Swanage

• Old Harry lies at the eastern edge of the Isle of Purbeck

• The headland is part of Ballard Down

• The chalk formations are commonly called the Old Harry Rocks and the name Old Harry refers to the single stack of chalk furthest out

• There was another stack as well until 1896 but it tumbled out to sea due to erosion and is now a stump

How does geology influence geomorphic processes on the Jurassic Coast

• The Jurassic coast is made of bands of resistant (chalk and limestone) and non resistant (clay) rock

• There are both concordant and discordant coastlines, resulting in a wide range of landforms

• Softer rock is easily eroded by hydraulic action

• Harder chalk and limestone are weathered and eroded more slowly, so stand out as headlands

Which climate factors influence geomorphic processes on the Jurassic Coast

• Temperature

• Wind

• Rainfall

How does temperature influence geomorphic processes on the Jurassic Coast

• The Jurassic Coast has warm dry summers and mild wet winters

○ Therefore freeze-thaw weathering is rare

• Salt weathering occurs on coasts as the evaporation of sea water causes salt crystals to build up

How does wind influence geomorphic processes on the Jurassic Coast

• South West prevailing winds can bring storms from the Atlantic

• High energy destructive waves increase erosion through hydraulic action, eroding cliff bases

  • Unstable cliffs means mass movement may occur

How does rainfall influence geomorphic processes on the Jurassic Coast

• There is relatively low annual rainfall

• Heavy rainfall during winter storms saturates soil, causing slumping of cliffs

Human activity on the Jurassic Coast

• Limestone, a valuable building material, is quarried on the Isle of Portland

• Quarries expose areas of rock and cause chemical erosion

• Coastal footpaths are also eroded by tourists and vegetation is trampled

○ This exposes underlying soil and rock to weathering

Impact of climate change on Jurassic Coast

• Rising global temperatures lead to higher sea levels

• The sea level around the UK is predicted to rise by 60 centimetres by 2100

• A warmer atmosphere makes intense storms more likely, creating larger and more powerful waves

○ This will increase rate of erosion

• Additionally, more intense rainfall leads to greater weathering of cliffs

○ Leading to mass movement of rocks, causing more landslides

What coastal management does the Jurassic Coast have

• Groynes

• Beach nourishment

• Sea wall

Pros and cons of groynes

• 👍 - Builds a beach, encouraging tourism

• 👎 - Trapping sediment starves beach further down the coastline

Beach nourishment on the Jurassic Coast

• In 2005, 90km3 of sand was deposited onto the beach

• This project took 1 year and cost £2.2 million

• Every 20 years, the beach in Swanage needs to be replenished with 40km3 of sand

Pros and cons of beach nourishment

• 👍 - blends in with existing beach, makes it more appealing for tourists

• 👎 - needs to be replaced often, expensive

Sea wall on the Jurassic Coast

• There is a 1.8km sea wall in Swanage

• It has not changed since the 1920s

Pros and cons of sea wall

• 👍 - protects base of cliff, protects against coastal flooding, forms a promenade for tourists

• 👎 - costs 2k / metre, doesn't fully stop erosion as waves can bounce of the wall and erode the beach instead

How successful were coastal management strategies - jurassic coast

• Tourism has increased 20% since the implementation of coastal management strategies according to the RGS

• Flooding has been prevented over the past 30 years thanks to the sea wall

Describe the River Eden

• A 120km long river in north-west England, between the Pennines and the Lake District

• It flows north west

What landforms have been created by geomorphic processes in the River Eden

• Waterfalls

• Meanders

• V-shaped valleys

• Floodplains

Describe the waterfall in the River Eden

• Hell Gill Force is a waterfall near the source of the River Eden

• It has formed where there is a change in rock type, from hard limestone to softer sandstone

• Below the waterfall there is a steep gorge, left behind as the waterfall has retreated up the valley

Describe the meanders in the River Eden

• As more tributaries join the River Eden, the bigger it gets, giving it more power for lateral erosion

• In the lower course, the river valley gets flatter ad wider, and meanders form on the valley

• As these meanders grow, some get cut off to form oxbow lakes

Describe the v-shaped valleys in the River Eden

• Many streams flow down the steep slopes of the hillsides at the basin

• Freeze-thaw weathering and erosion (by abrasion) have carved out steep v-shaped valleys

• E.g. In the north-east Lake District

Describe the floodplains in the River Eden

• Carlisle is built on the floodplain of the River Eden

• As meanders have migrated across the valley floor, the floodplain has become wider

• Sediment has also been deposited when the river has flooded, building up the floodplain

How does temperature impact geomorphic processes on the River Eden

• Around the source of the River Eden the temperature is very cold, due to higher ground

• In winter freeze-thaw weathering breaks the exposed rock on the valley sides in the upper course of the river, making landslides more common

How does rainfall impact geomorphic processes on the River Eden (landlsides)

• Near Cumbria there is a lot of rainfall

• When there is intense rainfall the land becomes more saturated, so heavier and less stable

• This can cause riverbanks to slide or slump into the river channel

How does rainfall impact geomorphic processes on the River Eden (erosion)

• Heavy rain flows quickly into the River Eden, increasing the volume of water

• This increases load transportation, increasing erosion via abrasion

• Additionally, when the water has more energy, lateral erosion occurs with more force, widening the river channel and forming meanders

How does geology impact geomorphic processes on the River Eden

• Igneous rocks are impermeable so when high rainfall occurs, it causes vertical erosion.

• This creates v-shaped valleys

How does deforestation affect the River Eden

• Natural woodland and heathland have been cleared from many upland areas in the River Eden basin

• This increases surface runoff when it rains, so more water ends up in the river channels more quickly

• This increase in volume gives rivers more energy for erosion, causing sliding and slumping of riverbanks

How does farming affect the River Eden

• Some upland areas have been drained of moisture to make them more suitable for farming

• This reduces the stability of the soil, meaning that more soil is washed into the river channel by rain

• The increased load of the river increases deposition downstream, changing the floodplain landscape

How has flooding affected the River Eden (Storm Desmond)

• Storm Desmond happened in 2015, bringing gusts of up to 81mph and record-breaking rainfall to the north of the UK

• Carlisle had 2100 properties flooded

• Before Storm Desmond, a $38 million flood defence scheme was introduced in Carlisle but it wasn't good enough for the 2015 storm's rain levels

What management will put into place in the future in the River Eden

$24 million is being invested into Carlisle to protect over 4000 homes

Are there flood walls in the River Eden

There is 10km of raised flood defences along the River Eden and in Caldew

Describe how afforestation was successful as a sustainable management strategy in the River Eden

• 213,000 more trees were planted over 170 hectares of estate

• This was effective because the soft engineering meant the river channel wasn’t damaged

• It was deemed one of England’s most productive woodland sites for 25 years

• Socially and environmentally sustainable

Describe how channel management is a sustainable management strategy in the River Eden

• Some areas have had artificial meanders put in them

• This was effective in slowing the rivers flow, which increases deposition and allows for the natural build-up of the floodplain

• Environmentally sustainable

Pros and cons of flood walls (rivers)

Pros

• Protect floodplains

Cons

• Require maintenance

• Interrupt natural processes like meanders

Pros and cons of afforestation

Pros

• Trees stabilise soil, reducing mass movement

• Trees soak up rainfall and reduce flooding

Cons

• Land can't be used for farming

• Doesn't prevent flooding, just reduces the risk

• Restricts meander formation

Pros and cons of channel management

Pros

• Can reduce natural build up of floodplain

Cons

• Can increase flooding downstream