Landscapes of the UK Revision Booklet Geomorphic processes
Landscapes of the UK Revision Booklet
Geomorphic processes change the shape of the land. They include erosion, weathering, transportation, deposition and mass movement. Geomorphic processes act over different timescales. Some happen very quickly whereas others can take thousands of years to change landscapes or create landforms. Erosion is the wearing away of materials by a moving force such as a river or waves. Hydraulic action Abrasion Water is forced into cracks, which creates weaknesses in rocks, splitting them apart. Sediment is thrown against a surface by water and causes the sediment to rub and wear away material. Attrition Solution Pebbles hit each other making the rocks break and get smaller and rounder. Rocks are dissolved in water by a chemical reaction. What is meant by a geomorphic process? (2) Explain how a river erodes (4)
Weathering is material that has been broken down by the atmosphere. Weathering tends to be a much slower process than erosion. Freezethaw weathering can take thousands of years. Mechanical weathering Biological weathering Chemical weathering The physical actions of rain frost and wind that create weaknesses in rocks. Actions of living organisms such as plants and burrowing animals breaking down rocks. Minerals in the rock reacting with chemicals such as the effects of acid rain. Use a sequence of annotated diagrams which explain how the freeze-thaw weathering works (4)
Transportation is when a river carries material from one pace to another after material has been eroded. The material carried by a river or the sea , is called its load. A river transports its load in four ways: Traction- Large boulders are rolled along the river bed or sea bed Saltation- Smaller particles are bounced along the river bed Suspension- Very fine particles float (are suspended) in the river current. Solution- Rocks such as chalk and limestone dissolve and are carried by the river. Draw a line from the name of the river transport method to its correct definition. Traction Dissolved rocks such as chalk and limestone are carried by the river. Saltation Large boulders in the upper course of the river are rolled along the river bed. Suspension Solution Ninety percent of a river’s load is carried in suspension whereby very fine particles float along in the river current. Smaller particles are bounced of the river bed over one another in a leapfrogging motion.
Mass movement is the sudden movement of material down a slope due to the pull of gravity. Gravity is an important force, as any steep slope or cliff will be constantly put under stress by processes which try to make it fall down. Sliding – where a section of land falls down a slope and dislodges other material on its way down. Slumping – where material at the bottom of a slope moves outwards. Create a spider diagram that is populated with all of the different types of geomorphic process.
Upland, lowland glaciated landscapes Describe the distribution of glaciated areas in the UK (3) Geology Igneous rocks- are very hard rocks such as granite and basalt. They are very old rocks. They are impermeable so often will have rivers on their landscapes. As they are hard they erode and weather very slowly so lead to highlands. Sedimentary rocks – are much softer than igneous rocks. They include rocks such as chalk and limestone. They form in layers over millions of years from the skeletons of dead sea creatures. They are permeable so will let water through them which means that there landscape is less likely to have rivers. They are soft so erode and weather more quickly than igneous rocks so they lead to lowland areas. Describe the distribution of hard igneous rocks in the UK (2)
What are the distinctive characteristics of the upland areas in the UK? • • • Thin soils Steep relief (steep slopes) Hard, igneous rocks Thin covering of vegetation Often sheep grazing Sparsely populated due to harsh climate Waterfalls Higher rainfall and lower temperatures V shaped valleys What are the distinctive characteristics of the lowland areas in the UK? • • Richer fertile soils Flat land Gentle slopes Meanders Arable farming Densely populated Drier with warmer temperatures
How has glaciation changed the characteristics of river valleys? Glaciation has happened many times in the UK. Large areas of land were covered by ice sheets or glaciers. This caused dramatic changes in the landscape. Areas which have been most affected by glaciation include The Lake District, The Scottish Highlands and Snowdonia in Central Wales. Diagram A shows a classic river valley before glaciation. Diagram B shows the same river valley after a glacial episode. Accurately annotate the diagrams using the labels below V-shape valley, U-shape valley, steep slopes, gentle slopes, interlocking spurs, truncated spurs Urban and rural landscapes A rural landscape is an area which is sparsely populated and has fewer services (e. g. countryside). An urban landscape is an area which is densely populated with a range of shops and services (e. g. towns and cities). How do climate and landscape affect land use in The UK? The greater the relief (height) of the land the colder and wetter the climate is. , then the less human activity there is. Sheep farming occurs in upland UK in areas such as Upper Teesdale (on the River Tees). This is because it is too cold and there are not enough hours of sunshine to grow crops and slopes are too steep to use machinery which arable (crop) farming needs. Arable (crop) farming happens in lowland UK, where there are warmer temperatures and flatter , lower lying land where machinery can be used. Explain why arable farming is not located in upland areas of the UK (4)
This is a diagram of a river basin. A river basin is all the land that is drained by a river. All rivers have three courses/stages Each course has different landforms and different characteristics. Source Waterfall Meander Mouth Ox bow lake
Bradshaw Model The Bradshaw model is a theoretical model that helps describe the changes we would expect as a river travels from its source in the upper course to the mouth in the lower course. Describe and explain the changes: a)Width of the river b)Depth of the river c)Velocity of the river d)Load particle size
Erosional landforms: V-shaped valley A V shaped valley is a steep sided, narrow river valley that takes the form of a V shape. It is formed by erosion as the river erodes vertically in the landscape. Vertical erosion happens due to hydraulic action and abrasion. It leaves very steep valley sides that are then attacked by weathering processes such as freeze thaw and biological weathering. This weakens the valley sides which may collapse or some material to move down slope due to mass movement processes such as sliding.
Erosional Landforms: Waterfall/Gorge High Force waterfall The UK’s largest waterfall at 21 metres high. It has taken many millions of years to form. Formation: • A band of harder more resistant rock (whinstone) was laid down on less resistant rock (limestone). • The soft rock (limestone) erodes first by hydraulic action and abrasion. • This leaves an overhang of hard rock. • Due to a lack of support and the pull of gravity the overhang collapses. • A plunge pool forms as the hard rock erodes the river bed due to hydraulic action and abrasion. • Over time the waterfall retreats and a steep sided gorge forms.
Draw a series ANNOTATED (not labelled) diagrams which explain the formation of High Force Waterfall.
Meander formation Meanders are very common features in the middle course of the River Tees. A meander is a bend or curve in a river. Formation: The fastest flow of water is on the outside bend and so there is greatest erosion here due to the river having more energy. The bank is undercut because of lateral erosion mainly hydraulic action and abrasion and so a river cliff is created. On the other hand the slowest flow of water is on the inside bend and so because the river has less energy deposition occurs, causing a slip off slope to form. ` River cliff Slip off slope Cross section of a meander
How does an ox-bow lake form? There is an oxbow lake close to the small town of Yarm which is located in the middle course of the Tees. Oxbow lakes are crescent shaped lakes which have been cut off from the main river channel. • Erosion(hydraulic action and abrasion) take place on the outside of a river bend. • The neck of the meander becomes narrower as the erosion continues. This is sometimes called a ‘swans neck’ meander • At times of high discharge (flooding) The river breaks through the neck of the meander. • The old meander is now separated from the main river channel and deposition of sediment will eventually fill it in. Once a river begins to meander the process tends to mean that the curves become more exaggerated. Meanders cut laterally (sideways) across the river valley, , which constantly changes the river’s path. . This is called meander migration. Explain how a meander may change in the future [3]
Levee formation Levees are naturally raised river banks. They are a characteristic of rivers that have experienced repeated flood events. There are numerous levees along the middle course of the River Tees. Especially around the small town of Middleton St George Levees form when: • The river floods • As the river is in flood it has a higher energy levels , so is able to transport alluvium (silt) over its banks. • As the water slows down it loses energy and so deposits material. • Heavier material is deposited closest to the river banks and finer material is carried further. • Successive floods will raise the height of the river banks. These are called levees. Natural levees are a feature caused solely by deposition To what extent do you agree? (8)
Floodplain A floodplain is the flat land either side of a rivers banks. It is formed over many thousands of years after a river floods and deposits fine material in layers either side of it. After successive floods the height of the floodplain increases as further sediment is deposited. Geology of the Tees The geology of the River Tees varies greatly. There is softer limestone which means that rates of erosion speed up. Where the harder more resistant rocks such as whinstone and the softer rocks such as limestone are present water falls such as High Force form. In the lower part of the River Tees Valley softer sandstones are present which increases the rate of weathering and erosion, leading to much more gentler , lower landscapes.
Case Study – a UK river basin Name of UK river basin: . . . . . Examine the impact of geomorphic processes on the formation of landforms in your chosen river basin [8 marks]
UK River Case study: The River Tees is located in the north of England. The source of the River Tees is located in the Pennines and it flows east to its mouth where the river joins the North Sea. Meander on the River Tees at Yarm High Force Waterfall on the River Tees
Impact of Human Activity on The River Tees Basin Human activity has had a massive impact on the River Tees Basin. The impact of human activity is far greater and far more rapid than natural geomorphic processes. Cow Green Reservoir, is a water reservoir 2 miles (3 km) long built between 1967 and 1971 to cope with the growing demand for water from the industries on Teeside. Negative impacts on the Tees River Basin. • The construction of the reservoir involved flooding part of North Pennine Area of Outstanding Natural Beauty. • Farmland was destroyed in the area. • Environmentalists were concerned about the rich flora and fauna of the area and especially rare plants like the unique Teesdale Violet. The population of the Teeside Violet has reduced due to the construction of the reservoir. • Concrete is required in the construction of reservoirs but the industrial process of making cement increases carbon dioxide emissions. • The construction of the reservoir was very costly. Positive impacts on the Tees River Basin • The reservoir supplies the industries of Teeside with water. • The reservoir captures so much water that it reduces the risk of flooding in places that are high risk of flood such as Yarm. • Money from tourism can be reinvested back into the area and to help with maintenance.
The Tees Barrage is a flood defence which started construction in 1991 and finished in 1995 and cost &54 million to construct. It consists of four 8 m moveable gates. It is located between Middlesbrough and Thornaby-on-Tees. Negative impacts of the barrage on the Tees River Basin The barrage has raised river levels further upstream which increases the risk of flooding and threatens delicate ecosystems further upstream where high risk species such as river otters live. It has increased the rate of erosion upstream as hydraulic action increases due to rising water levels. Positive impacts of the barrage on the Tees River Basin The barrage has decreased the risk of flooding down stream. Derelict brownfield sites were cleaned up when the barrage was built as there was a £ 500 million investment in offices, housing, education and leisure and shopping facilities. Also money is generated through tourism as the areas is used for watersports such as canoeing, jet skiing, dragonboat racing and incorporates a 1 km rowing course.
Meander (channel) straightening On the stretch of The River Tees between Stockton and the Newport Bridge the River Tees used to have several meanders. These were ‘cut off’ in the mid 19 th century to speed up the journey times of ships carrying cargo. This reduced flooding risk as the river now took less time to empty into the sea. Channel straightening The River Tees Dredging Parts of the River Tees are dredged to remove sediment and increase river capacity. This has reduced the risk of flooding along the course of the river.
UK Coastal Case Study –The Holderness Coast is 61 km long. It runs from Flamborough Head in the north to Spurn Point in the South. The major settlements are Withernsea, Hornsea and Bridlington. Mappleton is a well known village due to its controversial sea defences. On average the Holderness Coast erodes at approximately 5 m per year, making it the fastest coastline in Europe. The Geology of the coast is one of the reasons that it is eroding so quickly. It is mainly very soft boulder clay with some harder chalk at Flamborough Head. However, chalk will erode through solution and chemical weathering. Abrasion is very effective on this stretch of coastline due to the large amount of eroded material in the sea(load). Create a fact file which outlines key facts about the Holderness Coast
Geomorphic processes at the coast When answering any question on coastal landforms you must include the processes that occur at the coast. Mass movement, weathering, erosion and transportation all occur at the coast just like they do in rivers. The processes are almost identical but there is a slight difference in how erosion occurs at the coast, than it does at rivers. Coastal erosion Hydraulic action - air may become trapped in joints and cracks on a cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion. Corrasion - is when waves pick up beach material (e. g. pebbles) and hurl them at the base of a cliff. Abrasion - sediment in waves grind down cliff surfaces like sandpaper. Attrition - waves cause rocks and pebbles to collide and as a result they become smaller, rounder and smoother. Solution - acids contained in sea water will dissolve some types of rock such as chalk or limestone.
Landforms found at The Holderness Coast Sea Stack Flamborough Head Bay Bridlington Bay Coastal Spit Spurn Head How do headlands and bays form? • Flamborough head and Bridlington Bay forms a headland bay. It forms here because of the more resistant rock (chalk) at Flamborough and the soft rock (boulder clay) in Bridlington. • The rate of erosion for the rock types is different. Flamborough head erodes at approximately 0. 8 m per year. Bridlington erodes at approximately 3. 4 m per year. • It doesn’t have another headland on the other side of Bridlington like the generic headland bay formation. This is because the rock is uniform (the same) along the rest of the coast. Flamborough Head Bridlington Bay • Cliffs are usually composed of alternative bands of hard and soft rock. • Soft rock is less resistant to erosion and so erodes quickly because of hydraulic action, abrasion and corrasion. Forming a bay. • This leaves the hard rock behind, which is more resistant to erosion, forming a headland. Once the soft rock has been eroded it leaves the hard rock more vulnerable to erosion.
Crack, cave, arch, stack and stump - Flamborough Head Here is an image showing Flamborough Head and the coastal stack. The stack is made from chalk. This rock is sedimentary and in layers. It has many joints, which are points of weakness. This is where the sea attacks. Stage 1 – The sea uses hydraulic action and abrasion to attack the weak spots (joints) in the headland. This causes cracks to form. Stage 2 – erosion continues and causes the cracks to widen and deepen to form a sea cave. Freeze thaw weathering accelerates the process. Stage 3 - Further erosion will cause the cave to break through the headland to form a sea arch. Stage 4 -Over time further weathering and gravity will cause the roof of the arch to collapse, leaving a sea stack. Stage 5 – Eventually further erosion will cause the stack to become smaller and known as a stump.
Transportation at The Holderness Coast The sea transports material in the exact same way that rivers do. Traction - Pebbles and larger rocks are rolled along the sea bed. Saltation - The load is bounced along the sea bed, e. g. small pieces of shingle or large sand grains. Currents cannot keep the larger and heavier sediment afloat for long periods. Suspension Small particles are carried in water e. g. silts and clays, which can make the water look cloudy. Solution Minerals are dissolved in sea water and carried in solution. The load is not visible. Load can come from cliffs made from chalk or limestone How does material get moved by longshore drift? Longshore drift is when sediment is moved (transported) up and down the beach in a zig zag pattern. The swash is the movement of water up the beach at an angle due to wind. The backwash is the movement of waves down the beach at a 90° angle
How do coastal spits form? A spit is a feature of deposition. The cliffs at the Holderness Coast are made of soft boulder clay and are easily eroded. Longshore drift has moved the eroded material in a southerly direction and created a sea spit named Spurn Head. The diagram below shows the direction of the longshore drift and Spurn Head at the bottom of the coastline. Formation of a coastal spit • Sediment is transported along a coast by longshore drift. • It is carried onto the beach by swash and back off by backwash. • When the coastline changes direction or where a river mouth occurs the material continues to be deposited in the same direction which is out into the sea forming a spit. • The wind causes a hooked end at the end of the spit and the sheltered side of a spit forms a salt marsh.
How do beaches form? Beaches are composed of material that has been eroded in one place (by destructive waves) and deposited in another (by constructive waves). They are formed by constructive waves. The swash of these waves is stronger than the backwash so they deposit material leading to the formation of a beach. Beach profile Heavier, larger material is deposited at the back of the beach because the strong swash of the constructive wave has the power to transport material. Whereas the lighter material is dragged down the beach by wave’s backwash and so finer material tends to be next to the waterline finer material Shoreline Heavier material Explain how constructive and destructive waves lead to formations of beaches along the Holderness Coast(4)
Case Study – a UK coastal landscape Name of UK coastal landscape: . . . . . Examine the impact of geomorphic processes on the formation of landforms in your UK coastal landscape [8 marks]
So why is The Holderness coast the fastest eroding coastline in Europe? 1. The majority of the coastline is made of very soft boulder clay. This makes them very prone to erosion. 2. The waves have a very long fetch which gives them lots of erosive energy to attack the cliffs with. The fetch is the distance that a wave travels before it breaks. The waves that hit the Holderness coast have travelled across the North Sea. Holderness Coast fetch 3. The waves that attack the Holderness Coast are mainly destructive storm waves that have lots of erosive energy. Destructive storm waves attacking cliffs at Holderness. 4. Naturally narrow beaches - these beaches give less protection to the coast as it doesn't reduce the power of the waves.
The impact of human activity on the Holderness Coast 1. 2. 3. 4. Tourism Building at the coast Coastal Management Climate Change 1. Tourism • • • Tourism is worth £ 20 million along the Holderness coastline Tourism employs over 1, 000 people and involves over 5, 000 caravans. Tourists visit mainly within June to early September and so employment opportunities are seasonal and low paid. Litter increased as well as increased congestion and pollution in the area from increased tourist numbers. Also the development of tourist resorts are adding weight to the coastline. Spurn Head has been designated as a Site of Scientific Special Interest (SSSI) set up to protect vulnerable species from the threats of tourism but also threats from decreasing sediment because of the implementation of groynes stopping the process of longshore drift. 2. Building at the coast When homes are built near the cliff edge they are adding extra weight to an already vulnerable rock causing it to collapse leading to: • 29 villages have been claimed by the sea in 1000 years • In June 1993 the Holbeck Hall Hotel slumped into the sea • Holiday caravans have collapsed into the sea • Decreasing house prices • Many people struggle to get any home insurance or have high premiums due to the high likelihood of cliff collapse
3. Coastal Management Coastal management schemes have both positive and negative impacts. If you write about this in your exam it is essential that you explain that negative impacts are unintentional or that the negative consequences have been accepted by the decision makers as acceptable. Hard engineering is the most common form of coastal management used here. Positive effects of coastal management Coastal management schemes have reduced the rates of erosion: • In 1991, the decision was taken to protect Mappleton. A coastal management scheme costing £ 2 million was introduced involving two types of hard engineering – placing rock armour along the base of the cliff and building two rock groynes. • Bridlington is protected by a 4. 7 km long sea wall. • Hornsea is protected by a sea wall, groynes and rock armour. • Coastal management at Withersea has tried to make the beach wider by using groynes, and also uses a seawall to protect the coast. Negative affects of coastal management • Groynes , sea walls and rock armour have a negative effect on the coastline as they look unnatural and cause visual pollution. This can have a negative effect on tourism. • Great Cowden (further down the coast from Mappleton) is now facing increased cliff erosion because of the groynes and rock armour at Mappleton. The sea defences stop the natural process of longshore drift and so reducing sediment deposition further down the coast and so the beaches are narrower leading to increased rates of erosion. • Hard engineering strategies are expensive • Conflict can arise as some areas are not given protection leading to conflict between comunities
4. Climate change • Global warming is causing sea level rise and increased stormy conditions so more destructive waves creating more erosion increasing the vulnerability of the Holderness Coast. • However global warming increases temperatures so warmer summers will attract more tourists to the UK generating more income. Examine the impact of human activity on your UK coastal landscape [8]
Human activity has a greater impact on coastal locations than on river basins. To what extent do you agree? (12)
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