PAPER 1: Living with the physical environment SECTION C: Physical Landscapes in the UK KEY IDEA: Coastal Landscapes in the UK 1

Waves Waves are caused by the transfer of energy from the wind to the sea due to friction of the wind on the waters surface. Wave size depends on 3 things: The speed of the wind; strong winds result in stronger waves because more energy is transferred into waves. How long the wind has been blowing; the longer the wind has been blowing the more energy is transferred and the stronger the waves. The fetch (this is the maximum distance of open sea that a wind can blow over); the longer the fetch, the greater possibility of large waves.

Constructive & destructive waves

Coastal processes: weathering Chemical weathering - chemical reaction when rainwater hits rocks & decomposes rock or eats it away. (Acid Rain) Freeze Thaw weathering – water gets in cracks/ freezes/ expands and cracks rock open. Coastal processes: mass movement – sliding, slumping & rock falls Mass movement - the downslope movement of rock, soil or mud under the influence of gravity. Heavy rainfall usually the trigger, but the scale of movement is determined by the extent of weathering on the slope.

Coastal processes: erosion – hydraulic power, abrasion & attrition Marine erosion is the removal of material by waves.

Coastal processes: erosion – hydraulic power, abrasion & attrition Marine erosion is the removal of material by waves. Hydraulic action - Relentless force of destructive waves pounding base of cliffs. - Causes repeated changes in air pressure as water is forced in & out of joints, faults & bedding planes. - The forward surge of water compresses air in these cracks & as the wave retreats, there is an explosive effect as pressure is suddenly released. Attrition - The grinding down of load particles. During transport, pebbles collide with each other. Over time, this wears away jagged edges to make smooth, rounded pebbles. Some collisions may cause a pebble to smash into several smaller pieces. Abrasion - Destructive waves have enough energy to hurl sand & shingle at a cliff. Resulting in scratching & scraping.

Coastal processes: transportation – longshore drift Material/sediment from fine silt to large rocks is transported along the shore by Longshore (littoral) drift. The direction is determined by the prevailing wind. Material is transported in 4 different methods Traction – large sediment such as pebbles roll along the sea bed. Saltation – small pieces of shingle or large grains of sand are bounced along the sea bed. Suspension – small particles such as sand and clays are carried in the water; this can make the water look cloudy. Solution – some minerals dissolve in seawater and are carried in solution.

Coastal processes: deposition Deposition will happen: In calm conditions, e.g. in a cove or bay sheltered from the winds Where there is low wave energy (sometimes on coasts with a shallow gradient) In shallow water Where there a plentiful supply of sediment When there is a change in direction of the coastline

How geological structure & rock type influence coastal forms Concordant – alternating layers of hard & soft rock running parallel to the coast. Discordant – the alternating layers of hard & soft rock run at right angles to the shore giving rise to headland & bay formation.

Characteristics & formation of landforms resulting from erosion – headlands & bays, cliffs & wave-cut platforms

Characteristics & formation of landforms resulting from erosion – caves, arches & stacks

Characteristics & formation of landforms resulting from erosion – cliffs & wave cut platforms

Characteristics & formation of landforms resulting from deposition - beaches A beach is a landform of coastal deposition that lies between the high and low-tide levels. Most beaches are formed of sand, sand and shingle or pebbles, as well as mud and silt. There are two distinct types of beaches can be formed - A sandy beach and a pebble beach Characteristics Sandy beach Pebble beach Gradient Generally shallow, almost flat Generally steep Dominant wave Constructive Destructive Distance stretches inland A long way Not far Back of beach Sand dunes (sometimes) Storm beach with large pebbles Other characteristics At low tide, small water-filled depressions called runnels form. These are separated by small sandy ridges running parallel to the shore. The wet sand may have a rippled appearance. Pebbles increase in size towards the back of the beach.

Figure 10.27 Beach profile in summer Characteristics & formation of landforms resulting from deposition – sand dunes For a sand dune to form, it needs: A large flat beach A large supply of sand A large tidal range, so there is time for the sand to dry An onshore wind to move sand to the back of the beach An obstacle such as drift wood for the dune to form against Figure 10.27 Beach profile in summer

Characteristics & formation of landforms resulting from deposition – spits & bars How is a spit formed? A spit is a sand or shingle beach that is joined to the land but projects downdrift into the sea. Spits form where the coastline suddenly changes shape or at the mouth of an estuary. It’s an unstable landform. Will continue to grow until the water becomes too deep or until material is removed faster than it is deposited. How are bars formed? A bay bar (or barrier beach bar) is a ridge of sand or shingle that stretches from one side of a bay to the other, forming a lagoon behind it. Barrier beach bar formation is due to longshore drift transporting sediment from one side of a bay to the other.

An example of a section of coastline in the UK to identify its major landforms of erosion & deposition Dorset Coast Durdle Door = Arch Durlston Head = Headland/ Cliff Swanage Bay = Bay (Inbetweeners Geography Trip!) Hurst Castle Spit - Spit

The costs & benefits of soft engineering management strategies – beach nourishment & reprofiling, dune regeneration Social, economic & environmental

The costs & benefits of hard engineering management strategies – sea walls, rock armour, gabions & groynes Social, economic & environmental

The costs & benefits of managed retreat – coastal realignment CASE STUDY: Medmerry, West Sussex, UK The costs & benefits of managed retreat – coastal realignment The Environment Agency (EA) considered the area to the west of Selsey (West Sussex) to be the area of South East England most at risk of flooding due to climate change. A shingle ridge was the only protection from the sea, and from the 1990s beach reprofiling took place every winter, at an annual cost of £200,000. This was becoming unsustainable. If breached then 348 properties in Selsey, a water treatment plant and the main road between Chichester and Selsey would be flooded, along with many holiday homes and rental cottages. The last breach, in 2008, caused £5 million of damage.

An example of a coastal management scheme in the UK to show: the reasons for management The Holderness Coast is one of Europe's fastest eroding coastlines. The average annual rate of erosion is around 2 metres per year. The main reason for this is because the bedrock is made up soft rock There are three main reasons for this erosion: 1. Geology (rock type) 2. The fetch 3. Longshore drift and beach material

An example of a coastal management scheme in the UK to show: the management strategy

An example of a coastal management scheme in the UK to show: the resulting effects & conflicts