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Larger sediment particles roll and slide along the sea bed - it is intermittent because of the variation in energy input via waves



A skipping movement of sand grains that occurs along the seabed or on a dry beach when the currents flows or the wind blows with enough energy to entrain particles


Suspension + Solution

Sand grains and finer particles are kept moving by turbulent water

Limestone rocks such as chalk can be weathered and dissolved by seawater with the solute carried by the sea


Factors effecting the rate of erosion

- beach width : the wider the beach the greater the loss of energy will be and the slower the rage of cliff erosion

- breaking point of the wave : a wave which breaks as it hits the foot of the cliff releases the most energy and causes maximum erosion

- wave steepness : v steep and destructive waves have more energy which means they have a higher erosive power

- supply of beach material : a high supply of beach material protects the coast by absorbing the wave power

- depth of sea and direction of fetch : steeply selling beach creates higher and steeper waves - concentrate energy by the process of wave refraction


What is lithology?

Composition of the rock itself


Speed and nature of mass movement is influenced by ...

Angles of the slope : the steeper the slope the faster the movement

Rainfall : a lot of water will lubricate the cliff - lead to mid flows

Vegetation : with no vegetation there is nothing to impede the movement of debris


What are barrier islands?

These are coastlines paralleled by offshore narrow strips of sand dunes, salt marshes and beaches - separated from land by a lagoon


Submerged coasts

They form when river mouths are flooded due to rising sea level or disidente of land

This can form a ...

Fjord : formed when glacial troughs are flooded due to a rise in sea level

Rias : these are flooded river estuaries with valley sides emerging from the water, they occur when the floodplain of a river is submerged by relative sea level

Dalmatian Coast : it arises when sea level rise leaves the dividing hills of previously parallel river systems as long islands and


Emergent Coasts

Result of forced acting to raise the land surface or drop sea level.

Raised beach : beaches left higher than the current shoreline represent a fall in sea level relative to the land, vegetation may have subsequently colonised the former beach

Relict Cliffs : these are cliff lines that are higher than the current active wave action of the sea indicate a past higher sea level relative to land


Formation of Sand Dunes

- embryo dunes develop where wind speeds slow down and sand is deposited beyond the beach

- Drought - and salt - tolerant plants begin to colonise in the sand

- Starts to stabilise the dune as well as accumulate more sand by the decreasing wind velocity

- foredunes develop with higher sand accumulations

- other species of grass develop and the layer of the dune changes from yellow to grey

- dunes inland become fixed with considerable vegetative batting - can be easily damaged by funnelled high velocity winds or footpath erosion

- dune slacks may develop in between substantial dunes

- a dune Heath may develop inland from the dune system - drought tolerant larger shrubs grow and they help further modify soil pH, humus content and moisture retentiveness


What is sea level and why do they change ?

It is the average height of the oceans surface between high and low tide


Land based ice melting
Sea based ice melting


Eustatic Change and what causes it?

It is the change of sea level relative to then land and the fluid nature of oceans means the change is that of global scale

Tectonic activity can result in sea level change including spreading of ocean floods through plate divergence

Climate change
- rapid melting of once stable ice sheets and glaciers
- thermal expansion of warmer seawater


Isostatic Change

It is the change in height of land surface relative to the mean sea level - it is a more localised scale


Impacts on increased sea level

Inundation of low lying coastal land
Increased river flooding inland due to reduced long profile gradient
Saltwater contamination of coastal freshwater sources
Loss of productive coastal, delta and floodplain agriculture
Increased cost for flood protection methods
High rates of insurance
Greater mitigation away from coastal areas


Two types of cost of coastal management

Tangible - where costs and benefits are known and can be given a monetary value e.g building costs

Intangible - where costs may be difficult to assess but are important e.g the visual impact of a revetment


Hard engineering

This is making physical change to the coastal landscape by using resistant materials such as concrete, boulders, wood and metal

Usually this will be used in places where there is significant capital investment e.g. Buildings and communications

The costs of such defences are justified by the expense of replacing sea - damaged buildings and infrastructure


Soft engineering

This is a method using natural systems for coastal defence such as beaches, sand dunes and salt marshes and all of these are made with the capability to absorb and adjust to the differing wave energy



They develop in sheltered shorelines that are not exposed to powerful waves - often located in estuaries where rivers meet the sea or on the landward side of the spit

At low tide, the intertidal area of mud is left exposed, with water only left in permanent channels

EXAMPLE : Morecambe Bag, UK



Dry rock in the sunshine may absorb considerable heat , then be cooled rapidly by contact with the much colder sea ; repeated expansion and contraction may lead to outer layers of rock fracturing



The high salt content of seawater can lead to growth of salt crystals within rock under drier conditions - exert pressure within small joints and , over time , cause the rock to lose integrity


Freeze - thaw activity

Rainwater penetrates joints in exposed rock and if night temperatures drop below freezing , the resulting conversion to ice expands and exerts pressure within the rock, enlarging the fissure



Coastlines composed of chalk or limestone may be dissolved by acidic rain or seawater



Rocks containing iron compounds experience this when oxygen and water are readily available from air or sea


Sand dunes are likely to develop where :

Beaches that are largely sandy

There is a large tidal zone

The beach gradient is shallow - so the low tide reveals a large body of beach

There are persistent onshore winds to both dry the sand and move particles by saltation to the inland zone beyond the beach


Rock lithology can have a significant effect on the form and characteristics of the features that develop over time...these are

Rock Hardness : some rocks are more resistant than others due to chemical composition

Rock Structure : some rocks are more jointed and fractured

Structural alignment : sedimentary rocks often occurs in distinct layers - the angle of orientation of bedding where it is exposed at the coast can influence the rate of erosion and shape of the cliff


Isostatic Recovery

The sheer weight of ice sheets can have the effect of lowering the lands surface by depressing the crust into mantle - when the ice sheets melt, the land can 'bounce' back up


How many sediment cells in ENGLAND AND WALES ?



Equilibrium Budget

The sediment inputs and outputs are in equilibrium


Point source (store )

A specific coastal location where sediment is removed from (source) or deposited (store)



A state of constant change


Shoreline Management Plans (SMPs)

Documents describing and addressing the risks associated with coastal evolution


Four strategic options available :

Hold the line : put in place measures to stop further coastal retreat due to erosion

Advance the line : extend the coastline further from the existing shore with new defences seaward

Managed Re-alignment : (managed retreat ) construct defended further inland sacrificing identified land to sea

No active intervention : put no management schemes in place and allow natural processes to continue


Integrated Coastal Zone Management (ICZM)

A process for the management of the coast using an integrated approach to achieve sustainability - the intention is to manage all the components to permit the best sustainable future in the short and long term for the natural coast and human users of it



The Holderness Coast is a chalk headland that runs from Flamborough Head in the North to Spurn point in the South.

The coast has retreated over 3km since Roman times and the SMP for this section of the sediment cell looks to protect key settlements (Hornsea, Withernsea), important coastal roads (mappleton) ; a mix of coastal protection methods operate to HOLD THE LINE at these locations

Nevertheless, the policy is NO ACTIVE INTERVENTION for europe's fastest eroding coastline

// The practice of protecting Spurn Point by spits has been abandoned and instead the policy is to allow the spit to migrate westwards naturally , through a process of wash- over where sand is washed across the spit to be deposited in calmer waters on the western side



FLAMBOROUGH HEAD : chalk, headlands, caves, arches, stacks , stumps , wave cut platform

+ corrasion // corrosión // hydraulic action // attrition // freeze thaw // solution

- key issues : rock falls , tourist cliff accidents , ships hitting rocks

BRIDLINGTON BAY : boulder clay, bay, beaches , cliff slump , wave - cut notch , constructive / destructive waves , prevailing NE waves

+ coastal retreat // slumping // rotational slip // beach accumulation // beach reduction

- key issues : rapid cliff erosion , loss of farmland , transport disruption , decisions about coastal protection

SPURN POINT : spit , recurved head , nature reserve , migration route

+ river current convergence // deposition // spit extension // erosion of spit neck // cyclical spit development

- full erosion of spit , isolation of spit head , impacts of sea level rise