Geo the stuff i keep forgetting

What are the erosional landforms in coasts ?

Headlands and bays

caves

arches and stacks

wave cut platforms

How are headlands and bays formed

They form along a discordant coastline. They form along alternating bands of resistant and less resitant rocks along the coast. The less resistant rock will erode first forming headlands with steep sides. The resistant rock will then erode more slowly, jutting out forming a bay with a gentle slope

How are caves arches and stacks formed

The less resistant rock that forms headlands often has weaknesses like cracks. Waves crash into the headlands and enlarge the cracks. Repeated erosion and enlargement of cracks forms a cave. Erosion then continues to deepen the cave until it eventually breaks through the headland forming a arch. Lastly, erosion continues to wear away the rocks supporting the arch until it eventually collapses to form stack.

How are wave cut platforms formed?

waves cause most erosion at the foot of cliffs forming a wave cut notch which is enlarged over time. Repeated erosion causes the rock above the notch to become unstable and eventaully collpase. The collpased material is then washed away and a new wave cut notch starts to form. After repeated collapses, the cliff retreats leaving a wave cut platform.

Give examples of depositional landforms in coasts

sand beaches

shingle beaches

spits

bars

sand dunes

How are sand beaches formed

they are created by low energy waves and are flat and wide. Sand [articles are small so the weak backwash can move them back down the beach creating a long gentle slope. These beaches accumulate over time as sand is deposited.

How are shingle beaches formed

They are created by high energy waves which are steep and narrow. sand particles are washed away but larger shingle is left behind. The shingle particles are left behind to create a steep slope. This process results in a coarse material accumulation that reflects the energy of incoming waves.

describe spits

They form at sharp bends in the coastline. Longshore drift transports sand and shingle past the bend and deposits it in the sea. Strong winds and waves can curve the end of the spit. The area behind the spit is sheltered by waves so material accumulates and plants are able to grow. Over time the sheltered area can become mudflat.

Describe bars

A bar forms when a spit joins two headlands together. The bay between the headlands gets cut off from the sea meaning a lagoon can form behind the bar.

examples of erosional river landforms

waterfalls and gorges

meanders

ox bow lakesand river cliffs.

how are waterfalls and gorges formed

waterfalls are formed when a river flows over a area of hard rock followed by an area of softer rock. The softer rock is eroded first creating a step in the river. The softer rock is then eroded more and more creating a steep drop called a waterfall. The hard rock is eventaully undercut by erosion. The rock can then become unstable and collapse. The collapsed rock is then swirled around at the foot of the waterfall where they erode the softer rock by abrasion creating a deep plunge pool. Over time more undercutting causes more collpasing the water fall will then retreat leaving behind a steep sided gorge.

How are oxbow lakes formed

Erosion causes the outisde of the bends to get closer. Until there is only a small bit of land between the bends. The river then breaks through this land usually during a flood. The river then flows along its shrotest course causing deposition to break the meander forming a ox bow lake

examples of depositional river landforms

flood plains

levees

estuaries

describe flood plaisn

Its the wide valley floor on either side of the river which occasionalyl floods.

When rivers flood, the water slows down, loses energy and deposits any material its transproting which builds up the flood plain

Describe levees

They are natural embankments along edges of a river channel. Over time the eroded material s deposited closest to the river channel, because it dropped first when the river slows down and loses energy. Over time the deposited material builds up creating levees.

Describe destructive plat margins

They are when plates move towards eachother. They are when the oceanic plate meets the continental plate and the denser oceanic plate is sumbusted

What is hard engineering ?

man made structures built to control the flow of rivers aad reduce flooding

What are dams and resoivoirs ?

Hard engineering method in rivers. They are barriers built across rivers usually in the upper coarse. A resoivoir is formed behind the dam

What are benefits to dams and resoiroirs

• resoivoirs store water, control water flow and prevent flooding downstream

• They can also be used to generate hydroelelectric power

costs of dams and reservoirs

dams are expensive to build

creating a resoivoir can flood exisiting settlements

What is channel straightening ?

A method of hard engineering in rivers. They are when meanders are removed by building straighter artificial channels.

Benefits of channel straightening

water leaves the area quicker rather than building up so flood risk is lower. It can also improve navigation for boats and reduce sedimentation in rivers.

Costs of channel straightneing

flooding may happen downstream instead. faster moving water may cause more erosion downstream. It can also lead to habitat destruction and negatively impact aquatic ecosystems.

What are embankments ?

raised walls are built along river banks

benefits of embankemnts

The river can hold more water so floods are less frequent and it helps protect surrounding areas from erosion.

costs of embankments

EXPENSIVE

risk of flooding is the water rises above the walls

What is soft engineering ?

schemes set up using knowledge of rivers and its processes to reduce the effects of flooding

What is flood plain zoning ?

Soft engineering method. They are restrictions that prevent builidng on parts of a flood plain which are likely to be affected by a flood. This reduces potential damage and loss of property by keeping vulnerable areas undeveloped.

benefits of flood plain zoning

• flood risk is reduced due to fewer impermeable surfaces being created. This allows for better water absorption and management within the flood plain area.

costs of flood plain zoning

• the expansion of a urban area is limited if there arent any other suitablel building sites.

• it cant help in areas with existing buildings. Additionally, property values may decline in restricted zones, and affected landowners could face financial losses.

benefits of planting trees

provides habittat for wildlife

vegetation reduces soil erosion in the wildlife

costs of planting trees

less land for farming

what are hydrographs

they show how the discharge at a certain point in a river changes over time in relation to rainfalls

what are human factors that affect flood risk ?

• trees intercept rainwater on their leaves whch then evaportae. Trees also take up water, storing it from the ground. This means that cutting down trees increases the volume of water that enters the ground.

Physical factors that affect flood risk

geology -some rocks are impermeable so runoff isi increases

prolonged rainfall - prolonged rainfall can saturate the soil. Any further rainfall cant infiltrate increasing runoff into river channels

heavy rianfall - water arrives too quickly to infiltrate so there is a lot of runoff increasing dischARGE

What are estuaries

they are tidal areas where the river meets the sea.

they are found at river mouths

the water at eastuaries is tidal

Describe inerlocking spurs

In the upper course most of the erosion is vertically downwards creating V shaped valleys. The rivers lack the power to erode laterally so they have to wind around the high hillsides that stick out into their paths either side. The hillsides that interlock with eachother are called interlocking spurs

What is hydraulic action in rivers?

When the force of river water collides with rocks breaking rock particles away from the river channel

What is abrasion in rivers?

When erodes rocks are picked up by the river scraped and rub against the channel breaking rock particles away from the river channel

attrition in rivers

eroded rocks picked up by the rivers crash into the eachpther breaking into smaller fragments

slution in rivers

when the river dissolves some types of rocks

what is traction

when large particles like boulders bounce along the sea bed by the force of water

suspension

small particles like silt or clay are carried along in the water

saltation

pebble sixed particles are bounced along the sea bed by the force of water

solution

soluble materials dissolve in the water and are carried along

what is mechanical weathering ?

The breakdown of rocks without changing their chemical composition

what is mass movement?

When material falls down a slope. It happens when the force of gravity acting on the slope is greater than the force supporting it. It causes coasts to retreat rapidly. Its more likely to happen when the material is fillled with water. This causes water to act as a lubricant making the material heavier.

What are the three types of mass movement?

slides

slumps

rock falls

How does mass movement happen on a slide ?

material shifts down a straight line along a slide plain

How does mass movement happen along a slump

material rotates along a curved slip plain

how does mass movement happen on rock falls?

material breaks up, often along a bedding plain and falls down a slopeas loose debris due to gravity.

What are characteristics of destructive waves?

They are waves that erode the coast.

They have a high frequency

they are long

they are steep

their backwash is stronger than their swash

What are characteristics of constructive waves

waves that deposit material

they have a low frequency,

they are low

they are long

what is hydraulic power in coasts

when waves crash into the rocks compressing air into the cracks. This puts pressure on the rocks

abrasion in coasts

When eroded particles in the river, scrape and rub against the rocks removing small pieces A

attrition in coasts

erodded particles collide with each other, breaking into smaller, rounder pieces.

What is hard engineering ?

Man made structures built to control the flow of rivers and reduce flooding and erosion

what a sea walls?

walls made out of hard materials like concrete which reflect wavea back to the sea

Benefits of sea walls

It prevents erosion of the coast

They also act as a barrier to prevent floodingand provide a safe area for promenades and recreational activities.

cists of sea walls

They create a strong backwash which erodes under the walls

expensive to build and maintain

Gabions

Walls made out of wire cages filled wiht rocks usually built at the foot of cliffs

benefits of gabions

they absorb wave energy so reduce erosion

they are cheap and easy to build

Costs of gabions

ugly to look at

wire cages can corrode over time

rock armour

boulders that are piled up along the coast to protect against erosion and wave action. Bee

benefits of rock armour

absorbs wave energy therfore reducing flooding and erosion

cheap

Costs of rock armour

Boulders can be replaced so will need to be replaced

What is soft engineering

schemes that are set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion

What is beach nourishment and reprofiling

Sand and shingle from elsewhere in the beach are added to the upper parts of the beack

ADV of beach nourishment and reprofiling

it creates wider beaches which slow down the waves giving greater protection from flooding and erosion

Costs of beach nourishment and reprofiling

Taking material from the sea bed can kill organisms

What is managed retreat ?

Managed retreat involves removing current defences and allowing the sea to flood behind. Over time the land will become marshland which then protects the land behind it from flooding and erosion. Its cheap and doesnt need maintaining.

The marshland can also create new habitants for plants and animals

Howveer the flooding can also affect the livelihood of many farmers

on?