1.C Rivers, Coast Flashcards

Question

What is attrition

Answer 1

Erosion - material are carried by waves and bumped against each other, and one of smaller and smoother

Answer 2

Type of erosion - abrasion waves pick up material and hurl it at the coast

Answer 3

Erosion - water which is slightly acidic, dissolves the rock

Answer 4

- traction - Saltation - suspension - solution

Answer 5

- type of transportation - traction is where large heavy materials is dragged along the sea floor

Answer 6

Type of transportation - Saltation is where smaller material is bounced along the floor

Answer 7

Type of transportation - suspension is when fine material is held in the water

Answer 8

Type of transportation - Solution is dissolved material that is carried in the water

Answer 9

A process of deposition and transportation along the coast 1. Waves approached the beach at an angle due to the prevailing winds 2. As the waves break the swash carries materials up the beach at the same angle 3. As the swash dies away the backwash carries the material down the beach at 90° 4. The process repeats transporting materials along the beach in a zig-zag motion

Answer 10

- Deposition will happen when transported material is dropped from the seawater - this occurs when the velocity of the water flows slowdown - this means there is not enough force to hold/suspended the material in a water anymore and it’s dropped onto the ground

Answer 11

Bays Beaches

Answer 12

Shape of cliff - high and steep Cliff face - bare rock and rugged Foot of cliff - boulders and rocks

Answer 13

Shape of cliff - generally lower and less steep Cliff face - smoother evidence of slumping Foot of cliff - fewer rocks some sand and mud

Answer 14

Headlands & Bays Cliffs & Wave cut platforms Stack stump etc

Answer 15

Occur where there are alternating bands of hard and soft rock run perpendicular to oncoming waves (discordant coastline)

Answer 16

1. First the softer rock is eroded backwards forming an inlet 2. As the inlet continues to erode it curves inwards and a bay is formed usually a beach 3. The harder rock is left protruding out to sea as a headland

Answer 17

- cliffs along its sides - projects out to sea - usually longer the it’s wide - geology is of resistant rock

Answer 18

- a wide open entrance from the sea - a roughly semi-circular shape extending into the coastline - a bay may or may not have a beach

Answer 19

1. Usually there is hard rock above softer rock 2. The sea attacks the base of a cliff between the high and low water mark a **wave-cut notch** is formed 3. **Abrasion corrosion and hydraulic action** further extend the notch back into the cliff 4. The undercutting of the cliff leads to instability and collapse of the cliff 5. The backwash of the waves carries away the eroded material leaving behind a wave cut platform 6. The process repeats and the cliff continues to retreat leading to a costal retreat

Answer 20

1. As a wave approaches the shore, their speed is reduced as they move along the sea floor 2. This changes the angle of the waves and they will turn so the crest becomes parallel to the coat know as wave refraction 3. This **refraction concentrates erosive action** on all sides of the headland 4. The erosional processes of **hydraulic power, abrasion, and some corrosion** begin to attack any weaknesses in the headland 5. As the crack begins to widen **abrasion** will begin to wear away at the forming cave 6. The cave will become larger and eventually breaks through the headland to form an arch 7. The base of the arch continually becomes wider and the inner through erosion below and weathering from above 8. Eventually the roof of the arch collapses leavening behind an isolated column of rock called a stack 9. The stack is undercut at the base by waves action and sub-aerial weathering above until it collapses to form a stump

Answer 21

- beaches - sand dunes - spits - bars

Answer 22

Usually occur in the summer months when the weather is calmer - They form in sheltered areas such as bays though depositions, via constructive waves, where the swash is stronger than the backwash.

Answer 23

- The zone of a beach above the high tide line, only reached by severe storms or really high tides. Region of dune formation.

Answer 24

The larger material is deposited along the upper reach of the swash

Answer 25

Low water mark Mud Fine sand Coarse sand Shingle Beach berm

Answer 26

They are a dynamic ( In geography, dynamic means ever-changing, not staying same) environment, with quick changes It is the interaction of winds and vegetation that helps from sand dunes

Answer 27

- wind blows sand is deposited against an obstruction : pebble or driftwood - as more sand particles are caught, the dunes grow in size, forming rows at right angles to the prevailing wind - over time the ridges of the dunes will be colonised and fixed by vegetation in a process called succession ( the changes in ecosystems over time of the species that occupy it)

Answer 28

Sea - embryo dune - fore dune - yellow dune - grey dune - dune slack - mature dune

Answer 29

- wind blown dries sand is trapped by debris and deposition begins - pioneer species such as Lyme grass and sea couch grass begin to colonise - there is little soil content and high pH levels (alkaline) - embryo dunes are very fragile and reach a maximum highs of 1 metre

Answer 30

- the embryo dunes brings some protection against the prevailing wind - this allows other species of plant to grow such as marram grass - marram grass begins to stabilise the dune with its root system - theses plants add organic matter to the dune making the dunes more hospitable for plants that later grow - a microclimate from in the dune slack - maximum is 5 metres

Answer 31

- there are initially yellow but darken as organic matter adds humus to the soil - marram grass still dominates the vegetation, but more delicate flowering plants and insects are found in the dune slack - 20% of the dune is opposed, down from 80% - night does not exceed 8 metres

Answer 32

- grey dunes are more suitable , with less the 10% of exposed sand and have a good range of biodiversity - soil acidity and water content increases as more humus is added - shrubs and bushes begin to appear - height is between 8-10 metres

Answer 33

- as the name suggests there are the oldest and most stable of the dunes - they are found several hundred metres or more from the shoreline - the soil can support a variety of flora and fauna such as oak trees and alders - this is the final stage in succession which is know as the climax community stage

Answer 34

An extended stretch of sand or shingle that extends out to sea from the shore They occurs when there is a change in the coat line shape

Answer 35

- sediment is transported by the action if longshore drift - where the coast line changes direction a shallow sheltered area allows for deposition of sediment - due to increased friction more deposition occurred - eventually a spit slowly builds up to sea level and extends in length - if the winds change’s direction then the wave pattern alters and results in a hooked end - the area behind the spit becomes sheltered - silts ( find sand or sediment that is carried along by flowing water and then dropped) are deposited here to form salt marshes or mud flats

Answer 36

When a spit grows across a bay and joins two headlands together A bar of sand is formed (sandbar) They can also form offshore due to the action of breaking waves from a beach

Answer 37

Hard engineering Soft engineering

Answer 38

The aim of any coastal management is to protect the environment, but mostly protect people from the impacts of erosion and flooding. Not all coast areas can be protected or managed as the economic constraints.

Answer 39

- Hard engineering involves building some form of sea defence usually from concrete wood or rock. - Structures are expensive to build and need to be maintained. - Defence work against the power of the waves. - Each type of defence has own strengths and weaknesses - protecting one area can impact regions further along the coast which results in faster erosion and flooding. - Hard engineering is used when settlements and expensive installations are at risk: the economic benefit is greater than the cost to build.

Answer 40

- sea wall - groynes -rock armour -gabions - resentments - off-shore barriers

Answer 41

A wall usually concrete and curved outwards to reflect the power of the waves back out to sea

Answer 42

- most effective a preventing both erosion and flooding (if the walls are high enough)

Answer 43

- very expensive to build and maintain - it can be damaged if not maintained properly - restricts access to beach - unsightly to look at

Answer 44

Wood, rock or steel piling built at right angles to the shore, which traps beach material being moved by longshoreman drift

Answer 45

- slows down beach erosion - creates wider beaches

Answer 46

- stops material, moving down the coast where the material may have been building up and protecting the base of the cliff elsewhere. - starves other beaches of sand. wood groynes need maintenance to prevent wood rot. - Makes walking along the shoreline difficult.

Answer 47

Large boulders are piled up to protect a stretch of coast

Answer 48

- cheaper method of construction. - Works to absorb wave energy from the base of the cliff and sea walls.

Answer 49

- boulders can be eroded or dislodged during heavy storms

Answer 50

A wall of wire cages filled with stone, concrete, sand etc built at the foot of cliffs

Answer 51

- cheap form of coastal defence. - Cages absorb wave energy. - Can be stacked at the base of the seawall or cliffs.

Answer 52

- wire cages can break and they need to be securely tied down. - Not as effective other costal defences

Answer 53

Sloping wooden or concrete fences with a open plank structure

Answer 54

- Work to break the force of the waves. - Traps beach material behind them. - Set at the base of cliffs or in front of the seawall. - Cheaper than seawalls, but not as effective.

Answer 55

- Not effective in stormy conditions. - Can make beaches in accessible for people. - Regular maintenance is necessary. - Visually unattractive

Answer 56

Large concrete blocks, rocks and boulders are sunk offshore to alter wave direction and dissipate wave energy

Answer 57

-effective at breaking wave energy before reaching the shore. -beach material is built up. -Low maintenance. -Maintains natural beach appearance.

Answer 58

- expensive to build. - Can be removed in heavy storms. - Can be unattractive. - Prevent surfing and sailing

Answer 59

- Soft engineering works with natural processes rather than against them. - Usually cheaper and does not damage the appearance of the coast. - Considered to be more sustainable approach to coastal protection. - However, they are are not as effective as hard engineering methods.

Answer 60

- beach replenishment - dune regeneration - cliff regrading - managed retreat

Answer 61

Pumping or dumping sand and shingle back onto the beach to replace eroded material

Answer 62

- beaches absorb wave energy. - Widens beachfront

Answer 63

- has to be repeated regularly which is expensive. - can impact sediment transportation down the coast. - removing material from the seabed damage is fragile ecosystem, such as corals and sponges

Answer 64

Planting vegetation helps to create or stabilise Sandunes and beaches. It also reduces window erosion.

Answer 65

- Sandunes act as barriers between the sea and land. - The wave energy is absorbed, preventing erosion and flooding. - Cheap method of stabilising dunes

Answer 66

- hard to protect large areas of coastline cliffs with this method

Answer 67

The angle of a cliff is reduced to reduce mass movement

Answer 68

- preventing sudden loss of large sections of cliff. - Regrading can also slow down wave cut notching at base of cliffs as a wave energy is slowed.

Answer 69

- does not stop cliff erosion

Answer 70

Existing Coastal defences are a Abandoned or removed, allowing the sea to flood inland until it reaches Highland or a new line of defence

Answer 71

- No expensive construction costs. - Creates new habitats such as salt, Marshall

Answer 72

- Disruptive to people where land and homes are lost. - Salt, water damages, existing ecosystems. - cost of relocation can be expensive. - Compensation to people and businesses may not be paid.

Answer 73

it is a method which aims to use a range of methods, depending on the value of what is being protected. They aim to use a combination of methods to best reflect all stakeholders needs.

Answer 74

Coastal cells are mini systems they are self-contained areas of sediment circulating within, and are sometimes called a sediment or a literal cell

Answer 75

- risk of erosion and land retreat - risk of flooding

Answer 76

Shoreline management plans set out an approach to manage a coastal line from flooding and erosional risk. - The plan aims to reduce the risk to people settlements agriculture, land and natural environments. - There are four approaches available for coastal management within differing costs and consequences.

Answer 77

- hold the line - advance the line Managed realignment or retreat - do nothing

Answer 78

- managed retreat allows low value land to flood creating natural environments like salt marshals. - These absorb wave energy reducing erosion and the risk of flooding in land. - It relieves pressure Another coastal defences and helps the coastline adapt to sea level rises.

Answer 79

- All rivers have long and cross profiles - Each Rivers, long and cross profile are unique, but they do have some characteristics in common. - These profiles show changes in the rivers characteristics from the source to the mouth

Answer 80

the Long profile of a river shows the changes in the rivers gradient from the source to the mouth

Answer 81

Concave shape

Answer 82

Source - upper course - middle course Mouth - lower course

Answer 83

The source is usually found in upland area Upper course - steep with uneven surfaces Middle course - gradient decreases Lower course - decreases further until almost flat

Answer 84

The cross profiles of the river of cross-section from one side of the bank to the other

Answer 85

- shallow - steep valley sides - narrow - low velocity (speed) -large bed load - rough channel bed - high levels of friction - vertical erosion

Answer 86

- deeper than upper course channel - gentle valley sides - wider than upper coerces channel - Greater velocity - Material is the river decreases in size - smooth channel bed - lower levels of friction than upper course - lateral erosion

Answer 87

- deeper - flat floodplains - wider - greater velocity - material carried mainly sediment and alluvium - smooth channel bed - Lowest friction - deposition is dominant

Answer 88

**Deposition is when a river does not have enough energy to carry the material and drops it** • the courses include: - reduce discharged due to lack of precipitation or abrasion obstruction of stream. - decreased gradient. - Slower flow on the inside of the Riverbend or whether river is shallower. - When the river enters a sea or lake as the gradient is more gentle and the river flow is affected by tides

Answer 89

Bedload is the heaviest material that is deposited first Alluvium is the lighter material like gravel sand and silt they are carried further down stream

Answer 90

- waterfall - gorges - v-shaped valley - interlocking spurs

Answer 91

- Waterfalls form where there is a drop in the river bed from one level to another - this drop I’d often due to changes in the hardness of the rock, hard rock on top of soft rock - **hydraulic action and abrasion** main erosional processes - the soft rock erodes quicker, undercutting the hard rock and creating a plunge pool - this leads to the development of overhang of hard rock which eventually over time collapses - the overhang falls into the plunger pool increasing abrasion and making to plunge pool deeper - the process then begins again and the water fall retreats upstream leaving a steep sided gorge

Answer 92

- vertical erosion is dominant in the upper course of the river. - This comes down into the river bed and deepens the river channel. - Weathering and Mass movement leads to materials from the valley sides, collapsing into the river, forming a V shaped Valley.

Answer 93

- in the upper course of the river the channel starts to meander - erosion happens on the outside of the bend - in the upland areas this forms interlocking spurs

Answer 94

Meanders and oxbow-lakes

Answer 95

- in lowland areas lateral erosion is dominant - meanders increase in size - the faster water flow (thalweg) is on the outside of the river bends, leading to erosion: - the erosion undercuts the riverbank forming a river cliff - the river bank collapses on the edge of the meander moves further out - the slowest flow is on the inside of the river bend, leading to deposition - the deposits from a slip-off slope - deposition on one side and erosion on the other leads to the meander migrating across the valley

Answer 96

- with distance downstream the size of the meanders increases - the erosion on outside bends can eventually lead to the formation of a meander neck - at the time of the flood, the river may cut through the neck of the meander forming a straighter course for the water - the flow of water at entry and exit from the meander will be slower, leading to deposition - the meander becomes cut off from the main river channel, forming an oxbow lake

Answer 97

Flood plains and levees Estuaries

Answer 98

- floodplains are flat expanses if land on either side of the river - the migration of meanders leads to the formation of the floodplains - high discharge may cause the river to overflow the banks - more of the water is in contact with the land surface as the water spreads across the floodplain - Increased friction reduces velocity and material is deposited across the floodplain gradually increasing the floodplain height - the heaviest material is deposited first nearest to the river channel forming natural embankments called levees

Answer 99

- an estuary is where the river meets the sea - large deposits of sediment form mudflats and salt marshes - these are the result of the interaction between the river and tides - incoming tides bring in sediment which mixes the fresh water of the river, the river velocity drops and deposition occurs - the deposited sediment builds up in layers to form mudflats which rise above the water surface, particularly at low tide - eventually the vegetation starts to grow on the mudflats and from salt marshes

Answer 100

- when capacity of the river channel is exceeded - water overflows the banks - heavy or prolonged rainfall - lag time (time taken for the precipitation to reach the river) - shorter lag time = higher risk of flooding (the discharge increases faster

Answer 101

- deforestation - urbanisation - agriculture - climate

Answer 102

Lack of trees reduces interception and infiltration, increasing overland flow

Answer 103

Impermeable concrete and tarmac increase overland flow Water flows into the drains reaching the river rapidly

Answer 104

Bare soil and ploughing increases overland flow especially where ploughing is downslope

Answer 105

Rising global temperatures may increase storm frequency and intensity

Answer 106

-relief - rock type - soil - weather - seasonal variations - drainage density - vegetation

Answer 107

Steep slopes reduce infiltration and increase overland flow

Answer 108

Impermeable rocked reduce percolation and increase overflow

Answer 109

Frozen, saturated or compact soil reduces infiltration and increases overland flow Some soil types such as clay reduce infiltration and increase overland flow

Answer 110

Heavy prolonged rainfall means the the rate at which water reaches the surface exceeds the infiltration rate leading to increased overflow After a period of snow rising temperatures can cause rapid melting which increase overland flow

Answer 111

Flooding in Northern Europe tends to occur in the autumn and winter when rainfall is more frequent High temperatures in spring leads to snow melt in mountainous areas increasing overland flow

Answer 112

Where drainage density is high there are many tributaries taking water to the main channel causing a rapid increase in discharge

Answer 113

Where there is little natural vegetation there is reduced interception leading to increased overland flow

Answer 114

- Hydrographs can be used to understand the risk of flood because it shows the changes in discharge which results from a fainfall events

Answer 115

Prediction of flooding means that steps can be taken to manage flooding

Answer 116

1. Base flow - the normal level of river discharge 2. Peak rainfall - the highest rainfall level during the storm 3. Rising limb - this shows the increase in river discharge 4. Peak discharge - the highest level of discharge 5. Lag time - the time difference between the peak rainfall and peak discharge 6. Recessional limb or falling limb - the river discharge returning to normal

Answer 117

Short lag time Steep rising Limb High discharge

Answer 118

Longer lag time Gentle rising limb Lower discharge

Answer 119

Dams and reservoirs Embankment Straightening channels Flood relief channels

Answer 120

controls the river flow by blocking the river and letting water in a controlled way. This creates a reservoir defined the dam

Answer 121

- multipurpose can be used for energy production and water storage as well as flood control. - Provides opportunities for re-creation water sports, fishing.

Answer 122

- expensive. - Lots of farmland and homes due to reservoir creation. - Displacement of people. - Effects on ecosystems can affect fish breeding. - Reservoir splits up over time.

Answer 123

- artificially raise the banks of the river increase in channel capacity

Answer 124

- increase river capacity means it’s less likely to flood. - New riverbank habits may be created

Answer 125

- expensive. - Visually unattractive particularly if made from concrete. - May fall and lead to more serious flooding.

Answer 126

- straightening the river channel by removing meanders

Answer 127

- speeds up the movement of water over short distance. - Allows easy navigation for boats.

Answer 128

- May increase blood risk downstream as a discharge, reaches those areas more quickly. - Expensive. - Affect the river ecosystem due to changes in velocity.

Answer 129

- channels boots to allow excess water to flow around high value areas

Answer 130

- effective in reducing the flood risk in high-value areas. - New habitats may be created. - Insurance costs may be reduced for people living nearby.

Answer 131

- expensive. - Regular maintenance is needed. - Disruption to existing habitats. - Can be visually unattractive.

Answer 132

River restoration Floodplain zoning Afforestation Flood warnings

Answer 133

- restores the river to its natural state which meanders and wetland areas

Answer 134

-increase the number of habitats. - Restores wetland areas. - Slows down water flow reducing flooding downstream

Answer 135

- expensive to conduct to new channels. - Some areas will flood

Answer 136

- restricts land use in areas that are at high risk of flooding and ensures high values buildings are not in flood prone areas

Answer 137

- low cost - conserves habitats on floodplain and wetlands

Answer 138

- restricts areas where houses can be built and may impact on economic development - can only happen in places where development has not already happened

Answer 139

Planting trees to increase interception and infiltration Trees also use up large quantities of water

Answer 140

- inexpensive - absorbs and stores CO2 - slows down water transfer, increasing lag time

Answer 141

- can increase acidity in the soil - loss of farmland

Answer 142

- monitoring of rivers to provide people with warnings when flooding may occcur

Answer 143

- helps people to prepare and evacuate if needed - less expensive than hard engineering

Answer 144

- expensive to set up monitoring equipment - people may not take warnings seriously

1.C Rivers, Coast Flashcards

(168 cards)