rivers and coasts Flashcards

Question

explain how beaches are formed

Answer 1

beaches are formed by deposition - they are found on coasts between the high and low water marks - formed by constructive waves

Answer 2

created by high energy waves steep narrow sand particles have been washed away but larger shingles left behind

Answer 3

created by low energy waves flat wide sand particles are small so the weak backwash can move them back down the beach creating a long gentle slope

Answer 4

spits, bars and sand dunes, tombolos

Answer 5

- spits form at sharp coastlines - longshore drift transports sand and shingles past the bend and deposit them in the sea - string winds and waves curve the end of the spit the area behind the spit is sheltered from waves - plants can grow

Answer 6

a bar is formed when a spit joins 2 headlands | a lagoon is formed behind the bar

Answer 7

formed when sand is deposited by longshore drift is up the beach by wind obstacles cause the wind speed to decrease forming dunes high winds come from the see from prevailing wind (south west ) marron grass stabilises dunes and holds them together

Answer 8

arch formed by a concordant coastline | wave action opened up a crack in the side of the headland which developed into an arch

Answer 9

a tombolo formed by longshore drift. it joins the Isle of Portland to the mainland. Behind Chesil beach is a shallow lagoon called The Fleet Lagoon

Answer 10

A tombolo is a sediment deposit at the coast formed by wave refraction and diffraction at the edges of an obstacle (natural or artificial) originally detached from the mainland. a bar of sand or shingle joining an island to the mainland.

Answer 11

steep gradient, has v-shaped valleys, steep sides, narrow, shallow channel, slow, vertical erosion

Answer 12

medium gradient, gently sloping valley sides, wider, deeper channel faster, lateral erosion

Answer 13

gentle gradient, very wide, almost flat valley, very wide and deep channel, lateral erosion

Answer 14

shows how the gradient changes | the path of the river flows downwards

Answer 15

show you what a cross-section of the river looks like

Answer 16

deepens the river valley and channel making it V-shaped most common in upper course downwards erosion

Answer 17

this widens the river valley an channel during the formation of meanders dominant in middle and lower course

Answer 18

hydraulic action - the force of the river water colliding with rocks breaks rock particles away from the river channel abrasion - eroded rocks picked up by the river scape and rub against the channel attrition - eroded rocks picked up into each by the river crash and breaks into smaller fragments. Their edges are rounded off solution - river water dissolves some types of rocks

Answer 19

traction - large particles like boulders are pushed along the river bed by the force of water suspension - small particles like clay are carried along by the water saltation - pebble-sized particles are bounced along the river bed by the force of water solution - soluble material dissolve in the water and carried along

Answer 20

deposition is when a river drops material it's transporting its occurs when the a river loses velocity and energy the volume of the water falls the water is shallower less energy = slower at the mouth (common at meanders)

Answer 21

1. waterfalls forms where a river flows over an area of hard rock followed by area of softer rock (hard rock on top of the softer rock) 2. The softer rock is eroded more than the hard rock creating a 'step' in the river 3. As water flowed over the step it erodes more and more of the softer rock 4. A steep drop is eventually created which is called a waterfall 5. Hard rock is undercut by erosion and collapses 6. The collapsed rock swirl around the water at the foot of the water creating plunge pool 7. Overtime more undercutting causes more collapses. The waterfall retreats leaving behind a steep- sides gorge - hydraulic action, abrasion

Answer 22

1. In the upper course of a river most of the erosion is vertically downwards. This creates steep-sided, V-shaped valleys 2. The river lacks power to erode laterally so they have to wind around the hillsides 3. The hillsides that interlock with each other as the river winds around them are called interlocking spurs

Answer 23

Headlands and bays from where there is alternating bands of resistant and less resistant rock. less resistant rock erodes fasters forming a bay with a gentle slope. Because the more resistant rock erodes slowly it juts out forming a headland

Answer 24

limestone, chalk

Answer 25

sandstone, clay

Answer 26

meanders are formed by erosion and deposition. They are large bends in a river in the middle and lower course (where the channel are shallow and deep sections, faster) More erosion takes place on the outside of the bend forming river cliffs. the current in slower on the inside of the bend because the river is shallower so eroded material is deposited on the inside of the bend, forming slip-off slopes

Answer 27

meanders get larger overtime and eventually turn into oxbow lakes 1. Erosion causes the outside bends to get closer until there's only a small bit of land left between the bends (neck) 2. The river breaks through this land, usually during a flood 3. The river flows along the shortest course 4. deposition eventually cuts of the meander 5. this forms an ox bow lake

Answer 28

flat areas of land that floods on either side of a river when a river floods, the water slows down, loses energy and deposits the material that it's transporting. this builds up the flood plain. Deposition on the slip-off slopes of meanders also builds them up. Meanders widen as they migrate across floodplains laterally.

Answer 29

levees are natural embankments (raised banks) along the edges of a river channel Overtime deposited material from erosion builds up creating levees along the edges of the channel

Answer 30

tidal areas where the river meets the sea | - found at the mouth of the river

Answer 31

tells you the direction a river flows - orange lines - height is marked with numbers - steepness is determined by how close the lines are (steeper = closer together)

Answer 32

waterfalls marked on map cliff are marked with black blotchy lines close contour lines show evidence of upper-course waterfall river crosses lots of contour lines in a short distance (steep)

Answer 33

land is low no contours lines - flat land river doesn't cross contour lines = gently slopping

Answer 34

``` flows through Scotland 160km long source is in the Southern Uplands Mouth is in west coast of Scotland meanders, estuary, interlocking spurs, 4 waterfalls, gorge, floodplain ```

Answer 35

A hydrograph is a graph showing the rate of flow versus time past a specific point in a river, channel, or conduit carrying flow. RESPONSE OF A RIVER AFTER FLOODING

Answer 36

the highest discharge in the period of time you're looking at

Answer 37

the delay between peak rainfall and peak discharge

Answer 38

the increase in river discharge as rainwater flows into the river

Answer 39

the decrease in river discharge as the river returns to its normal level

Answer 40

``` PHYSCIAL heavy rainfall geology (rock type) prolonged rainfall relief (change in land height) density of drainage basin steep slopes glacial and snow melt HUMAN impermeable rock surfaces (urbanisation) deforestation human management global warning (melt) land use dams and dams breaking ```

Answer 41

hard engineering - man-mad structures built to control the flow of rivers and reduce flooding soft engineering - schemes set up using knowledge of a river and its processes to reduce the effects of flooding

Answer 42

``` dams and reservoirs embankments - flood walls levees dredging re-routing rivers / channel straightening ```

Answer 43

``` tree planting floodplain zoning sandbags flood water pumping river restoration flood warnings ```

Answer 44

- divert water away from densely populated areas - increase water storage in the floodplain - plant 20,000 trees - reusing excavated material to build new flood walls and embankments to protects areas that remain at risk

Answer 45

Social: - construction will disturb residents - improve public footpaths - more confidence Economic: - 120 million - 1000 homes and business protected Environmental: - lots more trees - new habitats

Answer 46

Banbury is a market town on the River Cherwell in Oxfordshire, England - Raising the A361 road in the flood storage are and adding improvements to the drainage beneath the road to prevent flooding - New earth embankments and flood walls to protect property and businesses - A new pumping station to transfer excess rainwater into the river below the town - The creation of a new Biodiversity Action Plan habitat with ponds, trees and hedgerows to absorb and store excess water

Answer 47

There were two major floods which occurred in 1998 and 2007. In 1998, the flood led to closing the town’s railway station, shutting local roads and caused £12.5 million of damage. More than 150 homes and businesses were affected. The social effect of the flood was that travel was stopped. The economic effect was that many homes and businesses were destroyed. The environmental effect was water entering the reservoir. The flood in 2007 extended over to much of Central England and Western England. Many homes and businesses were affected by the flood.

Answer 48

The raised A361 rout into Banbury will be open during a flood, to avoid disrupting people’s lives Quality of life for local people is improved with new footpaths and green areas. Reduced levels of anxiety and depression through fear of flooding.

Answer 49

Around 100000 tonnes of earth were required to build the embankment. This was extracted from nearby, creating a small reservoir. A new biodiversity action plan habitats have been created with ponds, trees, and hedgerows. Part of the floodplain will be deliberately allowed to flood if river levels are high.

Answer 50

The cost of the scheme was about £18.5 million. Donors included an environmental agency and Cherwell district council. By protecting 441 houses and 73 commercial properties, the benefits are estimated to be over £100 million

Answer 51

man-made structures built to control the flow of the sea and reduce flooding and erosion - sea wall - gabions - rock armour - groynes

Answer 52

schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion - beach nourishment and reprofiling - dune regeneration

Answer 53

powerful waves from the south west erode the sea cliffs causing them to collapse. Many properties were damaged. phase 1 - 1990-1995 new sea wall constructed. 1.4 million project to stabilise rocks , rock armour, promenades phase 2 - 2005-2007 beaches replenished, rock armour repaired, drainage system improved phase 3 - was meant to prevent land slides (never happened) phase 4 - 390 m sea walls and rock armour protecting roads and the town

Answer 54

positive - trade increased - rock armour absorbs energy - people feel more correct - more money with tourism negative - more tourists (more traffic) - important fossils being exposed - expensive

Answer 55

To say that a hydrograph is flashy means that the graph depicts sharp vertical jumps and equally steep vertical declines. Short lag time

Answer 56

hydrographs with gently inclined limbs, a low peak discharge and a long lag time.

Answer 57

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. The upper course has hard impermeable rocks. Here, vertical erosion has formed a V-shaped valley. High Force, the UK's largest waterfall at 21 metres high, is located in the upper course. An area of hard rock, called Whin Sill (or Whinstone), is located above a layer of soft rocks (sandstone and shale) and together they create this impressive waterfall. middle course As the River Tees starts to erode sideways (lateral erosion), it forms meanders. These can be identified in the middle course near Barnard Castle. Lower course Near Yarm, the meanders in the lower course are much larger, and oxbow lakes have formed. In this area there are also levees which have formed when the river has flooded. The River Tees has a very large estuary with mudflats and sandbanks which supports wildlife in the area. Sites such as Seal Sands are protected areas.

Answer 58

distance the wave travels before reaching the coastline

Answer 59

weathering

Answer 60

the action of plants or animals breaking rock apart

Answer 61

``` steep slope impermeable rock thin soil thin grass urbanisation used for industry, dam built high density ```

Answer 62

``` gentle slope permeable rock deep soil forest rural area limited use of river lower density ```

Answer 63

wetlands that form as rivers empty their water and sediment into another body of water

Answer 64

Hold the line – this is when coastal defences are built or maintained to protect a coastline against the impacts of sea level rise and coastal erosion/flooding. Often a mixture of hard and soft engineering strategies is used. This is often expensive but popular with local residents. Retreating the line (managed realignment) – this is when people move out of the dangerous, most vulnerable areas and there is no defence against the elements. The coastline is often eroded inland creating salt marshes. This is less expensive but not always popular with local residents.

Answer 65

Rock type – the cliffs are made from less resistant boulder clay (made from sands and clays) which slumps when wet. Naturally narrow beaches – these beaches give less protection to the coast as they don't reduce the power of the waves. Man-made structures – groynes have been installed to stop longshore drift and build up the beaches in certain places. This narrows unprotected beaches elsewhere even further, as new sand does not come down to replace sand eroded by waves. Powerful waves – waves at Happisburgh travel long distances over the North Sea (so have a long fetch) which means they will increase in energy.

Answer 66

- south coast tourist destination - population about 4000 growing in 16000 in summer powerful waves from the south west erode the sea cliffs causing them to collapse. Many properties were damaged.

rivers and coasts Flashcards

(90 cards)