River Landscapes Flashcards

Question

Describe the features in the up, mid, low course

Answer 1

Up - waterfalls, interlocking Spurs Mid - meanders, floodplain Low- meanders, floodplain, levées, ox-bow lakes

Answer 2

Up - angular boulders Mid- more rounded rocks Low - smooth, rounded pebbles

Answer 3

Causes changes to landforms and landscapes

Answer 4

Erosion rate will be higher with grater discharge, so rivers in wet climates will erode more material than those in dry climates, widening and deepening river valleys and increasing the amount of eroded sediment

Answer 5

The transport rates will be grater where the energy of the water is greater, so rivers in wet climates will transport more material than those in dry climates

Answer 6

The amount of discharge is affected by climate. Wetter climates mean greater discharge. Hotter temperatures mean greater evaporation so less discharge. The greeter the discharge, the height the velocity of the river

Answer 7

The weathering of rocks will be greater in some climates: for example, freeze-thaw weathering increase where temperatures range from just below freezing

Answer 8

More periods of heavy, intense rainfall meaning more water flowing into rivers, which then overflow

Answer 9

It bakes the upper soli is when it does rain the water runs off the surface, it can't soak in, reaching rivers and rapidly increasing discharge

Answer 10

Snowmelt cannot infiltrate and flows rapidly into rivers increasing flood risk

Answer 11

By erosion processes and the influence of geology in the upper course of the river

Answer 12

Near the rivers source, rivers are small and do not have a lot of power. They tend to flow around valley slide slopes, called Spurs, rather than being able to erode them. The Spurs are left interlocking, with those from one side of the valley overlapping with the Spurs on the other side

Answer 13

A waterfall is formed along a river when a band of hard, more resistant rock lies over a band of soft, less resistant rock. The river erodes the less resistant rock at a faster rate, gradually undercutting the more resistant rock. The continued erosion of the soft rock by abrasion and hydraulic action causes an overhang of the hard rock. Eventually the hard rock cannot support its own weight and collapses under the force of gravity. The force of the falling water and abrasion by large angular boulders leads to erosion of the river bed and formation of a plunge pool

Answer 14

After a waterfall is formed, as the soft rock continues to be eroded and the hard rock collapses, a steep-sided gorge is formed as the waterfall retreats upstream. Gorges form in hard rocks, where vertical erosion by rivers is dominant.

Answer 15

Weathering is the wearing away in situ of the river valley side. There are three weathering processes common to the river valleys

Answer 16

Hydraulic action and abrasion

Answer 17

A flood plain in the flag area of land either side of a river in its lower course. It is formed by erosion and deposition. Lateral erosion on the outside bends of meanders means they migrate across the valley floor and can erode the valley sides, so the valley floor becomes wide and flag. During floods, the flood waters spread out across the valley floor. As they slow down, with less energy for transport, the river deposits fine sediments called alluvium.

Answer 18

In the lower course, the river is nearing the sea and carries a huge amount of sediment (alluvium) When the river floods,excess water spills over the. Surrounding areas urging flooding, the velocity of the river is reduced, it loses energy, and deposits sediment , forming the floodplain The floodplain is shaped by the lateral erosion of meanders as they gradually migrate downstream and by deposition of material of the inner bends

Answer 19

Levees are natural embankments of sediment formed along the banks of rivers that carry a large load and occasionally flood. In times of flood, water and sediment come out of the channel as the river overflows its banks. As it overflows, the river immediately loses velocity and energy and deposits the larger and heavier sediment first, on its banks, repeated flooding causes these banks to get higher, forming levees.

Answer 20

On page 19

Answer 21

But the interaction of deposition and erosion process in the middle and lower courses of a river

Answer 22

Meanders are bends found in a rivers course, commonly found on a rivers flood plain. The flow of the water swings from side to side, directing the line of maximum velocity and the force of the water towards the outside of the bend. This results in lateral erosion by undercutting and an outer, steep bank is formed. This is called a river cliff. On the inside of the bend the velocity and force of the water is less, leading to deposition and the formation of gently sloping bank known as a slip-off slope. The material deposited is called a point bar and is characteristically curved in shape. Due to erosion and deposition, the cross section of a meander is asymmetrical-steep on the outside of the bend, gentle on the side.

Answer 23

In the outer bend of a meander, where the current is faster, there is greater erosion. This wears away the bank creating a river cliff

Answer 24

On the inner bend of a meanders, where the current is slower, there is greater deposition, creating a point bar

Answer 25

Narrow Neal of meander is gradually being eroded Water now takes the quicker route Deposition takes place, sealing off the old meander Meander neck has been cut through completely Ox-bow lake left behind meander completely cut off

Answer 26

Urbanisation has caused towns to grow, meaning they are fewer permeable surfaces. Water flows into the river, increasing discharge Increasing demand for housing has led to new houses being built on floodplain so. This changes the natural landscape River may be channelised or made to flow underground to make room for urban developments. If this happens, erosion and deposition cannot take place

Answer 27

Field drains can improve farmland, but quickly move water into streams and rivers, and can destroy natural wetland landscapes Forests can be felled yo make way for farmland. Trees intercept rainfall, helping to reduce surface run-off. Removing trees means water reaches rivers more quickly Abstracting water for irrigation reduces the flow and velocity of a river so deposition occurs rather than erosion Ploughing fields up and down a slope can increase the amount of sediment in rivers and increase deposition

Answer 28

Industry is a big user of water, so can reduce the amount of water in rivers, leading to less erosion Industrial processes can pollute if chemicals or waste are spiller or dumped into them. This can destroy plants and animals and change the natural landscape

Answer 29

By a combination of physical and human factors, and has a range of physical and human effects

Answer 30

A lot of rainfall over a short period of time prevents soil infiltration,

Answer 31

Rocks like granite are impermeable, so water is unable to percolate from thin soil above

Answer 32

At spring time warmer temperatures will melt snow creating more water

Answer 33

Steep-sided valleys or a lot of rebut arises means the water enters the river system quicker

Answer 34

Excess water will flow towards the river as surface run-off (overland flow) or groundwater Then water will reach the river channel more quickly and force the level or river to rise above the bank level of river to rise above the bank level. Flooding can then occur

Answer 35

Physical effects include landslides, soil erosion, loss of natural habitats, contamination of water supplies

Answer 36

Human effects include death, disease, damage to property, insurance claims, loss of livelihoods,moss of crops and farm animals, disruption to transport

Answer 37

To help protect river landscapes from flooding

Answer 38

It involves building structures as a defence against flooding

Answer 39

They are barriers constructed to hold back water in artificial lakes Advantages: you can store large volumes of water until needed, and they are long lasting; can be used to generate hydro-electric power (HEP) Disadvantages: expensive to build, sediment can build up in reservoirs Landscape impact - the natural river valley landscape is flooded It is hard engineering

Answer 40

Channelisation is deepening or widening the river channel Advantage: it allows water to flow more quickly from areas of flood risk Disadvantages: visually unattractive, and more water is taken downstream, increasing the flood risk to other settlements Landscape impact - replaces the natural meanders and floodplain with an artificial channel It is hard engineering

Answer 41

It uses natural processes to reduce the impacts of river flooding

Answer 42

Washlands are areas next to rivers that are deliberately flooded to avoid flooding residential or important agricultural areas Advantages: creates an area for floodwater to go All natural river processes such as deposition Disadvantage: might limit the use of land Landscape impact - preserves the natural floodplain landscapes in the mid and lower river courses It's soft engineering

Answer 43

The source of the river Dee is in Ddualt, an upland area in snowdonia, north wales, Here annual precipitation is high The Dee flows south-easterly, eroding this heavily glaciated upland landscapes formed of igneous and metamorphic rocks Near Chester the river meanders across a wide floodplain, eroding softer sedimentary rocks and depositing sediments A section is artificially straightened, giving a man-made landscape Further position occurs to form the Wirral estuarine landscape

Answer 44

1732-1736, channelisation of 8km improved navigation, increasing discharge and velocity and creating an artificial landscape Under the river Dee regulation scheme a series of reservoirs was built eg Llyn Celyn Early embankments were built along the middle course to protect agricultural land and properties, preventing further development of the floodplain landscape

Answer 45

Floodplain. Landscapes between Holt and Wothernbury with meanders, alluvium and river terrance deposits formed by active erosion and deposition, causing the river to change course over time. If sea levels rise by 1m by the year 2100, coastal landscapes will replace salt and freshwater marsh landscapes. In the Dee estuary, rises in sea level will destroy the estuary landscape. In periods of drought, river flows are low, by contrast, heavy rainfall and high surface runoff cause high river flows where most erosion and transportation occur

Answer 46

Long periods of rainfall cause the soil to become saturated and prevent further infiltration of rainwater, leading to increased surface run off

Answer 47

Different rock types in the catchment can affect flooding. Permeable rocks such as chalk allow water to soak in, so reducing surface runoff. Impermeable rocks such as clay do not allow water to pass through them, so rainwater will run off the surface and straight into the river channel

Answer 48

Water reaches the river channel much faster where slopes are steeper

Answer 49

Vegetation collects, stores and uses water from rainfall: this is called interception. Plant roots also encourage water to pass into soil and rock, so vegetation reduces runoff: if it is removed, more water can reach the river channel more quickly

Answer 50

In towns and cities, rainwater will not infiltrate the hard, impermeable surfaces of concrete and Tarmac. This causes the water to run off immediately into drains and river channels.

Answer 51

Warmer air can hold more water, which leaves to more rain and more intense storms, so there is more water

Answer 52

A graph that shows how a river responds to a storm event.

Answer 53

Cubic metres per second

Answer 54

It represents the rapid rise in water after a period of heavy rainfall

Answer 55

The difference between the time of the heaviest rainfall and the point at which the river contains the largest amount of water

Answer 56

Shows the reduction in the amount of rainfall reaching the channel

Answer 57

They are high banks built on or near river banks. They stop water from spreading into areas where it could cause problems such as housing, and they can be earth and grass banks, which blend in with th environment. However flood water may go over the top and then get trapped behind them and they can burst under pressure possibly causing even more damage This is hard engineering

Answer 58

They are extra channels that can be built next to rivers or leading from the. The relief channels can accommodate high flows so that a river will not overflow its banks. However they can be unsightly and may not be needed very often and costs can be high This is hard engineering

Answer 59

It's when the government allocate are ads of land to different uses, according to their level of flood risk. Flood risk management aims to prevent building homes and businesses in high risk zones. Here, such as open space for leisure and recreation are allowed because flooding would be less costly. However these may not be the best places for the different activities in terms of pubic accessibility and flood plains are attractive places to build This is soft engineering

Answer 60

Weathering is the breakdown and decay of rock by natural processes usually acting on the river valley sides

Answer 61

A drainage basin is the area of land usually drained by a river and its tributaries. When it rains, much of the water usually finds its way into rivers eventually, either by moving across the surface or by goi g underground and moving through the soil or rock beneath

Answer 62

The boundary of a drainage basin separates one drainage basin from another and is usually high land, such as hills and ridges

Answer 63

A stream or small river that joins a larger stream or river

Answer 64

The starting point of a stream or river, often a spring or lake

Answer 65

A point where two streams or rivers meet

Answer 66

The point where a river leaves its drainage basin and flows into the sea

Answer 67

It's a form of mass movement where masses of soil or rock, usually mixed with water, flow like liquid downhill

Answer 68

Steeper, causing more mass movement

Answer 69

River erosion involves the action of water wearing away the rocks and soils on the valley bottom and sides. Rivers have most energy for eroding and transporting sediment when there is a large amount of water and a steep gradient.

Answer 70

As a meander bends and develops, it's neck becomes narrower. Eventually the river may erode right through the neck, especially during a flood. Water then flows through the new, straight channel and the old bend is abandoned by the river. Deposition at the neck seals off the bend, which gradually begins to dry up, leaving behind a horseshoe-shoes lake.

Answer 71

It shows the height and distance downstream from the rivers source to its mouth. It is a curved shape, steeper near the source and flatter near the mouth.

Answer 72

The source of the river Dee is 460m above sea level on the slopes of Ddualt in snowdonia national park, north wales. Their annual average rainfall there exceeds 3000mm and runoff is high from the steep upland slopes. The geology is mainly hard igneous which are resistant to erosion. Near the source, the channel is narrow, shallow and full of angular stones, so friction with the bed and banks slows the river down. In the upper course the river erodes vertically, cutting down into the landscape and forming a v-shaped valley with steep slopes, where sliding and slumping takes place.

Answer 73

As the river Dee leaves its upland area and flows downstream, the valley becomes wider and flatter, creating areas of flood plain, and it's gradient decreases. The river now erodes sideways through lateral erosion as well as downwards, and there is some deposition, for example on the inside bends of meanders. Sooner or later the sediments will be eroded by the river again, so they become smaller and more rounded, and transported further downstream. As more tributaries join the river Dee its discharge increases.

Answer 74

The lower Dee valley, the climate changes, with average annual rainfall less than 750mm. The river flows through softer rocks, such as sandstone, towards Chester. Lateral erosion creates a wide valley with a flat bottom. The river channel widens. Because it's deep and smooth, there is less friction with the river bed and banks, so the rivers velocity is greatest. More tributaries increase the Dee's discharge. Here lateral erosion and transportation continue and the muddy river water shows its sediment load is high. This encourages deposition, for example at the river mouth where the flow is checked by the sea. After 110 km the river Dee reaches its mouth in the Irish Sea between Wales and Wirral peninsula. This part of the river near Chester is called the estuary because it's affected by rides

Answer 75

Width - increases Depth - increases Velocity - increases Discharge - increases Gradient - decreases Channel roughness - becaomes smoother, so less friction Sediment shape and size - becomes smaller and rounder

Answer 76

Contour line joining places of equal height above sea level. They also tell us how much the land slopes. Contours that are close together on the map show where the land slopes steeply. Contours further apart on the map show gentler slopes.mareas with few contours, or none at all, are flat: there is little or no gradient

Answer 77

Choose where you are going to make your cross section. Place a strip of paper across the contour lines on the map. Mark on the strip of paper each place where a contour line crosses it. Label the heights of the contours in you paper. Make the horizontal axis the same length as your strip of paper. The vertical axis is the height of the land from the lowest point to the highest point in a cross section Use the information on your strip of paper to plot the heights on the graph paper Joint the dots and label some of the landscape features

Answer 78

94% of catchment in rural, including forestry, sheep farming and pasture in upper valley, dairy and arable farming in lower valley. The river is a water source for 3 million people in Wales and north-west England The river supports large areas of habitats including plant and wildlife The river Dee and its estuary are famous for commercial and recreational fishing Parts of the catchment are popular for recreation and tourists. Key communication routes run along side the river Dee, including the Chester to Holyhead railway line, the A55 and A483 primary roads.

Answer 79

Responsible for managing the flood risk in England, as well as protecting the environment and water quality. It has produced a river Dee catchment flood management plan. By 2100, the plan predicts an increased risk of flooding caused by: Increasing population - more people will be in areas of risk. Urban development and changes in land use, causing more runoff. Climate change, including 20% increase in river flows, and 1m sea level rise. Together these factors will increase the number of properties in the catchment at risk from a 1% flood event from 4200 to 6400, with most impact on Chester.

Answer 80

Between £500 million and £1 billion

Answer 81

During periods of heavy rai fall, the soil and rocks can quickly become saturated. As infiltration is reduced, water flows over the surface and into the river at a faster rate.

Answer 82

In some places a lot of snow falls during the winter months. When temperatures rise above zero in the spring, all the snow that has built up melts, releasing large volumes of meltwater.

Answer 83

On 16 August 2004, a months worth of rain fell in one day, leaving the small village of boscastle in ruins. Around 100 homes and businesses were destroyed and 75 cars were washed into the sea. The tourist industry was significantly affected, with the Wellington hotels lower floor unrecognisable and many local businesses destroyed. The des astatine caused by the floods left many local residents struggling to deal with what they had to experience that day.

Answer 84

In 2012, it rained persistently from April to November. Between 21 and 24 November, a series of low-pressure systems crossed the UK, bringing strong winds and intense rain that fell on saturated ground, causing immediate surface runoff and flooding. North Wales, Cumbria and South west England were badly hit. 2012 was England's wettest and Wales third wettest year on record, causing flooding in many parts of the UK that killed 9 people, flooded 800 homes and ruined £600 million worth of crops

Answer 85

During July 2007, heavy rainfall caused the river Severn and Avon to flood, leaving 48000 homes affected and estimated repair cots for each home between £20000 and £30000. For the local councils economy the floods cost £140000 and for the British economy and estimated £3.2 billion. The floods left many local schools and businesses closed

Answer 86

During January and February 2014 in Somerset, persistent heavy rainfall resulted in disruption to transport (road and railway) because the flood waters took around 12 weeks to reduce. A total of 1000 hectares of farmland were left under water and six farms, including their animals, had to be evacuated. In the villages of moorland and fordgate homes were destroyed and local residents were evacuated because of fear for their safety

Answer 87

The main reasons are changes to land use and an increasing population and changes to weather patterns, particularly linked to climate change.

Answer 88

River restoration is restoring the rivers original course. Restoring rivers to a more natural course by taking away embankments aims to slow them down (eg restoring meanders). And natural rivers are more attractive and create natural habitats for wildlife. However some flood banks are often still needed, and like floodplain retention, changes in land use may bring some disadvantages.

Answer 89

They reduce the chances of a flood happening by managing rivers and land use, controlling development in flood plains and building flood defences. And reduces the impact of flooding by helping people prepare for flooding and giving flood warnings

Answer 90

They work out where flood defences would be most effective in preventing floods, and where they would not cause environmental damage. In the past people controlled floods by hard engineering methods, often building defences out of concrete. However these methods are expensive and do not reduce the risk of flooding in other parts of the catchment, and some may even increase it.

Answer 91

Soft engineering uses a more natural approach to managing floodwater. This approach aims to create space for flood water in the landscape, which also reduces the risk of flooding in other areas. Soft defences are usually cheaper, need little maintenance and often provides habitats for wildlife

Answer 92

It increases the amount and speed of surface runoff and river discharge. By contrast, improving land use aims to help rainwater infiltrate into the soil and slow runoff.

Answer 93

Because woodland intercepts rainfall, and tree roots encourage infiltration of water

Answer 94

Managing farmland can reduce runoff, for example by avoiding overgrazing by animals, and ploughing across slopes rather than downhill

Answer 95

Managing drainage in urban areas more sustainably helps reduce flash flooding, for example by increasing green areas and building ponds to store runoff

Answer 96

They use tv, the Internet, leaflets, helplines and training exercises to make people aware of they they should do before, during and after a flood, advice for homeowners include: lay tiles on the ground floor and use rugs instead of fitted carpets, raise the height of the electrical sockets to 1.5m above ground floor level, fit stainless steel or plastic kitchens instead of chipboard ones, position any main parts of a heating of ventilation system such as a boiler upstairs, fit removable barriers and non-return valves to al, drains and water inlet pipes, replace wooden window frames and door with synthetic ones

Answer 97

Gather essential items and go upstairs or to a high place. Fill jugs and saucepans with clean water. Move your family and pets upstairs, or to a high place with a means to escape. Turn off gas,melt trinity and water supplies when flood water is about to enter your home, do not touch sources of electricity when standing in flood water. Keep listening to local radio for updates or call flood line. Stay calm but call 999 if you in danger. Avoid walking or driving through the water, wash your hands if you touch it. Keep vulnerable people away from it.