Paper 2: UK geographical issues Flashcards
1
Q
what is the link that will help you with this topics revision ? :) You have to memorise it of course
A
https://www.coolgeography.co.uk/gcsen/PL_River_Valleys.php
2
Q
Abrasion definition
A
A form of erosion where loose sediment ‘sandpapers’ the walls and floors of a river, cliff, or glacier.
3
Q
Attrition definition
A
rocks bang against each other chipping away to make smaller, smoother rocks
4
Q
Hydraulic Action definition
A
The force of compressed air or water forced into cracks in a rock face will cause the rock to weaken and break apart
5
Q
Solution definition
A
Material dissolved in water and carried in the river current
Erosion and transportation process
6
Q
Backshore
A
the upper beach closest to the land, including any cliffs or sand dunes
7
Q
Beach nourishment
A
(soft engineering management strategy)
The addition of sand and sediment to an eroding beach by humans. The new material will be eroded by the sea which saves the cliffs or sand dunes from erosion and recession
8
Q
What are the 3 types of weathering?
A
Biological, chemical and physical
9
Q
What is biological weathering
A
Rocks broken apart by vegetation and roots, or chemical reactions from animal faeces erode the rock face
10
Q
Chemical weathering
A
The weak acid in rainwater will dissolve chemical compounds in the rock
11
Q
Physical weathering / Mechanical weathering. and some examples
same thing just different names for it
A
The breakdown of rocks due to forces, not chemical reactions
EG physical processes such as changes in temperature, freezing and thawing, and the effects of wind, rain and waves.
12
Q
Freeze thaw definition
A
A form of physical (sub-aerial) weathering where water freezes in the cracks of a rock, expands and enlarges the crack. This weakens the rock overtime leaving it more open to erosion.
13
Q
Soft management
A
The use of natural materials and environmentally sustainable approaches to reduce coastal recession.
14
Q
4 Examples of soft management
A
Beach nourishment, managed retreat, sand dune, encouragement
15
Q
Hard management
A
The use of concrete structures to reduce or halt the recession of a coastiline
16
Q
3 Hard management examples
A
Groynes, sea walls, rock armour
17
Q
Geology
A
The physical structure and arrangement of a rock
18
Q
mass movement definition
A
where there is a large downhill movement of material usually from a cliff-face. Here, the rock is often weak due to erosion and the movement is caused by gravity.
19
Q
concordant coastiline
A
a coastiline where bands of alternate geology run parallel to the coast.
20
Q
Corrasion
A
A form of mechanical (physical) erosion / weathering where waves pick up beach material (e.g. pebbles) and hurl them at the base of a cliff.
21
Q
Discordant coast.
A
A coastline where bands of alternate geology run perpendicular to the shore.
22
Q
What are the three rock types (geology)
A
Sedimentary rock, igneous rock and metamorphic rock
23
Q
What is sedimentary rock?
A
Rock that has formed as sediment and rocks become compressed and cemented together over thousands of years.
24
Q
Igneous rock
A
Rock that has formed from volcanic activity, often cooled magma on the Earth’s surface,
25
Metamorphic rock
Rock formed under intense pressure and heat, often close to tectonic plate boundaries.
26
What is a spit?
A long depositional landform, formed from sand and shingle
27
What are the 4 ways that a river transports the materials within it?
Suspension, saltation, traction and solution
28
Traction?
Large rocks and boulders are rolled along the bed of the river or sea.
29
Suspension
Small rocks that are light enough to float are carried in the water, rather than along the bed.
30
Saltation?
A form of transportation where smaller sediment bounces to reduce marine erosion at the base of cliffs.
31
what is a Groyne
A form of hard engineering. Low lying concrete or wooden walls, constructed perpendicular to the seafront and run out to sea. They encourage the trapping of sediment to reduce erosion caused by longshore drift or by winds
32
What is a sea wall?
A hard-management coastal defence, where a concrete wall is built parallel to the seafront, to redirect the energy of waves away from sensitive cliffs or the edge of a coastal town.
33
What are highlands?
Areas of land that are high elevation and tends to have a larger relief.
34
Lowlands?
An area of land that has a small relief, so tends to be flat and at a low elevation.
35
Longshore drift?
The transportation of sediment along a beach. Longshore drift is determined by the direction of the prevailing wind.
36
What is the fetch?
The length of water over which the wind has travelled.
37
What is relief?
The difference in height of land for a particular region. A large relief means a region has a large difference between the lowest and highest points.
38
What is a sand dune?
A depositional landform, where sand and sediment build up around driftwood and accumulate over time.
39
Erosion definition
The wearing away of rock
40
Deposition defnition
When material is deposited or left behind.
eg when a river loses its energy and is unable to carry its load any further, or waves move sand onto a beach but lack the energy to carry it away.)
41
sediment definition
Small fragments of rock and soil that form layers.
42
swash definition
The water flowing towards a beach when a wave breaks.
43
destructive wave definition
Waves which remove material from the beach. The swash is weaker than the backwash.
44
Constructive wave definition
Waves which help build up material on the beach. They tend to have a low frequency and strong swash. (stronger than the backwash)
45
backwash
The movement of water down the beach.
46
Impermeable (rock)
A rock that does not allow water to pass through it.
47
permeable (rock)
A rock that allows water to pass through it
48
what is a storm hydrograph?
It is a graph to show the variation of river discharge over a short period of time (days).
49
load
The particles of rock carried by a river.
50
There are some different types of mass movement. Name some (4)
Rockfall (scree is evidence of rockfall)
Soil creep
Landslides and slumping
51
What are the three processes which shape rivers and cause change in their characteristics?
Erosion
Transportation
Deposition
52
what is the (river) bank?
The side of a river channel. (river channel literally just means river / stream)
53
what is a (river) bed?
The bottom of a river. (The river flows over it.)
54
What is a drainage basin ?
1) the official definition
2) my own definition for understanding
A drainage basin is...
1) The area drained by a river and its tributaries
2) Basically the entire river from start to finish, with it's different features long the way eg the source, the tributaries.... there is a drainage basin diagram is the diagram with the source, confluence etc labelled.
55
What is the source?
The upland area where the river begins
56
What is a confluence?
The point at which two rivers join
57
What is the mouth?
Where the river flows into the sea, or sometimes a lake
58
What is a tributary?
A river which joins a larger river
59
Watershed?
The boundary dividing one drainage basin from another - a ridge of high land. A river's catchment area.
60
What is an estuary?
An estuary is where the river meets the sea. The river here is tidal
61
What is the difference between a mouth and an estuary?
An estuary is the zone of mixing between the river and the sea whereas the mouth is defined as the location at which the river ends and the sea body begins.
62
what is 'dissolved' (aka what is the stuff carried by solution)
Dissolved chemicals are carried along in solution, invisible to the eye.
63
what is carried in the river by suspension? (this is known as 'float')
Tiny particles of sediment are carried in suspension in hte river's curent.
64
What is carried in the river by saltation? (called skip or bounce)
Smaller stones or pebbles are picked up and then dropped again. This results in a 'skipping' motion called saltation.
65
What is rolled or dragged in the river (by traction)
Large stones are dragged along by traction
66
Do you need most energy for traction , saltation, solution, or suspension
Clearly, you need more energy/ faster flow for traction in order to move the large load/sediment
67
what is the long profile?
A long profile is a line representing the river from its source to its mouth
68
what is a cross profile?
simply shows us a cross-section of the river
69
difference between long and cross profile
The cross profile simply shows us a cross-section of the river, while the long profile shows us how the gradient changes over the course of the river.
70
What is bradshaw's model?
heoretical model that shows how a river's characteristics change as it goes downstream.
71
gradient definition (river terms)
The slope of the river valley (steeep, flat)
72
Load definition (river terms)
The material the river is transporting
73
width definition (river terms)
the length across the river channel
74
depth definition (river terms)
how deep the river channel is
75
velocity (river terms) definition
The speed of a river, measure in metres per second
76
Discharge definition (river terms)
The volume of water flowing in a river, measured in chibic metres per second
77
Bradshaw's model shows that the gradient reduces downstream...why?
Vertical erosion and getting to sea level. Erodes sideways (lateral erosion) in the middle and lower course
78
Load particle sizes get smaller and smoother downstream from bradshaw's model...why?
increased erosion- attrition and abrasion (load becomes smaller and smoother)
79
The river width gets wider in downstream from bradhsaw's model...why?
More discharge and lateral erosion occurs (erosion sideways further downstream)
80
The river depth gets greater in bradshaws theory downstream.why?
More volume. increasing erosion
81
Velocity (speed) increases in bradshaw's theory model downstream...why?
More water/volume, load is smoother, wider/deeper channel = less surface area and therefore less friction
82
Bradshaw's model/theory shows how discharge increases downstream..why?
Tributaries add more water downstream
83
What is a brook?
A brook is a shallow, small, thin stream of river.
84
What is a beck>
It is a small stream or brook
85
List as many typical features of the upper course as possible
large river load
large, angular rocks (uneroded- doesn't have enough energy to erode them away)
Slow flowing
Narrow
Shallow
Cliffs/ V shaped valleys
Interlocking spurs
^Winds and bends to avoid areas of hard /resistant rock
Erodes the landscape vertically (downwards)
86
In the upper course, although the stream is vital in eroding the valley, what happens on the valley sides is also important. Two things happen, what are they?
Weathing and mass movement
87
weathering definition
The physical, chemical or biological breakdown of solid rock by the action of weather 9eg frost, rain ) or plants
88
briefly explain how biological weathering has shaped the valleys of the upper course resulting in the shape of the river.
Although the rocks look solid, small cracks allow plant roots to penetrate in search of water and nutrients. As they grow, root cells force the cracks apart, widening them and breaking the rocks into pieces. Scree (this is angular rock pieces / fragments created)
89
briefly explain how physical weathering has shaped the valleys of the upper course resulting in the shape of the river.
Occurs when physical force breaks rock into pieces. in winter, cracks in limestone fill with rain. This freezes, expanding in volume by 10 percent and widening so that more water gets in. This process is known as freeze-thaw weathering. If this is repeated enough times, pieces of roc break away becoming scree at the base of the cliff
90
what is scree
this is angular rock pieces / fragments created
Overall, if scree piles up, weathering takes place more rapidly
91
briefly explain how chemical weathering has shaped the valleys of the upper course resulting in the shape of the river.
Is any chemical changes or decay of solid rock. Rainwater mixes with the atmospheric gases, eg CO2, to form weak acids which dissolve alkaline rocks such as limestone
92
What are the 2 types of mass movements that can affect the valley sides (of the upper course)
Rapid mass movement and slow mass movement.
93
What are examples of rapid mass moveemnts
Landslides and mudflows. These are less common in UK but do occur on railway cuttings and along cliff coastlines
94
what are example of slow mass movement and explain it.
Soil creep. It's caused by rain dislodging tiny soil particles each time it rains. Soil creep occurs slowly like 2cm a year , but over decades it has many effects, eg it can cause walls or telegraph or walls to lean or trees to bend
95
Describe the river Wharfe in its upper course
The river Wharfe us a stream or tributary of the River Ouse (which flows through York.)
Its source is above the village Buckden and then the river Wharfe flows through it.
Wharfe goes down to Bolten Abbey. On its route, it goes through many beautiful villages and waterfalls eg Linton Falls
Buckden beck ( a beck) is located is a tributary of the River Wharfe.
It also includes all of the features of a typical upper course as we previously discussed.
96
What course does a waterfall occur in?
The river's upper course.
97
Interlocking spurs definition
The area of hard rock in the upper course where the river can't go through them so they are left sticking out, as the river bends around them.
98
Water fall formation
A waterfall is a cascade of falling water un a vertical direction/drop.
It occurs in the upper course when the river meets a bed of a less resistant rock underneath starts, which leads to it undercutting the hard rock above. The river's energy creates a plunge pool at the bottom.
The less resistnat rock beneath is eroded more rapidly by solution, abrasion and hydraulic action. This creates the overhang to collapse into the river : a mass movement. After collapsing, it breaks into smaller pieces which also erode by abrasion.
The waterfall takes up a new position. The cycle begins again. The waterfall retreats upstream and a gorge develops
99
Middle course features
more energy, and higher volume of water (than upper course). gradient is gentle and lateral (horizontal erosion) has widened the river channel.
Channel has also deepened.
A large, smoother river channel means that there's less friction so water flows faster.
In wet weather, volume can be so great that river overfloods over the flood plain. During this time, sands and clays brought down by upper course settle over flood plain and form layers of alluvium. Flood plains are at risk of flooding but alluvium is fertile and attracts farmers
Meanders
Oxboow lakes
motion that describes how middle course flows = Helicoidal flow
Actual river current / flow in middle course = corkscrew motion
100
Describe River Wharfe in its middle course
By middle course, several streams eg Bucken Beck have joined the Wharfe making it wider and deeper.
Here the Bradshaw model changes
gradient is gentler and rivers discharge has increased as more tributaries add to it. channel is also smooter because smaller, rounder pebbles, muds and sands have replaced large stones and boulders creating less friction to slow down river. As a result, velocity increase. This provides more energy for river to erode laterally, creating meanders, point bars and flood plains. The valley changes shape from V to U , as the flood plain widens the valley floor
101
meander definition
a bend in the river
102
explain formation of a meander
(MIDDLE COURSE)
Rivers naturally flow curved/ they never flow in straight line. While this happens, the fast flow of the river towards the outside of the bend causes erosion (through abrasion and hydracaulic action) The slower flow on the inside of the bend causes deposition. The water flows naturally in a corkscrew pattern. This is called helicoidal flow. This process continues, making the meander to become more pronounced. As the bend becomes more extreme, the river current the rivers current will begin to erode the neck of the meander, known as ateral or sideways erosion. The meander neck continues to be eroded, becoming smaller and narrower overtime. Eventually , the neck will be breached, cutting off the meander to create an ox - bow lake.
103
Explain what happens in the oxbow lake
Because the river wants to travel the fastest it can, it chooses the fastest direction. the ox. Material will then be deposited at the side of the river bank. The new channel/ ox will become more prominent, which results in the original channel turning into a redundant loop, and beginning to dry up. Overtime, they'll become completely separated. Plants will colonise it and make it dry out
104
Features of the rivers lower course
```
Mudflats
Wide and flat
floodplain
alluvium
leveees
delta / estuary
```
105
Mudflat definition
flat coastal areas formed when mud is deposited by rivers and coasts
106
floodplain definition
flat land around a river that gets flooded when the river overflows
107
alluvium definition
small, really good sediment (mainly in lower course) that, when deposited, make the land fertile
108
Levee defintiion
a natural or artificial wall that blocks water from going where we don't want it to
109
delta definition
a low-lying area at the mouth of a river where the river deposits so much sediment that it extends beyond the coastline
110
how mudflats form
2 directions of flow take place at the estuary: outwards by river taking water out to sea and inwardly from incoming tides. Twice a day, incoming tides meet the outgoing river and the flow stops, forcing the river to deposit sediment. This forms a broad wide area of mud - hence the name mudflat.
(some rivers deposit so much that a delta forms)
111
What is a salt marsh?
A salt-tolerant vegetation growing on mudflats in bays or estuaries.
112
what does it mean when a river 'bursts its banks'
the water goes onto the land
113
slower water causes ______ to occur
deposition
114
explain the formation of floodplains and levees
Floodplains and levees are found in the lower course.
Floodplains are very wide and flat areas of land either side of the river where we have salt/built up sediment deposit.
When rivers burst their banks out onto floodplain, the friction caused by the vegetation slows the water down, which causes deposition, The larger and corser sediments are deposited first (because it has less energy to carry them) whereas the smaller sediment like alluvium will be carried further away into the floodplain.
When we have continuous flooding it means that any sediment deposited will increase over time and the small fine sediment will help to rise and build our floodplains- our flat areas of land whereas our large particles will build up our (natural) levees either side of the river bank
115
Evaporation definition
The transfer of water from the grounds/sea to the air as water vapour
116
transpiration definition
The transfer and change of water from plants into water vapour
117
condensation definition
water vapour in the air changes back into a liquid and as it cools it forms clouds, full of water droplets
118
Precipitation definition
The transfer of water from the air to the land as rain, hail, sleet or snow
119
surface water definition
The transfer of water back to the sea over the ground
120
ground water definition
The transfer of water back to the sea/rivers below the ground surface- in the rocks
121
the water cycle is also known as the ...
hydrological cycle
122
the hydrological cycle is the same thing as the ...
water cycle
123
say/ describe in words the water cycle
Energy from Sun evaporates water from land and sea forming water vapour. This rises up into clouds and then cools, condenses and falls as rain onto the ground, eg as precipitation. Some hits plants, Plants put down roots into soil to draw water and nutrients up into the stems and leaves. Some of this water is returned to the air by transpiration.Some precipitation lands on high valleys or hills it will run off (surface water) onto ground water and the water then drains into the sea and the water cycle starts again.
124
interception (zone) definition
the capture of rainwater by plants. Some evaporates again and the rest drips from leaves to soil
125
What things do the amount (of eg precipitation ) intercepted depend on
Vegetation (eg deciduous plants - those who lose their leaves in winter intercept more in summer when they are in the leef, so there would clearly be a higher chance of flooding in the winter)
The season (the amount of rainfall)
The amount of infiltration (because remember that often it evaporates)
126
Infiltration definition
the soaking rain water into the ground
127
When does a flood occur?
When a river bursts its banks and water spills onto the floodplain
128
The faster the rainwater reaches the river channel, the more ____ it is to flood. Ideally, the ____ journey of water to the river channels, the less chance of flood. (clearly some precipitation falls directly into the river channel)
likely
longer
129
Once water enters the soil, give several suggestions as to what happens
some is taken up by plants and transpired thro leaves into atmosphere
some seeps into river thro soil or spaces, known as throughflow
some continuous into solid rock, and saturates it. The upper limit of the saturated rock is called the water table. From here, water seeps slowly towards river as ground water flow, which keeps the river flowing even when there has been no rain
When water can no longer infiltrate into ground, it is saturated. The soil can't take any more rain water. Any extra rain therefore flows over ground , this is called surface run off. This increases the likelihood of a flood.
130
scree definition
Angular rock pieces created by freeze-thaw weathering
131
saturated soil definition
when soil is filled with water
132
surface run off definition
rainwater that runs across the surface of the ground and drains into the river
133
list (6) human reasons for flooding
```
urbanisation
deforestation
farming
building on a flood plain
lack of defences
fallow fields
```
134
list (6) physical reasons for flooding
```
heavy/prolonged precipitation
impermeable rock/soil
relief (steep slopes)
snow melt
antecedent rainfall
steep sided / v-shaped valleys
```
135
What is thalweg
the path of fastest water flow in a river
136
what is floodplain zoning
controlling where houses and buildings are built relative to the river to reduce their risk of flooding
137
what is a storm hydrograph
a graph which shows the change in both rainfall and discharge from a river following a storm
138
what are the two types of hydrographs that you could be asked about
flashy hydrography (leads to flood)
Gentle hydrograph (fine)
139
features of a flashy hydrograph
short lag time
rapid rising limb
high discharge
leads to FLOODING
140
features of a gentle hydrograph
longer lag time
gentle rising limb
lower discharge
NO FLOODING!:)
141
Lag time definition
the period between a rainfall event and a river's peak discharge
142
peak discharge definition
maximum discharge in the river (measured in m/s^2)
143
peak rainfall definition
maximum rainfall in an event (measured in mm)
144
drainage basin definition
an area of land which collects rainwater and feeds it into a network of streams and rivers
145
base flow definition
the normal day to day discharge of the river
146
falling limb definition
represents the falling flood water in the river
147
rising limb definition
represents the rising flood water in the river
148
What were the June / July 2007 flooding...aka briefly describe the event and where was affected by it
It was a flood that occured between June and July of 2007 where several periods of extreme rainfall gave widespread flood in parts of England and Wales. It was the wettest May-July ever since 1766. South Yorkshire suffered breaking-record floods, and Sheffield was especially badly effected
149
Nationally, how many houses and buisnesses were flooded in the 2007 June-July floods?
Nationally, 49000 households and 700 buisnesses were flooded.
150
What does antecedent rainfall mean?
Means rainfall that happened previously
151
How did the antecedent rainfall contribute to the Sheffield floods
Because on 15th June, rain fell (the anteceent tain) and on June 25th it rained again which means that the soil was already saturated and all of this ran off (the surface)
152
give impacts of the Sheffield 2007 floods
Hillsborough stadium flooded (sheffield wednsday matches cancelled)
Cadbury and Trebor bassets flooded
Brightside area was flooded (next to river Don)
Meadowhall shopping centre was flooded and closed for a week
100 evacuated
health risks as raw sewage escaped
3 people died
estimated 1 billion worth of damage
many businesses closed for months
in 2014, the council announced 56 million of new flood defences plan..since then, there has never been a flood like this again
153
Give a human cause and a prolonged rainfall cause (together) for the Sheffiled flood
Most of Shheffield is built up, like heavily urbanised areas meaning that there are a lot of impermeable areas. (The only way to cope with rainfall is an extensive drain network)
154
Three rivers have a confluence next to a football stadium which provoked the Sheffiled floods. Name these three rivers and where they met.
And what did this result in?
```
River Rivelin
River Loxley
River don
They met at the Pennine mountains
This resulted in an increased volume of water
```
155
____ along the rivers Sheaf, loxley and don blocked the river channels
trees
156
Sheffield is known as the city of seven hills, they are all steep, so ...
any surface run off occurs quickly. As this surface ran off, drains were blocked and overflowed.
157
Sudden downpours were so quick in sheffiled that...
predicting where floods may occur was difficult
158
On 15th June, 90mm of rain fell over Sheffield, more than one month's normal rainfall. What happened to the soil?
The soil became saturated
159
What are the Somerset levels?
They are a broad stretch of flat, low lying land between Taunton and Glastonbury
160
What is dredging?
The removal of sediment from river channels in order to increase the capacity so that in theory the river can hold more water
161
Why was flooding expected in Somerset anyway?
Somerset are wetlands. They were artificially drained in the 17th century using a system of ditches. They did this for things like better farming; the soils were fertile (too wet for crops tho) and wetlands made good summer grazing. However, during the drainage, the land shrunk so much and was below high water tides, making it vulnerable.
As well as this, Somerset has 7 rivers, in low, flat land and next to Briston Channell so rivers don't have anywhere to go but flood the land. Essentially, flooding was always expected there, but none so serious as those of winter 2014...
162
Explain how the (physical) cause of Jet Streams provoked the Somerset flood
Jet streams are high level winds. They blow across the Atlantic towards the Uk. They drive low pressure weather systems with rain and wind. Normally their track takes them to Northern Scotland, which is the stormiest part of Uk however in 2014, the jet streams moved south over to southern England, as a result, this winter 2014 brought:
12 major storms
Most rainfall since 1766
Rain already saturated the ground from antecedent rainfall
More days when high winds combined with very high tidal surges (rivers in the area can't easily drain into Bristol Channel)
163
Explain how the human causes made Somerset 2014 floods worse.
Somerset farmers claimed public spending cuts that had resulted in less dredging, causing the flooding as channels had less capacity. Dredging manages the river and unblocks our wet ways so they're clear and wide enough for water to continue flowing (this is debatable)
164
Explain why dredging can be debatable.
Dredging creates levees and makes the channel deeper but only for a while. During high rainfall, levees can make the problem worse by raising the river bed further, as the rivers natural adjust to its new channel banks, containing more water which ill flood in periods of heavy rainfall.
165
As well as the typical causes of a storm like saturated soil, urbanisation, impermeable surfaces, lack of vegetation, urbanisation, etc, another cause which particularly triggered the Somerset 2014 floods was climate change. Explain the things which climate change leads to.
climate change ------> sea levels to rise------>increased evaporation-------->more storms-------->more rainfall
(The Uk has seen a 10 percent rise in annual average rainfall by 2100 compared to 1985-2005.
Intense storms used to be a 1 in 100 year event whereas now they are likely to occur every 80 years in the south of the UK.)
166
river management definition
strategies that try to limit or prevent the impact and effects of flooding
167
difference between coastal management and river management
coastal management: to stop coastal erosion
| river management; try to limit or prevent the impact and effects of flooding
168
what are the two managements for river management
hard engineering and soft engineering
169
flood walls- how they work, advantages and disadvantaegs and coasts
Hard engineering
work: build a high wall alongside a river to increase its capacity to prevent flooding
Coast:depends on material used
Evalutating:
Fairly cheap and are 'one off' coatss, once built, it's done
Useful for city centres where space is limited
However can disperse (distribute in a diff direction) wate quickly and increase flood risks downstream
170
Construct/ artificial levees, how work and evaluation
Hard engineering
work : increases capacoty of river and normally built at a distance from river which increases capacity even more
evaluation: expensive up to a million, but they let ppl to live beside rivers or farm w reduced risk of flooding
can cause downstream flooding
can fail by overtopping (water rises over the levee), slumping or by erosion
171
Dredging: how works, evaluation
Hard engineering
dredge the river to increase capacit or line it w concrete to speed river flow to get flood water away quickly
Evaluation: Needs to be done every year as river fills w sediment each time it rains heavily
concrete lining is expensive but cheap to maintain
speeding up flow increases the flood risk down stream coast, about 50000
172
flood relief channel (artificial)How it works and evaluation
Hard engineering
Creates extra channels to divert excess water from city centre (eg Sheffield)
It protects built up areas but could cause flooding elsewhere,
cost- 1km 14million
7km 30 million
expensive
173
Flood plain retention How it works and evaluation
Soft engineering
The level of flood plain is lowered, and their surfaces restored to shrubs or grasslands so they retain water over a period and release it slowly into the river
Increased ability to store floodwater
flooding was reduced in 2007 in spite of high rains in Darlington
The only flooding in Darlington in 2007 was due to backlogged water in drains, not by rivers
coast is abt 1.2 million for 2km stretch? check
174
River channel restortation how it works and evaluation
meaners rebuilt, lengthening the irver and slowing down river water, banks were lowered to make the river flood the park instead of Darlington, concrete and other high engineering materials were stripped away and replaced with sediment, and planted with trees
Improvedecology with a 30 percent increase in birds and insects within one year
ppl like the more natural look, a survey showed 82 percent liked it mostly or strongly
cost 1.2 million for 2 km strtcg? check
175
What is the Environment Agency
It;s the government department responsible for managing the risk of flooding in England and wales
176
How does the Environment agency manage the risk of flooding in England and wales
by reducing chanes of. a flood happening by managing rivers and land use, controlling development of flood plains and building flood defences
Reducing the impact of flooding by helping people and educating them on how to prepare for floods and giving them flood warnings
177
Reducing the chances of flooding is known as what
catchment management
178
what is catchment management
reducing the chances of flod
179
What does EA stand for
Environmental agency
180
The EA now believe that hard defences are not the solution . They cost a lot and are rarely big enough to cope with the largest floods. Instead, what do they suggest
they suggest more natural methods like:
upstream, upland areas should beplanted with trees to reduce surface run off
river channels should be restored to their natural state
planning [permission should no longer be given for building near rivers
181
In Darlingotn (named example) EA has restored 2km of the river Skerene. The methods were natural. Together, the work created a river side park as an outdoor space.. The EA belives that these methods make flood management more sustainable , why?
In the long run, they hope to reduce River Skeme's response so that it's more like a gentle hydrogrpah everytime it raisn
182
Embankments are the same as what?
levees (i think)
183
embankments , what are they, evalutation
(levees) are high banks bult on or near riverbanks
They stop water from spreading into areas where it could cause problems scuch as in settlements
flood water may go over the trap, then get trapped behind them
They can be earth and grass banks, which blend inwith the environment
They can burst under pressure, possibly causing even greater damage
184
What is the famous USA river known for its natural and engineered levees?
Mississipi
185
Name the motion that. describes the river flow in the Middle course
Heilicoidal flow
186
What motion/ pattern is helicoidal flow
corckscrew motion/pattern
187
What is the name of the diagram that shows how a river and its characteristics change from source to mouth?
long profile
188
What are the 4 types of erosion
Hydraulic action, abrasion, attrition, and solution
189
What is the fastest current (mainly in the middle course) called?
The Thalweg
190
Name the process where water can soak into the soil/ground
Infiltration
