River Management - Paper 1

Question 1

What are 4 hard engineering river managements?

Answer 1

-Damns and Reservoirs
-Straightening
-Embankments
-Flood relief channels

Question 2

What are damns and reservoirs?

Answer 2

A dam is a large concrete barrier built across a river to impede its flow. This causes the valley behind the dam to flood, forming an artificial lake called a reservoir.

Question 3

What do damn and reservoirs specifically prevent?

Answer 3

Flooding downstream.

Question 4

Name an example of a dam and reservoir:

Answer 4

Kielder dam and reservoir in Northumberland.

Question 5

What are 2 environmental benefits of Kielder dam?

Answer 5

-Promotes new habitats: these develop in and around a reservoir

-Forestry: Areas around reservoirs may be planted with forests.

Question 6

What are 4 social benefits of Kielder dam (1 of which are also economic)?

Answer 6

-Source of drinking water:

-Highly effective against floods

-Boosts tourism

-Provides hydroelectric power

Question 7

What rare animal does Kielder dam have due to conservation areas?

Answer 7

Red squirrels.

Question 8

How many trees were planted at Kielder and what other non-environmental factor did this support?

Answer 8

Over 150 million trees were planted, providing a valuable source of employment.

Question 9

How big of a reservoir did Kielder dam create which holds how much drinking water to supply who?

Answer 9

Kielder dam created a 10km reservoir, holding almost 200 million litres of water, to supply drinking water to industrial North East England.

Question 10

What about Kielder dam makes there virtually no risk of flooding?

Answer 10

Releases of water are highly controlled so there is virtually no risk of flooding.

Question 11

How do dams and reservoirs boost tourism, what was tourism at Kielder dam and reservoir like?

Answer 11

Reservoirs are attractive. Kielder dam attracts 300,000 tourists a year, which boosts the local economy by £6 million.

Question 12

How much electricity from hydroelectric power does Kielder dam generate?

Answer 12

It generates 6MW of electricity, enough to serve a town of 10,000 people.

Question 13

What is an economic benefit of dams and reservoirs?

Answer 13

Boosts tourism

Question 14

What is a social cost of dams and reservoirs?

Answer 14

The flooding of a valley displaces people, usually farmers from their homes.

Question 15

How many families were displaced at Kielder from the flooding of the valley? What does this cause?

Answer 15

58 families were displaced. This causes distress and breaks up communities

Question 16

What are 2 economic costs of dams and reservoirs?

Answer 16

-Very expensive

-Reduced crop yields as soils downstream can become less fertile through lack of sediment from floods.

Question 17

How much did Kielder dam cost and why have it may been a waste of money?

Answer 17

Kielder dam cost £167 million. It may have been a waste of money as loss of industry in North East England meant that demand for water and HEP was less than expected.

Question 18

What are 6 environmental costs of dams and reservoirs?

Answer 18

-Interferes with path of migrating fish

-Algae often collects behind a dam which deoxygenates water

-If there were a sudden release of water through sluice gates, river bank erosion could happen downstream

-Building of a dam may trigger an earthquake

-Landslides often occur on side of reservoirs. This increases sediment and creates shock waves which damage buildings.

-Reservoirs often flood areas of outstanding natural beauty.

Question 19

What outstanding natural beauty was lost from reservoir flooding because of Kielder dam?

Answer 19

1.5 million trees along with 2,700 acres of farmland. This had a negative effect on habitats. New plantings are confined to Sitka Spruce.

Question 20

What is channel straightening?

Answer 20

When a meandering section of a river is engineered to create a widened, straightened and deepened course. The more efficient course improves navigation and reduced flood risk.

Question 21

Give 2 examples of where channel straightening has occurred:

Answer 21

-In the 19th century a new course was cut across a large meander loop on the river tees to improve navigation.

-Centuries of straightening have also taken place on the River Parret, to reduce flood risk in the low-lying Somerset Levels.

Question 22

What is a social benefit of channel straightening?

Answer 22

Reduces flood risk.

Question 23

How does channel straightening reduce flood risk?

Answer 23

It moves water out of the area quicker, as there is less friction with the beds and banks. The faster flowing water also removes sediment that would otherwise build up the height of the river bed.

Question 24

What are 3 economic benefits of channel straightening? (involve 1 specific example)

Answer 24

-The historic cuts on the River Tees reduced the length of the river by 4.4 km. This straightened course improved navigation considerably and increased trade in Stockton’s Port.

-Home owners gain confidence to invest in their property as they no longer expect to be flooded.

-Insurance costs also go down.

Question 25

What is a social cost of channel straightening

Answer 25

It makes the river more likely to flood further downstream, because once the flow meets a meandering section downstream, such as Burrowbridge in the Somerset Level, velocity reduces. This causes sedimentation of the channel, so the river is more likely to flood, causing problems in another area.

Question 26

What are 3 economic costs of channel straightening and specific examples?

Answer 26

-River straightening is expensive

-Dredging a river to remove silt accumulation is also expensive. After the 2014 flood damage the EU authorised the £5.8 million dredging of a 5 mile section of the Rivers Parret and Tome near Burrowbridge

-Sometimes the impact of a straightened section down stream is so severe that the river is restored to its original course. At Lewisham, London, £1.1 million was spent putting meanders back into the River Quaggy.

Question 27

What are 3 environmental costs of channel straightening?

Answer 27

-Changes in hydrology and flooding downstream that can occur endanger animals and destroy habitats. The river’s ecosystem is changed.

-A straightened river may have a concrete lining. This is visually unattractive and it deprives burrowing river bank animals of their habitat.

-In straightened sections, there is some evidence of increased pollution on the land from agro-chemicals, as run-off can not drain into the river as easily.

Question 28

What are embankments?

Answer 28

An artificially raised river bank.

Question 29

How do embankments reduce risk of flooding?

Answer 29

In raising the banks, more water is contained in the channel.

Question 30

How are embankments made?

Answer 30

By bulldozers moving huge mounds of impermeable soil onto the river banks to build up their height.

Question 31

What are some embankments reinforced with?

Answer 31

Gabions (wire cages filled with stones) or lined with concrete.

Question 32

What are 2 social benefits of embankments?

Answer 32

-Risk of flooding is reduced as it is less likely to bursts its raised banks.

-Provide walking routes and footpaths. Embankments make attractive walkways for local people.

Question 33

What is an economic benefit of embankments?

Answer 33

It’s cheap compared to other methods of hard engineering.

Question 34

What is an environmental benefit of embankments?

Answer 34

Earthen embankments provide habitats for riverbank animals such as water voles, kingfishers and otters.

Question 35

What are 2 social costs of embankments?

Answer 35

-They deprive people of easy access to the river for fishing and boating

-Their presence gives people a false sense of security as they are are not as reliable as other types of hard engineering. People may not be prepared for floods.

Question 36

What are 2 economic costs of embankments?

Answer 36

-Higher maintenance costs than other hard engineering methods as they need constant monitoring and repair.

-Earthen embankments will occur a dredging cost if flooding is to be avoided as they are prone to erosion and will increase sediment downstream.

Question 37

What are 3 environmental costs of embankments?

Answer 37

-If the embankment is breached, water lies on the land for a long time.
-Gabions and concrete linings displace riverbank animals from their habitats.
-If these reinforced sections break, wire mesh or huge slabs of concrete litter the river bed.

Question 38

What is a flood-relief channel?

Answer 38

An artificially made channel that is designed as a backup channel for a river that frequently floods. It works like a bypass. The newly engineered channel runs roughly parallel to the main river.

Question 39

Name an exmaple of where flood-relief channels are:

Answer 39

-The river Exe at Exeter has 3 flood-relief channels, the largest of these channels is the Exwick spillway.

Question 40

What are 4 social benefits of flood-relief channels?

Answer 40

-Removes the risk of flooding from a designated area

-Footpaths and cycle tracks are built along a new channel

-Calm water provides areas for model boating and canoeing

-Where reed beds have been including, bird watching and nature reserves may be set up.

Question 41

What are 3 economic benefits of flood-relief channels?

Answer 41

-Insurance costs are lower in the vicinity

-The value of homes increases and houses are easier to sell

-There is a more secure environment for setting up business ventures.

Question 42

What are 2 environmental benefits of flood-relief channels?

Answer 42

-Some relief channels provide new habitats by introducing artificial reed beds and grass-covered concrete sides.

-When full of water, they provide a tranquil setting.

Question 43

What are 2 social costs of flood-relief channels?

Answer 43

-People living in the path of the relief channel have to be moved, this causes destruction.

-Settlements downstream of a relief channel suffer from increased flooding, as the merging of water from the relief channel swells this part of the river. This raises the question of the ethics of protecting some settlements for the detriment of other.

Question 44

What are 3 economic costs of flood-relief channels?

Answer 44

-Expensive

-Sometimes they run out of funds, (like the Jubilee River), they also need to be maintained and repaired.

-Schemes take a long time to come into effect.

Question 45

How long did Exeter’s relief channel take to build?

Answer 45

12 years.

Question 46

What are 3 environmental costs of flood-relief channels?

Answer 46

-During their construction, habitats are destroyed

-The level of water in a relief channel varies considerably, providing an unreliable habitat

-Look unattractive in times of low flow, when vast expanses of concrete and gabions are exposed.

Question 47

What are 5 soft engineering river managements?

Answer 47

-Flood plain zoning
-Flood warnings
-Preparation
-Planting trees
-River restoration

Question 48

What is flood plain zoning?

Answer 48

Where land in a river valley is used in such a way as to minimise the impact of flooding.

In England and Wales, the Environment Agency (EA) categorises land into 4 flood-risk zones and issues flood-risk maps.

More permanent structures can be installed further away from the river without any substantial economic or social costs, should flooding occur.

Question 49

What agencies co-ordinate efforts to plan and carry out action plans for areas at risk?

Answer 49

The EA, district councils, the Water and Highways Authorities.

Question 50

Where is updated flood alert information provided from?

Answer 50

The meteorological office analyses data from its 200 weather stations and passes this to the EA, who uses it, along with river level data, to provide updated flood alert information.

Question 51

What publisises flood alert information?

Answer 51

The media, and occasionally sirens or loudspeakers.

Question 52

What does the EA provide for flood warnings and preparation?

Answer 52

-A flood map website
-A three day flood forecast
-Personalised warnings
-Information on how to prepare oneself.

Question 53

How does planting trees help reduce flooding?

Answer 53

Planting shelter belts of trees across slopes and woodland in floodplains (rewilding) reduces the risk of flooding as intercept water by taking it up through their roots.

Question 54

Who is planning to plant how many trees to reduce flooding?

Answer 54

Wales plans to plant 10 million trees over the next 5 years.

Question 55

What is river restoration?

Answer 55

When a river that has previously been hard engineered is restored to a natural channel.

Question 56

Give an example of where river restoration has occurred:

Answer 56

Near Sutcliffe Park in Greenwich, River Quaggy had previously been re-routed through underground drains, but by 2007 it was brought back to the surface and restored close to its original meandering course.

Question 57

What are 4 benefits of flood plain zoning?

Answer 57

-Impermeable surfaces do not increase by restricting building on the active flood plain, so the risk of flooding is reduced

-Low-cost; only administration costs are involved

-Traditional water meadows by a river are protected

-By conserving the flood plain, planners provide a welcome green space un UK towns.

Question 58

What are 4 costs of flood plain zoning?

Answer 58

-It has limited impact as many UK cities have already sprawled over the active flood plain

-It is very difficult to get planning permission to extend or rebuild homes in the flood plain

-There is a housing shortage in the UK, restricting building makes the problem worse. Restricted supply will inflate house prices.

-Habitats are destroyed due to increased building on other greenfield sites.

Question 59

What are 3 benefits of flood warnings and preparation?

Answer 59

-Very cheap way of protecting people and their property

-Warning in advance can make people protect their valuables earlier

-Good way of ensuring peoples’ safety without having to invest in high-cost hard engineering.

Question 60

What are 2 costs of flood warnings and preparation?

Answer 60

-Only effective if people listen and take action, not everyone listens to, or has access to the media or the internet

-It does not help people who live in areas prone to flooding. The clear-up operation is distressing, people may have to temporarily move, insurance costs will increase and their house will be difficult to sell

Question 61

What are 4 benefits of planting trees?

Answer 61

-Reduces water flowing downstream as shelter belts of broad-leaf trees can reduce surface run off.

-More carbon dioxide is absorbed

-Increases biodiversity

-Relatively inexpensive.

Question 62

What are 2 costs of planting trees?

Answer 62

-Changed appearance eg countryside wooded rather than open grass

-Loss of potential grazing land

Question 63

What are 3 benefits of river restoration?

Answer 63

-Creates new wetland habitats and increases biodiversity

-Increased water storage reduces risk of flooding

-Aesthetically pleasing

Question 64

What are 3 costs of river restoration?

Answer 64

-Possible loss of agricultural land and flooding of crops near the river

-Can be expensive

-Not always most effective