Rivers part 5

Created by

Hasset Kifle

Cards (23)

Describe embankments 
An artificially raised river bank which helps contains the water in the channel which reduces flood risk. Made by bulldozers moving huge mounds of impermeable soil onto river banks to build up their height
What are the advantages and disadvantages of embankments
Disadvantages:
-deprive people of easy access to the river for fishing, not as reliable as other methods
-has a high maintenance cost, prone to erosion which increases sedimentation downstream
-displaces riverbank animals from their habitats, unattractive
Advantages:
-cheap compared to other methods of hard engineerng
-habitats for riverbank animals
-makes an attractive walkway for local people
-safer from flooding (channel now has increased carrying capacity)
Example of embankment 
Bridge of Allan in Shirling, Scotland
What is hard engineering
Hard engineering involves building artificial structures which try to control natural processes.
What is soft engineering
Soft engineering involves working with natural river processes to manage the flood risk. Unlike hard engineering it does not involve building artificial structures or trying to stop natural processes.
Example of soft engineering strategy
Wetlands and flood storage area
Floodplain zoning
River restoration
Flood preparation
Describe Wetlands and flood storage
-wetland environments are very efficient in storing water
-wetlands are deliberately allowed to flood to form flood storage areas
-water can be stored to reduce the risk of flooding downstream
What are the advantages and disadvantages of wetlands and flood storage areas
advantages:
-habitats can flourish since humans aren't interfering
-cheap
-fertilise land
disadvantages:
-land cant be used for agriculture so will effect the economy of the country in the long run
Describe floodplain zoning 
-floodplain zoning restricts different land uses to certain locations on the floodplain
-areas close to the river are used for low value activites such as farming, parkland or playing fields
-expensive things (houses) are put far away from the river
What are the advantages and disadvantages of floodplain zoning
advantages:
-the cost to insure your house will decrease
-saves money
disadvantages
-can cause land prices to fall
-difficult to implement if houses have already been built
Describe river restoration 
-Where the course of a river has been changed artificially (hard engineering- river straightening), river restoration can return to its original course
-it uses the natural processes and features of a river such as meanders and wetlands to slow down river flow and reduce the likelihood of flooding downstream
What are the advantages and disadvantages of river restoration
advantages:
-less likely to flood downstream
-improved wildlife since natural processes are being used
disadvantages:
-process takes many years
-money has been wasted since river was previously straightened
Describe flood preparation 
-River basins are monitored using satellites and computer technology and river levels are measured
-computer models are used to predict discharge and identify areas at risk of flooding
-flood warning are then issued by the Environment agency set at 3 levels of warning
What are the 3 levels of flood warning
-flood watch
flooding of low lying land and roads is expected. Be prepared and watch river levels
-flood warning
threat to homes and businesses. Move items to upper floors and turn of electricity and water
-severe flood warning
extreme danger to life and property. stay in the upper level of your home or evacuate
How can people plan for floods
-using flood gates and sand bags to stop water flooding property
-planning which items they will move upstairs
-where they will go if they have to be evacuated
What are the advantages and disadvantages of flood preparation
advantages:
-less damage to community as they are aware of the flood
disadvantages
-up to the residence to enforce the warnings and take action
Case study about managing floods
Banbury
Where is Banbury 
Banbury is located in the Cotswold Hills about 50km north of Oxford. The town has a population of around 45,000. Much of the town s on the floodplain of the River Cherwell, a tributary of the River Thames
How has Banbury been affected by flooding?
- 1998: flooding led to closure of the town's railway station, shut local roads and caused £12.5 million of damage. more than 150 homes and businesses were affected.
- 2007: floods hit again and the river burst its banks affecting many more homes and businesses were affected.
What has been done to reduce the risk of flooding in Banbury
-In 2012, Banbury's new flood defence scheme was completed. A 2.9km earth embankment with a height of 4.5m was built parallel to the M40 motorway to create a flood storage area-capable of holding 3million cubic metres of water
-The flood storage are is located mainly on the natural flooplain of the River Cherwell-collects rainwater that would have swelled the river and caused it to burst its banks
-Two flood control structures were built in the embankment- - the specially designed openings control the rate of flow downstream towards Banbury
What are the social advantages and disadvantages of managing floods in Banbury
-The raised A361 route into Banbury will be open during a flood to avoid disruption
-Quality of life for local people is improved with new footpaths and green areas
-reduced level of anxiety and depression through fear f flooding
What are the economic advantages and disadvantages of manging floods in Banbury
-scheme cost £18.5million
-environment agency and Cherwell District Council
-By protecting 441 houses and 73 commercial properties, the benefits are estimated to be over £100million
What are the Environmetal advantages and disadvantages of manging floods in Banbury
-100,000 tonnes of earth were required to build the embankment-extracted nearby, creating a small reservoir
- a new biodiversity action plan habitat has been created with ponds, trees and hedgerows
-part of the floodplain will be deliberately allowed to flood rivers levels are high