Why Is Channelisation Needed

Question 1

What is the aim of channelisation

Answer 1

To increase the efficiency of the river channel to move water and sediment downstream quicker

Question 2

What are the 5 reasons for channelisation

Answer 2

Flood control
Land drainage
Navigation
Construction
Erosion control

Question 3

Flood control (what is channelisation needed to increased (2) why, what encouraged modification where)

Answer 3

Channelisation is needed to increase efficiency and river capacity of the channel so that water and sediment move downstream quicker. Also unexpected floods encouraged modification of the channel to protect the homes and resources , rivers Tone and parrett somerset levels

Question 4

Example of where flood control is used

Answer 4

Rivers Tone and Parrett Somerset levels

Question 5

Land drainage (why are floodplains attractive, how is agriculture improved and what has to be in order to be effective, methods)

Answer 5

Floodplains are attractive due to the flat and fertile land. To improve agriculture, land quality can be improved by draining water from surrounding areas into the channel, methods include drainage ditches and underground field drains. However for this to be effective the river must have the ability to carry the additional water away, or else floods will occur

Question 6

Navigation (what are rivers key for, especially in what areas and what causes difficulties ) example

Answer 6

Rivers are key transport for the world, especially in remote isolated areas with limited access. Variation in river depth and stream velocity poses many difficulties for shipping (LOWER MISSISSIPPI NAVIGATION SCHEME)

Question 7

Example of river NAVIGATION scheme

Answer 7

Lower Mississippi navigation scheme

Question 8

Construction (what 3 developments require channelisation and what does this reduce/divert)

Answer 8

Bridges, motorways and urban development sometimes requires the river to be channelised, either to reduce flood risk or divert river away from construction site

Question 9

Erosion control (what can channelisation prevent, explain problems associated with erosion of adjacent land and what has been done to reduce this, give examples)

Answer 9

Channelisation can prevent the river from eroding into farmland or urban development. The erosion of land adjacent to rivers is a major problem, migrating meanders mean a loss of land for farmers and urban buildings and transport routes may be destroyed so many rivers running through cities have artificial and reinforced channels

Question 10

What is hard engineering

Answer 10

Hard engineering INTERVENES directly with the rivers natural processes, it usually involves BUILDING e.g concrete embankments alongside a river channel (channelisation)

Question 11

What is soft engineering

Answer 11

Soft engineering aims to work with the rivers natural processes, it usually involves less building of man made structures and has a reduced negative impact on the environment e.g the creation of wetlands on a floodplain to store water

Question 12

Define channelisation

Answer 12

Channelisation refers to the hard engineering methods. It can be an attempt to alter the natural course of the river, helping to prevent flooding by increasing the channel capacity and preventing bank erosion. E.g straighter, deeper channels can also help drain wetlands and provide more manageable rivers

Question 13

Define channelisation

Answer 13

Channelisation refers to the hard engineering methods. It can be an attempt o alter the natural course of the river, helping to prevent flooding by increasing the channel capacity and preventing bank erosion. E.g straighter, deeper channels can also help drain wetlands and provide more manageable rivers