Water on the land 2017

Hydraulic Power - Force of the water hitting the beds and banks

Abrasion - The load of the river hits the bed and banks causing material to break off

Attrition - Rocks are knocked together and produce smaller rocks

Solution - Rocks made smaller by chemical action because the acids in the water dissolve them

Traction - Bouders/stones rolled along the river bed due to being too heavy to carry

Saltation - Pebbles are bounced along the river bed

Suspension - Fine particles are float along in the water

Solution - Material is dissolved due to being soluble

Deposition - where a river drops its load as it slows down because it does not have the energy to continue transporting its load

• The larger material is dropped first and smaller material is deposited further downstream

Source - V shaped valley and mountainous

• Shallow, narrow valley
• Vertical erosion
• Erosion - hydraulic action, abrasion and attrition
• Deposits large material
• Large load

As it travels downstream

• Wider, deeper channel
• Some vertical erosion, and lateral
• Depostion of material is more obvious
• The size of the load has reduced

Mouth - U shaped valley and flat ground

• Less erosion, a little of lateral
• Suspension dominant
• Fine material is deposited
• Large amount of load but very small sizes

Formation waterfall, gorge and rapids

1. A band of hard rock lies over a band of soft rock

2. Soft rock is quickly eroded by abrasion and solution

3. This leaves an overhang of hard rock which eventually collapses due to lack of support

4. The hard rock erodes the river bed and creates a plunge pool by hydraulic action and abrasion

5. As the waterfall retreats (moves back) it leaves a steep sided gorge

6. As the river continues downstream , it comes across bands of hard and soft rock where it erodes the soft rock and creates rapids

The formation of Ox-bow lakes 

1. Erosion on the outside bend of a meander happens because this is where the fastest flow of water is

2. This causes the neck of the meander to become more narrow

3. In times of flooding, the river will take its shortest course and cut through the neck of the meander

4. This leaves the meander isolated forming an ox-bow lake

• Sand and shingle deposited on inside of bend

• Bank on outside of bend being undercut by lateral erosion

• Slip off slope

• Fine material (suspension)

Formation of levees

1. River will flood onto floodplain

2. Water will slow down due to friction and this causes deposition to occur

3. Heaviest sediment is dropped first due to rivers loss of energy

4. Finer sediment is deposited further onto the floodplain

5. After many floods, the levees build up and form a natural flood defence

Short lag time

• Deforestation
• Impermeable surfaces 
• Steep slopes
• Heavy rainfall

Long lag time

• Vegetated areas
• Permeable surfaces
• Gentle slopes
• Light rainfall

Effects

• Over 1300 homes were flooded and were unable to move back in for at least a year
• People had to be evacuated
• Final insuarance cost was £100 million
• Four bridges collapsed and 12 were shut
• One man died - PC Bill Barker

Responses

• Government paid £1 million to help with clean up and repairs and agreed to pay for road and bridge repairs in Cumbria
• Cumbria Flood Recovery Fund was set up to help victims of the flood
• Network rail opned a temporary raiway station
• £4.4 million pound management scheme
• New flood defence walls created
• River dredged more regularly to deepen channel
• New embankments raise channel height to reduce likelihood of extra floods

Effects

• 1781 Fatalities
• 2966  People injured
• 23% of crops ruined
• £1.5 billion agriculture loss
• Food shortages
• 1.9 million houses damaged
• Mudslides took place on steep slopes in mountainous areas
• Spread of disease

Responses

• Appeals were launched immeditely such as the UK's Disasters Emergency Committee
• Pakistan's government tried to raise money to help the people affected
• Foreign governments donated millions of dollars
• The UN's World Food Programme provided crucial food aid

Hard engineering

• Dams and reservoirs - regulates the discharge of a river by storing water in a reservoir and releasing it in small amounts
• Dredging - Widening and deepening the river so capacity increases
• Flood wall - Increases capacity of river
• Storage areas - Temporarily pumps water out of a river and stores it to reduce river levels

Soft engineering 

• Levees - Enbankment by deposition of material
• Flood plain zoning - Build high value buildings away from rivers so reduce impermeable suraces close by
• Afforestation - Planting trees to intercept rainfall

Water transfer scheme - Transferring water from an area of surplus( too much water) to an area of deficit (not enough water)

Reasons for increasing demand of water

• the UK's growing population - more to drink
• More people need more houses
• Use in buiding industry
• Agricuture - crops
• Drought and water shortages possible, due to global warming rising
• The introduction of appliances - washing machine and dishwashers, etc

Reasons for the location of a reservoir

• Impermeable rock
• Sparsely populated
• Large flat bottom valley with steep sides
• High annual rainfall