Physical Landscapes in the UK 2 Flashcards
Examples of Hard Engineering defenses
Groynes
Sea Walls
Gabions or Rip Rap
Examples of Soft Engineering defences
Beach Nourishment
Managed Retreat
Water Cycle Key Terms
Precipitation
Interception
Surface Runoff
Infiltration
Transpiration
Precipitation
Moisture falling from clouds as rain, snow or hail
Interception
Vegetation prevent water reaching the ground
Surface Runoff
Water flowing over surface of the land into rivers
Infiltration
Water absorbed into the soil from the ground
Transpiration
Water lost through leaves of plants
Examples of Physical causes of Flooding
Prolong and Heavy rainfall
Relief
Geology
Examples of Human causes of Flooding
Land use
Prolong and Heavy rainfall
Long periods of rain causes soil to become saturated leading runoff
Relief
Steep-sided valleys channels water to flow quickly into rivers causing greater discharge
Geology
Impermeable rocks causes surface runoff to increase river discharge
Land Use
Tarmac and concrete are impermeable. This prevents infiltration & causes surface runoff
Lower course of a river
Near the river’s mouth, the river widens further and becomes flatter. Material transported is deposited
Formation of Floodplains and levees
When a river floods, fine silt/alluvium is deposited on the valley floor. Closer to the river’s banks, the heavier materials build up to form natural levees
What do floodplains and levees cause
Nutrient rich soil that makes it ideal for farming
Flat land for building houses
What are the two types of river management schemes
Soft Engineering
Hard Engineering
Examples of Soft Engineering (rivers)
Afforestation
Demountable Flood Barriers
Managed Flooding
Examples of Hard Engineering
Straightening Channel
Artificial Levees
Deepening or widening river
Afforestation
plant trees to soak up rainwater, reduces flood risk
Demountable flood barriers
put in place when warning raised
Managed flooding
naturally let areas flood, protect settlements
Straightening channel
increases velocity to remove flood water
Artificial levees
heightens river so flood water is contained
Deepening or widening river
to increase capacity for a flood
What is River Discharge and Hydrographs
River discharge is the volume of water that flows in a river. Hydrographs who discharge at a certain point in a river changes over time
What is Peak Discharge
The discharge in a period of time
Lag time
Delay between peak rainfall and peak discharge
Rising limb
Increase in river discharge
Falling limb
the decrease in river discharge to normal level
Location and Background of the River Tees
Located in the North of England and flows 137km from the Pennines to the North Sea at Red Car.
Upper course of the River Tees
Features include V-Shaped valley, rapids and waterfalls. Highforce Waterfall drops 21m and is made from harder Whinstone and softer limestone rocks. Gradually a gorge has been formed
Middle course of the River Tees
Features include meanders and ox-bow lakes. The meander near Yarm encloses the town
Lower course of the River Tees
Greater lateral erosion creates features such as floodplains & levees. Mudflats at the river’s estuary
Management of the River Tees
Towns such as Yarm and Middleborough are economically and socially important due to houses and jobs that are located there
Dams and reservoirs in the upper course, controls river’s flow during high & low rainfall
Better flood warning systems, more flood zoning and river dredging reduces flooding.
Location and Background of Lyme Regis
Lyme Regis is a small coastal town on the south coast of England. It lies at the heart of the world heritage site known as the Jurassic coast and is one of the most spectacular coastlines in the UK, famous for its fossils. It is a popular tourist destination
Geomorphic Processes in Lyme Regis
Unstable cliffs made from clays and limestone
Powerful waves from the South West attack the cliffs, eroding the cliff more rapidly than any other coastline in Europe.
Considerable erosion of the foreshore.
Flooding has occurred regularly in the past
Management in Lyme Regis
West Dorset District Council set up the Lyme Regis Environmental Improvement Scheme in the early 1990s to provide long term coastal management.
This was completed in 3 phases
Phase 1
(1995) new sea walls and cliff stabilisation completed
Phase 2
(2005-7) Extension of rock armour and beach widening
Phase 3
Cliff stabilisation further down the coast and new sea wall.
This had both positive and negative outcomes
Upper course of a river
Near the source, the river flows over steep gradient from the hill/mountains. This gives the river a lot of energy, so it will erode the riverbed vertically to form narrow valleys.
Formation of a waterfall
- River flows over alternative types of rocks
- River erodes soft rock faster creating a step
- Further hydraulic action and abrasion form a plunge pool beneath
- Hard rock above is undercut leaving cap rock which collapses providing more material for erosion
- Waterfall retreats leaving steep sided gorge
Middle course of a river
Here the gradient get gentler, so the water has less energy and moves more slowly. The river will begin to erode laterally making the river wider
Formation of Oxbow lakes step 1
Erosion of outer bank forms river cliff. Deposition inner bank forms slip off slope
Formation of Oxbow lakes step 2
Further hydraulic action and abrasion of outer banks, neck gets smaller
Formation of Oxbow lakes step 3
Erosion breaks through neck, so river takes the fastest route, redirecting flow
Formation of Oxbow lakes step 4
Evaporation and deposition cuts off main channel leaving an oxbow lake
Groynes
Wood barriers prevent longshore drift, so the beach can build up
Benefit : Beach still accessible
Drawback : No deposition further down coast = erodes faster
Sea walls
Concrete walls break up the energy of the wave . Has a lip to stop waves going over.
Benefits :
Long life span
Protects from flooding
Drawbacks : Curved shape encourages erosion of beach deposits
Gabions or Rip Rap
Cages of rocks/boulders absorb the waves energy, protecting the cliff behind
Benefits :
Cheap
Local material can be used to look less strange
Drawbacks :
Will need replacing
Beach Nourishment
Beaches built up with sand, so waves have to travel further before eroding cliffs
Benefits :
Cheap
Beach for tourists.
Drawbacks :
Storms = need replacing.
Offshore dredging damages seabed
Managed retreat
Low value areas of the coast are left to flood & erode
Benefits :
Reduce flood risk
Creates wildlife habitats
Drawbacks :
Compensation for land
Causes of the Chile earthquake
The Nazca plate and South American plate move towards each other on a destructive plate margin
The magnitude 8.8 earthquake struck just off the coast of Chile
Causes of Nepal Earthquake
. On a destructive plate margin, involving the Indo-Australian & Eurasian plates.
. Magnitude 7.9 earthquake
