Theme 0ne Revision

When discribing distinctive landscapes, talk about:

• Land use
• Culture
• Geology
• Vegetation

Eg. Abergavenny is a distinctive landscape because it hosts cultural events such as the Food Festival and the Abergavenny Eisteddfod. The land in Abergavenny is used mainly for shops. There is also a castle and Linda Vista Gardens which attract lots of vistors. There are seven hills around Abergavenny. As well as this, the river Gavenny flows through Abergavenny to give it a distinctive geology. Abergavenny is based in a rural location which means it has a range of vegetation such as maize, oil seed **** and oats.

To answer this question you must give a balanced answer (include both positive and negative).

Positives

• Can provide local employment opportunities
• Could bring money into the area
• Could improve facilities eg. roads

Negatives

• Can lead to loss of habitat for animals
• Can ruin vegetation
• Could cause the ground to erode

Set out this answer by making a point, developing it and showing the knock on effect.

Eg. If lots of people visit the Pembrokeshire coast, there might be an increase of litter which could be harmful for local wildlife. However this could lead to more awareness of the issues of litter and result in more bins ect.

There are three key techniques for landscape managent.

Plan - eg. make paths so people use them instead of disturbing wildlife

Repair- eg. replant vegetation to stop people using side paths

Ban- eg. fence off areas with rare flora and fauna

The marine code and agreement encourages users to act thoughtfully and responsibly

Agreed climbing restrictions is a leaflet of places where climbing is not permitted.

Rangers communicate with climbers about how to avoid wildlife and vegetation damage

Cliff top markers display areas where climbers can climb

Eg. One strategy to manage landscapes that are under pressure (eg. the Pembrokeshire coast) would be to introduce "agreed climbing restrictions". This would mean people are unable to climb in certain areas which prevent damage to the landscape.

Erosion

Solution/Corrosion - Acid in water breaks down rocks

Attrition - Rocks hit against each other causing them to break down

Abrasion - Rocks hit against bad and banks

Hydraulic action- The force of water weakens cracks in rock and forces them open.

River Transportation

Saltation - Material is bounced along the bed of a river

Traction - Large material is pulled along with the current

Solution - Dissolved material is also carried by the river

Suspension- Small materials can be carried as small particles in the river current

Material is moved along the coast by long shore drift. This is when the prevailing wind pushes the waves on to the beach at an angle (swash) and the waves run back vertically (backwash). Over time this results in material being pushed along the coast.

When the coast changes direction, often near a river estury, the sand being moved by long shore drift is pushed across in a straight line. Deposition occurs as the current of the river prevents the sand from continuing across the whole estuary.

The end of a spit curves during a storm. As the wind and wave direction changes, the storm pushes sand towards the shore.

A marsh develops as plants colonise the area that has been cut off by the spit. This is because material deposited in the spit has been blown across.  

Weather Events

Storms can change the direction of the wind and waves which could cause damage to spits

Storms can cause high tides and cliff collapses

Geology

Where there is a discordant coastline soft rocks erode quickly

Hard rocks don't erode as fast, this makes headlands

Headlands can shelter bays from prevailing wing, which preserves beaches

Human Activity

Groynes are built along beaches to stop long shore drift, this means beach material isn't replaced further up the beach leaving exposed to the waves 

Drainage Basin- An area of land drained by a river

Tributary- Smaller river flowing into main river

Watershed- The edge of a drainage bassin (high ground)

Confluence- The point where two rivers meet

Flows

Overland flow - Water flows over the surface, perhaps as rivers or just as run-off

Infiltration- Water soaking into the ground

Interception- When rain water is stoped in its path eg. by trees

Through-flow- Water that flows downhill through soil

Stores - stores can be lakes, soil, puddles or vegetation

Rainfall- Heavy rainfall might reduce the amount of interception because heavy rainfall will fall faster and move vegetation

Human Land Use-In urban areas where there are lots of buildings and impermeable material eg. concrete, there will be less infiltration compared to a rural area. Thi is because the water can't soak into the ground

Vegetation - If there is more vegetation there will be more interception of water. This also means there is less infiltration as the water doesn't reach the ground.

A constructive wave has a strong swash and goes further up the beach. It usually occurs in a place that is sheltered from the prevailing wind so it would have a shorter fetch.

A deconstructive wave has a strong backwash and doesn't go far up the beach. The waves crash vertically. It usually occurs in a place that faces the prevailing wind. It also has a long fetch which means the waves can gather momentum.

Prevailing wind - where the wind comes from

Fetch - how far the waves travel 

All stacks and stumps start as a fracture in the rock. Hydraulic action and corrosion erodes the fracture to form the cave. The back of the cave is eroded until it breaks straight through the headland to form an arch. Overtime weathering might cause the top of the arch to collapse because there isn't any rock left to support it. This forms a stack. Further erosion could cause the stack to collapse forming a stump. 

Factors that influence flooding

Precipitation - the type and intensity of rainfall

Geology - the type and structure of the underlying rock

Impermeable- rock that doesn't allow water to flow into it

A Flood Hydrograph - is a graph that shows the flood risk in an area

The Lag Time- is the time it takes for water to read the river after a storm/difference in time between peak rainfall and peak discharge (when the river is at its highest)

How human activity can alter lag time

One way human activity can alter lag time is by replacing forest areas with grassland. This would reduce the lag time. This is because there would be less trees to intercept and store precipitation. This means the precipitation runs into the river faster.

Hard Engineering - Altering the river's channel in an artificial way

Soft Engineering- Working with the natural processes of the river to manage flooding

Examples of Hard Engineering- Dams, Levies, Channel Straightening

Examples of Soft Engineering - Land-use Planning, Preparation, Afforrestation

Advantages and Disadvantages of Hard Engineering

Large projects like dams can come with lesuire advantages and are effective in the short term. However flood risk downstream can increase and structures are expensive to build and maintain.

Advantages and Disadvantages of Soft Engineering

They are cheap to build and maintain and can protect wildlife or create ecosystems. It can take years for the benefit to be seen and it limits the area where building can happen

Waterfalls

• Water flows over hard rock onto soft rock
• The soft rock erodes rapidly undercutting the hard rock and forming a plunge pool
• The hard rock over hangs and then collapes because the weight of the rock cannot be supported by the soft rock
• Over time this means that the waterfall retreats to form a gorge

Meanders

• The outside of the bend is where the area of fastest flow occurs so this is where the erosion takes place. This forms a river cliff.
• The inside of the bend has a slower flow so this is where deposition takes place. This forms a point bar or slip off slope.

Ox Bow Lakes

• As the neck of the meander narrows, water cuts erodes through. Deposition cuts off the Ox Bow Lake

Causes of the Flood

Human Factors

• Water run off increased by concrete and drains
• Bridges block the river causing it to flow and build up
• Trees removed from valley in order to build
• Reduced vegetation due to livestock farming

Physical Factors

• A months worth of rain in two hours
• Steep sided valley
• Two rivers meet (Valency and Jordan)
• Impermeable rock and soil

Social

• Four houses completely destroyed
• Dozens of houses in need of downstairs refurbishment
• Over thirty cars swept into harbour

Economic

• £10million damage
• 50 businesses temporarily closed
• Fishing boats over-turned

Environment

• Harbour full of mud
• Trees and vegetation destroyed

Dredging the river - makes the channel deeper and faster. The water is swept away quicker and more water is needed to flood

New bridges - wider span and are taller. Don't get blocked, water doesn't build up

Afforestation- intercepts and stores water so less water gets to the river

New Levees- allows the river to rise higher without flooding