The Coast As A System

Question 1

What are the inputs, outputs, transfers and stores

Answer 1

• Inputs: energy from wind, waves and tides, sediment from weathering and erosion processes
• outputs: sediment removed by longshore drift and sediment deposited as landforms such as dunes
• transfers: process of erosion and transportation that can move sediment around the system
• stores: sediment deposited in landforms

Question 2

What is the sediment budget

Answer 2

This is the balance between the input, store and output of sediment

• when the input=output the budget is in a state of equilibrium
• factors such as human activity can reduce sediment input and this makes the budget out of balance

Question 3

What is steady state equilibrium

Answer 3

Changes in energy and the resulting change in coastlines do not vary much from the long term averages
- beach profile adjusts in summer and winter as wave energy changes but the average gradient stays the same

Question 4

What is meta stable equilibrium

Answer 4

The coastal zone changes from one state of equilibrium to another due to an event causing a change in conditions
- eg. Sediment is removal from dredging changes the beach profile or removes the beach. There is a new equilibrium with a reduced beach

Question 5

Dynamic equilibrium

Answer 5

• the state of equilibrium changes over a longer period of time meta stable equilibrium
• eg. Climate change causing rising sea levels allow new areas of land to be influenced by wave energy changing cliff profiles

Question 6

How are tides created why are they important

Answer 6

• gravitational pull from the moon and the sun raise water levels
• the high tide occurs on both sides of the earth in line with tech moon, the other two sides experience low tides
• twice a month the earth moon and sun are aligned, so the gravitational pull is greatest creating Spring tides (large tidal range)
• when the sun and moon are at right angles weaker tides: Neal tides are created (small tidal range)
• the tidal range is the difference in height between the high and low water during the monthly tidal cycle it’s IMPORTANT because it’s where the coastal processes occur

Question 7

Characteristics of a high energy coast and what processes affect them

Answer 7

Erosive, rocky coastline

• physical, chemical biological weathering
• mass movement eg. Rock falls
• transportation processes eg long shore drift
• examples of high energy coasts are cliffs and wave cut platforms

Question 8

What are low energy coasts

Answer 8

• deposition is the dominant process, creating sandy coastlines and associated features such as sand dunes, spits and bars.
• Estuarine coastlines are low-energy coastlines where features such as mudflats develop