Topic 2 - Sediment sources, cells and budgets

Question 1

What are the different sources of sediment?

Answer 1

• Rivers - sediment in rivers accounts for vast majority of coastal sediment, deposited into river mouths and estuaries and reworked by waves, tides and currents
• Cliff erosion
• Lsd - sediment is transported from stretch to stretch of coastline
• Wind - in glacial or hot environments, wind-blown sand can be deposited in coastal regions
• Glaciers - ice shelves calve into the sea, depositing sediment trapped in ice
• Offshore - sediment can be transferred into the coastal zone by waves, tides and currents

Question 2

What is the sediment budget?

Answer 2

• The balance between inputs (erosion) and outputs (deposition)
• Positive budget; surplus sediment leads to input greater than output and the shoreline builds up towards the sea
• Negative budget; deficit of sediment leads to output bigger than input and the shoreline retreats downwards