The sediment cell concept

What is a sediment cell?

• a section of coastline where erosion, transport and deposition operate in a system with sources, transfers and sinks

What is a source?

• where erosion takes place and produces sediment

What is a transfer?

• traction

• Saltation

• Suspension

• Solution

What is a sink?

Where sediment is deposited

Processes in a Sediment cell

• each cell is a relatively closed system with little transfer from one cell to another unless there is a storm

• Dynamic equilibrium takes place. The source will be balanced by the deposition in the sink which is transferred by LSD

• the amount of sediment that is gained and lost can be quantified by a ‘sediment budget’

• This calculation can allow for appropriate management to be put in place

What are losses and gains in a sediment budget?

• losses - sediment deposited in sinks e.g. spits, bars, sand dunes

• Gains- coastal erosion (sediment broach by rivers, cliffs and offshore sources

How permanent are sinks?

• dependant on time scale as overtime can be destroyed by sea rise and storms

• Sediment budget seeks dynamic equilibrium but never has it due to these above as they change the amount of sediment in a cell

Examples of cells

• Christchurch bay (cell 4)

• Holderness coast (cell 2)

• Happisburg (cell3)

What is a cost-benefit analysis?

A cost-benefit analysis is a systematic approach to estimating the strengths and weaknesses of alternatives, used to determine options that provide the best approach to achieving benefits while preserving savings.