Coast casestudy: Sandbanks, Dorset. Flashcards
Coastal landscape management
Why is Sandbanks a good example of management?
The Sandbanks peninsula is heavily managed
Who is involved in the management of Sandbank’s peninsula?
- Poole Harbour Commissioners
- Poole Borough Council
- The Environmental Agency
Where is Sandbanks?
Dorset
Name the 3 strategies implemented by the Environmental Agency
- Hold the Line (HTL)
- Managed Realignment (MR)
- No Active Intervention (NAI)
What does the Environmental Agency’s strategy of Hold the Line involve?
Maintaining, sustaining or improving existing defences
What does the Environmental Agency’s strategy of Managed Realignment involve?
When existing defences are moved to more sustainable positions, usually further inland.
What does the Environmental Agency’s strategy of No Active Intervention involve?
Where areas of low economic value and/or high environmental value are not protected
For what reasons does Sandbanks require management?
- Commercial properties
There are a large number of high value commercial properties built here. These include Sandbanks Hotel and Haven Hotel, providing employment and generates local economic income. - High demand of residential properties
Residential properties are in high demand and command premium prices. Large, detached houses command prices in excess of £10M each, with many luxury apartments being over £2M. - Beach is a tourist attraction, being popular for families and water sports
- Harbour for commercial ships
The end of the peninsula is the entrance to Poole Harbour, which is used by cross channel ferries and commercial ships. Longshore drift could cause the harbour entrance to become shallow. - Climate change
Climate change threatens properties and the connection of the peninsula to the mainland.
As a result of climate change, what sea level rise is predicted in Sandbanks in the next century?
- In the next century, sea levels are predicted to rise 0.6m
If no management strategies are applied, what is the predicted damage in Sandbanks in the next 20 years?
- If no management strategies are applied, £18M of damage to residential properties are predicted in the next 20 years.
What are the two major management strategies implemented in Sandbanks?
- Rock groynes
- Beach recharge
How do rock groynes implemented in Sandbanks have an impact?
- Rock groynes minimise the movement of sediment along the beach by longshore drift.
- From preventing longshore drift, this restricts sediment from entering the harbour entrance.
- In addition, as longshore drift is prevented, sediment accumulates and is able to absorb wave energy, reducing rates of erosion. Without this, it is estimated that erosion rates would be around 1m a year.
Without management of rock groynes, what would be the estimated rate of erosion?
- Around 1m a year
How does beach recharge implemented at Sandbanks have an impact?
- Beach recharge conserves beaches.
- Sand dredged from offshore is sprayed onto the beach, in a process called ‘rainbowing’, adding to it’s size. (£20/mcubed)
- Another, cheaper, recharge strategy is dumping sediment dredged from the harbour just offshore to allow natural currents to transport it onshore. (£3/mcubed).
What are the limitations of the two main management strategies deployed at Sandbanks?
- Rock groynes can cause sediment starvation downstream of the longshore drift course - enhancing erosion there.
- Beach recharge was reviewed in Sandbanks that suggested only 3% of the 30,000 m cubed of sediment dumped offshore reached the beach after 18 months.
Overall, how much sediment has been added to Poole bay beaches?
Over 3.5 million mcubed of sediment.
Why is beach recharge an example of management attempting to work with nature?
- Dumping sediment dredged from the harbour offshore relies on natural currents transporting sand onshore, which eventually builds up beaches.
What is the impact of rock groyne construction on flows of material, processes and/or energy through the coastal system.
(Such as sediment budget) AT SANDBANKS
- Rock groynes at Sandbanks inhibit the process of longshore drift.
- This inhibits flows of material along the beach into Poole harbour.
- As a result, energy is more easily dissipated from accumulation of sediment not transported by longshore drift
What casestudy is Sandbanks an example of?
Intentional human activity in a coastal landscape
What is the impact of beach recharge on flows of material, processes and/or energy through the coastal system - such as sediment budget at Sandbanks?
- Beach recharge
