CASE STUDY - Sandbanks, Dorset (coastal landscape management)

Question 1

Who is responsible for the management of the Sandbanks peninsula?

Answer 1

Responsibility lies collectively with Poole Harbour Commissioners, Poole Borough Council and the Environment Agency, and the strategies employed form party of the Two Bays Shoreline Management Plan, based on the sediment cell covering Poole Bay and Christchurch Bay

Question 2

Why does the area need to be managed?

Answer 2

• Has a large number of high value commercial properties built on it, includes Sandbanks Hotel and Haven Hotel, which both provide significant employment opportunities and generate spending in the local economy
• Residential properties are in high demand and command premium prices (currently fourth most expensive in the world per m^2), large detached houses command prices in excess of £10 million, with many luxury apartments costing over £2 million
• The beach is a major tourist attraction, has a blue flag award for water quality and being gently sloping, is safe for family swimming
• Beach also provides protection and shelter from waves for Poole Harbour, which is therefore a popular and safe place for water sports, such as wind-surfing, sailing and water-skiing
• At the end of the peninsula is the entrance to Poole Harbour, used by cross-channel ferries and catamarans, as well as commercial ships carrying goods such as timber, longshore drift of beach sediment could cause the harbour entrance to become clogged and shallow
• Climate change means that sea levels are expected to rise here be about 0.6m in the next 100 years, this would not only cause flooding of many properties but could breach the peninsula at its lowest and narrowest point (2m above sea level and 50m wide), which would effectively cut off the end of the peninsula from the mainland, estimated that if no management strategies are applied, £18m of damage to residential properties will occur in the next 20 years

Question 3

How have groynes been used?

Answer 3

To maintain a deep and wide beach, rock groynes have been constructed to minimise the movements of sediment along the beach at Sandbanks by longshore drift, this not only restricts sediment from entering the harbour entrance (keeping access free for shipping) but also absorbs wave energy and reduces rates of erosion, estimated that without this, erosion rates would be about 1.6m per year

Question 4

How has beach recharge/ nourishment been used?

Answer 4

Used to conserve the beaches, sand dredged from offshore is sprayed onto the beach, a process known as ‘rainbowing’ adding to its size, this currently costs about £20/m^3, however a recent trial of dumping sediment dredged from the harbour just off-shore is a much cheaper alternative, costing only £3/m^3, natural currents will eventually transport this sand on-shore where it will help to build up beaches, in total over 3.5 million m^3 of sediment has been added to Poole Bay beaches - example of management working with nature