Poole Bay- Coastal Management 1
Shoreline management plan for this stretch of Coastline is to 'Hold the line' using hard and soft engineering- needed becasue soft rock which erodes at 1-2m per year without protection. Long fetch of 3000miles across atlantic btong powerful destructive waves that erode the coastline through the processes of hydraulic action and abrasion. Valuable land to be protected.
- 100 wooden groynes costing £100,000 each, creating 7miles of golden beaches
- 'Long Groyne' large rock groyne at Eastern end of Poole Bay
- Rock armour groynes at Westerns end of Poole Bay at Sandbanks.
- 5 new rock groynes at Branksome Beach, Poole 2008-2009, each measuring between 545m-75m in length. invloved 20,000 tonnes of rock being delivered to beach.Took 5 months and cost £1.9 billion
- Beach Nourishment- Between 2005-2008 the coastline benfited from 1.8 million cubic metres of beach material. Bournemouth beach 2008-2010 top up was from Isle of Wight. Water of Poole Bay is so shallow the dredger needed to pump the sand ashore through a long pip that lay on the seabed. Beach levelled by bulldozers
Poole Bay- Coastal Management 2
- Coastal management expensive- 100 groynes cost £100,000 each= total of £10 million.
- £1 million spent on repair of 4 groynes
- Material trapped by groynes in Poole bay has an adverse effect on other coastal resorts downdrift of Bournemouth. Settlements in Christchurch Bay such as Barton-on-sea are starved of beach material, resulting in increased erosion rates of 1-2m per year
- Access to beach is difficult when maintenance/ beach nourishment works is taking place; e.g. beach at South ourne closed from 10 days whilst pumping 70,000 cubic metres sand in September 2010.
- Money could be spent on other things such as schools etc... for community
- has to be spent in order to keep tourists and save homes/ buisnesses
Poole Bay- Coastal Management 3
- Groynes create bigger beaches by trapping sediment carried by Longshore drift. The 100 groynes+Long groyne creates 7 miles of beach. With more sand there is graeter friction and wave energy is the reduced so less erosion.
- Bournemouth relies upon its beaches fro tourist industry woth £440 million a year.
- SMP for Bournemouth protects 3,114 residential and 109 commercial properties at risk from coastal erosion. Bournemouths cliffs are very soft , made out of sands and clays and without the defences they would erode at a rate of 3ft a year
- Rock groynes (now replacing some wooden groynes) become cloinised by plants such as algae and linches, followed by limpets, crabs and other life forms that are able to adapt to rockey shorelines- bringing ecological benefits and diversity of beach life.