South Devon & Dorset

South Devon & Dorset

1. BACKGROUND

   • SMP
     • Shelf life of 15-25 years
     • SMP1 - 1990 to 2005
     • SMP2 - 2005 to 2025
       • Part of this coastal strategy
     • SMP3 - 2025 to 2050
     • SMP4 - 2050 to 2100
   • From Durlston head to Rame head
     • 300km coast
   • Unique coast with rich biodiversity and artifacts from epochs of years
     • UNESCO heritage site
   • There are 17 sub cells here
   • From Bridport to Portland Bill are 13/190 total sediment cells of smp2

2. Proposals and why?

   • Evidence of this sediment cell of an erosion rate 1mm/year over last 2000 years
   • Storm events can cause a years erosion in 1 night
     • February 2014
       • dawlish railway undermined
   • 1. Hold the line
   • 2. Managed Realignment
   • 3. Don Nothing
   • All considered short, medium and long term defence
   • High energy coastline with waves of fetch of over 8000km

3. 4 MAJOR MANAGEMENT STRATEGIES

   • A) South Chesil Beach
     • Chiswell & Portland: Hold The Lines
       • 1. Hard Engineering
         • 300m recurved sea wall
         • Steel Piles to underpin walls
         • 900m drainage channel reducing pressure from behind
         • Costed £5mil
     • SUSTAINABILITY
       • Physical
         • Deflected wave energy increases Scarring of beach
         • Construction disturbs wildlife and natural habitats
         • Spoils natural aesthetics of the coastline
       • Human
         • Expensive
         • Unsustainable - work may need repair in 50/60 years
         • CBA shows it's a good investment saving business in Chiswell and the crucial A354
         • Withstood storms of Feb 2014
   • B) Chesil Beach
     • Managed Retreat
       • Broad shingle beach used as defence
       • Shingle ridge at Chesil will move eastwards shrinking the fleet
     • 2. Soft Engineering
       • Using earth-moving machinery re-profiling the shingle beach
       • Managed realignment will continue if and until the A354 comes under threat then hard engineering will be used
       • SUSTAINABILITY
         • Physical
           • Wading birds & habitat "fleet" threatened as the lagoon shrinks
           • Immediate impact on wildlife of chesil beach very little
           • LSD can continue
         • Human
           • Homes around area may have to be abandoned , but compensation is minimal due to low number
   • C) East Clff to Top of Chesil Beach
     • Area of SSSI
     • Impacted by landslides and requires est. £2m to protect
     • Home to rare grayling butterfly, EIA dictates beach recycling and managed retreat is best option
     • Soft Engineering
     • SUSTAINABILITY
       • Physical
         • Wildlife around Warren nature reserve protected
         • Landslides continue due to rain saturation of lias clay
         • Natural beauty preserved for generations to come
       • Human
         • South West Coastal path maintained encouraging tourism
         • Landslides expose fossils - attracts tourists to area
         • Minimal impacts on residents & business
   • D) Lyme Regis
     • Hard Engineering - Hold The Line
       • Rock Armour protects harbour at the Cobb
       • Sea walls along beach & cliff base heading east to Charmouth
       • Rock Groynes at beach
       • Soft Engineering
         • Beach nourishment finished in Feb 2014 sand imported from France cost £10m
     • 1995-2005
       • Concrete piles to support cliffs
     • Cost £60m
   • SUSTAINABILITY
     • Physical
       • LSD disrupted east of LR heading towards Charmouth under sever erosion
         • Landslides more common between LR and C due to lack of protection east of LR
     • Human
       • CBA shows the £60m investment is worthwhile saving £225m (2017) tourism industry
       • Helps preserve South West Coastal path 650mile trail
       • Sea walls, groynes and nourished beaches continue to make LR attractive to tourists with its marina and wide shandy beach
       • Increased tourism issues
         • overcrowding
         • air pollution
         • traffic congestion
         • litter
         • environment degradation
         • UNSUSTAINABLE
       • Withstood Feb 2014 storms battered coast
         • Longetivity limited as estimated to need replaced every 50/60 years
           • Questions sustainability of recurring £60m investment

Bilder und Dateien der Mindmap