4. Environmental considerations
Geographers will be aware of case studies showing the damage to areas further up the coast, from hard engineering solutions to coastal defence problems. Clearly, any major engineering scheme such as the 2002 West Bay Coastal Defence and Harbour Improvements Scheme (WBCDHIS) could only be considered after detailed studies of the likely Environmental Impact on an area with so many environmental designations.
1. West Bay is central to the 95 miles of World Heritage Site known as "The Jurassic Coast". UNESCO describes the site as " An outstanding example representing major stages of the earth's history, including the record of life, significant ongoing geological processes in the development of landforms, and significant geomorphic and physiographic features."
The site includes unspoilt cliffs and beaches from Exmouth in East Devon through to West Dorset, Weymouth and Portland and ends near the Old Harry Rocks in Purbeck. See figure 11.
2. West Bay is in an Area of Outstanding Natural Beauty.
Figure 12 shows the environmental designations of the area, with the following key:
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3. The centre of West Bay is a designated Conservation Area including the ancient piers The information in figure 13 reveals the extent of the consultation, which took place with all the "stakeholders" and local businesses. The site includes unspoilt cliffs and beaches from Exmouth in East Devon through to West Dorset, Weymouth and Portland and ends near the Old Harry Rocks in Purbeck. Impact on sediment movements along the coast English Nature's main concern with the proposed WBCDHIS was the effect it might have on the supply of sediment to the Chesil Beach. Geomorphological and sediment transport studies were carried out by consultants High Point Rendell. They concluded that the construction of the new outer harbour wall would not affect the sediment movements within the local bay or "cell". They also looked into the effect of removing beach material from Burton Freshwater (3km east of West Bay) to replenish the defence bank on the East Beach at West Bay and the effect this may have on the Chesil Beach. A schematic model of the evolution of the beaches either side of West Bay is shown at figure 14. Conclusions of the geomorphological and beach sediment transfer surveys were: a. The beaches on this coast are relict features that have received little natural supply of shingle in recent years b. Chesil Beach is not receiving a fresh supply of material from the west, east, the cliffs or offshore and is considered to be in a fragile state c. There is a possibility that any West Beach material could move round to the east Beach in storms, but the denuded state of the West Beach means that in fact very little is available for transport. This is unlikely to change as we are seeing successive compartmentalisation of the coast into pocket (bays) beaches d. There is a potential for East Beach to be supplied naturally from the Chesil if there are sustained easterly winds and longshore drift. This has not happened since the 1980s e. There are signs of a slow breakdown of the structure of the Chesil especially the lowering at the western end-East beach f. There is some evidence that a new pocket beach is forming at Burton Freshwater. Implications of the sediment studies for the beach management plan The area to the east of the harbour is the least defended part of the coast at West Bay and potentially vulnerable to flooding if the sea defence bank is breached or overtopped. The Beach Management Plan of 2002 states that the East Beach sea defence bank needs to be replenished every 5 years with shingle from Burton Freshwater, part of the Chesil Bank. In order to ensure the removal of material does not affect the structure of the Chesil Bank, a costly monitoring programme is in place, including the direct link of CCTV to the Environment Agency at Blandford along with other monitoring. However, the conclusion is that it is unsustainable to keep recycling shingle from Freshwater to East Beach for more than about 10 years due to the poor supply. Alternatives for the Beach Management Plan are: i. To construct a hard structure at East Beach The hard structure would be a steel sheet piled wall with rock armour protection to reduce wave reflection. Its estimated construction cost is #2 million.
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