Coastal erosion at Studland Bay
Many school children studying geography visit Studland’s beaches to see an example of an eroding coastline. Studland has also been in the news over the years when storms and tides from the east and south-east have washed away large amounts of sand.
Why do Studland’s beaches erode?
Sand is always in motion, moved by the waves and wind. At Studland the predominantly south-westerly winds naturally move sand from the south of the peninsula and deposit it to the north. The supply of sand to the south cannot keep up, which leads to erosion.
Easterly storms also have an impact on Studland’s beaches, causing large amounts of sand to be washed from the beach into the bay. Some sand may wash back into shore over time but much will not return.
Can we stop the erosion?
Little can be done to prevent the movement of sand in the bay that would not alter the natural character of the beach. Hard defences seen on other sea fronts tend to be used to protect roads and railways in built up areas. Natural sites cannot be fixed in place in the same way without losing the features that make them unique. Studland’s sandy peninsula will move and shift over time but there will always be sandy beaches at Studland.
How is the National Trust managing erosion at Studland?
The National Trust monitors the erosion of Studland’s beaches with the help of volunteers, and has developed a coastal adaptation strategy for managing the bay. The Trust works with local authorities, the Environment Agency and community groups as part of a Poole Harbour-wide coastal management plan. The Shifting Shores report outlines the Trust's approach to coastal management.
Why isn’t the Trust doing more to protect Middle Beach?
The gabion baskets at Middle Beach, which were installed during the 1980s, are reaching the end of their life. Current research on beach erosion concludes that hard defences have a detrimental, scouring effect on sand that would naturally accumulate.
Our proposal is to remove them as part of our overall strategy which also includes relocation of the existing facilities to new buildings nearby. We are currently engaging with the local community over this proposal with the aim of agreeing a plan in late spring of 2017.
Why not use more boulders to slow erosion at Middle Beach?
Although boulders reduce the impact of the waves, they result in the same scouring of the sand as gabion baskets and over time will contribute to the loss of the beach.
Would groynes, like those at Bournemouth, be beneficial at Middle Beach?
Groynes (long wooden or stone defences) are generally used to stop the movement of sand along a beach. However, where the groynes end erosion occurs as the supply of sand stops, so the problem is effectively moved further along the coast. Groynes provide no protection from easterly storms, as the waves approach parallel to the beach and draw sand out into the bay.
What do the experts say?
An independent assessment of Middle Beach was carried out on behalf of the National Trust by WSP Parsons Brinckerhoff Engineering Services and published in October 2016. You can read the full text below, along with the appendices.