Case Study Site 2 – Poole Harbour and Studland, Dorset









Case Study Site 2 – Poole Harbour and Studland, Dorset

1.         Location

The case study site extends from Canford Cliffs to the west of Bournemouth southwards to the southern end of Studland Bay; it also includes Poole Harbour and Brownsea Island within it. 

2.         Why was the Case Study Site selected?

This case study site is of interest because it illustrates the impacts of coastal erosion and cliff instability on heritage assets at Canford Cliffs, together with new approaches to coastal management affecting environment and heritage sites owned by the National Trust at Brownsea Island and Studland beach. 

3.         Summary of the Geology, Geomorphology & Coastal Processes

The whole of this case study site lies within sand, silt and clay formations of the Bracklesham and Barton Groups of the Eocene epoch.  In terms of sediment transport the prevailing direction is from west to east between Poole Harbour and Bournemouth, although there is some movement in the opposite (anti-clockwise) direction; beach sediments are also accreted from material being driving onshore.  Within Poole Harbour, again the general trend is from west to east, with inputs from the Wareham Channel and Lytchett Bay in the west.  Sediment circulates general from west to east along the south coast of Brownsea Island whilst erosion around the shores of the harbour contributes sediment to the overall system (Royal Haskoning,20111). 

4.         Risks to Heritage Assets along the Case Study Frontage

Between Canford Cliffs and Poole Head retreating cliffs, as a result of coastal erosion of the soft sands and clays, have led to the loss of both Simpson’s Folly at the foot of the cliff and a ‘Martello Tower’ on the eastern side of Canford Cliffs Chine (Figures 2.1 - 2.3).  

Figure 2.1: ‘Simpson’s Folly’ was built at the foot of Canford Cliffs near Bournemouth in 1878.  Insufficient consideration was given to coastal erosion and the property had to be demolished soon after its occupation.

Image Courtesy: Private Collection. 

Figure 2.2: The remains of ‘Simpson’s Folly’ remained on the shore for many years until it was incorporated within a new promenade. 

Image Courtesy: Private Collection. 

Figure 2.3: The tower on the cliffs, which succumbed to coastal erosion despite having been located further from the coast. 

Image Courtesy: Private Collection. 

In Poole Harbour, Brownsea Island contains Brownsea Castle, originally a fort constructed by Henry VIII between 1545 and 1547 to protect Poole Harbour from French attack (Figures 2.6-2.8).  In 1726 the castle was converted into a private residence and, together with adjacent historic properties, occupies a waterfront location on the Island’s southern shore (National Trust, 19932). 

Figure 2.4: ‘Poole Harbour’ by William Daniell RA, an aquatint engraving produced in 1825.  Although Daniell said that Poole’s buildings ‘did not bear much beauty’ many still exist such as the Grade I Woolhouse or Town Cellars, which is incorporated in the Watersfoot Museum complex. 

Image Courtesy: Private Collection.

Figure 2.5: The artist David Addey retraced Daniell’s tour of the south-west coast of England and painted this watercolour from the same spot at Constitution Hill in 1990.  This view shows the extensive harbourside development that has taken place. 

Image Courtesy of David Addey.

Figure 2.6: ‘Brownsea Castle’ – a nineteenth century engraving of this much illustrated building.  Brownsea Island is in the ownership of the National Trust.

Image Courtesy: Private Collection.

Figure 2.7: A close view of Brownsea Castle, which dates back to 1548.  The Castle had been extensively remodelled during the nineteenth century. 

Image Courtesy: Private Collection

Figure 2.8: A detailed watercolour of ‘Brownsea Island’ by the Pre-Raphaelite follower, William Buck, c.1870s.  Buck was renowned for his detailed and accurate observations of the coastlines of the Isle of Wight, Hampshire and Dorset. 

Image by kind permission of the Russell Cotes Museum and Art Gallery, Bournemouth.

Seventeen properties on Brownsea Island are currently at risk of flooding in the vicinity and this number is likely to increase by the end of the century although existing defences limit the annual risk of flooding to less than 5%.  The approach to coastal management at Brownsea Island represents an example of the National Trust’s national planning policy for coastal change and a locally focused adaptation strategy for the future management of the Island based on the Shoreline Management Plan recommendations (Royal Haskoning, 20111).

Within Poole itself there are numerous Listed Buildings particularly in the Old Town, Quay and High Street Conservation Areas. Poole Quay has been subject to overtopping and since the 1950s it has been raised several times. Replacement with a new wall is now under consideration (Environment Agency, 20143A). The old quayside is depicted in numerous paintings with fine examples in the Poole Museum collection.

The Studland Bay frontage (Figures 2.11-2.14) has been included in this case study because, although there are no heritage assets in the immediate vicinity, the principles being established through the National Trust’s approach at Swanage are likely to become more widely applied, in line with current government guidance, which is aimed at managing coastal change through taking a long-term perspective and working with natural processes (National Trust, 20144; Environment Agency, 20143B).  This policy has heritage implications elsewhere across the CHeRISH case study sites such as Mullion Harbour in Cornwall. 

Figure 2.9 (left): ‘Shipping in Poole Harbour’ by Herbert Kerr Rooke.  Oil on Canvas.  1900. 

Image Courtesy of Torre Abbey, Torquay, Devon/Bridgeman Images.

Figure 2.10 (below): ‘Poole Quay on a Busy Day with Ships and Figures’ by Bernard Finnigan Gribble.  Oil.  C.1935. 

Image Courtesy of Borough of Poole Museum Service.

Works of this kind provide a detailed visual record, in colour, of the changing Poole Harbour waterfront through the twentieth century providing physical, heritage and social detail.  The Quay has flooded occasionally and proposals to reduce flood risk are currently under consideration.

Figures 2.11 and 2.12: The watercolour by Alfred Robert Quinton (left) was painted c.1920 and looks north along Studland Beach.  Here the beach has been accreting towards Poole Harbour entrance.  The present day view is shown below. 

Image Courtesy of J. Salmon Limited of Sevenoaks.

 

Figures 2.13: In this view looking south along Studland Beach by Quinton Handfast Point can be seen in the distance.  The beach here has been subject to significant coastal erosion and has necessitated changes in future management by its owner, the National Trust.  Figure 2.14 (below) shows the view in the 1950s. 

Image Courtesy of J. Salmon Limited of Sevenoaks.

5.         How can historical Imagery inform heritage risk management?

Along the Canford Cliffs frontage two examples of the impacts of coastal erosion and cliff instability on heritage are illustrated. In 1874, a landowner, Captain John Hawkins Simpson, decided to build a row of seaside villas on the shore at Canford Cliffs between Flaghead Chine and Shore Road.  Having obtained the permission of the landowner, and of the local authority the first of these houses was built (see Figure 2.1).  The square flat-roof structure took four years to build and was completed in 1878 with a large seawall protecting it.  However, the house had been built on a foundation of clay and sand and the sea quickly washed under the defences, making it unstable.  The foundations were undermined and Captain Simpson was forced by the local authorities to abandon the property within weeks of its occupation.  The property stood empty and the sea continued to undermine the property (Figure 2.2). By 1889 the whole property was collapsing.  Poole Corporation ordered the demolition of the building for safety reasons and in 1890 the local authority blew up the remains of the property with gun powder.  A high pile of concrete blocks and rubble was left in this location for many years until, in 1957, Poole Corporation was given the foreshore, and between 1960 and 1961 they constructed a promenade between the Shore Road promenade and the one at St Anne’s, incorporating much of the rubble in the foundations of the new promenade, which was completed in 1962. 

A structure known as a ‘Martello tower’ was situated on the eastern side of Canford Cliffs Chine; the stone for its construction is reputed to have been imported from Beaulieu Abbey.  In fact, this structure was not a defensive Martello tower but was actually a gazebo/folly built in 1857 for Sir Charles Packe of Branksome Park.  It was used as a smoking room for the owners of the Canford Cliffs Hotel in the 1930s, before serving as staff quarters for a time.  It gave its name to a magnificent Edwardian house, Martello Towers, which was subsequently demolished to make way for the present block of flats.  Although the old tower had been moved back previously from the retreating cliffs, eventually it succumbed following a cliff fall.  These case study sites illustrate the vulnerability of properties constructed too close to eroding or unstable cliff lines.  Although the tower had been relocated, this was insufficient to save it from further retreat of the sea cliff (Figure 2.3). 

Brownsea Castle and the other historic buildings located along the southern waterfront of the Island are defended by modest seawalls and other structures, which are largely suitable for the more sheltered environment within Poole Harbour (see Figures 2.6-2.8).  However, studies undertaken by the National Trust and others have indicated that there is a residual flood risk, which is likely to be exacerbated as a result of sea level rise over the next century.  The Trust has implemented a policy of ‘hold the line’ for the historic frontage, whilst allowing around the remainder of the Island’s coast natural coastal processes take their course.  The need for effective maintenance and possible future improvement of flood defences is highlighted at this location.

Within Poole Harbour itself Poole Quay has a great maritime history, which has been illustrated by many artists. Their works often show the many historic building, which line the waterfront. Fine examples of detailed oil paintings exist showing gradual changes through the twentieth century as trading and development patterns have resulted in adaptation of many of the buildings (see Figures 2.9 and 2.10).

At Studland Bay the beautiful beach has been particularly popular with tourists for decades.  As sea levels rise and weather patterns become increasingly unpredictable, it is unlikely that sufficient funds will be available to maintain locations such as Studland. Therefore, the National Trust has developed a national plan for coastal change, and a more locally focused adaptation strategy for the future management of the coast at Studland, which involves ‘no active intervention’.  Comparison of the watercolour drawings dating from the late nineteenth and early twentieth centuries with the present day photographs show how Studland’s beach has continued to grow at its northern end near the entrance to Poole Harbour, whilst at the southern end coastal erosion is particularly active (Figure 2.11-2.14).  This erosion process will continue and may increase, and inevitably result in the loss of space currently occupied by tourism facilities, such as the National Trust’s current visitor at Studland.  It has been recognised that the maintenance of such assets is not always practical in the longer term, hence the adoption of the ‘no active intervention’ strategy. 

6.         Key Issues – What can be learnt from this site?

In terms of the cliffed frontages a thorough understanding of coastal processes and the rate of change is essential for the safe and sustainable management of cliff top heritage assets.  For locations prone to flooding, suitable strategies for protection of assets such as those on Brownsea Island involves not only an understanding of the likely rate of change in sea levels and the impacts of storm surges and storm events, but also a necessity for funding to carry out necessary flood defence improvements in the future. 

Policies for adaptation to coastal change, such as those being implemented by the National Trust at Brownsea Island and Studland Beach, are likely to be adopted more widely by necessity around the English coast.  Long-term adaptation strategies are, therefore, likely to be required with implications for other heritage sites in the south-west particularly where maintenance of defences is no longer practical or economically justifiable.

7.         References

1.         Royal Haskoning & Bournemouth Borough Council, 2011. ‘Poole and Christchurch Bays SMP Review’.

2.         The National Trust, 1993. ‘An Illustrated Souvenir of Brownsea Island’. 30pps.

3A.      Environment Agency, 2014. ‘Poole Bay, Poole Harbour & Wareham Flood and Coastal Erosion Risk Management - Final Strategy’.

3B.      Environment Agency and Partners, 2014. ‘LICCO – Living with a Changing Coast’. Final Report of the Interreg IV Project for the European Commission.

4.         The National Trust, 2014. The Residents’ Guide to Coastal Change in Studland’. Case study report from the European Union ‘LICCO’ Project.47pps.