Palaeo-environmental Study Area P5 Bay and Haven, , UK

PALAEO-ENVIRONMENTAL STUDY AREA P5

SANDOWN BAY AND BRADING HAVEN, ISLE OF WIGHT, UK

AN ASSESSMENT OF ARCHAEOLOGICAL AND PALAEO-ENVIRONMENTAL SITES ON THE CHANGING COASTLINE OF , ISLE OF WIGHT, UK.

Plate P5 Harbour, part of a low-lying belt of land linked to Sandown Bay on the south-east coast of the Isle of Wight, UK

1. LOCATION

Sandown Bay lies on the south east shore of the Isle of Wight on the English Channel coast of southern . The shore of the bay accommodates the of Sandown. This town lies 13km south of the major seaport of .

2. MODERN GEOGRAPHY

The sandy beach-head of Sandown Bay is some 6.5km long. On the central section of this shoreline lies Sandown, a seaside resort which was established in the mid 19th century when the and the sheltered aspect of the bay were an attraction to Victorian visitors and developers. This town occupies a relatively low position and it is partially bounded by drained marshlands which border the most northerly section of the sandy shore. The attractions of the sandy shoreline were also responsible for the development of the neighbouring town of . This town occupies the southern end of the bay and it is mostly built on the top of a

1 Palaeo-environmental Study Area P5 Sandown Bay and Brading Haven, Isle of Wight, UK

sandstone cliff. The centres of the twin towns of Sandown and Shanklin lie some two kilometres apart but residential development during the 20th century has visually unified the two into a single landscape unit. A railway connecting both towns to a mainland ferry service at was responsible for the rise of a successful tourism trade in the 19th century and this still remains the key economic base to both towns. In the latter part of the 20th century an increased demand for retirement homes has also boosted the population. The total resident population figure for the two towns is now some 18,000 but in summer this is increased by approximately 20,000.

3. THE CONTEMPORARY COASTAL PROBLEM

Much of the coastland at Sandown is low-lying, the topography having been determined by the course of an earlier Holocene river system which has since been truncated by the encroachment of the sea into the bay. In the northern section of the bay the persistent advance of the sea has been well documented since a Stuart fort was lost to in the mid 17th century (Jones 1979). A measure of the the historic advance of the sea since the c.AD 1800 has also been conveyed in the modified view of Sandham Castle presented in part 1 of this LIFE report.

The shoreline management plan for the bay has divided this coastline into eight units. At the northern end of the bay units SAN 1 and SAN 2 embrace a chalk and greensand cliff-line where a policy of do nothing has been set. Where the shoreline cuts across the old palaeovalley of the a policy of hold the line begins and this is sustained throughout all of the remaining management units within the bay. Along this latter sector of the coast a beach is headed by variable bodies of storm beach shingle set at the foot of a well- maintained concrete seawall. Longshore drift is resisted by regular series of wooden groynes.

Two principal problems can be perceived on this shoreline. The indented configuration of the bay demonstrates a long history of encroachment by the sea and this is confirmed by historic observations. In the northern sector of the bay, in SAN 3 and SAN 4, the presence of the palaeochannel signifies that the coastline is particularly vulnerable. Here there are a number of buildings sited on and within the vicinity of the drained marshlands behind the seawall. This includes properties on the eastern boundary of Sandown town.

At Shanklin, development in the 1860's spawned hotels and houses at the foot of the sea cliff in a location which is currently protected by a promenade and a sea-wall. There are economic needs to hold the line along the whole of the defended coast but with sea-level rise and predictions of increased storminess two practical issues must be assessed. These are the need to avert overtopping of the sea defences and the need to predict the future behaviour of the natural buffer of sand and shingle which currently protects this coast.

4. KNOWN HISTORY AND PALAEO-ENVIRONMENTAL SETTING

Other than historic evidence covering the past three centuries little is known of the behavioural history of natural coastal processes in Sandown Bay. Maps of the late Tudor period are too imprecise to show significant difference from today’s coastline even though some notable advances coastal erosion have been noted in the 17th century. An illustration of AD 1545 suggests that the Yar estuary map may have formerly opened into the sea at Sandown Bay but this is unconfirmed. There are, however, earlier historical accounts of seasonal difficulties in crossing the valley floor between the medieval settlements of Brading and and these seem to favour a past history of periodic flooding.

5. ARCHAEOLOGICAL AND PALAEO-ENVIRONMENTAL STUDIES AND POTENTIAL

Three principal sources of palaeo-environmental information can be identified in Sandown Bay. In the off-shore zone the sediment archive in the inundated catchment of the Eastern Yar offers evidence of the local environment prior to earlier Holocene sea-level rise and coastal change. On-shore, in the drained marshland, offers palaeo-environmental evidence of the nature of the coastline after the sea has truncated the accrued sediments off-shore. Finally, where development has proceeded at the foot of Shanklin cliffs, there remains a need to retrieve

2 Palaeo-environmental Study Area P5 Sandown Bay and Brading Haven, Isle of Wight, UK

evidence which might establish when this location was last subject to wave attack. This may be viewed in relation to a possible return period. See Figures P5.1 and P5.2.

5.1 Geophysical prospection on the floor of the bay

During the closing stages of the LIFE project commercial side-scan and sub-bottom surveys were carried in Sandown Bay prior to the planning of a new off-shore waste-water out-fall. This work, commissioned by Southern Water, was followed by the sinking of geo-technic bore-holes. The geophysical prospection identified the course of a significant palaeo-channel on the floor of the bay and this was considered to be a former element of the Eastern Yar river system prior to Holocene inundation. This palaeo-channel was traced to a depth of c.-20m OD. A preliminary assessment of the core samples by Dr Scaife suggests that a fill of valley peat was accruing in this palaeo-channel in pre-Boreal and possibly Boreal times. At present it is uncertain whether further analytic work will proceed on these cores.

5.2 Palaeo-environmental investigation of coastline history from on-shore sediment archives at Yaverland

Stratigraphy of the Holocene sediments at Sandown waste treatment works

Trenching activity for the laying of pipelines on Sandown Marshes exposed a sequence of peats and sediments to a depth of some 3-4 metres. It is suggested that the sequence has accumulated primarily in response to rising sea-level during the late Prehistoric period (positive eustatic change and subsequent marine retrogression. Monolith profiles were taken which span this waterlogged sequence from upper salt marsh deposits down into possible basal palaeosol and basal sands. These monoliths have subsequently been sampled for pollen assessment and described in the laboratory.

The Stratigraphy

The profile was described as follows in Table 1 using Munsell colour charts for colour description.

3 Palaeo-environmental Study Area P5 Sandown Bay and Brading Haven, Isle of Wight, UK

Depth in cm. Colour in core 100-107 Grey (10YR 5/1) fine silty clay with brown vertical organic rootlets penetrating from above.

107-111 A darker grey, more organic horizon (10YR 4/1 or 0YR 3/1). A possible stabilisation horizon 111-185 Grey silt/clay (10YR 5/1)rapidly oxidizing to 10YR 4/2.Homogeneous but containing vertical rootlets and marine shells (cf. Scrobicularia).

185-195 Transition between overlying grey silt/clay and lower organic fen peat

195-239 Brown (2.5Y 3/2 or 10YR 3/2). Stratified monocot. peat with Phragmites or Typha reed. Some silt, vertical rootlets and occasional wood fragments.

239-249 Peat with medium/coarse sand (10YR 3/1

249-257 Grey organic silt and sand with some orange/yellow mottled sand-transition

257-268 Yellow sand with some grey mottling (10YR 4/1 or 10YR 3/1).

268-291 Predominantly yellow sand with occasional grey mottles.

Table 1 Stratigraphy at Sandown Bay, Isle of Wight, UK

Interpretation of the sediment archive

Depth of trenching and safety did not allow solid bedrock to be reached (i.e. Lower Greensand). However, the basal sediment sampled appears to represent a waterlogged, disturbed basal sand deposit. Whilst there is a possibility that this is a beach or marine deposit, the overall character appears to be that of disturbed upper material of the bedrock Greensand. A degree of grey mottling increases upwards into more organic sands which may be a palaeosol developed in the basal sands and sealed by subsequent peat formation.

A well developed highly, humified, fibrous monocotyledonous peat overlies the possible basal palaeosol at 239cm. Although this peat has a quite high detritus content, there is some evidence of a stratified structure. This includes fibrous horizons containing monocotyledonous. remains (cf. Phragmites). This peat is typical of other valley fen peat deposits in the Isle of Wight and southern England as a whole. This of course contrasts with typical acid Sphagnum moss peat typical of areas of acid bedrock and high rainfall. The depositional environment was clearly one of wet grass-sedge fen with larger reeds and possible fringing carr woodland (alder/willow).

This peat possibly formed in response to rising (positive eustatic) sea-levels which had the effect of ponding back the local river systems. This could increase the local groundwater table and create anaerobic conditions suited to the development of a fen and peat environment. Subsequently, inspite of upward peat accumulation, rising sea-level progressively overcame this and the transition of peat to grey silt/clay between 195-185cm appears to represent the onset of salt marsh and brackish water conditions and clearly in the main, grey silt/clay sediment unit between 185-111cm. This is attested by the presence of some marine molluscs (Scrobicularia).

4 Palaeo-environmental Study Area P5 Sandown Bay and Brading Haven, Isle of Wight, UK

A darker, more organic horizon (11-7cm) marks a stabilisation horizon possibly the result of lowering of sea-level or more likely due to the effects of reclamation of this low lying area.

A thin horizon (107-100cm) of silty clay with vertical roots penetrating may be overbank alluvial sediments of freshwater origin. This is, however, somewhat speculative and the saline status of this (and the other sediment units) could be investigated using diatom analysis.

These waterlogged, un-oxidised sediments are overlain by a dark red/brown heavily oxidised ?colluvial or alluvial deposits. The extreme oxidation (redness) of this upper unit has undoubtedly resulted from fluctuating water table and the high Fe content of the local Lower Greensand geology.

Potential for palaeo-geographical and palaeo-environmental reconstruction

The stratigraphical profile observed at this site (Dr. Robert G. Scaife) clearly show the effects of late Holocene marine incursion on the low lying areas of East Wight. This is similar to that discussed for Ranelagh North (Scaife, Figure P2.3). The peats and sediments exposed during trenching activities on Sandown Marshes offer enormous potential for pollen studies which could determine the ecological status of this low-lying sector of the coastline while the sea was advancing into the bay in later prehistoric times. The sequence appears to show the major effects of late prehistoric sea-level rise which caused freshwater fen development and subsequently, with continued sea-level rise, marine inundation and development of salt marsh. Radiocarbon measurements of the upper and lower peat levels are required to date the events which occurred and should form part of a future research project. However, it is tentatively suggested that these changes occurred during the Late Neolithic-Bronze Age (circa 4000-3000 BP) by analogy with data previously obtained from Wootton-Quarr. Analysis of this site should provide valuable data on Holocene sea-level changes and reconstruction of the prehistoric vegetation and environment of the coastland and the near Chalk and Greensand ridges. For these areas there is currently little available data. The position of this site adjacent to open sea rather than on makes dating of this profile interesting and important since eustatic changes may have been occurring at different times around the Isle of Wight coast. This should form part of a larger research study embracing the submerged peat filled palaeochannel which has been identified off-shore in Sandown Bay.

Summary and conclusions on the Yaverland core

The peats and sediments exposed during trenching activities on Sandown Marshes have been described and sampled for environmental analysis. The sequence appears to show the major effects of late prehistoric sea-level rise which caused freshwater fen development and subsequently, with continued sea-level rise, marine inundation and development of salt marsh. The peat and sediment which accumulated as a result of this event have potential for pollen and diatom analysis. The former would allow reconstruction of the prehistoric vegetation and environment of the near Chalk and Greensand ridges. Pollen, diatoms and radiocarbon dating together would provide valuable data on Holocene sea-level changes.

6. THE ON-SHORE ARCHAEOLOGICAL EVIDENCE FOR SHORELINE CHANGE.

On-shore archaeological evidence pertinent to coastal change can be suspected at several locations in vicinity of Sandown Bay. At Shanklin there is a need assess the history of long-term coastal processes at the foot of the cliffs. This is a location which has since been colonised by 19th and 20th century development. A helpful comparison might be drawn with the foot of the neighbouring cliff at where old stone buildings could be seen in a similar position in the early 19th century. These building have since been destroyed by rejuvenated wave attack.

Within the blanket of peats and silts in the Western Yar valley there remains good preservative conditions for the survival of both archaeological and palaeo-environmental material. This makes all drainage and other disturbances in this area appropriate activities for mitigatory archaeological monitoring. Two areas of particular interest are the valley fills in the vicinity of

5 Palaeo-environmental Study Area P5 Sandown Bay and Brading Haven, Isle of Wight, UK

Brading Roman villa and the road crossing at . The Roman villa was extensively disturbed in the 19th century yet there may yet remain assemblages of marine fauna which can shed light upon the character of the coastline in the early 1st millennium AD.

7. CONCLUSIONS ON CURRENT INVESTIGATIONS AT SANDOWN BAY

Sandown Bay is an example of a modern populated coastline where recent patterns of settlement and development have not necessarily been guided by insight gained from the past. Recent commercial disturbance of sediment archives in the on-shore and off-shore zone have demonstrated that palaeo-environmental evidence can yet be gained of the long-term history of marine advance into the bay. Unfortunately no further information can be gained until provision is made to analyse and interpret the evidence proffered by the geo-technic cores.

8. DESK-TOP ASSESSMENT SCORES

The total number of sites identified in this study area was 191. Those scoring 8 point or above amounted to 20 (see Apendix P5.1).

9. CURRENT APPROACH TO IDENTIFICATION AND PROTECTION OF THE ARCHAEOLOGICAL RESOURCE

Sites of known and perceived archaeological significance are recorded in the Sites and Monuments Record which is maintained by the Isle of Wight Council. In its Structure Plan the Council formerly upheld a strategic planning policy:

‘to seek to identify all archeological..and areas of archaeological interest and protect them from damage, decay or loss’.

This commitment to identify had formerly offered an opportunity to seek and protect sites such as those in the coastal zone which might reveal evidence of past coastal configurations and sea-level change. In reviewing and replacing its long-term planning strategies in a new Unitary Development Plan the Council has not renewed this explicit commitment to identify. The new policy appears to represent a shift or withdrawal to a narrower array interventions which can be focussed upon sites which are already known. Here, intervention could be restricted to only those sites which have prompted attention through the submission of a planning application. This shift in the strategic gathering of archaeological field data may have weakened the identification and protection of those concealed archaeological and palaeo-environmental resources which offer the potential to improve knowledge and understanding of past, present and future coastal changes. Such sites may also be vulnerable to processes and activities which lie outside the protective blanket of planning control. UK Government Planning Policy Guidance on Coastal Planning advises Local Planning Authorities that:

‘ in preparing their development plans they should co-operate in order to define ... policies for safeguarding the environment including policies for .. the protection of natural and historic landscapes and archaeological sites and monuments’. (PPG20, 4.5).

This advice, issued in 1992 also recommends that for the purpose of sound strategic planning:

‘information may be needed landscape assessments of natural and historic landscapes.. and ...sites of archaeological and built heritage interest.’ (PPG20, 4.6).

Unfortunately these recommendations do not seem to have influenced the case for retaining a policy which formerly allowed for the on-going gathering of field information on historic landscapes and sites of archaeological interest, including those with particular relevance to evolution of the coastal zone.

10. CURRENT APPROACH TO IDENTIFICATION AND PROTECTION OF THE PALAEO- ENVIRONMENTAL RESOURCE

6 Palaeo-environmental Study Area P5 Sandown Bay and Brading Haven, Isle of Wight, UK

Some sites of potential palaeo-environmental significance have been incidently noted in the gathering of archaeological field data for the Sites and Monuments Record of the Isle of Wight. There are, however, no specific expectations that sites of this kind should be noted or monitored by the local authority. Government planning policy guidance on this issue is ambivalent, observing that the Local Planning Authority may find that:

‘information may be needed on the current state of the environment and the nature scale and pace of coastal change.... and that appropriate topics may include.. earth science and other aspects of scientific interest.... (PPG20, 4.6)’.

The use of the term may in the above quoted text admits means by which precautions of this nature can be discounted according to the relative interest or awareness of individual local authorities on the coastline.

11. SUCCESSES AND PROBLEMS IDENTIFIED BY THE LIFE PROGRAMME

Despite the regional importance of this coastline this particular study area is able to show few elements of success. Off-shore and on-shore palaeo-environmental information gathered by the commercial utility agency Southern Water in the course of its geo-technic coring programme was promptly notified to the Archaeological Unit of the Isle of Wight Council. The assessment details were also kindly made available to the LIFE programme. An environmental impact assessment of the proposed off-shore pipeline also included an underwater archaeological inspection of the seabed but while this revealed cultural information it was unable to offer any additional information on the chronology of coastal change within the bay.

Problems identified in this case study principally concern those arising from the imprudent siting of 19th century seaside resort towns on the margins of sandy coasts where there is poor evidence of coastal stability. This case study has shown that in this instance there survived a small number of palaeo-environmental contexts which could offer an opportunity of securing evidence of past coastal behaviour. These opportunities have yet to be fully grasped. It is also evident in this case that the local authority has not been well equipped or well assisted in the task of recognising or interrogating archaeological and palaeo-environmental sites of this kind. It also appears that a shift in planning policy by the local authority has weakened the identification and protection of concealed resources of this nature. This offers a poor level of cost benefit where coastal planning and coastal defence still require long-term factual data to anticipate future natural changes and future community needs.

12. SOCIAL INCLUSION AND COMMUNITY INVOLVEMENT

The policies of the shoreline management plan have been published as a an information leaflet by the Isle of Wight Council and up-dates on coastal studies are regularly presented through the medium of the Isle of Wight Coastal Visitors Centre. The topic of shoreline management has also been readily adopted in the geography curriculum of all of the Island’s high schools.

13. CONCLUSIONS AND KEY ISSUES

This case study has examined an area of coastline where there is a sufficient resident population to prompt a specific need for an improved understanding of past, present and future coastal changes. The archaeological and palaeo-environmental resources proffering this information are nevertheless very poorly understood. The key issues are:-

The identification of archaeological and palaeo-environmental sites pertinent to the understanding long-term shoreline changes need to be actively pursued by local authorities in the coastal zone.

The burden of this responsibility deserves recognition and support by Central Government

Sites of this nature should not be damaged or lost by default

7 Palaeo-environmental Study Area P5 Sandown Bay and Brading Haven, Isle of Wight, UK

The regard and protection accorded to palaeo-environmental sites should be of no lesser measure than that given to the cultural heritage and the living elements of the natural environment.

In this particular instance greater cost benefit could be achieved if the Planning Policy Guidance on coastal planning (PPG20) acknowledged that

‘information will be needed on the current state of the environment and the nature, scale and pace of coastal change.. Topics should include earth science information including geology, geomorphology, palaeo-environmental history and archaeological evidence past coastal settlement, changing shorelines and environments.’

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iueP. Stratigraphy of Sandown SewageTreatment Works, Sandown Marsh Figure P5.2 DEPTH cm 300 200 100 0 (see No.5 onFigure P5.1). marine shells Homogeneous butcontainingverticalrootlets and Grey silt/clay(10YR5/1)rapidlyoxidisingto104/2. Predominantly yellowsandwithoccasionalgrey mottles. mottled sand-transition. Grey organicsiltandsandwithsomeorange/yellow Peat withmedium/coarsesand(10YR3/1). rootlets andoccasionalwoodfragments. with Brown (2.5Y3/2or10YR3/2).Stratifiedmonocot.peat organic fenpeat. Transition betweenoverlyinggrey silt/clayandlower 10 YR3/1).Apossiblestabilizationhorizon. A darkergrey, more organichorizon(10YR4/1or Oxidised alluvium/colluvium(2.5YR3/4) Phragmites (cf. Scrobicularia). or Typha reed. Somesilt,vertical