Palaeo-environmental Study Area P13 Selsey Bill - Pagham, West Sussex, south coast UK PALAEO-ENVIRONMENTAL STUDY AREA P13 SELSEY BILL - PAGHAM, WEST SUSSEX, SOUTH COAST, UK AN ASSESSMENT OF ARCHAEOLOGICAL AND PALAEO-ENVIRONMENTAL EVIDENCE FOR COASTAL CHANGE ON THE EASTERN MARGIN OF THE SOLENT REGION AT SELSEY, WEST SUSSEX, UK Plate P13 beach regrading along a shingle ridge in Bracklesham Bay, near Selsey, east Solent, UK (HR Wallingford Ltd. And Chichester District Council) 1. LOCATION Selsey Bill is a low-lying coastal peninsular occupied by a 19th century resort town. The peninsular is an southward extension of the Sussex coastal plain and it projects some 6km into the English Channel. The landscape comprises low-lying pasture and arable land seldom exceeding 5m in height (Plate P13). The soft light soils of the peninsular rest on the Bracklesham Beds, a unit of Tertiary sands which offers little resistance to coastal erosion. Selsey lies within the county of West Sussex which is responsible for strategic planning and the maintenance of environmental data-bases on the natural and historic environments of the area. The control of development and the defence of the coastline is the responsibility of Chichester District Council. There are few special designations affecting this coast. However, Pagham Harbour is an internationally designated Ramsar Site for the protection of birds and a meadow adjacent to the Broad Rife stream is recognised as a Site of Nature Conservation Interest. 2. MODERN HUMAN GEOGRAPHY The resort town of Selsey now accommodates some 10,000 residents but during the summer the population increases to 25,000 when the number of visitors is boosted by a very large 1 Palaeo-environmental Study Area P13 Selsey Bill - Pagham, West Sussex, south coast UK caravan park west of the town. Effectively, the town reached its optimum size and the present development plan shows very little new land allocated for new housing or industrial use. A major constraint is the low-lying land in the region of the old Broad Rife. This is protected by countryside planning policies and it is also highly vulnerable to flooding (Figure P13.1). 3. CONTEMPORARY COASTAL PROBLEMS The entire coast of the Selsey peninsular is naturally fronted by storm beach material which is vulnerable to natural fluctuations and depletions This coastline has been divided into three management units. On the east side of the Bill the beach is composed of shingle and sand which is strongly affected by wave-driven littoral drift. This coastline is heavily defended by groynes. There is a strong ebb current flowing out of Pagham Harbour and this has produced a large shingle delta at the entrance to the channel. The near-shore wave height varies between 3'9 and 4.7m during a 10 year period. The tip of the Bill has seawall defences and a further series of groynes. West of the tip of the Bill the shoreline is fronted by a shingle ridge which offers poor protection to low-lying land and a large caravan park. Here, the potential for wave induced transport exceeds the rate of natural supply here and the beach has tended to deteriorate. This beach is now maintained by frequent re-charge schemes and regular regrading operations. Inshore, substantial areas are vulnerable to coastal flooding and these include the low-lying margins of the old Broad Rife channel and Pagham Harbour. Particularly vulnerable is the West Beach which, without major defence works, may admit the sea to the rear of the town. This beach is already subject to shingle-loss and periodic overtopping. 4. KNOWN HISTORY, ARCHAEOLOGY AND PALAEO-ENVIRONMENTAL SETTING OF THE COASTAL COMMUNITY The coastal history of the Selsey peninsular is one of progressive erosion which can be traced with difficulty over the historic period.. General advice by the UK’s coastal protection administration (MAFF) advocates the use of old cartographic evidence to detect the progress of past coastal erosion. Unfortunately the simple ogival shape of the Selsey peninsular has not been plotted with sufficient accuracy on early maps and this makes the history of shoreline recession difficult to detect and quantify over the past four centuries. The history and archaeology of human settlement is more revealing. The archaeology of the peninsular suggests that during the 1st century BC a substantial Iron Age coastal community had established itself at the tip of the Bill at a location which now lies off-shore. During the 20th century a number of archaeological features and Iron Age and Roman artifacts have been recovered from the beach and the sub-tidal zone in this vicinity. These have included Iron Age gold coins and some other gold artifacts. Such artifacts suggest that the site may have been used for the operation of a mint. These activities might be equated with an important tribal centre such as a fortified town or oppidum. Immediately on-shore, a large Iron Age ditch has been identified leading in a seaward direction. This seems to be a remnant of an Iron Age settlement which has otherwise been lost to the sea. The establishment of a tribal capital or civitas at Noviomagus (Chichester) suggests that the Selsey community may have transferred to a new and safer site inland during the 1st century AD. It is interesting to observe that the new site at Chichester is not actually situated on the coast but lies some 2km east of the ria inlet which is known as the Chichester Channel. Such a siting contrasts with the shoreline position of Roman towns such as London, Southampton and Chester and we might suspect that particular precautions may have arisen at Chichester after a specific inundation event had occurred on the neighbouring coastline at Selsey during or before the early 1st century AD. While Chichester grew to become a successful prosperous coastal town there is evidence to suggest that the Roman community at Selsey was not entirely eclipsed. Roman buildings, putatively those of villas, have been identified at three locations in close proximity to 19th century Selsey and these attest the continued presence of prosperous rural population. After the close of the Roman period occupation continued at Selsey, the location being given a particular boost in the 7th century when St Wilfred set up a religious community at this spot. The 2 Palaeo-environmental Study Area P13 Selsey Bill - Pagham, West Sussex, south coast UK settling of Wilfred at Selsey does not necessarily suggest that this location was highly regarded at that time. Bede describes the place as Selesea, that is the island of the sea-calf and he adds that here Wilfred was granted land of eighty-seven families to maintain his company, who were in banishment. In AD 711 Wilfred’s church at Selsey gained cathedral status under Bishop Eadberht, a designation which was to continue until c.AD1075. Traces of Late Saxon goldsmith’s hoard, found in 1879 suggest that community was then a prosperous one (site 16724). During the 11th century AD there is reason to suspect a further retreat of the population from Selsey. The first hint of marine incursion comes from a neighbouring Saxon coastal settlement on the Chichester Channel at Bosham. This is a small coastal port which is undeniably the subject to the marked effects of sea-level rise and it is here that the Saxon king Canute is claimed to have delivered his commands against the advancing sea. This claim for Bosham is not, however, well substantiated. At Selsey the history of the community and diocese is less dramatic but during the episcopate of Stigand, after AD1070, the see of Selsey was abandoned in favour of a new diocese based inland at Chichester. This move accorded with a recommendation of the Council of AD1075 that episcopal seats should be transferred from villages to towns. This, and a modest return in the Domesday survey of AD1086 offers arguable evidence that Selsey was then a failing coastal community unable to maintain its acquaintance with the sea. 4.1 Historic evidence for physical changes in the coast The physical nature of Selsey during historical times is not well documented. Bede, writing in the early 8th clearly cites an island but his description could be figurative rather than literal. The configuration of an island seems difficult to reconcile with the present shape of the peninsular but this is due to the changing nature of an old sea channel which had effectively truncated the tip of the peninsular by connecting Pagham Harbour with the beach at Bracklesham Bay. Cartographic evidence indicates that from at least the late 16th century the channel was not truly open and that a link of some kind tied ‘Selsey Iland’ to the mainland at Bracklesham Bay (Palmere 1587). Nevertheless, the Tudor route to the `island’ completely ignored the link at Bracklesham and instead approached by means of a ferry. This suggests that the link was probably the product of sand and shingle accretion and was unsuited to regular or wheeled traffic. Effectively, Selsey remained isolated until the shallow tidal channel was finally cut further east by a causeway which was constructed at the ferry point in AD1809. The course of the old channel is now marked by a cut-off stream known as Broad Rife and a building which is still known as Ferry House. Prior to its unification with the mainland the configuration of Selsey island is poorly understood and this makes the prediction of further coastal change difficult to calculate. An important question is whether the long term erosion of the peninsular has been sustained or episodic. To investigate this issue it will be necessary to know how much land has been lost over a substantial time trajectory.