The Wantsum Channel separated the Isle of Thanet from the East Kent peninsular. It ran from Reculver in the northwest to Richborough in the southeast. This area is now marsh land with numerous drainage ditches draining into the River Stour, and then to the sea.
Early maps show water between the Isle of Thanet and the mainland and place names including “Ferry” point to the existence of a former expanse of water. The following gives a brief history of the disappearance of that channel.
The geological maps show the marshes to be underlain by Tidal Flat Deposits, which are young sediments, evidence of a recent silting up of the channel. The geological maps show that these deposits are about 3km wide opposite Minster which inicates the original width of the Wantsum Channel.
An analysis of borehole core samples taken from the southeastern extremity of the marshes, record an increase in the occurrence of peat deposits and their associated flora over the last few thousand years as a result of the regression of the shoreline (Long, 1992). This trend was not uniform. Reductions in peat deposits were also noted which indicated an increase in marine influence over time (a marine transgression). Two transgressions were identified, one between 4,300- and 3,900-years BC and another between 3,000- and 1,600-years BC. The dates were determined by Carbon-14 dating of borehole core samples.
The more recent stages of the regression are recorded in historical documents, either directly or by inference.
A sand bank island, “Stonar Bank”, began to develop across the south-eastern end of the Wantsum Channel at an early stage and was sufficiently well established as an island for it to be occupied in Roman times (Hearne C. M. et al., 1995). Its development restricted the southeastern entrance to the Wantsum Channel which was then only accessible via two narrow entrances each end of the island, one at the northeastern end opposite Ebbsfleet and the other to the southwest opposite Richborough. Both entrances remained throughout much of historical time.
Meanwhile, seaward and east of the Stonar Bank, the Deal Spit started to grow north across the Richborough entrance. The growth of the spit caused the Stour to be diverted northward via an ever-lengthening narrow estuary. However, it was the northern Ebbfleet entrance which eventually silted up, presumably because water flowing though it was tidal and intermittent, whereas the flow through the Richborough entrance was augmented by the River Stour.
The following paragraphs are a selection of documented events, primarily taken from Hardman F. W. & Stebbing W. P. D., (1941), which illustrate stages in the loss of navigability of the Wantsum Channel:
The Wantsum Channel provided a short-cut for boats travelling from the continent and the south coast destined for Canterbury, via the Great Stour, and to London via the Sheppey Channel. There is a suggestion that the southern passage was the preferred entrance, presumably because it was on the mainland side of the channel. The Romans clearly regarded this to be the main entrance, as it was here where they established their port and fort at Richborough serving the southern end of the channel.
During Saxon times, access into the southeast end of the Wantsum Channel was still possible via the two entrances at Ebbsfleet and Richborough. St Augustine, in 597, is said to have landed via the northern, Ebbsfleet, entrance rather than rather than via the southern Richborough entrance. Legend has it that Hengest and Horsa used this entrance in 449 or 456. Whether or not this is true, the originators of the legend clearly thought that the Ebbsfleet entrance would have been the obvious choice for their visitors. This tends at add weight to this being the favoured entrance during these times.
The establishment of the monastery at Minster around 670 seems to have been instrumental in maintaining the Ebbsfleet access as it provided the more direct access to the harbour serving Minster. However, it would hardly have been an inconvenience to sail the short distance north to Lundenwic across the channel from the Sandwich entrance. So perhaps the interest in maintaining a separate entrance at Ebbsfleet, to access Minster, is an indication that the middle of the channel was beginning to silt-up and navigation across it wasn’t possible. This is feasible, as in the process of silting up, tidal scour would have maintained navigable channels opposite the north and south ends of the Stonar Bank but not necessarily across the centre of the channel.
In the early 8th century, Bede referred to the waterway as a river which could only be crossed in two places (Colgrave & Mynors, 1969). So, at the latest, by Bede’s time the Wantsum Channel seems to have ceased being a broad expanse of water.
From the late eighth century, following several raids by people from southern Scandinavia and northern Germany, the monastery at Minster began to decline. A raid in 978 burned the monastery with loss of life and it was finally abandoned in 1009 when Kent was overrun. Without the influence of the Abbey, there appears to have been little incentive to maintain the Ebbsfleet entrance.
In 1027, Aelfstan, Abbot of St Augustine’s Abbey Canterbury (the new owner of the monastery at Minster) noted that although tides still swept in and out, the Ebbsfleet entrance was in a poor condition and of no use as an entrance for shipping. In 1052 King Harold and Earl Graham were recorded as sailing from Dover to London via the Wantsum Channel suggesting that the southern entrance was still navigable at this time.
There was a conflict of interest from an early stage between maintenance of the Ebbsfleet entrance for the benefit of the monastery’s access, and the provision of good quality agricultural land by reclamation from the sea. References to dredging of the Ebbsfleet entrance shortly after the Conquest suggests that the northern access was becoming restricted at that time. Watermills were constructed across part of the northern channel which impeded the tidal scour and promoted its silting up. Two water mills were burnt down by locals in 1266 because they were obstructing the Ebbsfleet channel. In 1313 the Ebbsfleet access was closed for the last time to prevent flooding of newly reclaimed agricultural land (Hardman F. W. & Stebbing W. P. D., 1941) so from this time onwards agriculture had taken precedence over access for shipping.
The continuing growth of the Deal Spit deflected the mouth of the Sandwich River ever further northward so that access to the remaining Richborough (Sandwich) entrance was via an increasingly long and winding estuary.
A late reference to the Wantsum Channel being navigable in the reign of Henry VIII, in the first half of the 16th century, is quoted in Graves (1850, pp188).
The first accurately surveyed maps, the mid-19th century Ordnance Survey maps, show the River Stour and various creeks, which either flow into the Stour or directly to the sea.
Andrew Coleman
Rev. 12/10/2024
References:
Colgrave, B., & Mynors, R. A. B. (Eds.). (1969). Bede’s ecclesiastical history of the English people. Clarendon Press.
Graves, J. (1850). The Bay and Town of Bannow. No. 1. Transactions of the Kilkenny Archaeological Society, 1(2), 187–193.
Hardman F. W., & Stebbing W. P. D. (1941). Stonar and the Wantsum Channel Part II – Historical. Archaeologia Cantiana, 54, 41–55.
Hearne C. M., Perkins D. R. J., & Andrews P. (1995). Sandwich Bay WWT Scheme Archaeolgy Project 1992-1994. Archaeologia Cantiana , 115, 239–354.
Long, A. J. (1992). Coastal responses to changes in sea-level in the East Kent Fens and southeast England, UK over the last 7500 years. Proceedings of the Geologists’ Association, 103, 187–199. https://doi.org/10.1016/S0016-7878(08)80229-5
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