Tuesday, May 6, 2025

The Sea Wall - our oldest civil engineering structure

 


I thought this week I should get back to describing some of the permanent built infrastructure and stuff which you can see around the Borough.  Perhaps it would be a good idea to begin at the beginning

 The oldest and very much the largest structure in our Borough is the ‘sea wall’ – and it is the called the ‘sea wall’ rather than ‘river wall’ because it is protecting us from the tidal river. For those of you who object to me saying ‘sea wall’ can I point out that on, for instance, the early 19th century Metcalf plan very clearly shows the riverbank at Deptford Creek described as ‘sea wall’.

 We have no idea how old the ‘wall’ is but without it most of our urban area would be under water and/or never been built at all. The river walls must be the largest civil engineering project in the Borough – and certainly the one with the most influence on our environment.   However it needs constant vigilance and is constantly being repaired and upgraded.

At some point in the past people began to take land from the river, and they did it by building barriers along the riverside and on the wet marshlands – ‘inning’ they called it.   There have been suggestions that the Romans were responsible but what we know about is only once written records are available.  I can remember on the Peninsula when The Dome was being built some of the blokes on one of the wharves nearby claimed to have found Roman remains among the building debris.  I don’t know if what they said is true and how they knew they were Roman or what happened to the stuff they were finding.  I have never seen mention of the Romans in any report from an archaeologist.

 Records of who was responsible for flood barriers exist only from the early medieval period.  Much serious ‘inbanking‘ was done by religious orders – abbeys and monasteries - who had the money, man power and who, as corporate bodies, could to take the long view. Earthen banks or ‘walls’ were built on the riverside. Locally there are records of work done on the marshes by Lesnes Abbey at Abbey Wood but gradually the religious bodies which had maintained the marshes were replaced, by necessity, by civil authorities or their nominees.

 How the river walls were built is not certain and there must have been local variations. They may well have been nothing more than simple earth banks, perhaps first laid on hurdles with timber pieces to stabilise it as well as mixing reeds into the earth. The land behind them was divided by cross-walls and drained by ditches. These walls were often breached and there were frequent floods in the fields. Sheep were put on the reclaimed marshes to graze and in time ‘improve’ the new land.

 The legal framework for marsh administration and maintenance of the sea wall was based on that set up for Romney Marsh. That marsh was and is protected by the Dymchurch Wall - now once again newly rebuilt.  However this ‘wall’ originated in the 13th century and has always needed professional maintenance staff.

 The lower Thames may have been embanked as early as the Saxon period. Later, because the Thames walls needed constant care commissioners were appointed to oversee the work. One early Commission was set up in 1315, known to have been a year of heavy floods, "to overlook river walls and ditches".

 Local property transactions refer to responsibilities for the river walls of the Thames and Ravensbourne from the 13th century - in 1238 a grant of marshland in East Greenwich included an obligation to maintain the walls and ditches. In 1342 and 1376 an obligation to maintain the walls were included in the Ghent Abbey's leases of their property in Greenwich and later, in 1535, by the City of London’s Bridge House for their property near Deptford Bridge. Manorial tenants who had a responsibility to repair the wall were specified in 1475 and 1481-2 and it was repaired in 1470-1 with work on fences and hedges, and this was done again in 1481-2.

 There was a series of Royal Commissions to review and repair the river banks on the south side of the Thames. The earliest known was in 1295 although there may have been similar activities for some centuries before this. Commissioners were active in Greenwich and Deptford particularly between 1378 and 1409. Breaks in the River wall were of concern and in the 14th century flooding led to a permanent loss of 60 acres of land in Lewisham and Greenwich and in 1313 and 1325 Commissioners were concerned with a break in the river wall between Bermondsey and Greenwich.

 In 1293 there was a large pond with an outlet to the Thames in the Deptford Strand area which was probably the result of a breach and it was that which eventually became the first basin of the Royal Dockyard. It is also thought that there was a break in the river wall on Greenwich Peninsula before 1600– this is the area which has been called ‘Bay Wharf; and it is where a new boat building yard has been sited.

 In 1527 there were floods in Plumstead and a ‘cross wall’ was built from the River to the village inland - enclosing and creating the marsh.  This work was paid for through a new tax - the ‘wallscot’ - which was a fund raised from the relevant landowners to pay for future flood defence systems.

 On the Greenwich Peninsula by the 15th and 16th centuries attempts had been made to reclaim and protect some of the land with sluices to draw the water away and the area made useable for farming. One main drainage outlet was Bendish Sluice which discharged into the river on the west side of the Peninsula from under the steps at Enderby Wharf and which continued to be visible until the new flats were built on site.  At the southern end of the Peninsula was Arnold's Sluice, slightly down river of Blackwall Point and probably near the Pier which the Clippers use.  There was also a nether nameless sluice west of this. Both of these are now somewhere under the Dome and the Knight Dragon estate.  The fourth, King's Sluice, was down near Horn Lane and the Ecology Centre.

 Supervision of work on the wall and ditches was often down to foreign experts - some of whom were in England to work on major schemes elsewhere - in particular work on Fen drainage in East Anglia. Work on the Plumstead Marshes was done by Jacobus Acontyus, an Italian engineer whose religion had brought him to England and in 1566 John Baptista Castillion, one of Elizabeth’s inner  household, oversaw the reclamation work on Plumstead Marsh. These ‘engineers’ of course had staff to do the actual work - like the ‘walreves’,  appointed before 1329 at Greenwich to watch over and maintain the river walls. Nearly five hundred years, later in 1800, Greenwich Marsh - the Peninsula – had a full time bailiff, with labourers working under him

 In 1546 work was done to improve the drainage of Greenwich Marsh and in the early 17th century a permanent system was set up. This was a ‘court’ was made up of landowners who levied a ‘wallscot’ rate. The minutes of the Marsh Court from 1625 are extant and can be read at the London Metropolitan Archive - although written in Secretary’s hand they are direly difficult to read.  It is perhaps also fair to say that the main subject matter concerns the growth of nettles and brambles throughout the centuries.

The river itself was managed by Commissioners from the mid 18th century; with the lower river the responsibility of the City of London and taken over by The Thames Conservancy from 1857.  Permission to open the river wall had to be got them. A local example from 1800 was William Johnson who applied to them for permission to build a causeway - some of us may remember it - which went from the end of Riverway into the River, and which was sadly removed by the New Millennium Experience Company for no apparent reason in 1998. There are also, I’m afraid, several examples of large sections of river wall being weakened as stone was stolen from it for ships and by lightermen needing ballast. There are constant complaints about their activities.

 

In October 1825 a section of the wall on the Peninsula was threatening to give way. It was decided by the Marsh Court that the Commissioners should buy it and that all landowners should contribute but that the actual purchaser should be the wealthy charity, Morden College.  Reports were obtained from leading civil engineers. The younger John Rennie said that previous work – 'a wooden framing consisting of poles and land ties' together with 'several hundred tons of Kentish ragstone' - was making it worse.  The wall would have to be rebuilt. A second report from Thomas Telford said that an exposed portion of the bank and the opening of the new West India Docks had caused the problem and that there was an imminent danger of a breach. Telford was asked to do the work which consisted of a completely smooth new earth bank with a drain at the bottom of the inner slope and the whole structure to be covered in turf. 

 

Recently in 2022 there was a public protest at the removal of willows growing on the wall and a look at Greenwich planning consents over the years will find frequent references to repair and maintenance work. Every so often there are archaeologists on the foreshore, seeing what they can find before work is done.

 

The wall is our oldest piece of infrastructure – but constantly repaired and renewed so that it is also all very new. Like the River itself the wall is always with us.

 

 

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