EROSION ON THE TIDAL THAMES FORESHORE

Wapping  :A stroll down memory lane

It’s now been nearly 5 years since I joined the FROG (Foreshore Recording and Observation Group) within the Thames Discovery Programme. It is time to reflect on my own observation of our tidal river and how erosion has  changed the foreshore locally.

I will start with Wapping foreshore, as it was one of the first sites I visited during fieldwork in 2011.

There is a growing public and community interest for the Thames.

Community projects such as TDP, Citizan and London’s Lost waterway, give an opportunity to Londoners or anyone passionate about the Thames to participate in community archaeology, while encouraging the assessment, survey and monitoring of the foreshore.

More recently, the PLA has launched the Thames Vision project: Londoners were asked to share their views on the river in a survey, for a better understanding, to help shaping the future of our river together. Meetings with members of the public and stakeholders are about to take place in London this month. It is an exciting time ahead for anyone interested in the river use.

Overall there is a demand from members of the public to protect the historical heritage of estuaries’ foreshores and sea coastline, continually eroded by the tidal scour or the river use, when not dramatically exposed or damaged in the event of floods or powerful storms.

Monitoring the archaeology on the foreshore is the primary role of the FROG volunteer within Thames Discovery Programme. Significant archaeological sites are being washed away.

Monitoring and measuring erosion on a monthly basis creates a full and long-term picture of erosion or deposition on determined foreshore areas.

I have decided to display below some photographs I have taken during foreshore trips at Wapping between Autumn 2011 and Spring 2015. It shows how erosion is permanently changing the Thames foreshore and why archaeological remains are at risk of being washed away permanently.

River Access : Wapping Old Stairs

   Timber feature on the foreshore, near Wapping Old Stairs

 The Remains of Gun Dock

 The brick culvert near Wapping Old Stairs

 Mysterious iron wheel feature

Bankside: A photographic report on erosion

Retrospective 2011 – 2015

Bankside

It’s time for an update on what I have witnessed during countless walks on the Thames foreshore in London.

More precisely, I would like to reflect on erosion locally at Bankside, based on my own observation and my personal photographic records.

Monitoring the archaeology on the foreshore is the primary role of the FROG volunteer within Thames Discovery Programme.

In October 2011, I decided to regularly walk on the foreshore in the City near Bankside, more precisely in an attempt to monitor on a long-term basis the foreshore area between the modern Blackfriars Bridge and Southwark Bridge. A few volunteers gladly came along to help with the monitoring and assessment for a few visits, and the reports were forwarded to TDP professional team for archiving and review.

However after some time, it became difficult to organize events and a challenge to complete the monitoring of over 100 archaeological features during a low tide, due to the volunteers personal commitments and the popularity and extent of the site.

Low tide Bankside September 2012

Low tide at Bankside – area in front of Tate Modern in September 2012

The foreshore at Bankside is extremely popular, taken over by tourist guides and large enthusiast groups of members of the public and schools descending on the foreshore for beachcombing or educational tour activities. This made monitoring tasks difficult to complete. There were additional time management & health and safety issues to consider in the site visits and risk assessments.

After a year of frequent walks and visits, I had collected enough evidence for erosion at the site.

I decided that realistically I would only continue the erosion assessment with a discreet presence, compiling a photographic and digital record of significant features getting dramatically eroded on an occasional basis. Taking photographs on site to illustrate erosion is a good compromise when you are short on time and visiting on your own.

I was also certain that professional archaeologists and mudlarks were actively present in the area and that the area was well-documented.

At this stage, I didn’t set a foot on the Thames foreshore at Bankside for almost a couple of years, moving out for professional reasons and focusing on other river sites that were overlooked whenever I had a chance. I have, since then, dedicated my time working in larger volunteer groups supervised by senior archaeologists, part of a team, during fieldwork or workshop activities.

Blackfriars Bridge causeway in September 2012Causeway near Blackfriars Bridge at low tide in September 2012

So, why monitoring erosion matters? It helps define recording priorities for local archaeology community groups, assess if the access (river stairs) has changed, if the main archaeological features have changed, if new historical discoveries can be made, if new health and safety issues or potential risks emerge across the same zone.

However, the pictures gallery below speaks for itself, showing signs of erosion across the zone.

BANKSIDE – GLOBE STAIRS

Globe Stairs Picture Gallery – explanation

In October 2011 : a long horizontal timber is surviving on the last eroded step of the stairs, with consolidation block made of glass waste, concrete, etc. A couple of wooden planks fixed with big nails are fully exposed. The entire structure is probably associated with the bargebed feature nearby.

In October 2012: the horizontal timber is gone.The planks visible on the left of the stairs are gone and only the nails survive on site.The consolidation block is now scattered and most of it is no longer visible.

In May 2015 : more erosion is visible on the last step of the stairs, fragments of the consolidation block on the left are missing and more vertical timbers are exposed.

October 2012 : more vertical timbers and consolidation block made of glass/waste/ concrete were associated with the river stairs. May 2015 : not much is left.

THE VICTORIAN CART WHEELS NEAR BANKSIDE – A retrospective – 2011- 2015

December 2011: only one cart wheel was identified and exposed on site as a mooring feature near Bankside Old Stairs. October 2012 :only the chain and a vertical timber pile remain visible since March 2012. May 2015 : I was unable to find remains of the feature

In October 2011, we know this feature not far from Globe stairs on the foreshore as an ‘unclassified structure of 5 squared posts around an iron-banded roundwood post’. In March 2012, it is is now identified as a second cart wheel and was possibly re-used as a mooring feature on the site. In October 2012, the cart wheel is more exposed than ever. In May 2015, the cartwheel has been dramatically damaged by the tidal scour. It looks like it has been dug, exposing the internal features, while much wood is missing.

May 2015

May 2015 : Just realized that another cart wheel is now fully exposed on the foreshore area near Blackfriars station/ OXO Tower, in what used to be a zone mixing up concrete blocks, vertical and horizontal timber structures that could indicate an old jetty structure.

EROSION NEAR BLACKFRIARS BRIDGE

THE HYDRAULIC FEATURES

There are quite a few intriguing modern hydraulic features at Bankside foreshore. These are helpful to assess erosion on a yearly basis.

In March 2012: the above feature, which was described as a ‘foundation and well for hydraulic crane’ is made of timbers, concrete and metal structures, 3 sub-squares and 1 circular (one of the sub-squares is underwater in the picture from May 2015).

In October 2012 : one of the sub-square showed signs of serious erosion as the water has dug under the horizontal timber, now uncovered. Fast erosion could have been a result of the building works undertaken at Blackfriars Bridge for the new railway station. Pipes and drains were then becoming visible on the third sub-square (partially under water on the 2nd picture from October 2012).

In May 2015: the foundation bases of the structure and the side timber works are getting even more exposed.

EROSION ON A METAL & TIMBER FEATURE

As you can see on this mysterious feature in the area near Blackfriars Bridge, it has been naturally uncovered by the tidal scour

A CULVERT/ BRICK FEATURE NEAR BLACKFRIARS BRIDGE

Since December 2012, erosion has uncovered much of it and we can now notice a concrete or stone block ino the middle on the above brick feature : is it a culvert/ associated to sewage waste ?

May 2015 - detail of the brick work

May 2015 – detail of the brick work from the structure near Blackfriars Bridge

MORE MOORING FEATURES GETTING ERODED

EROSION NEAR SOUTHWARK BRIDGE

Near Southwark Bridge, more timber and brick foundations are exposed on the foreshore since 2011. On the river wall, since 2011, at least 2 wooden fenders have gone missing on the modern structure.

The old river stairs and causeway timber baselines beneath Southwark Bridge is getting more exposed since 2011

EROSION OF THE CAUSEWAY NEAR OXO TOWER