Notes on Semi-Circular River-wall Buttresses

These observations are based on photographs included in the Thames Discovery Programme Flickr collection. Both sites have previously been investigated by Museum of London Archaeology as part of developer funded projects.

Buttress at Thames Wharf

The first buttress is located at Thames Wharf. There is a marked difference between the embankment walls up- and down-stream of this buttress; in particular at the height to which they were first built (i.e. just below the concrete blocks which were used to raise the height more recently), the tops are finished in completely different ways. Upstream it is finished in what appear to be grey engineering bricks laid as a line of headers over stretchers; downstream these two brick courses are replaced by what appear to be long granite coping stones. On the downstream side the buttress does not appear to be bonded into the embankment wall, there appears to be a distinct crack separating the two. On the upstream side there is no such crack and the bricks of the wall and buttress seem to be bonded (based on alignment of the mortar courses) suggesting that this wall and the buttress were a single phase of building. The buttress seems to taper towards the top, sloping sharply back to meet the embankment wall 8 or 9 brick courses below the coping stones.

Buttress at Thames Wharf, photo by Nathalie Cohen

There is no obvious need to strengthen the walls with a buttress at this point nor does it have an obvious functional purpose (for example, the taper would suggest that it is not a base for a crane). A possible explanation is that this structure is a means of demarcating the end of one length of riparian (or river bank) ownership from another. If this is correct it would have been built by the owner of the upstream wall. Historical records may show whether there were changes of ownership at this point – there may even be different names for the upstream and downstream wharfs.

If this is indeed the sole purpose of this structure it raises some questions: Why was it so massive and why was it semi-circular? Answers to both questions can only be matters of speculation. As a point of separation between two different wharfs it would be useful if it was big enough to be readily seen and recognised from the river by boats heading for one wharf or the other. A simple timber post would not be adequate since this would not be so very different to the timber rubbing posts or strakes which line many of the wharfs. If it is correct that it has to be big in order to be seen then making it curved has two advantages:

1. It is better than an angled shape from a hydrodynamic point of view – fewer eddy currents are created and thus there is less erosion on the adjacent walls and the buttress itself.

2. Boats and barges which collide with it will tend to be deflected – with un-powered craft being manipulated with sweeps, poles and ropes when mooring and leaving the wharf this is not a trivial consideration. Of the two advantages the second is probably more important than the first.

Buttress at Hammersmith Embankment

The second buttress is at Hammersmith Embankment, shown in the image below. There are two buttresses, one semi-circular and the other rectangular, either side of a blocked arch. Surrounding the arch is a second arch, seen most completely on the upstream side. The area between the two arches is infilled with brick and directly above the centre of the lower arch are two almost identical stone plaques. The plaque on the upstream side is engraved ‘HP 1865’ and the downstream one ‘FP 1865’. A little above the higher arch on the upstream side is the end-flange of an iron pipe with a chain hanging from it.

Photo by Andy Chopping

The site is at the boundary between the historic parishes of Fulham and Hammersmith, demarcated by Parr’s Ditch which flowed into the Thames. Most sources say that this ditch, which is mentioned as the boundary in medieval documents, was entirely man-made but a few suggest that it might have followed natural channels. Nicholas Barton, in his book The Lost Rivers of London, suggests the former but then hedges his bets by showing a dotted line linking Parr’s Ditch to the natural Stamford Brook.

The interesting thing about Parr’s Ditch is that Barton says that it remained open until 1876, when it was converted into a sewer yet the date on the plaque shows 1865. It would therefore be worthwhile doing a careful study of the build sequence on this bit of wall. Barton also notes that i“n the low-lying areas there are pumping-stations to pump storm water out of the sewers into the Thames: these are situated at the mouths of Parr’s Ditch …” The iron pipe may have had something to do with this.

The buttresses here may have had exactly the same purpose as the one at Thames Wharf – to demarcate lengths of different riparian ownership. The relatively short length of embankment wall between the round and the square buttress, (the exit for Parr’s Ditch), would be an area of joint responsibility for both parishes. Downstream of the square buttress would be either just Fulham’s responsibility or that of a private riparian owner. Upstream of the semi-circular one would be the responsibility of just Hammersmith Parish or a different private owner. Mid-19th century parochial records might confirm or refute this explanation.

Here the reason for one being round and the other square might just be a desire to assert difference. In the modern streetscape for example, neighbours in identical terrace houses paint their doors different colours; neighbouring borough councils have different coloured bin wagons.