Our understanding on the arc of history around hidden hydrology is informed with maps and accounts from early explorers and settlers to areas, augmented with records, diaries, and oral histories. Often this neglects and misses the valuable stories of indigenous inhabitants of areas, and leaves us with a significantly shorter timelines for reference. The role of archaeology is vital to unlocking the layers of hidden hydrology that don’t emerge from these illustrative written histories, so I was really intrigued with a recent tweet from the Museum of London Archaology (MOLA) (Twitter: @MOLArchaology) that told of their current work, called London’s lost river: the Tyburn. From their site, the project is the result of “…a team of expert geoarchaeologists whose work is helping us to understand London’s lost rivers. As an educational charity, we want to share what we’ve learnt, so please join us to explore the story of this long-lost river.”
Using the interactive ESRI Story Map, MOLA developed a narrative to describe the process and some of the key findings. Much of the work is conducted along with construction sites, which gives an opportunity to look below the surface while excavation is happening. The River Tyburn flowed on the north bank of the Thames, and most famously, was routed and defined the space called Thorney that Westminster Abbey was located, seen in this view circa 1530.
The origins of the river are tied to the longer history of the Thames, which is illustrated (see header image) and reaches back to the last glacial period of 11,500 years ago. From there in, “…this new epoch, known as the Holocene, the Thames began to take the shape we know today, but many channels still criss-crossed the river’s floodplain within the wide gravelly valley. One of these channels was the Tyburn, which flowed into the Thames.” In this zone, there are hundreds of sites, or ‘deposit logs’ that are recorded, and these are modelled to create a snapshot, particularly focusing on the depths of land (depicted below as green – high ground and purple – low ground. From this model, “projected possible courses for the River Tyburn, following the lowest-lying areas of the modelled 11,500-year-old topography.” with a caveat that “the river would have migrated over time.”
Drilling down (literally) into the specificity of the deposits shows the ranges of material and how it can inform, looking at “ancient flora and fauna” and focusing on things like Diatoms, Pollen, and fossils of things like “Ostracods, the remains of small crustaceans, can indicate salinity, water depth, temperature, water acidity/alkalinity”.
Below is “…a cross section, or transect, running north–south from Westminster to Vauxhall Bridge, along the north bank of the Thames. This connects deposit sequences recorded in trenches and boreholes, and helps us look at these sequences over wide areas.”
They also connect their study with the work of Barton and Myers 2016 book ‘The Lost Rivers of London‘ (see here for a post on the same), which speculated on a number of scenarios for the Tyburn, and various routes. There’s some graphic things I’d change here (namely it’s hard to read the Barton and Myers layers) but the concept is interesting, to overlay varying studies and ‘proof’ the concepts of routing. In essence, does the data reflect the speculation on routes, either reinforcing or disputing what was speculated? The below map is a composite of this
There’s links to some coverage in London Archaeologist, such as a 2014 article in which “… Tatton-Brown and Donovan used historic documents and maps to suggest that the medieval waterways separating Thorney Island from Westminster were man-made and that the Vauxhall Bridge route was the original and only course of the river.” The 3D views of the route and the illustration of the provide a speculative view of the area. From the site: “Our topographic model supports Barton and Myers’s suggestion that discussing two distinct branches (towards Westminster and towards Vauxhall Bridge) is an over-simplification of what was probably a more complex delta-like network, as shown [below] (artist Faith Vardy). This geoarchaeological study provides a baseline for reconstructing the evolving landscape; when combined with historical records and archaeology, even more detailed models could be created. The research done by others, such as Tatton-Brown, which focuses on later periods, may be supported by geoarchaeological work undertaken in the future.”
The concept of geoarchaeology is pretty fascinating as well, and worthy of some further exploration. In the interim, you can check out the MOLA site for what their team does, which focuses on using “…auger or borehole surveys and interpret the archaeological soils and sediments retrieved, allowing us to reconstruct past landscapes and environments.” The reason for this particular subset is to pick up “…where the archaeology is too deeply buried for traditional excavation techniques to succeed. It is also a cost-effective archaeological evaluation tool and geoarchaeological deposit modelling, which maps buried landscapes and deposits.” This is relevant as the surface remnants of these, but the underground deposits, so they work in a “…wide range of depositional environments, including alluvial floodplains, fluvial environments and estuarine/intertidal zones. Using palaeo-environmental proxy indicators, such as pollen and diatoms, we reconstruct past environments. Our specialists also use a range of sedimentological techniques.”
These techniques don’t answer every questions, but coupled with expertise and interdisciplinary research, enables us to see further, and deeper than previousl. The role of archaeology and geoarchaeology in hidden hydrology is vital, as shown above. While we often rely on maps, photos, sketches, and written histories to reconstruct places,
HEADER: Artist’s reconstruction of a cold climate, braided river, such as the Late Glacial Thames (artist Faith Vardy) – via
An interesting tidbit on this was discovering the amazing Lakes of Washington by Ernest E. Walcott published in the early 1960s which was the basis for much of the bathymetric info included on the King County site and other resources. I’ll expand on at a later date, but in that vein, while outside of the city proper, the range of bathymetric maps, 
Many maps come via 
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And speaking of other non-historic maps, not specific to hidden hydrology, I’d be remiss without mentioning the New York version of Rebecca Solnit’s atlas collection 
image – Ghosts of Minnesota
