Back to the Future

So we have been granted a short break from the paperwork and are heading back down to site this week. No major excavation though, just the supervisors monitoring a few small holes and a sewer heading. However it got us thinking about what we were doing this time last year… and after looking through the site photos it seems we had just started excavation in our main area of site. A year ago, I know! Although the weather wasn’t quite as nice then.

Excavation July 201

Excavation July 2012 (look how close to the street level we are!)

We also had some small areas of excavation under way elsewhere on site

We also had a few small areas of excavation under way elsewhere on site

The main area of excavation was so recently started we hadn't machined all the modern material away yet

The main area of excavation was so recently started we hadn’t machined all the modern material away yet

This wasn’t the start of the project, not by a long way – our involvement stretches back as far as 2005.

Why such the long lead into an excavation? Well, it is because of a number of reasons, but mainly because archaeologists and developers like to have as much information as possible available before beginning a project. Also this site has the added excitement and responsibility of the Temple of Mithras.  So we bet you are all wondering how an excavation like this starts life… well luckily enough we are about to tell you!

It all starts with someone deciding they want a new building, or road, or railway, or sewer, or swimming pool, any construction project in fact. And as buildings don’t last very long these days, it has come to the point where we are revisiting sites that were excavated in the not too distant past. For each project a planning application has to be made to the local authority, and their decisions to grant planning permission (or not) is guided by the Nation Planning Policy Framework (NPPF). This advises local authorities on what to consider when a new scheme is proposed, including any archaeology that may be on the site. Previously it had been guidelines PPG 15 & 16, later followed by PPS 5 that had advised local authorities how to protect ‘heritage assets’ or archaeology sites and old buildings to you and me. This policy means local authorities can impose any number of environmental conditions (not just archaeological), or sometimes none if they don’t think it is necessary. This is why archaeologists and other environmental groups can be viewed as ‘getting in the way’. Their involvement is usually imposed upon developers and they have to bear the cost. However a lot of developers, like ours, welcome our presence and the information and discoveries we can make.

So if archaeological conditions have been put on the application the land owner or developer contracts an archaeological company, such as MoLA, to complete any works that may have been specified. It may be that the local authority doesn’t have enough information about the potential historical sites and archaeology in the area, and so requests investigations are carried out before full planning permission is granted. In this case we often complete what is called a Historic Environment Assessment (HEA), Environmental Impact Assessment (EIA) or Desk-based Assessment (DBA), whereby historical maps, previous excavation work on the site and in the area, and current underground services or basements etc. are taken into consideration to assess the likely potential of finding archaeological remains or important historical buildings.

Example of an historic map

Example of a historic map

The deep foundations required for the new office building, seen here, would destroy any archaeology beneath them (c) Cementation 2012

Excavation, old skool style (c) Cementation 2012

This document would then outline any further work that needs to be carried out. Sometimes we undertake small-scale excavations, known as evaluations, prior to planning consent to ‘test’ what is under the ground, particularly in areas where we have little information or do not know how the current or previous buildings have truncated any archaeological remains. The evaluations usually take the form of small targeted test pits or trenches.

Test pit 2008

A fearless archaeologist down a very small test pit in 2008

After these investigations the information retrieved would be used to decide if any further work is needed. Sometimes the work reveals that there is limited or no archaeology left in the ground and so no further work, or only monitoring work by watching brief (whereby an archaeologist stands and watches the construction company reduce the ground level and records any archaeology that may appear) is required. Sometimes, as with our Walbrook site, it is identified that there are large areas of archaeology left in the ground and that the proposed footprint of the new building will require that material to be removed. In this case, a condition is added to the planning consent that a full-scale excavation must be carried out.

On our site and on neighbouring sites a large amount of work had already taken place. As highlighted in previous blogs, excavations were undertaken in 1952 and 1954 by Professor Grimes on the bomb-damaged area bounded by Queen Victoria Street and Walbrook, revealing the Roman Temple of Mithras. The ground reduction over a wider area of the site was monitored by Ivor Noel Hume. Looters were a problem during the groundwork and contributed to archaeologists eventually being barred from the site. In 2005 MoLA undertook a first phase of archaeological evaluation on the site, and a second phase of evaluation in 2008, where small trenches were excavated around the site to locate the temple and to find the level at which archaeology survived underneath the basement. In 2011 a trench was excavated to relocate the temple foundations and surrounding area, create an accurate location plan, and to see exactly what was left in the ground. Through the evaluation work and looking at previous excavations the developers were able to design their building sympathetically around the temple, and provide information for the project design as to where excavations needed to take place and how long they were likely to be. It highlighted areas where there was the highest potential for survival and where the archaeologists should do a full-scale excavation, resulting in the wonderful finds you have seen on here! And where there was low potential for archaeology and we should complete watching briefs. A series of Written Scheme of Investigation or Method Statements outline what we, the archaeologists, have to do, how long we have and when in the project schedule our work fits in. As with all large-scale construction projects though, this time scale can be a bit fluid!

Temple plan after evaluations

Temple plan after evaluations

Any archaeological work undertaken is monitored by a Planning Archaeologist or County Archaeologist or English Heritage. No construction work can begin until all the archaeology has been excavated.

So that is a brief (and slightly dull) look at what goes into designing an archaeology project… and why this week we will be back on site wedged in a sewer. It’s not that we love being underground in 30 degree heat, it’s that previous investigation had revealed there is potential for archaeology in the area of the sewer and we have a responsibility (and the passion!)  to record all archaeology. It doesn’t always occur in nice open area excavation…

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