Why do you need archaeologists when you’re building a road?

Before construction on the A428 Black Cat to Caxton Gibbet improvements can begin, National Highways work with archaeologists to carry out investigations along the proposed route. In fact, most archaeological work in the UK takes place because of infrastructure and construction projects, such as the building of new roads or houses. This is developer-led archaeology, and that’s where we come in!

Developer-led archaeology is really important because it gives archaeologists the opportunity to excavate large areas, often including multiple sites. This means we can build up a much deeper understanding of how a whole landscape would have looked in the past. Often, we would never have made these discoveries without the development. We also then share our findings through various events and activities, creating opportunities for local people to discover more about their area’s past.

The role of archaeology in development projects is to identify, record and preserve any archaeological remains - and to share what we have found with the public! Because we carry out all of our work before construction begins, there also won’t be any unexpected archaeological finds which might cause delays later on.

But what exactly do we do? Here’s an insider guide to developer-led archaeology feat. the A428 Black Cat to Caxton Gibbet improvement scheme!

Step 1. Identification

The first thing we have to do is identify where there might be archaeology.

To do this we use lots of different types of evidence – we visit local archives to view old maps and photographs of the area. We also use historic documents and records. Did you know people have been recording archaeological finds and monuments since at least the end of the Middle Ages?

One very useful source are reports from previous excavations in the area. On the A428, these different types of evidence have given us clues as to what might be lying hidden under the fields of Cambridgeshire and Bedfordshire…

This process also helps us plan how long our excavations will take, the different methods we will use to record the archaeology, and even what work we will need to do after the dig is completed. All before we’ve lifted a trowel!

Step 2. Evaluation

Once we have identified where there might be archaeology, we carry out the evaluation stage. Using different types of archaeological survey, such as geophysics and trial trenching we can identify sites of interest within our excavation area.

We carried out evaluation for the A428 excavations in 2020. Geophysical surveys were very useful as they showed us archaeological sites which has been buried for hundreds or thousands of years. We then used targeted trial trenches to understand how much archaeology was still remaining below the surface.

Take a look at just this small section of our geophysical survey, where would you put in trial trenches?

We only excavate a small section of a site with trial trenches, because we can target areas based on the geophysics. Some of the finds we make from the trial trenches, such as pieces of pottery give us an early idea of when people were living or working at the site. And of course, some of our trial trenches have nothing in them! This helps us rule out areas which we already thought might not contain any archaeological remains based on the geophysics.

Step 3. Mitigation

The main stage of excavations in developer-led archaeology is called mitigation. Here we excavate the sites identified through the evaluation. We record finds and features and slowly begin to build up a picture of how the area would have looked in the past.

On the A428, we are even getting some early finds which indicate the people living in Cambridgeshire and Bedfordshire around 2000 years ago were accomplished cooks. In one large pit we have found what looks like the rubbish from a big communal meal, it is full of animal bone and even cooking vessels. Delicious!

Step 4. Post-excavation

Archaeology doesn’t stop when the excavations finish! There is lots more work to be done in what we call the post-excavation process. This involves everything from conserving and analysing pottery, to processing soil samples. It’s also where we make some of our most fascinating finds! Post-excavation work carried out for our first stage of excavations on the A428 (the Roman Trading Post) showed evidence that people were possibly brewing their own beer!

So archaeology is clearly a crucial part of the development process, but don’t just take it from us! Here is what Lorraine Bennetts from National Highways thinks about archaeology’s role within the wider improvement scheme...

"The work archaeologists carry out is vital to any of our road improvements, allowing local communities to engage and connect with their past through a variety of historical artefacts . As well as this, excavating before construction starts helps keep the overall programme as short as possible and helps reduce disruption for the local community."

Want to be the first to find out about developments in our excavations? You’re in luck! We’re really excited to bringing you news direct from the trenches along the A428 scheme – our archaeologists in the field will keep you up to date with the latest finds and features via social media.