CPD: Archaeology and construction projects
Our rich heritage means many construction projects are likely to encounter archaeological remains. And as Tim Malim and Andrew Townsend of SLR Consulting explain, ignore them and your scheme could become history itself.
Recording of a Victorian gas regenerator at Network Rail’s Ashburys site, Manchester, in 2012.
Archaeology is a fascinating subject, but it can quickly turn into a major headache for developers and contractors. Whether dealing with buried remains or standing buildings, not considering archaeology from the early stages of your development can have serious consequences, including delays to the programme, costly redesign work or bringing the entire construction process to a halt. There is also the risk of long-term reputational damage if things go wrong. So alongside other environmental considerations, archaeology should occupy a prominent place in the risk management of your project.
Most archaeological work in the UK takes place within the planning system, prior to submission of a planning application, before determination of that application, or afterwards as a condition of the consent, and is often part of a legal agreement/obligation.
In certain cases, usually with large projects, an environmental impact assessment (EIA) will be required, which would assess the potential impact from development on the physical historic environment and also intangible heritage, collectively called “cultural heritage”. This EIA process might need to undertake, and incorporate the results from, archaeological site investigation to identify any significant effects.
Archaeology follows a staged approach which can be directly correlated with RIBA’s Plan of Work (see Table 1 below). Inclusion of these archaeological stages at the right point within the design and construction process will ensure integrated project planning, reduced risk to project timetable and budget, and will enhance the management of health and safety on site.
Failing to carry out the full requirements of the archaeological work could lead to problems in having the planning conditions discharged by the local planning authority (LPA), or in some cases could constitute a criminal offence. It is therefore essential to integrate archaeology into the project programme and employ professionals to achieve correct standards.
Archaeology and the historic environment
Buried archaeological remains and above-ground historic features are collectively called the “historic environment”. Individual features of the historic environment are known as “heritage assets”. These include buildings, parks and gardens, battlefields, monuments and buried archaeological remains. Nationally important heritage assets often receive a degree of legal protection such as listing or scheduling. These are known as “designated heritage assets”. The presence of designated heritage assets, or other nationally important remains that might be “spot designated”, should be a key consideration when assessing land for development.
The historic environment of a development site will often include adjacent land and adjoining features. Your site could be part of a conservation area, or lie within a world heritage site. Less tangible, but no less important than physical elements of the historic environment, is the setting of heritage assets, and if the visual aspects of the site are considered to be significant in historical terms.
Such factors would be taken into account by the LPA when processing applications, and could prevent or restrict development. Any impact on the historic environment will have to be balanced against the public benefit that the development would bring and, if consent is granted, would usually require some form of mitigation involving archaeological fieldwork.
Construction-related archaeological fieldwork
The archaeological methods and techniques can be either “intrusive” or “non-intrusive”. Non-intrusive work (or survey), can be undertaken at the site itself, remotely, or through a combination of on- and off-site techniques. A typical example is the preparation of a heritage statement or an archaeological desk-based assessment (DBA), but it could also include recording buildings or general site-survey work.
Where possible, it is useful to combine archaeological work with other investigative operations such as archaeological monitoring in combination with geotechnical surveys as this can provide valuable information for use by the rest of the professional team and for the regulator in deciding the planning application. In general, non-intrusive work will take place before an application to develop land is submitted (RIBA stages 0–3) and the findings used as supporting evidence to aid the planning authority in reaching a planning decision.
Finding a tiled floor during trial trenching
Intrusive investigation (RIBA stages 3–5) takes place at the site either pre-determination or as a result of a condition on planning consent, and will usually entail ground disturbance. Archaeological excavations comprise site investigation works (evaluation or trial trenching), “full” excavation as mitigation, or watching brief, or a combination of these.
Existing buildings on a development site could be heritage assets, which might require protection during the construction work or recording prior to renovation or demolition (RIBA stages 3–5). Buildings, parks and gardens can be included if they have special local architectural/historical interest. Such “locally listed” features will be considered by the LPA when deciding planning applications and need to be identified alongside other significant heritage assets. It is important to ensure that resultant archaeological work or conservation measures are built into the overall construction programme.
The more information that can be obtained about a site during the project planning and design stage (RIBA stages 0–3), the more chance there is of capturing and managing risk, especially where buried features are concerned.
A DBA for the historic environment is one of the first steps towards identifying archaeological issues and will often be carried out alongside studies being undertaken by other disciplines such as ecology, land quality and ground stability.
Sometimes it will be useful to undertake geophysical survey work to
aid in the assessment of the site. Information obtained during the DBA and geophysical survey can also be of use to other members of the professional team such as those responsible for ground engineering.
The DBA and geophysical survey, however, should not be used as a guarantee of the presence or absence of archaeology on a site. Studies that lack thorough research could result in a report that is misleading. Using the services of an accredited organisation should ensure a study that can be used with confidence.
Site work (excavation)
An archaeological DBA might result in the need for a field evaluation (trial trenching) on the site. This is usually carried out before a planning application is submitted or determined, and is chiefly used to ascertain the presence of archaeological remains at a development, their character, date and likely extent. This information is used by the LPA to help decide whether planning consent should be granted.
Where consent is granted, the LPA might attach conditions for further archaeological work to take place on the site, which could entail mitigation excavation for targeted features or large areas, and/or an archaeological watching brief (monitoring of construction activities and inclusion of a stopping brief so that archaeological investigation and recording can be undertaken if remains are discovered during construction activities). This would correspond with RIBA stages 4–5.
The LPA might require important archaeological remains present on a site to remain undisturbed in situ, (avoidance mitigation strategy, frequently called conservation measures or preservation in situ) or building over/around them in a manner that they are not harmed (known as an engineered mitigation strategy).
Where there are important archaeological remains on a development that have to be avoided or engineered over/around, it is useful to gain information about this at the earliest possible opportunity so that this can be “designed in” to the project. In some cases, the presence of highly significant heritage assets on a site (such as previously unidentified nationally important remains, or human burials) could prevent development altogether.
A major element of any archaeological project will be the work required after the site work has been completed, generally known as “post-excavation” (RIBA stages 6-7). This can take up a large part of the overall budget and take longer than the site work, especially if much specialist work is required.
A prehistoric log-boat
The post-excavation archaeological work is normally part of a planning condition and will vary according to the nature of the work being undertaken. A typical programme of post-excavation work would initially include processing of the finds and site records and assessment of the samples/records gathered during site work, so that a statement on the potential for analysis and resourcing requirements can be output as a Post-excavation Assessment and Updated Project Design (PXAUPD) document.
This report allows agreement between the client, the archaeological supplier and the LPA over the extent of analysis and reporting. The post-excavation programme would then continue with specialist analysis (for example pottery, stone tools, wooden objects, food remains, metallurgy, or ecofacts — organic material that reveals details about the past environment). The next stages would be further comparative research, interpretation of the integrated results of analysis, production of a report, publication, dissemination of the results, indexing, organisation and deposition of the site archive at an approved repository (museum), obtaining transfer of title from the legal owner (developer or landowner) and any conservation work on the finds.
As with the archaeological site work, it is vital that the post-excavation programme is factored in to the overall development programme and advice should be sought by the project design team early on in the planning process.
Commercial archaeology in the UK is generally unregulated, which means that there are presently no professional barriers to entry for setting up as an archaeological company. The Federation of Archaeological Managers and Employers (FAME) and the Institute for Archaeologists (IfA) are the two principal organisations for the commercial sector of archaeology, but membership of either is not compulsory to practise archaeology. Organisations and/or individuals accredited by the IfA are, however, required to comply with its professional code of conduct.
Compared to other elements of the construction supply chain, the commercial archaeology sector is relatively small, with some 3,500 archaeologists employed in the UK. There are a small number of large organisations (with more than 100 employees) who operate on a national basis, a greater number of regionally focused organisations of medium size, but the majority comprise small organisations, often operating as sole traders. All of these can maintain professional standards, but some archaeological projects could require very specialist work, or large amounts of labour, that smaller companies might not be suited to.
The importance of achieving high professional standards for all types of archaeological work cannot be overstated. Benchmark standards for archaeological work established by the IfA are commonly stipulated in a brief issued by an LPA archaeologist in response to a planning condition and written scheme of investigation issued by an archaeological contracting unit in response to the brief.
Procurement protocols and contractual arrangements for commissioning archaeological work are often poorly defined. The Institution of Civil Engineers (ICE) published Conditions of Contract for Archaeological Investigation in 2004, but appointments are more commonly via letter or email, which leaves the appointee in particular exposed to risk. FAME has produced a document – The Procurement of Archaeological Services: Guidance and Best Practice for Managing Risk – and it is advisable to adopt a sound procurement protocol for archaeological work on your project such as that recommended in this guide.
The IfA publishes a yearbook and directory containing member details and registered organisations and is in the process of producing a client guide. Before appointing, check the professional status of an individual or organisation through the IfA, as an “approved list” held by other organisations does not guarantee professional accreditation.
As with fee proposals and quotations received from other subcontractors and suppliers, evaluate tenders for archaeological work, ensuring they include all that is required by the LPA. This will usually include publication and dissemination of fieldwork results.
Tips for archaeological work on developments
- The sooner any potential archaeology on your site is considered, the greater the chance of mitigating risk in later stages of the project, for example before land or property is acquired or other commitment is made.
- Undertake studies and site investigation at an early stage, in the same way as early topographical, geotechnical, ecological, land quality, flood risk, hydrology, highways etc.
- Pre-application discussions with a commercial archaeological organisation and/or the LPA help in identifying heritage constraints and means to mitigate the impacts of the proposed development on them.
- Establish a procurement protocol for the archaeological work such as that developed by the Federation of Archaeological Managers & Employers (FAME).
- Engage the services of an accredited archaeological organisation, preferably one registered with the Institute for Archaeologists (IfA) that will undertake all the work to recognised professional standards.
- Treat known and potential archaeology, on your site as a project risk. Do not assume nothing is there, or that it would have been destroyed by modern activities. Never leave commissioning archaeological assessment work until a planning application has been submitted.
- When commissioning work such as a geotechnical investigation, include an archaeologist to observe the operations as this could provide valuable evidence for use later in the planning process.
- Where there are conditions for archaeological work attached to a planning consent, ensure that the full scope of work required to satisfy them is fully understood and their implications included in project planning and budgeting. “A programme of archaeological work” can be applied to different types of work. Ensure proper evaluation of tenders for archaeological work.
- Ensure that the “post-excavation” element of the archaeological work has been fully resourced, including provision for publication.
- Consider the public relations value of the archaeological work being commissioned in terms of what it contributes to local historical knowledge and the way it can enhance the sense of place for the local community. This could involve open days, participation of local people in the work and permanent displays (at the site or in the public realm
such as a local museum).
- Consider taking out archaeological risk insurance.
Tim Malim is technical director for archaeology and heritage at SLR and also chair of FAME. Archaeologist Andrew Townsend MCIOB is an associate (archaeology) based at SLR’s Bristol office and a CIOB Ambassador.
Table 1: RIBA Plan of Work 2013 and archaeological 'stages'
|Strategy||Brief||Concept||Definition||Design||Build & Commission||Handover closeout|
||Preparation and brief
||Technical design||Construction||Handover and closeout|
|Archaeology stage||Due diligence, options appraisal
||Heritage statement, pre-application validation process
||Defining scope of work
||Assessments: desk-based, site investigation (evaluation), heritage significance, magnitude of impact
||Mitigation design||Implementation of mitigation design, conservation, programme of archaeological work, excavation recording||Preservation in-situ, post-excavation assessment, updated project design, analysis, report|