EIA and archaeological risk management
Rachel Morse from Mouchel describe how to manage the risks posed to a development by the potential discovery of archaeological remains
Buried archaeological remains rarely prevent development, but it can come as a surprise and can cause delays to the overall development programme and bring unplanned costs if not managed from the early stages of any scheme.
Known unknowns
The risk that the archaeological resource poses to development lies not in what is known, but what is unknown.
The environmental impact assessment (EIA) process provides the framework within which the likely significant effects of a scheme on known cultural heritage resources are identified and reported in the environmental statement.
The EIA process does not, however, assess archaeological risk or a means of managing that risk through the EIA process and into construction.
Previous experience of major infrastructure schemes demonstrates that the risk can be significantly reduced by acknowledging the unknown and making contingencies for unexpected discoveries by developing a cultural heritage strategy in parallel with the EIA process.
The strategy should recognise that there will be impacts on known cultural heritage resources and focuse on the adoption of design measures with a view to reducing the order of impact.
It should also recognise that unknown resources will be at risk and should seek to establish a framework for approaching that risk throughout the planning, assessment, design and implementation of the proposed scheme.
The intention should be that the principal parties responsible for ensuring the cultural heritage resource is conserved and protected can have confidence that appropriate and effective measures are being adopted throughout the process.
Guiding principles
The strategy should set out the guiding principles for managing impacts on cultural heritage resources during the development of the design through to construction.
The principles on which the strategy should be founded are that:
- the collective cultural heritage resource, including historic buildings, historic landscapes and archaeology, is protected from disturbance from construction activities as far as is reasonably practicable;
- the effects of impacts on cultural heritage are mitigated in accordance with good practice guidance; and
- investigations and mitigation measures are informed by a clearly focused research strategy that is cost and time effective.
It is helpful to include in the strategy a timeframe demonstrating the key stages in the archaeological and risk management processes, aligned with the important phases of the project from the assessment of a proposal through to early construction.
More investigation
It is an inevitable consequence of the process, and the powers available to the developer relating to access, that levels of information on any cultural heritage resource becomes more detailed as planning, design and implementation progresses.
The strategy should reflect this and explain at which stages investigations and information can be obtained with certainty based on the developer’s powers.
It can also recognise that permission can be sought from landowners to enable parts of the investigative process to be progressed prior to construction. It should, however, acknowledge that some of the activities are less likely to be undertaken prior to the developer being given rights of access by virtue of a consented scheme.
The key difficulty in archaeological assessment arises where the desk-based investigations progress to a point where intrusive investigation is required prior to the scheme being granted approval and landowners are reluctant to grant access for works which will disturb the ground.
The result is that the establishment of the status of the cultural heritage resource; the recognition of impacts that will result from the construction of the scheme; and the identification of appropriate mitigation measures, often progresses beyond the assessment and into construction phase.
While undertaking intrusive investigative works during the construction phase is not ideal, when it is necessary the work can be programmed in conjunction with the main construction contractor during preparation of the detailed construction programme.
This ensures that areas of the site subject to the early stages of construction are investigated first and any necessary subsequent archaeological works can be agreed and progressed to mitigate potential impacts on the construction programme.
It is not possible to totally eliminate archaeological risk and there is always a possibility that unexpected discoveries will occur.
The potential risks can, however, be substantially reduced and controlled by developing a suite of measures to reduce uncertainty and to allow contingencies for how to deal with residual uncertainty.
The preparation of a cultural heritage strategy enables the financial, commercial and programme risks caused by archaeology to be appropriately managed.
This article was written as a contribution to the EIA Quality Mark’s commitment to improving EIA practice.
Rachel Morse is a principal heritage consultant at Mouchel