Advice and Support

Assessing impacts on the historic environment

How to assess impacts on the historic environment using baseline data and survey, and how to explore mitigation measures for potential impacts.

1 Overview

A suitably experienced archaeological or historic environment specialist should be engaged where an Environmental Impact Assessment (EIA) is required.

They will be able to advise on:

  • the detailed assessment of impacts on the historic environment, and carry out this assessment
  • mitigation strategies, where necessary

Assessing impacts will typically involve:

  • gathering historic environment baseline data
  • a walk-over survey and field evaluation
  • consideration of the potential impacts
  • exploring possible mitigation strategies

2 Historic environment baseline data

The starting point for any assessment is to develop an understanding of the historic environment baseline.

Source of baseline information

The PastMap website has information on all archaeological or historic sites held in the National Monuments Record of Scotland. This includes the location of sites and, where appropriate, the extent of scheduled monuments, listed buildings and gardens and designed landscapes.

Our Decisions Portal holds data on:

  • listed buildings
  • scheduled monuments
  • Inventory gardens and designed landscapes
  • Inventory battlefields

Historic Environment Scotland can also provide more information on all such sites, and on impacts on the setting of category A listed buildings.

Planning authority archaeological and conservation services can give information and advice about:

  • unscheduled archaeological sites
  • listed buildings
  • conservation areas
  • non-Inventory gardens and designed landscapes

Other relevant documentary and cartographic sources may hold further baseline information. 

3 Walk-over survey and field evaluation

Fieldwork should supplement the baseline information gathered.

The survey and field evaluation should identify and describe the site and setting of historic environment assets, both within the:

  • boundary of the development area
  • wider area where significant impacts on setting may occur

It should also assess the likelihood of new archaeological discoveries being made in the area.  

Fieldwork must be non-invasive.

Extent of assessment

Applying a Zone of Theoretical Visibility model can help to identify monuments beyond the development area that are likely to experience a significant impact.

We can agree the sites included the assessment, and the level of detail required for each, as part of any pre-application engagement.

The Environmental Statement should set out the:

  • extent of the area within which impacts on setting have been assessed
  • reasons for the cut-off point

4 Potential impacts

Impacts on historic environment features can:

  • depend on the land-take related to infrastructure and other ancillary development
  • be avoided or reduced using appropriate locational measures
  • be direct or indirect

Direct impacts cause loss of and/or damage to a feature of the historic environment.

Indirect impacts include:

  • effects on the setting of historic environment assets
  • changes to surface drainage patterns
  • the removal of peat

Direct impacts

Development designs should avoid direct impacts on scheduled monuments.

This includes in relation to any associated ancillary development. For example, the development of a wind farm may require access roads, cable routes, work compounds, laydown areas and other site infrastructure as well as the turbines themselves.

Developers should contact Historic Environment Scotland as early as possible if direct effects on scheduled monuments seem to be unavoidable. This will avoid delays later in the planning process.

Impacts on setting

Development designs should also avoid, or reduce, impacts on the setting of heritage assets. This approach should guide the design process from its early stages.

Visualisations help to support the assessment of impacts on setting. Wirelines or photomontages may be most appropriate. Historic Environment Scotland can discuss and agree the details of the visualisations to be used.

5 Mitigation measures

Mitigation may take three forms:

  • avoidance measures
  • reduction measures
  • offsetting measures

Mitigation’s main aim is to avoid impacts.

Where impacts are unavoidable, mitigation instead aims to reduce these impacts as far as possible.

Where it’s not possible to avoid or reduce impacts, mitigation may instead try to offset impacts.

Offsetting methods – including prior archaeological excavation of threatened features – may be appropriate in some cases. It is important to note that offsetting is at the lower end of the mitigation hierarchy.

Your Environmental Statement (ES) should provide information on the mitigation measures considered in your development design.

We are always keen to discuss appropriate mitigation measures for significant impacts likely to affect:

  • scheduled monuments and their setting
  • listed buildings and their setting
  • Inventory gardens and designed landscapes
  • Inventory battlefields
  • World Heritage Sites
  • Historic Marine Protected Areas

We prefer to do this before an application and ES are submitted.

You can view the mitigation hierarchy in the Planning Advice Note on Environmental Impact Assessment.

Download the Planning Advice Note 1/2013 – Environmental Impact Assessment [PDF, 372KB]

Find out more about the Environmental Statement.