Heritage impact assessment

A heritage impact assessment is an international project assessment tool. It is expected by UNESCO if there are large-scale development or infrastructure plans likely to adversely affect the OUV or state of conservation of a World Heritage Property (Guidelines, Articles 169 and 1721).

This may involve projects bearing on transport or energy infrastructure, construction that visually disrupts the scenery or operations in the subsoil… This assessment method is also a guide for designing a project in keeping with the character of the place and the OUV and thus for ensuring legal certainty when implementing the project.  

This assessment is the responsibility of the lead contractor of the project being considered. The State submits it to the World Heritage Centre which forwards it to UNESCO’s official advisory bodies for consideration and opinion: ICOMOS (International Council on Monuments and Sites) and IUCN (International Union for Conservation of Nature) for natural sites. The French committees of ICOMOS and IUCN may also be called on to advise the lead contractor and, through national and international work, help to strengthen and update the practice.  

In France, the environmental impact assessment concerning projects is governed by the Environment Code2.The assessment’s contents are tailored to the environmental sensitivity of the site, in its broadest sense, in terms of resources, natural heritage and cultural heritage, including as regards the archaeological, architectural and landscape aspects. 

For any project located directly inside or in the vicinity of a World Heritage Property that is likely to adversely affect it, it is recommended that the analysis include a chapter on the heritage impact assessment on the OUV. 

OUV and the heritage impact assessment

The purpose of the assessment is to ascertain the extent of change that the project is expected to generate and to objectively demonstrate whether the project is compatible with the objective of protecting the OUV. 

It must answer the following questions:  

• what are the key components of the Property’s OUV that risk being impacted?
• what are the changes wrought by the project?
• can the negative impacts be avoided, reduced, or even offset, and how?

This may concern a development within the boundaries of the UNESCO Property or in the surrounding areas known as the “buffer zone”. At the request of the World Heritage Centre, in 2010 ICOMIS drew up a method which is currently being updated to improve the procedure and strengthen consideration of a heritage enhancement approach in the project’s design.