Abstract
As the challenges of soil preservation gain visibility within society, the French law of 22 August 2021, known as the Climate and Resilience Law, incorporates into in French legislation a goal of "zero net artificialization" (ZAN) and introduces the notion of compensation for soil artificialization, thus establishing a logical link with the "avoid, reduce, compensate" sequence (known as the ERC sequence). Introduced into French law by the Nature Protection Act of 10 July 1976 and consolidated by the law for the reconquest of biodiversity, nature and landscapes of 8 August 2016, the ERC sequence is a mechanism widely used internationally to limit the ecological impact of works, projects, schemes, and planning documents (plans, schemes, programmes). This sequence isimplemented through actions aimed at avoiding, reducing and then, if necessary, compensating for losses by providing ecological gains equivalent to, or even exceeding the losses (ecological additionality).In this context, we examined the way in which soils and their multifunctionality are currently taken into account in the application of the ERC sequence in France.To this end, a survey was carried out among fourteen regional players, working in the instruction departments or participating in regional environmental authority missions, and six experts in compensation and its dimensioning. The stakeholders were asked about their vision of the integration of soils in the application of the ERC sequence, in particular during the diagnosis of the initial state and for the dimensioning of compensation, about the knowledge and resources available to take soils into account duringthe application of this sequence and about the possible levers of action.This survey work was complemented by an analysis of documents from impact studies of development projects, based on a reading of the files by keywords defined according to a functional approach to soil. Seven files were selected (after 2016, the date on which the mitigation hierarchy regulation was strengthened), which made it possible to study a range of projects of different types, in different regions and under different regulatory procedures. In addition to these files studied, four opinions issued by the environmental authority on development projects and three guidelines on methods for sizing compensation and assessing the functions of wetlands were also studied.The experts interviewed were unanimous in stating that very little account is currently taken of soil in the application of the mitigation hierarchy, believing that current regulations on soil are not sufficiently restrictive to ensure that soil is systematically included in impact studies. In fact, an analysis of the documents shows that very little attention is paid to soil in impact assessments, and that the multifunctional nature of soil is not taken into account right from the initial diagnosis of the area to be developed. Sols et Séquence ERC 349Etude et Gestion des Sols, 30, 2023.This work has made it possible to identify four areas in which action can be taken to improve the effective consideration of soilsin the mitigation hierarchy: the legal framework, the match between regulatory requirements and technical response capacities, training and information for territorial stakeholders, and finally the spatial scale to be considered in the implementation of the mitigation hierarchy.