View of a site contaminated by mercury distilling (Algeria, 2007). © BRGM

Decision-support tools for local area management

12.13.2016
Thanks to the methodological tools it has developed, the BRGM helps local government agencies to plan their land use management and remediation of potentially polluted brownfield sites.

As Mathilde Scamps explains, "urban area managers are faced with a paradoxical situation in which they have to meet housing and infrastructure needs, which often require new building land, while also preserving farmland and natural areas. Often their only solution is to rebuild on vacant land, which may be degraded or polluted".

The redevelopment of urban brownfield sites requires very long-term planning based on an integrated approach to all socio-economic, environmental, health and financial constraints. "The BRGM", explains Mathilde Scamps, "has developed specific tools to meet these needs. We work with local government bodies on particular R&D projects, but we also provide scientific and technical assistance in developing the methodological framework for the project". 

The BRGM conducts historical urban inventories (IHU) to detect potentially polluted sites and soils on the cadastral scale. When combined with an urban geochemical background study (FGU), they are an essential tool for spatial diagnoses supplementing the provisions of the ALUR Act. Multicriteria analysis tools are then used to compare redevelopment hypotheses. "The RefrinDD project run by the Ademe", says Mathilde Scamps, "is designed to test scenarios for redeveloping potentially polluted brownfield sites in order to choose the most relevant strategy in view of environmental, technical and other constraints, issues at stake and the priorities of the players concerned".

Redevelopment of the Union site along the Roubaix canal in northern France. © BRGM

In many cases, the BRGM's work is applied directly for operational purposes in redevelopment projects. This was the case with the TERRASS project, a databank set up to facilitate the reuse of excavated earth.

The BRGM's overall expertise in this area is also applied at other levels.

One example is the European HOMBRE project on anticipating the emergence of brownfield sites via relevant indicators. On behalf of the Ministry of Ecology, the BRGM is revising the national methodology for depolluting and redeveloping polluted sites.

It is also partnering the ASURET project to improve the characterisation of deposits and flows of materials and waste. Finally, the BRGM is working on the potential uses of polluted sites and soils for storing water or energy (where there is less pressure on land), as an intermediate solution prior to redevelopment proper.

Polluted sites and soils: depollution and its impacts

The priority objective in the management of polluted sites and soils is to protect human health. The ADEME Solenv project is working to help professionals to plan ahead by taking overall environmental considerations into account in their choice of depollution techniques, since degraded soils, as well as the risks they raise for human health, also affect the health of ecosystems.

After a review of existing and applicable environmental assessment tools, the project put forward an overall methodology. This is similar to the French national approach to brownfield site management and rehabilitation and is based on a multicriteria method combining Life Cycle Analysis (LCA) to assess impacts arising from treatment operations with health and ecological risk analyses (ARS/ARE) to assess the risks arising from the presence of pollutants in soils and groundwater.

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