Projet Labex DRIIHM (2016-2019)
Partners : ESPACE (Samuel Robert), Métropole Aix-Marseille Provence, Ville de Marseille
PhD student : Jesùs Diaz Sanz
Soils are considered as a major constituent of anthroposystems as well as a non-renewable resource. They are of utmost importance for the economical and social development of territories. They are a resource for food and energy production but they also fulfill various ecological functions, essential to human beings, such as support, filtering of water, or biodiversity tank. The so-called services that they offer are based on these intrinsic functions that have been listed in the former proposal Thematic Strategy for Soil Protection (COM (2006) 232). However soil quality (SSSA, S-581 in Karlen et al., 1997) is not protected by law either in Europe or in the United States. Because of urban sprawl, soil contaminations due to human activities, as well as urban waste land, soil management and soil conservation have emerged as a critical issue (Bone et al. 2011), which is part of the environmental challenge that human societies face today. Because the world population is going to live more and more in urban areas, it is necessary to know better urban and periurban soils. They are of utmost importance in the frame of urban renewal strategies and in the context of climatic change which encourages the design of a new kind of urbanism, especially in areas which concentrate human activities and where space is scarce. Therefore, conservation of the soil resource appears crucial for sustainable land management.
To achieve this goal, there is a need for tools and dedicated approaches that would 1) raise awareness on the importance of soil quality in urban planning, and more specifically on soil variability, and 2) alert on early soil quality changes, especially given the additional constraint of climatic change, through the use of relevant indicators.
The project aims at investigating whether and how a scientific knowledge on soil quality can be integrated into urban planning so as to allow soil quality to be taken into account to preserve at best soil multifunctionality. The objectives are:
1) the production of a scientifically-sound Soil Quality Index (SQI) including all soils and all urban and periurban land use types, adapted to the needs of land planners, spatialized and visualized through maps. It will be based on the prototype that we have developed in a previous project (Uqualisol-ZU, Robert et al. 2012). It is provided at a 25 m spatial resolution and combines soil functions (quantified using soil parameters) with land use categories, in a ”land use polyvalence index”. Already tested on two municipalities, it is not operational yet. It deserves adaptation to be applicable to other territories and specific research developments for urban and peri-urban areas (like research on the appropriate scale and the change of scales necessary to obtain a full panorama of the soil multifunctionality for a given territory).
2) to build this application on the Marseille 16th district in connection with local land planners and local stakeholders, in order to: make them more concerned with the issue of soil functions / soil quality; to get their own understanding of such an assessment in the frame of land planning, urban renewal and climatic change; and to discuss with them about the advantages they could draw from a sustainable land management integrating soil quality. The Marseille 16th district is a contrasted urbanized coastal territory where dense urban fabric can be found next to scattered buildings into the forest, (remediated) former or actual industrial areas, quarries, relict of agricultural fields and natural grounds. The latter are of high interest for the French Conservatoire du littoral that aims at acquiring land to put it under protection.
3) to study at a larger scale (0.6 m resolution or better) the soils enclosed within the urban and peri-urban area. This will consist in quantifying and mapping soils still existing within the urban matrix. These small surfaces will then be studied by relating their bio-geo-physico-chemical characteristics to their surface state and historical background (successive land use over time), in order to draw functions that would help to extrapolate their quality to be included in the index. “External” parameters that could help to weigh the index such as the size of the soil unit or the distance between soil patches, the existence of blue or green continuities will be required for a better assessment of the soil quality. An additional output will be the building of an urban soils typology.