Metodologia de delimitació de la zona d'alimentació de captacions d'aigua potable i la seua vulnerabilitat enfront de contaminacions difuses

Degut als problemes de contaminació d’origen difús a l’estat francès (nitrats i pesticides bàsicament) les institucions franceses encarregades de la gestió dels recursos hídrics (Agències de l’Aigua, BRGM, Ministeri de Medi Ambient) volen protegir les captacions d’aigua potable enfront d’aquests contaminants a nivell de tota la zona d’alimentació. Aquesta protecció es basarà en la identificació de la zona d’alimentació de la captació a protegir i en veure’n quines són les zones més vulnerables en funció de diferents criteris, per tal de poder jerarquitzar les accions a dur a terme. Aquest treball proposa una metodologia a seguir per a delimitar la zona d’alimentació en tres tipus de medi aqüífer (continu, càrstic i fissurat) i per avaluar la vulnerabilitat. Els criteris emprats en l’avaluació de la vulnerabilitat estan basats i inspirats en mètodes ja existents com ara DRASTIC, RISKE o DISCO. L’avaluació es fa sempre mitjançant Sistemes d’Informació Geogràfica (SIG). Aquesta metodologia s’ha aplicat en sis casos reals de la conca del Sena-Normandia i Bretanya, que han permès veure els punts forts i febles, les limitacions i l’aplicabilitat del mètode. En general el mètode permet trobar les zones més vulnerables i per tant evita el haver de protegir tota la zona d’alimentació. Mots clau: hidrogeologia, hidrologia subterrània, vulnerabilitat aqüífers, contaminació difusa, SIG, modelització numèrica aqüífers, delimitació zona d’alimentació de captacions, protecció captacions aigua potable, Agència de l’Aigua Sena-Normandia, BRGM, França

Multi-risk governance for natural hazards in Naples and Guadeloupe

Technical and institutional capacities are strongly related and must be jointly developed to guarantee effective natural risk governance. Indeed, the available technical solutions and decision support tools influence the development of institutional frameworks and disaster policies. This paper analyses technical and institutional capacities, by providing a comparative evaluation of governance systems in Italy and France. The focus is on two case studies: Naples and Guadeloupe. Both areas are exposed to multiple hazards, including earthquakes, volcanic eruptions, landslides, floods, tsunamis, fires, cyclones, and marine inundations Cascade and conjoint effects such as seismic swarms triggered by volcanic activity have also been taken into account. The research design is based on a documentary analysis of laws and policy documents informed by semi-structured interviews and focus groups with stakeholders at the local level. This leads to the identification of three sets of governance characteristics that cover the key issues of: (1) stakeholders and governance level; (2) decision support tools and mitigation measures; and (3) stakeholder cooperation and communication. The results provide an overview of the similarities and differences as well as the strengths and weaknesses of the governance systems across risks. Both case studies have developed adequate decision support tools for most of the hazards of concern. Warning systems, and the assessment of hazards and exposure are the main strengths. While technical/scientific capacities are very well developed, the main weaknesses involve the interagency communication and cooperation, and the use and dissemination of scientific knowledge when developing policies and practices. The consequences for multi-risk governance are outlined in the discussion

Metodologia de delimitació de la zona d'alimentació de captacions d'aigua potable i la seua vulnerabilitat enfront de contaminacions difuses

Degut als problemes de contaminació d’origen difús a l’estat francès (nitrats i pesticides bàsicament) les institucions franceses encarregades de la gestió dels recursos hídrics (Agències de l’Aigua, BRGM, Ministeri de Medi Ambient) volen protegir les captacions d’aigua potable enfront d’aquests contaminants a nivell de tota la zona d’alimentació. Aquesta protecció es basarà en la identificació de la zona d’alimentació de la captació a protegir i en veure’n quines són les zones més vulnerables en funció de diferents criteris, per tal de poder jerarquitzar les accions a dur a terme. Aquest treball proposa una metodologia a seguir per a delimitar la zona d’alimentació en tres tipus de medi aqüífer (continu, càrstic i fissurat) i per avaluar la vulnerabilitat. Els criteris emprats en l’avaluació de la vulnerabilitat estan basats i inspirats en mètodes ja existents com ara DRASTIC, RISKE o DISCO. L’avaluació es fa sempre mitjançant Sistemes d’Informació Geogràfica (SIG). Aquesta metodologia s’ha aplicat en sis casos reals de la conca del Sena-Normandia i Bretanya, que han permès veure els punts forts i febles, les limitacions i l’aplicabilitat del mètode. En general el mètode permet trobar les zones més vulnerables i per tant evita el haver de protegir tota la zona d’alimentació. Mots clau: hidrogeologia, hidrologia subterrània, vulnerabilitat aqüífers, contaminació difusa, SIG, modelització numèrica aqüífers, delimitació zona d’alimentació de captacions, protecció captacions aigua potable, Agència de l’Aigua Sena-Normandia, BRGM, França

Consideration of Complexity in the Management of Construction and Demolition Waste Flow in French Regions: An Agent-Based Computational Economics Approach

For each region of France, there is currently a program to implement a plan for regional prevention and management of construction and demolition waste (CDW) used in the buildings and public works (e.g., roads) sector, also called the BTP (from the French Bâtiment et Travaux Publics) sector. To implement such a plan, its complexity must be considered; i.e., account (a) for how different scales are endogenously connected and (b) for decision-making rules at each scale being introduced. However, this complexity has rarely been taken into account in the literature. Using the PACA region as a case-study, this paper presents the first results of modelling that determines a hypotheses for the geographic distribution of the road renovation rate in each municipality (microscale) and Department (mesoscale) in a region of France. Such a renovation requires recycled aggregates (gravel) and asphalt supplies simultaneously. To consider this endogenous connection between scales, the model at the micro-scale must also be calibrated so the simulated values emerging at a higher-scale approach a supply–demand balance. We also discuss the transposition of the model to another French region (Ile-de-France). The method we used is the Agent-based Computational Economics (ACE) modelling approach. In addition, the coherent interplay between scales is determined by an approach called pattern-oriented modelling (POM). Our research revealed, at a thematic level, that for a circular economy to develop, the network of facilities in the territory is very important, and effective commercialization of secondary resources is major in the areas that group together recycling platforms and nearby asphalt plants. At a methodological level, our research revealed that in any multi-level modelling exercise, POM can be seen as an essential approach to accompany the ACE approach, particularly for a macroeconomic (here macro = regional) looping of a model designed at a microscale. However, convincing the BTP sector to integrate ACE/POM as a full part of a methodological support for regional prevention and management of CDW remains a challeng

Simulations numériques de tsunamis sur la côte méditerranéenne française : le cas d'Antibes

Le projet ALDES a consisté à étudier, par des simulations numériques détaillées, le risque tsunami sur 3 sites pilotes de la côte méditerranéenne française, pour des scénarios sismiques et gravitaires. Malgré l'intensité modérée des tsunamis susceptibles d'affecter ces côtes, Antibes apparait particulièrement exposée, en particulier pour un scénario comme le glissement de terrain de l'aéroport de Nice de 1979. Cet événement, à l'origine de nombreux dommages sur Antibes, a été simulé en s'appuyant sur des caractérisations du glissement menées par l'IFREMER. L'utilisation de calculs emboités (codes GEOWAVE et SURF-WB) a permis d'affiner la simulation jusqu'à une résolution de 3,75 m en intégrant explicitement les éléments urbains (modèle numérique d'élévation intégrant le bâti). Les résultats s'avèrent cohérents avec les observations historiques, en termes de temps d'arrivée et de polarité de la vague sur la Baie des Anges et en termes d'inondation sur Antibes. La simulation montre que le quartier de la Salis est atteint au bout de 6 minutes par un tsunami dépassant les 3 m à la côte. Cette première vague, la plus importante, entraine une submersion conséquente avec des courants localement élevés et des run-up pouvant atteindre 4 m. Plusieurs tests de sensibilité ont été menés sur ce cas, permettant de mettre en évidence l'importance du choix des équations (Boussinesq - Saint-Venant) et de la description du glissement pour simuler un tsunami d'origine gravitaire. Enfin, ces résultats permettent de souligner l'intérêt d'une prise en compte explicite du bâti pour la représentativité des simulations de submersion en milieu urbain

Limits on the potential accuracy of earthquake risk evaluations using the L'Aquila (Italy) earthquake as an example

International audienceThis article is concerned with attempting to ‘predict’ (hindcast) the damage caused by the L’Aquila 2009 earthquake (Mw 6.3) and, more generally, with the question of how close predicted damage can ever be to observations. Damage is hindcast using a well-established empirical-based approach based on vulnerability indices and macroseismic intensities, adjusted for local site effects. Using information that was available before the earthquake and assuming the same event characteristics as the L’Aquila mainshock, the overall damage is reasonably well predicted but there are considerable differences in the damage pattern. To understand the reasons for these differences, information that was only available after the event were include within the calculation. Despite some improvement in the predicted damage, in particularly by the modification of the vulnerability indices and the parameter influencing the width of the damage distribution, these hindcasts do not match all thedetails of the observations. This is because of local effects: both in terms of the ground shaking, which is only detectable by the installation of amuch denser strong-motion network and a detailed microzonation, and in terms of the building vulnerability, which cannot be modeled usinga statistical approach but would require detailed analytical modeling for which calibration data are likely to be lacking. Future studies shouldconcentrate on adjusting the generic components of the approach to make them more applicable to their location of interest. To increase thenumber of observations available to make these adjustments, we encourage the collection of damage states (and not just habitabilityclasses) following earthquakes and also the installation of dense strong-motion networks in built-up areas

Material requirements and impacts of the building sector in the Shared Socioeconomic Pathways

The significant weight of the building sector in global material demand has been addressed in several publications, but a lack of consideration of the energy-materials nexus was identified. To fill this gap, we developed a stock-flow dynamic model from 1950 to 2100, using scenarios of the International Energy Agency and the Shared Socioeconomic Pathways of the academic literature. We find that (i) the increasing stocks in the less developed countries results in a rise of the inflows; (ii) strong inequalities are observed in the in-use stocks per capita of materials in the SSPs, despite optimistic material intensities projection, (iii) a growing materials demand translates into larger final energy demand of material production, which could question the feasibility of some low-energy demand scenarios, and that (iv) the recycled concrete aggregated display a significant potential to enhance the reduction of accumulated concrete stocks in landfills and green concrete could decrease the energy demand of concrete production. We furthermore highlight the crucial temporal aspect of policies to successfully implement these solutions, as long lifetimes are observed in the building sector