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Orléans, France

Narayan S.,University of Southampton | Nicholls R.J.,University of Southampton | Clarke D.,University of Southampton | Hanson S.,University of Southampton | And 14 more authors.
Coastal Engineering | Year: 2014

Coastal floodplains are complex regions that form the interface between human, physical and natural systems. This paper describes the development, application and evaluation of a conceptual foundation for quantitative integrated floodplain risk assessments using the recently-developed SPR systems model. The SPR systems model is a conceptual model that combines the well-established Source-Pathway-Receptor (SPR) approach with the concept of system diagrams. In comparison to the conventional approach, the systems model provides spatially explicit quasi-2D descriptions of the floodplain in terms of constituent elements and possible element linkages. The quasi-2D SPR, as it will henceforth be referred to in this paper, is not the final product of this work, but is an important intermediate stage which has been pursued as part of a wider European flood risk project THESEUS (www.theseusproject.eu). Further research is currently on-going to provide full quantification of the quasi-2D SPR, and to add further refinements such that hydraulic assessments could follow on easily and rapidly from the results of these appraisals.The first part of the paper synthesises current conceptual treatment of coastal floodplains and identifies areas for improvement in describing coastal floodplains as complex systems. The synthesis demonstrates that the conceptual foundation of a 'typical' flood risk study often achieves a less comprehensive and integrated description of the floodplain than the quantitative models which it informs. From this synthesis, the quasi-2D SPR is identified as a more robust and informative conceptual foundation for an integrated risk assessment. The quasi-2D SPR has been applied to seven European coastal floodplains as part of the THESEUS project. The second part of the paper discusses in detail the application of the quasi-2D SPR to three contrasting floodplain systems - an estuary, a coastal peninsula and a mixed open coast/estuary site. The quasi-2D SPR provides a consistent approach for achieving comprehensive floodplain descriptions that are individual to each coastal floodplain. These are obtained through a robust, participatory model-building exercise, that facilitates developing a shared understanding of the system. The constructed model is a powerful tool for structuring and integrating existing knowledge across multiple disciplines. Applications of the quasi-2D SPR provide key insights into the characteristics of complex coastal floodplains - insights that will inform the quantification process. Finally, the paper briefly describes the on-going quantitative extension to the quasi-2D SPR. © 2013 Elsevier B.V. Source

Guignot S.,Bureau de Recherches Geologiques et Minieres | Touze S.,Bureau de Recherches Geologiques et Minieres | Von der Weid F.,CEO of the SELFRAG AG Company | Menard Y.,French Geological Survey | Villeneuve J.,French Geological Survey
Journal of Industrial Ecology | Year: 2015

Summary: The present study addresses the topic of recycling materials from construction and demolition (C&D) wastes by proposing an environmental comparison between two recycling schemes for gravel wastes. The first scheme is the baseline process, and leads to direct most of the gravel to road construction. The second scheme relies on an innovative technology for the processing of gravel, based on electrical fragmentation, which leads to a clear separation between the aggregate contained in the gravel and the cement paste. The purity of the obtained materials opens new recycling outlets-as part of high-quality structural concrete for the aggregate and as a substitute to natural minerals in clinker kilns for the cement paste. This shift towards more-specific outlets for the materials found in reclaimed gravel carries significant modifications in the overall handling of C&D wastes and in the supply of natural and non-natural materials for road construction and concrete formulation. The environmental implications of these modifications are evaluated according to a life cycle assessment methodology, which specifically addresses the influence of the distances and modalities of transportation of wastes to the crushing processes, as well as of natural and recycled aggregate to construction and demolition sites. The results point out significant environmental gains for the alternative recycling scheme, in all the considered impact categories and whatever the implemented scenarios. These gains are modulated by the various transport distances of the heavy materials heeded in the global system. © 2015 by Yale University. Source

de Michele M.,French Geological Survey | Raucoules D.,French Geological Survey | Arason Thordur,French Geological Survey
Remote Sensing of Environment | Year: 2016

In this paper we present a method to restitute the volcanic gas/ash Plume Elevation Model (PEM) from optical satellite imagery. As the volcanic plume is moving rapidly, conventional satellite based photogrammetric height restitution methods do not apply as the epipolar offset due to plume motion adds up to the one generated by the stereoscopic view. This is because there are time-lags of tens of seconds between conventional satellite stereoscopic acquisitions, depending on the stereo acquisition mode. Our method is based on a single satellite pass. We exploit the short time lag and resulting baseline that exist between the multispectral (MS) and the panchromatic (PAN) bands to jointly measure the epipolar offsets and the perpendicular to the epipolar (P2E) offsets. The first are proportional to plume height plus the offsets due to plume velocity in the epipolar direction. The second, are proportional to plume velocity in the P2E direction only. The latter is used to compensate the effect of plume velocity in the stereoscopic offsets by projecting it on the epipolar direction assuming a known plume direction, thus improving the height measurement precision. We apply the method to Landsat 8 data taking into account the specificities of the focal plane modules. We focus on the Holuhraun 2014 fissure eruption (Iceland). We validate our measurements against ground based measurements. The method has potential for detailed high resolution routine measurements of volcanic plume height/velocity. The method can be applied both to other multifocal plane modules push broom sensors (such as the ESA Sentinel 2) and potentially to other push-broom systems such as the CNES SPOT family and Pléiades. © 2016 Elsevier Inc. Source

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