Development of the Chrono-Systemic Timeline as a Tool for Cross-Sectional Analysis of Droughts—Application in Wallonia

peer reviewedDrought is a complex hazard with multiple and often dramatic impacts, depending on the environmental and societal context of the affected area. In recent years, due to global warming, this phenomenon has been occurring more intensely and frequently, affecting regions worldwide, including Wallonia, the southern part of Belgium. This study aims to enhance our understanding of the interdisciplinary dynamics of drought in order to improve its anticipation and crisis management by stakeholders. To achieve these objectives, a cross-disciplinary analysis tool has been developed: the chrono-systemic timeline. Applied here to the severe drought of 2018 in Wallonia, this tool provides a comprehensive visual representation of the crisis, simultaneously offering temporal and multi-sectoral perspectives. The data incorporated into the model encompass environmental conditions, economic and social contexts, as well as political and administrative decisions made during the case study. The analysis of the chrono-systemic timeline reveals numerous interdisciplinary connections, a prolonged period of significant impacts, a gradual return to a ‘normal’ situation, and a reactive form of crisis management. In conclusion, the study emphasizes the importance of giving due consideration to the risks associated with water deficits and advocates for the implementation of anticipatory and adaptive management strategies to enhance our ability to effectively address droughts.13. Climate action6. Clean water and sanitation12. Responsible consumption and productio

Spatial analysis of hydraulic conductivity for slope deposits at catchment scale in Northern Tuscany, Italy

Hydraulic conductivity (K) is a relevant engineering geology property of slope deposits (SD) overlying the geological bedrock. This parameter is relevant at the field scale to simulate infiltration and runoff processes, hillslope stability numerical analysis, hydrological studies and environmental issues. Direct measurements (field and laboratory tests), as well as indirect estimations (e:g. correlations from grain size distribution, pedotransfer functions) are available in the literature for estimating K. Many measurements are required to obtain significant results since K depends on many factors such as grain size distribution, bulk density, organic matter, etc. A big set (about 750) of K field measurements in the vadose zone of SD in Northern Tuscany (Italy) has been performed by means of constant and/or falling head permeameter. For each test site (a total of 150 locations), other engineering geology properties of SD such as depth, texture, bulk density, Atterberg limits and grain size distribution have been determined. In this work the local variability of K has been estimated thanks to a statistical analysis of K for each test site. Moreover geostatistical techniques have been applied to infer the spatial correlation of K at the catchment scale. The results show that K varies across the SD profile and in the geographic neighborhood of the test site exhibiting high spatial variability within the study area. The new pedotransfer function, that has been developed with satisfactory results (the determination coefficient R2 = 0.84), suggests that the depth of SD and d20 (is the diameter corresponding to 20% finer in the particle-size distribution) play a relevant role in the prediction of K:These parameters can be considered with profit in spatial analysis of K for SD allowing to produce K maps in the study area

The catastrophic flash-flood event of 8–9 September 2002 in the Gard region, France: a first case study for the Cévennes–Vivarais Mediterranean Hydrometeorological Observatory

The Cévennes–Vivarais Mediterranean Hydrometeorological Observatory (OHM-CV) is a research initiative aimed at improving the understanding and modeling of the Mediterranean intense rain events that frequently result in devastating flash floods in southern France. A primary objective is to bring together the skills of meteorologists and hydrologists, modelers and instrumentalists, researchers and practitioners, to cope with these rather unpredictable events. In line with previously published flash-flood monographs, the present paper aims at documenting the 8–9 September 2002 catastrophic event, which resulted in 24 casualties and an economic damage evaluated at 1.2 billion euros (i.e., about 1 billion U.S. dollars) in the Gard region, France. A description of the synoptic meteorological situation is first given and shows that no particular precursor indicated the imminence of such an extreme event. Then, radar and rain gauge analyses are used to assess the magnitude of the rain event, which was particularly remarkable for its spatial extent with rain amounts greater than 200 mm in 24 h over 5500 km2. The maximum values of 600–700 mm observed locally are among the highest daily records in the region. The preliminary results of the postevent hydrological investigation show that the hydrologic response of the upstream watersheds of the Gard and Vidourle Rivers is consistent with the marked space–time structure of the rain event. It is noteworthy that peak specific discharges were very high over most of the affected areas (5–10 m3 s−1 km−2) and reached locally extraordinary values of more than 20 m3 s−1 km−2. A preliminary analysis indicates contrasting hydrological behaviors that seem to be related to geomorphological factors, notably the influence of karst in part of the region. An overview of the ongoing meteorological and hydrological research projects devoted to this case study within the OHM-CV is finally presented

HyMeX: A 10-Year Multidisciplinary Program on the Mediterranean Water Cycle

Drobinski, P. ... et. al.-- 20 pages, 10 figures, 1 table, supplement material http://journals.ametsoc.org/doi/suppl/10.1175/BAMS-D-12-00244.1HyMeX strives to improve our understanding of the Mediterranean water cycle, its variability from the weather-scale events to the seasonal and interannual scales, and its characteristics over one decade (2010–20), with a special focus on hydrometeorological extremes and the associated social and economic vulnerability of the Mediterranean territoriesHyMeX was developed by an international group of scientists and is currently funded by a large number of agencies. It has been the beneficiary of financial contributions from CNRS; Météo-France; CNES; IRSTEA; INRA; ANR; Collectivité Territoriale de Corse; KIT; CNR; Université de Toulouse; Grenoble Universités; EUMETSAT; EUMETNET; AEMet; Université Blaise Pascal, Clermont Ferrand; Université de la Méditerranée (Aix-Marseille II); Université Montpellier 2; CETEMPS; Italian Civil Protection Department; Université Paris- Sud 11; IGN; EPFL; NASA; New Mexico Tech; IFSTTAR; Mercator Ocean; NOAA; ENEA; TU Delft; CEA; ONERA; IMEDEA; SOCIB; ETH; MeteoCat; Consorzio LAMMA; IRD; National Observatory of Athens; Ministerio de Ciencia e Innovación; CIMA; BRGM; Wageningen University and Research Center; Department of Geophysics, University of Zagreb; Institute of Oceanography and Fisheries, Split, Croatia; INGV; OGS; Maroc Météo; DHMZ; ARPA Piemonte; ARPA-SIMC Emilia-Romagna; ARPA Calabria; ARPA Friuli Venezia Giulia; ARPA Liguria; ISPRA; University of Connecticut; Università degli Studi dell'Aquila; Università di Bologna; Università degli Studi di Torino; Università degli Studi della Basilicata; Università La Sapienza di Roma; Università degli Studi di Padova; Università del Salento; Universitat de Barcelona; Universitat de les Illes Balears; Universidad de Castilla-La Mancha; Universidad Complutense de Madrid; MeteoSwiss; and DLR. It also received support from the European Community's Seventh Framework Programme (e.g., PERSEUS, CLIM-RUN)Peer reviewe

The chrono-systemic timeline: a tool at the crossroad of disciplines. Application to hydrological extremes.

Nous vivons à une époque de plus en plus marquée par les extrêmes climatiques. Absence ou fortes pluies semblent se succéder dans une alternance de plus en plus intense et fréquente. Si le changement climatique n’est pas étranger à ce constat, force est de constater que les caractéristiques à la fois naturelles et sociétales d’un territoire jouent un grand rôle dans l’ampleur des impacts et dans la vulnérabilité des populations face aux sécheresses et aux inondations. L’analyse de ce type d’événements aux conséquences souvent dramatiques et toujours multisectorielles ne peut dès lors se faire qu’à travers une vision holistique croisant les disciplines. Et, la « frise chrono-systémique », pièce centrale de ce webinaire, est un outil qui permet, en un schéma synthétique, de comprendre les processus dynamiques et transversaux qui animent ces extrêmes pluviométriques. Ce webinaire détaille, tout d’abord, le concept de cet instrument novateur et propose ensuite quelques exemples de frises et d’applications opérationnelles. Enfin, les perspectives, les précautions et les développements futurs de cet outil sont abordés.13. Climate actio

Systèmes d'information géographique : outil d'aide à la gestion territoriale

International audienceAn object or event localized in space is, together with its attribute data, geographic information. The Geographic Information Systems (GIS) allow for obtaining, managing, using and transmitting such information by treating the graphic aspect of the object but also its semantic content. The geographic information can have varied origins, objects are localizable by nature, others by association of similar or different themes. The application domains of GISs are vast and cover territorial development up to geomarketing. From these analyses models or simulations are derived which make of GISs and their components (materials, software, personnel, data) a territorial decision tool.Un objet ou événement localisé dans l'espace constitue, avec ses données attributaires, une information géographique. Les Systèmes d’Information Géographique (SIG) permettent d'acquérir, de gérer, de manipuler et de transmettre ce type d'information, en traitant le volet graphique de l'objet, mais également son contenu sémantique. Les informations géographiques peuvent avoir des origines variées, des objets sont localisables par nature, d'autres par association, de thématiques identiques ou différentes. Les domaines d'application des SIG sont vastes, et couvrent l'aménagement du territoire jusqu’au géomarketing. De ces analyses découlent des modèles ou des simulations qui font des SIG et de leurs composantes (matériel, logiciels, personnel, données, méthodes) un outil d'aide à la décision territoriale

Contribution à la spatialisation du modèle opérationnel de prévision des crues éclair ALHTAÏR [Alarme Hydrologique Territoriale Automatisée par Indicateur de Risque] (approches spatiale et expérimentale, application au bassin versant du Gardon d'Anduze)

Le modèle de prévision des crues ALHTAÏR est développé depuis bientôt 5 ans par le Service d'Annonce des Crues du Gard (SAC-30). Ce modèle, à vocation opérationnelle, a pour finalité la production d un hydrogramme de crue en temps réel en tout point choisi comme exutoire de la zone sous surveillance du SAC-30. Deux versions de ce modèle de prévision de crues existent. La première version, ALHTAÏR en mode bassin versant , permet un calage des paramètres du modèle par bassin versant étudié. La seconde, ALHTAÏR en mode spatialisé , permet de réaliser un calage en fonction de caractéristiques telle que la capacité d infiltration des sols. Les travaux de recherche engagés visent ainsi à contribuer à l établissement de cette version du modèle de prévision de crues. Une double approche, expérimentale et spatiale, a été mise en place pour entreprendre cette démarche. Une cartographie de la perméabilité des sols sur le bassin versant pilote du Gardon d Anduze a été réalisée. Les simulations avec ALHTAÏR en mode spatialisé montrent l intérêt d une telle démarche, sous réserve d affiner la méthodologie mise en place pour réaliser cette spatialisation, notamment dans l adéquation entre essais expérimentaux et calibration du modèle. Ces compléments de recherche sont indispensables pour envisager d étendre l utilisation d ALHTAÏR en mode spatialisé à l ensemble de la zone de compétence du SAC-30 et plus spécifiquement aux bassins versants non jaugés, objectif in fine de ce modèle.The flood forecasting model ALHTAÏR is developed for five years by the flood-warning service: Service d'Annonce des Crues du Gard (SAC-30). This model, with an operational orientation, aims at a flood hydrograph for each location of the rivers for the supervision area of the SAC-30, in a real time processing. Two versions of this flood forecasting model exist. The first one, ALHTAÏR in "watershed" mode, allows to affect the model parameters by catchment area. The second version, ALHTAÏR in "spatialised" mode, allows to realize a model calibration according to the catchment area characteristics such as the infiltration capacity. These research works propose a contribution to the establishment of flash floods forecasting model version. A double approach has been proposed: experimental field tests combined with spatial analyses (Geographical Information System GIS). Cartography of the permeability on an experimental watershed (The Gardon d'Anduze ) was realized. The simulations with ALHTAÏR in "spatialised" mode show the interest of this approach provided that the methodology is refined to realize the cartography of the permeability and the model calibration. Further researches are required to consider an expansion of the use of ALHTAÏR in "spatialised" mode to the whole area under supervision of the SAC-30 more especially to the non-gauged watersheds, which are the in fine objective of this model.AIX-MARSEILLE1-BU Sci.St Charles (130552104) / SudocSudocFranceF

La frise chrono-systémique, un outil à la croisée des disciplines: Cas d’applications aux extrêmes hydrologiques

International audienceNous vivons à une époque de plus en plus marquée par les extrêmes climatiques. Absence ou fortes pluies semblent se succéder dans une alternance de plus en plus intense et fréquente. Si le changement climatique n’est pas étranger à ce constat, force est de constater que les caractéristiques à la fois naturelles et sociétales d’un territoire jouent un grand rôle dans l’ampleur des impacts et dans la vulnérabilité des populations face aux sécheresses et aux inondations.L’analyse de ce type d’événements aux conséquences souvent dramatiques et toujours multisectorielles ne peut dès lors se faire qu’à travers une vision holistique croisant les disciplines. Et, la « frise chrono-systémique », pièce centrale de ce webinaire, est un outil qui permet, en un schéma synthétique, de comprendre les processus dynamiques et transversaux qui animent ces extrêmes pluviométriques.Ce webinaire vous détaillera, tout d’abord, le concept de cet instrument novateur et vous proposera ensuite quelques exemples de frises et d’applications opérationnelles. Enfin, les perspectives, les précautions et les développements futurs de cet outil seront abordés, avant de laisser place à une séance d’échanges et de débats entre les participants

Using GIS for emergency management: a case study during the 2002 and 2003 flooding in south-east France

International audienceEmergency management has always required tools to get geographic information from the affected area. The objectives are to have a general view of the theatre of operations with its geographic characteristics, troop's location, roads and railways, and fighting location. The emergency management of natural hazards is specific because it is necessary to evaluate the appropriate number of emergency units for the dimension and probable evolution of the situation; it is necessary to know how to transport emergency units, to anticipate the outcome of the situation and to give the best missions to the units. Geographic aspects are essential because every minute is important when rescuing people. This paper aims to outline the position of Geographic Information Systems (GIS) for emergency management of natural hazards, and especially during the 2002 and 2003 south-east flooding in France

Landscape Drivers of Floods Genesis (Case Study: Mayo Mizao Peri-Urban Watershed in Far North Cameroon)

Landscape has significant effects on hydrological processes in a watershed. In the Sudano-Sahelian area, watersheds are subjected to a quick change in landscape patterns due to the human footprint, and the exact role of the actual landscape features in the modification of the hydrological process remains elusive. This study tends to assess the effects of landscape on the genesis of the runoff in the Mayo Mizao watershed. To achieve this goal, 62 infiltration tests were performed at different points and depths (5 cm and 20 cm) using the double-ring method and the Porchet method. The results show that the combination of many factors (soil type, land use, and farming practices) can guide the hydraulic conductivity behavior of soils. For example, at 5 cm depths, clayey-evolved soils, such as vertisols and halomorphic soils, inhibit infiltration, as opposed to non-evolved mineral soils, such as lithosols and clayey-sandy soils. However, at 20 cm depths, gray soils with halomorphic tendencies followed by vertisols have a low sensitivity to infiltration, as opposed to soils derived from loose materials and halomorphic soils. For a given soil type, rainfed crops are the primary land use that runs against infiltration. However, the effect of tillage varies according to the soil type. Finally, given the extent of vertisols and halomorphic soils in the Far North region of Cameroon in general, and in the Mayo Mizao watershed in particular, and regarding the increase in cultivated areas, a probable reduction in the infiltration capacity of soils in this region is to be expected in the medium term. The results of this study can be used as a basis for land-use planning and sustainable watershed management in semi-arid tropical zones