Rapport général. Sensibilisation et formation

Relations between scientists, médias, public and politicians are analysed taking into account the motivations of each group. Some questions are so formulated : What kind of information ? What kind of education ? What are the objectives ? What are the means of action ?Les relations entre le milieu scientifique, les médias, le public, le monde politique sont examinées au travers des motivations de chacun des partenaires. Quelques questions sont posées : Quelle information ? Quelles formations ? Quels objectifs ? Quels moyens ?Bocquillon Claude. Rapport général. Sensibilisation et formation. In: L'avenir de l'eau. Quelques réponses des sciences hydrotechniques à une inquiétude mondiale. Vingt deuxièmes journées de l'hydraulique. Paris, 15-17 septembre 1992. Tome 5, 1992

9. - La formation des hydrologues en France

The 7th "Journées Hydrologiques", meeting held in Montpellier on September 18th-19th 1991, both by ORSTOM and the University of Montpellier II, brought more than 150 participatings, university and research members, teachers and professionals of hydrology. The first day dealt with education for research in hydrology and the second with education for operational hydrology. Both of them led to make an inventory of the existent trainings pieces of advice. This paper draws up a statement of the present situation of hydrologists’education in France, in the basic and applied research and in the engineering sectors.Les journées hydrologiques, organisées les 18 et 19 septembre 1991 à Montpellier, conjointement par l’ORSTOM et l’Université de Montpellier II, ont réuni plus de 150 participants, universitaires et chercheurs, formateurs et professionnels de l’hydrologie. Consacrées l’une à la formation à la recherche, l’autre à la formation pour l’hydrologie opérationnelle, ces deux journées ont permis de faire l’inventaire des formations existantes en France, de donner un état des insuffisances et de faire quelques recommandations destinées à y remédier. Cette communication dresse un bilan de la situation actuelle en France sur la formation des hydrologues dans les secteurs de la recherche fondamentale et appliquée et de l’ingénierie.Bocquillon C., Jaccon Gilbert. 9. - La formation des hydrologues en France. In: L'avenir de l'eau. Quelques réponses des sciences hydrotechniques à une inquiétude mondiale. Vingt deuxièmes journées de l'hydraulique. Paris, 15-17 septembre 1992. Tome 5, 1992

On the use of the diffusive wave for modelling extreme flood events with overbank flow in the floodplain

Corresponding author. fax: +33 4 67 63 26 14. E-mail address: [email protected] (R. Moussa).International audienceCatastrophic flood events are frequently chosen as reference events, for modelling the impact of scenarios of river bank remediation to prevent inundations. However, these rare events are poorly understood due to the poor hydrological knowledge available, and due to the lack of data. A model for routing flood events adapted to the few available data during historical extreme events was developed. The model subdivides the floodplain into cells linked to the main channel, and the diffusive wave model with overbank flow was used to route floods in the main channel and through the inundation floodplain. The linearized equations are resolved by an implicit numerical scheme to ensure stability and convergence. The flood event of October 1958 on the Herault river, which caused one of the largest inundations Southern France during the XXth century, was studied as the application case. As input data, the model requires a Digital Elevation Model, geographical map and cross sections in order to subdivide the channel network into cells. The model parameters are the Manning roughness coefficients in the main channel and in the floodplain. The model was applied to simulate the flood event of 1958, and was validated on other flood events under similar hydro-meteorological conditions. Then, the model was applied to quantify the impact of scenarios of river bank remediation. Fourteen scenarios of construction of dams, embankments, or coupling both dams and embankments, were modelled. The model simulates hydrographs in the main channel, the water depth, the area and the volume on both right and left banks of the floodplain cells. Results show that the model developed herein, with relatively little hydraulic modelling, is well adapted to simulate extreme flood events, and is useful for environmental managers to study the impact of river bank remediation on inundation

Distributed hydrological modelling of a Mediterranean mountainous catchment - Model construction and multi-site validation

Corresponding author. fax: +33 4 67 63 26 14. E-mail Addresses: [email protected] audienceA multi-site validation approach is necessary to further constrain distributed hydrological models. Such an approach has been tested on the Gardon catchment located in the mountainous Mediterranean zone of southern France using data gathered over a 10 year period on nine internal subcatchments. A spatially distributed hydrological model linked to a Geographical Information System, was developed on the basis of simplified physical process representations (infiltration, evapotranspiration, base flow, interflow,overland flow, channel routing), using conventional hydro-meteorological data and readily accessible geographical maps. The model. parameters were estimated from a Digital Elevation Model, soil and land-use maps; and only five parameters were calibrated for the whole catchment. Three procedures with different levels of calibration and validation were conducted at a daily time step, and the results of both calibration and validation were compared on the basis-of their performance with regards to objective criteria representing the water balance, the Nash and Sutcliffe efficiency and the correlation coefficient. The first application corresponds to the case of an ungauged catchment i.e. a simple application of the model without calibration. In the second application, the model. was calibrated using discharge values measured at the outlet on the first five year period and validated using data from intermediate gauging stations and on the remaining period at the outlet. In the third application, a multi-site calibration and validation was conducted simultaneously for all available stations using the first five year period and validated on the second five year period for all stations. Calibration against the outlet station and internal validation against eight additional stations revealed some short-comings for a few upstream tributaries. Further calibration against additional discharge stations improved the model's performance at the subcatchment level. These different calibration and validation tests challenge the predictive capability of the model both at the catchment and subcatchment level and hence illustrate the model's possible improvements (structure, data and parameterisation strategy) for predictions on ungauged catchment

3. - Modélisation de la gestion des ressources en eau dans les zones littorales méditerranéennes. Application au cas du bassin versant du Lez

Water resources management deals with multiple interacting factors. An integrated model applied to a mediterraneen river bassin includes the relation between the watershed, human activities, and surface and underground water, both in terms of water quantity and water quality. Some of its simulation results disturbs the outlook into the pollution water quality relation, leads to reflections on water quality monitoring, and reveals the potential and the limits of an integrated approach to water management.La gestion des ressources en eau requiert la prise en compte de multiples facteurs en interactions. Le modèle présenté, appliqué à la gestion de l'eau d'un bassin méditerranéen, intègre la relation entre le bassin versant, les activités humaines et les milieux superficiels et souterrains, du point de vue des quantités aussi bien que de la qualité. Quelques résultats de simulation à l'aide de ce nouvel outil remettent en question les tiens entre pollution et qualité de l'eau, engagent une réflexion sur le suivi de la qualité de l'eau, et mettent en exergue les capacités et les limites d'une approche intégrée de l'eau.Colas H., Bocquillon C., Valette F. 3. - Modélisation de la gestion des ressources en eau dans les zones littorales méditerranéennes. Application au cas du bassin versant du Lez. In: L'avenir de l'eau. Quelques réponses des sciences hydrotechniques à une inquiétude mondiale. Vingt deuxièmes journées de l'hydraulique. Paris, 15-17 septembre 1992. Tome 3, 1992

Specific climate classification for Mediterranean hydrology and future evolution under Med-CORDEX regional climate model scenarios

International audienceThe Mediterranean region is one of the most sensitive regions to anthropogenic and climatic changes, mostly affecting its water resources and related practices. With multiple studies raising serious concerns about climate shifts and aridity expansion in the region, this one aims to establish a new high-resolution classification for hydrology purposes based on Mediterranean-specific climate indices. This classification is useful in following up on hydrological (water resource management, floods, droughts, etc.) and ecohydrological applications such as Mediterranean agriculture. Olive cultivation is the characteristic agricultural practice of the Mediterranean region. The proposed approach includes the use of classic climatic indices and the definition of new climatic indices, mainly precipitation seasonality index I-s or evapotranspiration threshold S-PET, both in line with river flow regimes, a principal component analysis to reduce the number of indices, K-means classification to distribute them into classes, and finally the construction of a decision tree based on the distances to class kernels to reproduce the classification without having to repeat the whole process. The classification was set and validated by WorldClim-2 at 1 km high-resolution gridded data for the 1970-2000 baseline period and 144 stations' data over 30 to 120 years, both at monthly time steps. Climatic classes coincided with a geographical distribution in the Mediterranean ranging from the most seasonal and driest class 1 in the south to the least seasonal and most humid class 5 in the north, showing the climatic continuity from one place to another and enhancing the visibility of change trends. The MED-CORDEX ALADIN and CCLM historical and projected data at 12 and 50 km resolution simulated under the RCP4.5 and 8.5 scenarios for the 2070-2100 period served to assess the climate change impact on this classification by superimposing the projected changes on the baseline grid-based classification. RCP scenarios increase the seasonality index I-s by +80% and the aridity index I-Arid by +60% in the north and I-Arid by +10% without I-s change in the south, hence causing the wet season shortening and river regime modification with the migration north of moderate and extreme winter regimes instead of early spring regimes. The ALADIN and CCLM regional climate models (RCMs) have demonstrated an evolution of the Mediterranean region towards arid climate. The classes located to the north are slowly evolving towards moderate coastal classes, which might affect hydrologic regimes due to shorter humid seasons and earlier snowmelts. These scenarios might look favourable for Mediterranean cultivation; however, the expected impact on water resources and flow regimes will surely expand and directly hit ecosystems, food, health, and tourism, as risk is interconnected between domains. This kind of classification might be reproduced at the global scale, using the same or other climatic indices specific to each region, highlighting their physiographic characteristics and hydrological responses

Classification climatique méditerranéenne pour l'hydrologie

La Méditerranée est une zone tempérée occupée par diverses populations la rendant une des régions les plus sensibles aux changements anthropiques et climatiques. L'objectif de ce travail est d'établir une classification climatique pour l'hydrologie qui met en évidence la continuité climatique d'un lieu à un autre et pourrait évaluer les tendances des changements. La démarche proposée comporte une Analyse en Composantes Principales pour réduire le nombre des indices climatiques et ne considérer que les plus contributaires, une classification en K-moyennes pour distribuer les stations en un certain nombre de classes, ici 5 et finalement la construction d'un arbre de décision à partir des distances aux noyaux des classes climatiques pour déterminer si un lieu quelconque possède ou non un climat méditerranéen et à quel type appartient-il. Les données de 144 stations au pas de temps mensuel dans 20 pays méditerranéens sont utilisées pour caler la classification, 36 autres stations pour vérifier cette classification en Méditerranée et 21 stations pour la vérifier au Chili et en Afrique du Sud connus pour leur climat à caractère Méditerranéen. Les résultats montrent que la distribution en 5 classes coïncide avec une distribution géographique en Méditerranée et l'analyse de la connexité interclasse montre que l'évolution du climat se fait de façon continue, puisqu'une même station peut obéir aux critères d'appartenance de plusieurs classes

Etude préliminaire du couvert neigeux et modèle de fonte des neiges pour le Mont Liban

Correspondance: [email protected], [email protected] audienceThe physical properties of snow, including apparent density, snow cover distribution and snowmelt in the Nahr El Kelb basin (Mount Lebanon), were studied in order to design a simple empirical snowmelt model. In February 2001, snow covered an area of 1600 km2 on Mount Lebanon, representing a water equivalent of 1.1 . 109 m3. The snow surface area was calculated by combining TM5 images with a digital elevation model, and field observations made every three days, from 1400 to 2300 m altitude. The depletion of snow cover was measured from the end of December 2000 to the end of June 2001. The snowmelt was measured from surface depletion on a degree-day basis. A simple model relating the daily snowmelt to the product of wind speed and average positive daily air temperature, is presented and discussed. For Mount Lebanon, this model gave a better approximation of snowmelt than a simple degree-day model.Les caractéristiques physiques de la neige, celles de sa répartition sur les versants, et de sa vitesse de fonte ont été étudiées sur le haut bassin du Nahr El Kelb (Mont Liban) en vue de produire un modèle de fonte empirique simple. En février 2001, la neige a couvert le Mont Liban sur une superficie de 1600 km2, soit une quantité équivalente à 1.1 . 109 m3 d’eau. Cette superficie a été calculée à partir d’imagettes satellites TM5, d’un modèle numérique de terrain et d’observations faites sur le terrain à toutes les altitudes, tous les trois jours. L’évolution dans le temps de cette superficie a été suivie entre fin décembre 2000 et fin juin 2001. Un modèle simple calcule la fonte journalière du manteau neigeux par rapport au produit de la moyenne des températures positives et de la vitesse du vent calculées de manière journalière. Ce modèle donne une meilleure approximation de la fonte qu’un simple modèle degré-jour