Inondabilité : une méthode de prévention raisonnable du risque d'inondation pour une gestion mieux intégrée des bassins versants

Une partie de la réponse aux impacts économiques, sociaux et humains des inondations réside en une meilleure gestion de l'occupation des sols. La méthode Inondabilité permet d'apporter une réponse opérationnelle aux acteurs en charge de la gestion et l'aménagement des cours d'eau. Elle permet de mesurer dans la même unité et de comparer les deux facteurs indépendants que sont l'aléa et la vulnérabilité, pour aboutir à une quantification objective du risque. Sa mise en oeuvre sur un bassin versant consiste en une modélisation de l'hydrologie grâce aux modèles Débit-durée-Fréquence, de l'hydraulique ainsi que de l'occupation du sol pour aboutir à une représentation cartographique du risque.L'originalité de la méthode Inondabilité tient à la quantification de l'aléa et de la vulnérabilité en une même unité, une période de retour qui permet une comparaison objective de deux grandeurs très différentes. De plus, la quantification du risque est estimée à l'aide d'une différence (Risque=∆ (aléa, vulnérabilité)) contrairement aux approches traditionnelles qui privilégient souvent un produit (Risque=Coût X probabilité ), permettant ainsi la définition d'un risque acceptable (∆ négatif).In recent years, the incidence of flood damage in France and Europe has demonstrated that we still have some progress to achieve if we are to cope with inundations. To do so, prevention, forecasting and promotion of risk culture or awareness are possible tools. They should be used together because of their complementary nature and their common field of application. In risk prevention, it seems that conceptualizing risk by dividing it between a socio-economic dimension (vulnerability) and a hydrological dimension (hazard) is a productive approach.The first factor, "vulnerability", takes into account how a certain land use can deal with the phenomena, regardless of its occurrence. It is mostly relevant to the fields of sociology and economics. The second factor, "hazard", summarizes the natural phenomena, the occurrence of which could create human or economic damage. Both of these factors are relevant to hydrology and hydraulic sciences and have been studied for years. A given land area could be considered as "risky" when the probability of occurrence of the hazard is higher than what can be tolerated. Both hazard and vulnerability should be estimated as objectively as possible. The main difficulty in comparing these two factors is to define a similar measure for the two concepts, with a single unit. This is the purpose of the Inondabilité method: to produce a similar reference allowing an objective comparison.The aim of Inondabilité is to define a method to quantify both hazard and vulnerability in a compatible manner and then to build easy-to-understand, synthetic maps of risks as the basis for a real negotiation in the land-use planning process. Such maps allow the comparison of different evolution scenarios, taking into account the two components of risk, and their possible changes.Hydrology should give a synthetic description of the flow regime of the studied river. This can be based on flow-duration-frequency (QdF) models which describe the statistical functioning of the catchment and facilitate the calculation of the probability of events. Such synthetic models also yield synthetic hydrographs that are useful for hydraulic modelling and allow the quantification of vulnerability. Hydraulics is specially used to calculate hazard. Using hydrological results, a hydraulic model calculates flooded areas for flows of various return periods, from frequent to extreme. Each land parcel could be affected by the return period of the first flooding discharge corresponding to its hazard level. The same model will then be used to estimate the consequences of hydraulic works.Describing land use allows us to attribute a reasonable protection target to each land type. Varied areas such as natural (forests, grass lands, …), rural (crops fields, orchards, …) and urban (camping areas, leisure areas, cities …) should be treated differently. Each land-use type is characterized by a target expressed in terms of frequency, duration and depth of an acceptable flood, resulting from local reviews and consultations. Then, an equivalent measure could be calculated, according to flow-duration-frequency models. Its unit is a return period expressed in years.After these two steps, that is to say hazard and vulnerability analysis, it is possible to build different maps. Hazard maps show the flooded areas for different return period flows. Vulnerability maps show the spatial distribution of this measure, equivalent to the need for protection allocated to each parcel according to its land use. The two variables being expressed in the same units, a return period in units of years, it is easy to compare them for each parcel and to convert this comparison into an easy-to-understand colour code:- either hazard is higher than vulnerability (the hazard's return period is lower than that of vulnerability): this shows an incompatibility between the desired protection target and the actual hydraulic constraint, and the parcel is colored in red ; - or hazard is lower than vulnerability (the hazard's return period is higher …), which shows a reasonable safety of the parcel according to its land use, and the parcel is colored in green ; - or the parcel is away from the maximum flooded area: there is no risk at all, and the parcel is colored in yellow . The same formalism allows the representation of the results for any kind of solution, structural options such as hydraulic works, or non-structural options such as changes in land-use planning, and their comparison. Synthetic maps are a more efficient way to compare management scenarios and their effect on the distribution of risk all along the river than are classical design flow studies. They should facilitate real negotiation and lead to a more sustainable river management.The Inondabilité method offers advantages from other commonly used methods. First, it doesn't deal with only one referenced flood but with floods of various frequencies. It provides a good description of the overall regime of the catchment. Second, the definition of the risk as a difference ( Risk=∆ (Hazard, vulnerability)) implies a search of an acceptable solution instead of an optimized solution, usually impossible to reach. Third, the projection of vulnerability and hazard in a 1D space makes it very easy to draw a risk map, and this map is easy to understand for anybody, even non technical personnel.The originality of Inondabilité method lies in the quantification of vulnerability and hazard in the same unit, a flood return period. However, in the future more economic and social concepts have to be introduced to better fit the complex reality

Genetic variation of CYP2C19 affects both pharmacokinetic and pharmacodynamic responses to clopidogrel but not prasugrel in aspirin-treated patients with coronary artery disease

The metabolic pathways leading to the formation of prasugrel and clopidogrel active metabolites differ. We hypothesized that decreased CYP2C19 activity affects the pharmacokinetic and pharmacodynamic response to clopidogrel but not prasugrel. Ninety-eight patients with coronary artery disease (CAD) taking either clopidogrel 600 mg loading dose (LD)/75 mg maintenance dose (MD) or prasugrel 60 mg LD/10 mg MD were genotyped for variation in six CYP genes. Based on CYP genotype, patients were segregated into two groups: normal function (extensive) metabolizers (EM) and reduced function metabolizers (RM). Plasma active metabolite concentrations were measured at 30 min, 1, 2, 4, and 6 h post-LD and during the MD period on Day 2, Day 14, and Day 29 at 30 min, 1, 2, and 4 h. Vasodilator-stimulated phosphoprotein (VASP) and VerifyNow (TM) P2Y12 were measured predose, 2, and 24 +/- 4 h post-LD and predose during the MD period on Day 14 +/- 3 and Day 29 +/- 3. For clopidogrel, active metabolite exposure was significantly lower (P = 0.0015) and VASP platelet reactivity index (PRI, %) and VerifyNow (TM) P2Y(12) reaction unit (PRU) values were significantly higher (P < 0.05) in the CYP2C19 RM compared with the EM group. For prasugrel, there was no statistically significant difference in active metabolite exposure or pharmacodynamic response between CYP2C19 EM and RM. Variation in the other five genes demonstrated no statistically significant differences in pharmacokinetic or pharmacodynamic responses. Variation in the gene encoding CYP2C19 in patients with stable CAD contributes to reduced exposure to clopidogrel's active metabolite and a corresponding reduction in P2Y(12) inhibition, but has no significant influence on the response to prasugrel

Single high-dose erythropoietin administration immediately after reperfusion in patients with ST-segment elevation myocardial infarction: results of the Erythropoietin in Myocardial Infarction Trial

Background Preclinical studies and pilot clinical trials have shown that high-dose erythropoietin (EPO) reduces infarct size in acute myocardial infarction. We investigated whether a single high-dose of EPO administered immediately after reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) would limit infarct size. Methods A total of 110 patients undergoing successful primary coronary intervention for a first STEMI was randomized to receive standard care either alone (n = 57) or combined with intravenous administration of 1,000 U/kg of epoetin β immediately after reperfusion (n = 53). The primary end point was infarct size assessed by gadolinium-enhanced cardiac magnetic resonance after 3 months. Secondary end points included left ventricular (LV) volume and function at 5-day and 3-month follow-up, incidence of microvascular obstruction (MVO), and safety. Results Erythropoietin significantly decreased the incidence of MVO (43.4% vs 65.3% in the control group, P = .03) and reduced LV volume, mass, and function impairment at 5-day follow-up (all P &lt; .05). After 3 months, median infarct size (interquartile range) was 17.5 g (7.6-26.1 g) in the EPO group and 16.0 g (9.4-28.2 g) in the control group (P = .64); LV mass, volume, and function were not significantly different between the 2 groups. The same number of major adverse cardiac events occurred in both groups. Conclusions Single high-dose EPO administered immediately after successful reperfusion in patients with STEMI did not reduce infarct size at 3-month follow-up. However, this regimen decreased the incidence of MVO and was associated with transient favorable effects on LV volume and function

Modifying effect of dual antiplatelet therapy on incidence of stent thrombosis according to implanted drug-eluting stent type

Aim To investigate the putative modifying effect of dual antiplatelet therapy (DAPT) use on the incidence of stent thrombosis at 3 years in patients randomized to Endeavor zotarolimus-eluting stent (E-ZES) or Cypher sirolimus-eluting stent (C-SES). Methods and results Of 8709 patients in PROTECT, 4357 were randomized to E-ZES and 4352 to C-SES. Aspirin was to be given indefinitely, and clopidogrel/ticlopidine for ≥3 months or up to 12 months after implantation. Main outcome measures were definite or probable stent thrombosis at 3 years. Multivariable Cox regression analysis was applied, with stent type, DAPT, and their interaction as the main outcome determinants. Dual antiplatelet therapy adherence remained the same in the E-ZES and C-SES groups (79.6% at 1 year, 32.8% at 2 years, and 21.6% at 3 years). We observed a statistically significant (P = 0.0052) heterogeneity in treatment effect of stent type in relation to DAPT. In the absence of DAPT, stent thrombosis was lower with E-ZES vs. C-SES (adjusted hazard ratio 0.38, 95% confidence interval 0.19, 0.75; P = 0.0056). In the presence of DAPT, no difference was found (1.18; 0.79, 1.77; P = 0.43). Conclusion A strong interaction was observed between drug-eluting stent type and DAPT use, most likely prompted by the vascular healing response induced by the implanted DES system. These results suggest that the incidence of stent thrombosis in DES trials should not be evaluated independently of DAPT use, and the optimal duration of DAPT will likely depend upon stent type (Clinicaltrials.gov number NCT00476957

The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2-7 m, while providing data at sub-mm to mm scales. We report on SuperCam's science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.In France was provided by the Centre National d'Etudes Spatiales (CNES). Human resources were provided in part by the Centre National de la Recherche Scientifique (CNRS) and universities. Funding was provided in the US by NASA's Mars Exploration Program. Some funding of data analyses at Los Alamos National Laboratory (LANL) was provided by laboratory-directed research and development funds

Réalimentation en eau du lac Tanda

Hydraulic computation of the Tanda lake water filling in Mali to use it for fall cropping. Reactualization of a study completed in 1986 using recent typographic data (1990) and revised hydrologic data. Proposals for additional installations for the channel recalibration in order to ease the water filling. / Calcul hydraulique de remplissage du lac Tanda au Mali pour le mettre en valeur par cultures de décrues. Réactualisation d'une étude faite en 1986 à partir de données typographiques récentes (1990) et de données hydrologiques actualisées. Propositions de travaux complémentaires de recalibrage du chenal pour faciliter le remplissage

Avancées du Cemagref sur le plan morphologique

This article presents the last works of hydrology-hydraulic division of Cemagref (Lyon) in the field of geomorphology and river dynamics. It presents some first results and, as a conclusion, proposed some reflexions and future research activities. / Cet article fait le point des derniers travaux de la Division Hydrologie - Hydraulique du Cemagref (Lyon) dans le domaine de la dynamique fluviale et de la géomorphologie des cours d'eau. Il présente quelques premiers résultats et en, conclusion propose quelques pistes de réflexions sur les directions qu'il serait bon d'approfondir à l'avenir

Crues et inondations : quelques définitions et principes généraux

This article is a brief summary of general principles related to risk management that any contractor should keep in mind when designing a development project or any project aimed at reducing flood hazards. / L'article rappelle brièvement des principes généraux en matière de gestion du risque, que tout aménageur devrait constamment garder à l'esprit lors de l'élaboration du projet d'aménagement, et destinés à réduire le risque d'inondation

Solidarité du bassin versant pour la maîtrise du risque d'inondation : l'exemple de la Bourbre

River and flood risk management must respect general rules : multiple functions and uses, natural variability of the system, hydraulic laws, socio - economical constraints... The example of general studies managed on river Bourbre catchment and general river management they lead to show that it is possible and necessary to take in account a real solidarity between all the communes of the catchment in order to manage efficiently flood risk, solidarity between all the communes of the catchment in order to manage efficiently flood risk, to an acceptable level, respecting water resources. We assume that such a new approach will lead to more sustainable rivers management. / Aménagement de rivière et maîtrise du risque d'inondation nécessitent de respecter certaines règles : fonctions et usages multiples, variablité naturelle du système, lois physiques des écoulements, prise en compte de contraintes socio - économiques... L'exemple des études entreprises sur le bassin versant de la Bourbre et des travaux sur lesquels elles débouchent montre qu'il est possible et nécessaire de mettre en place une solidarité intercommunale à l'échelle du bassin versant dans son ensemble pour un aménagement efficace et harmonieux d'une rivière, permettant de maîtriser à un niveau acceptable le risque d'inondation tout en respectant la ressource en eau.On peut penser que ces nouvelles approches permettront des aménagements plus durables des cours d'eau

Risque d'inondation : conflits d'usage ou solidarités de bassin versant ? Quel rôle peut jouer le monde rural...

This article deals with risk management in accordance with water resource and environment preservation. It tries to show how rural areas can play an important function to improve a risk situation of a catchment, due to their low vulnerability. / Cet article présente rapidement les principes d'une gestion du risque compatible avec la préservation de la ressource en eau et du milieu et tente de montrer comment le monde rural peut contribuer, grâce à sa faible vulnérabilité à une amélioration générale de la situation de risque d'un bassin versant