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International audience; Le changement climatique accentue les phénomènes extrêmes comme les sécheresses. À l’échelle mondiale, la concurrence pour l’usage de l’eau sera donc exacerbée. Des progrès considérables ont été réalisés récemment concernant le réservoir utile en eau des sols et ses modes d’estimation, tant dans les techniques d’évaluation de ce réservoir et de sa cartographie, que dans le suivi du stress hydrique des plantes. La vigne est un cas particulier en raison de son système de conduite et de son mode d’enracinement, ainsi que de l’influence du régime hydrique sur la qualité organoleptique et sanitaire des raisins. Sous un climat comparable, des sols très différents peuvent avoir des effets similaires sur la régulation de l’alimentation estivale de la vigne. Nous évoquons les progrès et les lacunes en matière de suivi de l’alimentation en eau de la vigne. Nous soulignons leurs possibilités et leurs limites d’extrapolation, d’utilisation et de transfert vers des outils d’aide à la décision (OAD). Nous explorons les principaux verrous de connaissance à lever en priorité et les interrogations relatives à la gestion de l’eau en contexte viticole.

International audience; Les effets du changement climatique ont plusieurs impacts sur la vigne en France et sont aujourd’hui bien documentés : Aussi bien la tendance au réchauffement que la fréquence et l’intensité d’évènements extrêmes ont des répercussions sur les rendements viticoles en région Centre-Val de Loire et plus largement dans le Val de Loire. Si l’élévation de la température a atténué une acidité parfois problématique, elle provoque un débourrement plus précoce qui rend les vignes vulnérables au gel. Aussi, la grêle, les vagues de chaleur, les épisodes de sécheresse sont autant d’évènements extrêmes qui amènent à des pertes de rendement devenues régulières et problématiques. Dans ce contexte, le présent article s’intéresse à montrer comment la question de la relocalisation du vignoble, et ce à différentes échelles spatiales, est au cœur des stratégies d’adaptation des exploitations viticoles au changement climatique. Entre ré-allocation des cépages dans une exploitation, ré-organisation du périmètre des AOC et nomadisme, comment les viticulteurs viennent à considérer cette option comme une stratégie d’adaptation ?

With the motivation to improve the understanding on the national and local levels of governance, this chapter focuses on the actors at these two levels, such as ministries, provincial and municipal authorities, and non-governmental organizations (NGOs). It specifically aims to create insights into the involvement of these actors in the design, implementation, and evaluation of drought resilience measures, and seeks to identify recommendations to improve this involvement. The chapter presents a comparative review of the six cases that were included within the scope of the 'DROP' (Benefits of governance in DROught adaptation) project. The geographical boundaries of the case studies included in the DROP project and compared in the chapter cover sub-national 'regions' that consists of several cities or towns. Amongst the six cases, the only case that covers a formally defined jurisdictional region is the Belgian case, where Flanders is examined as an entire federal region.

International audience

This chapter proposes an analysis of the water and drought governance contexts in case studies of two countries of North West Europe (NWE) that have been jointly impacted during the past severe droughts, France and the United Kingdom (UK) with respectively two case studies: the Vilaine catchment in French Brittany, and the Somerset Levels and Moors in south west UK. It presents a comparative analysis of the outputs of the implementation of the Governance Assessment Tool developed by H. Bressers et al. with the Contextual Interaction Theory, the theory at the origins of the GAT. After a brief description of the two case studies, the chapter describes the methodology used to study drought governance, both the GAT as refined in the European DROP‐project for drought‐governance analysis and the Contextual Interaction Theory. It also presents the main results and discussion. The chapter further presents general conclusions for drought‐governance resilience in NWE.

This chapter discusses the strategies that are of importance in the development of policy responses to the water‐scarcity issues. Different packages of measures are possible to increase resilience towards drought. Three general strategies can be discerned. These strategies are reactive, preventive, and adaptive. Each of these strategies can be coupled with types of measure. To improve the evaluation of past experiences, for the development of a more long‐term orientation, and the involvement of all stakeholders and their interests, people need to increase their consciousness of the natural conditions and socio‐economic factors that affect water utilization patterns and the problems of drought and water scarcity that might result. This leads to a fourth necessary strategy that can be labelled as supportive measures, consisting mostly of research and communication measures. The chapter elaborates the taxonomy of drought measures and gives several examples.

Rainfall-induced peaks in pesticide concentrations can occur rapidly; therefore, low frequency sampling may largely underestimate maximum pesticide concentrations and fluxes. Detailed storm-based sampling of pesticide concentrations in runoff water to better predict pesticide sources, transport pathways and toxicity within the headwater catchments is actually lacking. High frequency monitoring (2 min) of dissolved concentrations and loads for seven pesticides (Dimetomorph, Fluopicolide, Glyphosate, Iprovalicarb, Tebuconazole, Tetraconazole and Triadimenol) and one degradation product (AMPA) were assessed for 20 runoff events from 2009 to 2012 at the outlet of a vineyard catchment in the Layon catchment in France. The pesticide concentrations reached 387 g/L. All of the runoff events exceeded the mandated acceptable concentrations of 0.1 g/L for each pesticide (European directive 2013/39/EC). High resolution sampling used to detect the peak pesticide levels revealed that Toxic Units (TU) for algae, invertebrates and fish often exceeded the European Uniform principles (25%). The instantaneous and average (time or discharge-weighted) concentrations indicated an up to 30- or 4-fold underestimation of the TU obtained when measuring the maximum concentrations, respectively, highlighting the important role of the sampling methods for assessing peak exposure. High resolution sampling combined with concentration-discharge hysteresis analyses revealed that clockwise responses were predominant (52%), indicating that Hortonian runoff is the prevailing surface runoff trigger mechanism in the study catchment. The hysteresis patterns for suspended solids and pesticides were highly dynamic and storm- and chemical-dependent. Intense rainfall events induced stronger C-Q hysteresis (magnitude). This study provides new insights into the complexity of pesticide dynamics in runoff water and highlights the ability of hysteresis analysis to improve the understanding of pesticide supply and transport.

International audience; The European Water Framework Directive (2000) required to achieve good ecological and chemical status in surface waters of the EU Member States in 2015. For pesticides, this means ensuring that concentrations in rivers do not exceed 0.1 g/L per molecule and 0.5 g/L for the sum of the concentrations of the different molecules found. At national scale, EcoPhyto plan (2008) aimed to reduce pesticide use by 50% within 10. This plan has been revised and postponed to 2025 as observed pesticide use is varying between years and concentrations in river did not decrease as expected.Although vineyards cover a small percentage of agricultural land surfaces, they contribute to 20% of national pesticide use. The presence of pesticides in rivers surrounding wine territories is therefore a current environmental concern. Thus, the recovery of the water quality requires local action programs to reduce pesticide contamination in rivers.The Layon catchment comprises 13% of vineyard. It is therefore subject to an action program led by the local water committee: the SAGE Layon-Aubance-Louet. Its goal is to ensure pesticide concentrations are reduced to 1 g/L in 2018 and 0.5 g/L in 2027. In this context, one of the actions of the SAGE, with the assistance of the University of Angers, addresses the study of peaks in pesticide concentrations during runoff events in a small catchment covered by vineyards. Between 2009 and 2016, one of the two farmers has converted to organic farming with consequent decreases in pesticides input to the case study which thus complied with the EcoPhyto objectives. Results demonstrate first a peak intensity of pesticides in runoff waters in relation with the date of application with a decrease of concentrations during time after the treatment and second a relation between peaks of SPM and pesticides. Transfer of pesticides in this catchment is strongly linked to runoff. Thus, even if the increase of grass surface within vineyard improves the soil stability and decreases erosion sensitivity, it is not sufficient to stop all transfer of pesticides. Following the results of this study, neither the objectives of national policies to reduce by half the pesticide use nor the local objectives to decrease partially the un-weeded surface of vineyards would permit to achieve good chemical status, as confirmed by the current state of the water quality of the Layon river monitored by local water managers. Thus, in the continuation of all its efforts

National audience; Au-delà des incertitudes sur les causes, le réchauffement climatique est une certitude. L'élévation de la température moyenne des océans ne laisse aucune ambiguïté sur l'ampleur des modifications à attendre sur le cycle hydrologique. Toutefois , les résultats du couplage des modèles climatiques et hydrologiques sont incertains. Alors, à quelle ampleur de modifications nos sociétés doivent-elles se préparer? Pourquoi établit-on un lien entre changement climatique, eau et sécurité? Le présent article souhaite, après une description des certitudes et des incertitudes sur le changement climatique observé et projeté, notamment par les travaux du GIEC, se focaliser sur l'impact du changement climatique sur le cycle de l'eau et les zones les plus vulnérables pour les sociétés humaines.

This chapter presents a summary of the analysis results of the governance of drought-related issues in the Flanders region of Belgium. In the context of the Interreg IV-B project DROP, a team of researchers from four universities and knowledge institutes visited Flanders twice to perform interviews with authorities and stakeholders (October 2013 and May 2014). The visit was supported by colleagues at the Flemish Environment Agency (Vlaamse Milieumaatschappij, VMM). The exchange was held in the form of individual and group interviews and workshops with stakeholders including representatives from different institutions and sectors, e.g. from the drinking water company, national and local nature protection organizations, local farmers and local and national farmers organizations, the Flemish Environment Agency, different provinces, e.g. Province Vlaams-Brabant, and local municipalities, e.g. Kortemark Municipality. The analysis was guided by the drought-related Governance Assessment Tool (GAT) developed for the project

Historically, flooding has dominated the physical and political landscape of Somerset—particularly over the winter of 2013/2014 when a devastating and high profile flood hit the region. However, the area is also sensitive to drought and water scarcity (DW the extent of the relationships and capacities that were increasingly being built to deal with policies and on-the-ground measures for DW and the increasing visibility of the issue of D&WS for the region after a period of extended dryness. The implications for drought governance in the context of flooding recovery are also discussed, particularly engaging with critical geographical literatures on the emotional and political work underpinning water management in the region, and how such processes are underpinned by broader meta-governance failures in the English water sector.

North-West Europe will increasingly face drought periods that may se-riously affect inter alia agricultural production, natural ecosystems and fresh water supplies. In addition to implementing hard adaptation measures, enhancing regional water governance is crucial for effective drought adaptation. One of the objectives of the DROP project is to identify possible improvements to regional governance settings in six case study areas: Flanders (BE), Somerset (UK), Eifel-Rur (DE), Vi-laine (FR), Vechtstromen (NL) and Groot Salland (NL). The basis for the analysis is a Governance Assessment Tool adapted for the analysis of the resilience of the system to face droughts and water scarcity. This tool is elaborated from a concept of “governance” as a modification and extension of the concept of “policy”. The paper introduces this Governance Assessment Tool and presents insights of its application in the six case study areas.

International audience

International audience; Within the framework of the EU-founded CLIMB project (Climate Induced Changes on the Hydrology of Mediterranean Basins) the water balance model mGROWA (Herrmann, 2013) was applied in order to simulate the water balance within the Thau Lagoon catchment (France) under present and possible future climate conditions. The model was originally developed in order to simulate actual evapotranspiration and runoff components (e.g. groundwater recharge) in daily time-steps and with high spatial resolution (50 m grid). Area-differentiated groundwater recharge and soil water content can be simulated consistently using mGROWA because of an integrated multi-layer soil water module. In the framework of CLIMB, this module has been extended by routines to calculate drought statistics.

Date du colloque: 2014

International audience

International audience

National audience

Date du colloque: 2012