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Any change in the components of the water balance in a coastal aquifer, whether natural or anthropogenic, can alter the freshwater–salt water equilibrium. In this sense climate change (CC) and land use and land cover (LULC) change might significantly influence the availability of groundwater resources in the future. These coastal systems demand an integrated analysis of quantity and quality issues to obtain an appropriate assessment of hydrological impacts using density-dependent flow solutions. The aim of this work is to perform an integrated analysis of future potential global change (GC) scenarios and their hydrological impacts in a coastal aquifer, the Plana Oropesa-Torreblanca aquifer. It is a Mediterranean aquifer that extends over 75 km2 in which important historical LULC changes have been produced and are planned for the future. Future CC scenarios will be defined by using an equi-feasible and non-feasible ensemble of projections based on the results of a multi-criteria analysis of the series generated from several regional climatic models with different downscaling approaches. The hydrological impacts of these CC scenarios combined with future LULC scenarios will be assessed with a chain of models defined by a sequential coupling of rainfall-recharge models, crop irrigation requirements and irrigation return models (for the aquifer and its neighbours that feed it), and a density-dependent aquifer approach. This chain of models, calibrated using the available historical data, allow testing of the conceptual approximation of the aquifer behaviour. They are also fed with series representatives of potential global change scenarios in order to perform a sensitivity analysis regarding future scenarios of rainfall recharge, lateral flows coming from the hydraulically connected neighbouring aquifer, agricultural recharge (taking into account expected future LULC changes) and sea level rise (SLR). The proposed analysis is valuable for improving our knowledge about the aquifer, and so comprises a tool to design sustainable adaptation management strategies taking into account the uncertainty in future GC conditions and their impacts. The results show that GC scenarios produce significant increases in the variability of flow budget components and in the salinity., Unidad de Granada, Instituto Geológico y Minero de España, España, Universidad Católica de Murcia, España, Universitat Jaume I, Castellón de la Plana, España

A physically based hydroclimatological model (AMUNDSEN) is used to assess future climate change impacts on the cryosphere and hydrology of the Ötztal Alps (Austria) until 2100. The model is run in 100 m spatial and 3 h temporal resolution using in total 31 downscaled, bias-corrected, and temporally disaggregated EURO-CORDEX climate projections for the representative concentration pathways (RCPs) 2.6, 4.5, and 8.5 scenarios as forcing data, making this - to date - the most detailed study for this region in terms of process representation and range of considered climate projections. Changes in snow coverage, glacierization, and hydrological regimes are discussed both for a larger area encompassing the Ötztal Alps (1850 km2, 862-3770 m a.s.l.) as well as for seven catchments in the area with varying size (11-165 km2) and glacierization (24-77 %). Results show generally declining snow amounts with moderate decreases (0-20 % depending on the emission scenario) of mean annual snow water equivalent in high elevations (> 2500 m a.s.l.) until the end of the century. The largest decreases, amounting to up to 25-80 %, are projected to occur in elevations below 1500 m a.s.l. Glaciers in the region will continue to retreat strongly, leaving only 4-20 % of the initial (as of 2006) ice volume left by 2100. Total and summer (JJA) runoff will change little during the early 21st century (2011-2040) with simulated decreases (compared to 1997-2006) of up to 11 % (total) and 13 % (summer) depending on catchment and scenario, whereas runoff volumes decrease by up to 39 % (total) and 47 % (summer) towards the end of the century (2071-2100), accompanied by a shift in peak flows from July towards June. © Author(s) 2018.

Climate change impacts need to be considered in water resource planning. This work aims to study of the impacts climate change on Lavrinha headwater watershed, located in the Mantiqueira Range, southeastern Brazil. The impacts from climate change (RCP 8.5 scenario) in the Lavrinha watershed runoff were analyzed based on the "Distributed Hydrology Soil Vegetation Model" (DHSVM), forced with the climate simulated for this future climate change scenario. These simulations, in turn, were generated by the Eta regional climate model coupled to Global Climate Model (GCM) HadGEM2-ES for the 2011-2040, 2041-2070 and 2071-2099 periods. The results of this study showed that the runoff is very sensitive to rising temperatures and reduced precipitation, both projected for the RCP 8.5 scenario. The hydrological simulation projected a reduction in the monthly streamflow between 20 and 77% over the twenty-first century (2011-2099), corresponding to drastic reductions in the runoff behavior and consequently in the water production capacity of the region. RESUMO O impacto das mudanças climáticas precisa ser considerado no planejamento dos recursos hídricos. Este trabalho tem por objetivo o estudo dos impactos das mudanças climáticas na bacia de cabeceira Lavrinha, localizada na Serra da Mantiqueira, Sudeste do Brasil. Os impactos oriundos das mudanças climáticas (cenário RCP 8.5) no escoamento da bacia hidrográfica Lavrinha foram analisados com base no modelo "Distributed Hydrology Soil Vegetation Model" (DHSVM), forçado com as condições climáticas simuladas para este cenário futuro de mudanças climáticas. Estas simulações, por sua vez, foram geradas pelo modelo climático regional Eta acoplado ao Modelo Climático Global (MCG) HadGEM2-ES, nos períodos de 2011-2040, 2041-2070 e 2071-2099. Os resultados deste estudo mostraram que a vazão é bastante sensível ao aumento da temperatura e diminuição da precipitação, ambos projetados para o cenário RCP 8.5. A simulação hidrológica projetou uma redução na vazão mensal entre 20 e 77% ao longo do século XXI (2011 a 2099), correspondendo a reduções drásticas no escoamento e, consequentemente, na capacidade de produção de água da região.

Precipitation extremes play a key role in flooding risks over the Huaihe River Basin, which is important to understand their hydrological impacts. Based on observed daily precipitation and streamflow data from 1958 to 2009, eight precipitation indices and three streamflow indices were calculated for the study of hydrological impacts of precipitation extremes. The results indicate that the wet condition intensified in the summer wet season and the drought condition was getting worse in the autumn dry season in the later years of the past 50 years. The river basin had experienced higher heavy rainfall-related flooding risks in summer and more severe drought in autumn in the later of the period. The extreme precipitation events or consecutive heavy rain day events led to the substantial increases in streamflow extremes, which are the main causes of frequent floods in the Huaihe River Basin. The large inter-annual variation of precipitation anomalies in the upper and central Huaihe River Basin are the major contributor for the regional frequent floods and droughts.

International audience; Forest fire can modify and accelerate the hydrological response of Mediter- ranean basins submitted to intense rainfall: during the years following a fire, the effects on the hydrological response may be similar to those produced by the growth of impervious areas. Moreover, climate change and global warming in Mediterranean areas can imply consequences on both flash flood and fire hazards, by amplifying these phenomena. Based on historical events and post-fire experience, a methodology to interpret the impacts of forest fire in terms of rainfall-runoff model parameters has been proposed. It allows to estimate the consequences of forest fire at the watershed scale depending on the considered burned area. In a second stage, the combined effect of forest fire and climate change has been analysed to map the future risk of forest fire and their consequence on flood occur- rence. This study has been conducted on the Llobregat river basin (Spain), a catchment of approximately 5,000 km2 frequently affected by flash floods and forest fires. The results show that forest fire can modify the hydrological response at the watershed scale when the burned area is significant. Moreover, it has been shown that climate change may increase the occurrence of both hazards, and hence, more frequent severe flash floods may appear.

This report presents the water and climate adaptation plan (WATCAP) developed for the Sava river basin (SRB) as result of a study undertaken by the World Bank. The WATCAP is intended to help to bridge the gap between the climate change predictions for the SRB and the decision makers in current and planned water management investment projects that will be affected by changing climate trends. The purpose of the report is to: (i) assist stakeholders and decision makers in assessing and planning for the risks generated by climate change impacts on water resources; (ii) provide a basis for future plans and studies of adaptation to climate change impacts in the SRB; and (iii) stimulate cooperation and debate across the basin toward additional and more detailed studies on climate change impacts at the regional and basin scale. The SRB is projected to experience small increases in water use by the public water supply, industry, energy, and agricultural and irrigation sectors. However, it is widely expected that new hydropower plants (HPPs) will be constructed in the near future, making energy (primarily through hydropower) the most important water use in the SRB.

The impacts of invasions by alien plant species on the quantity of rainwater that reaches rivers and streams have been studied in several countries. Some studies have found that there is a large impact and others have found little or no impact. These conflicting conclusions can be explained largely by differences in the structure (e.g. height, depth of root systems) and the physiology (e.g. evergreen, deciduous, water stress tolerance) between the alien and the indigenous plant species. The greater the differences between the two, the greater the impact is likely to be., There have been many studies of the diverse impacts of invasions by alien plants but few have assessed impacts on water resources. We reviewed the information on the impacts of invasions on surface runoff and groundwater resources at stand to catchment scales and covering a full annual cycle. Most of the research is South African so the emphasis is on South Africa's major invaders with data from commercial forest plantations where relevant. Catchment studies worldwide have shown that changes in vegetation structure and the physiology of the dominant plant species result in changes in surface runoff and groundwater discharge, whether they involve native or alien plant species. Where there is little change in vegetation structure [e.g. leaf area (index), height, rooting depth and seasonality] the effects of invasions generally are small or undetectable. In South Africa, the most important woody invaders typically are taller and deeper rooted than the native species. The impacts of changes in evaporation (and thus runoff) in dryland settings are constrained by water availability to the plants and, thus, by rainfall. Where the dryland invaders are evergreen and the native vegetation (grass) is seasonal, the increases can reach 300–400 mm/year. Where the native vegetation is evergreen (shrublands) the increases are ∼200–300 mm/year. Where water availability is greater (riparian settings or shallow water tables), invading tree water-use can reach 1.5–2.0 times that of the same species in a dryland setting. So, riparian invasions have a much greater impact per unit area invaded than dryland invasions. The available data are scattered and incomplete, and there are many gaps and issues that must be addressed before a thorough understanding of the impacts at the site scale can be gained and used in extrapolating to watershed scales, and in converting changes in flows to water supply system yields.

Se realiza una descripción sintética de la hidrogeología de la masa de agua subterránea (M.A.Sb.) de Lebrija (Sevilla-Cádiz), y en particular del sector meridional de la misma donde se asienta la laguna de Los Tollos. El establecimiento de una explotación minera de arcillas fibrosas en el entorno de la laguna, así como las extracciones de aguas subterráneas para facilitar las labores mineras y para el abastecimiento urbano y el uso agrícola, produjeron impactos importantes sobre el funcionamiento hidrogeológico natural, principalmente caídas en los niveles piezométricos y migración de aguas salinas. La evolución hidrogeológica en el entorno de la laguna tras el cese de las actividades impactantes, indica una recuperación general de niveles en todos los subsistemas, y una tendencia a la igualación de los mismos. Esta recuperación, aunque positiva, es aún insuficiente de cara a la restauración ambiental que persigue el proyecto en que se enmarca este trabajo, A brief description of the hydrogeology of the GroundWater Body (GWB) of Lebrija (Cadiz-Seville) has been made, especially of its southern part, where Los Tollos shallow lake is located.An open pit mine of fibrous clays in the vicinity of the lake, as well as groundwater withdrawals to facilitate the mining and supply for urban and agricultural use, produced significant impacts on the natural hydrogeological functioning of the shallow lake. Such impacts where mainly a general lowering of the water table in the area and migration of saline water.The hydrogeological evolution of the area, after the ending of the environmental pressures, shows both a general recovery in all the aquifers of the GWB and a tendency for equilibrium. This recovery, although positive, is still not enough to achieve a complete environmental restoration of the lake,which is the main objective of the project in which this work is framed

Climate change is expected to alter the hydrological cycle resulting in large-scale impacts on water availability. However, future climate change impact assessments are highly uncertain. For the first time, multiple global climate (three) and hydrological models (eight) were used to systematically assess the hydrological response to climate change and project the future state of global water resources. This multi-model ensemble allows us to investigate how the hydrology models contribute to the uncertainty in projected hydrological changes compared to the climate models. Due to their systematic biases, GCM outputs cannot be used directly in hydrological impact studies, so a statistical bias correction has been applied. The results show a large spread in projected changes in water resources within the climate–hydrology modelling chain for some regions. They clearly demonstrate that climate models are not the only source of uncertainty for hydrological change, and that the spread resulting from the choice of the hydrology model is larger than the spread originating from the climate models over many areas. But there are also areas showing a robust change signal, such as at high latitudes and in some midlatitude regions, where the models agree on the sign of projected hydrological changes, indicative of higher confidence in this ensemble mean signal. In many catchments an increase of available water resources is expected but there are some severe decreases in Central and Southern Europe, the Middle East, the Mississippi River basin, southern Africa, southern China and south-eastern Australia.

Se realiza una descripción sintética de la hidrogeología de la masa de agua subterránea (M.A.Sb.) de Lebrija (Sevilla-Cádiz), y en particular del sector meridional de la misma donde se asienta la laguna de Los Tollos. El establecimiento de una explotación minera de arcillas fibrosas en el entorno de la laguna, así como las extracciones de aguas subterráneas para facilitar las labores mineras y para el abastecimiento urbano y el uso agrícola, produjeron impactos importantes sobre el funcionamiento hidrogeológico natural, principalmente caídas en los niveles piezométricos y migración de aguas salinas. La evolución hidrogeológica en el entorno de la laguna tras el cese de las actividades impactantes, indica una recuperación general de niveles en todos los subsistemas, y una tendencia a la igualación de los mismos. Esta recuperación, aunque positiva, es aún insuficiente de cara a la restauración ambiental que persigue el proyecto en que se enmarca este trabajo A brief description of the hydrogeology of the GroundWater Body (GWB) of Lebrija (Cadiz-Seville) has been made, especially of its southern part, where Los Tollos shallow lake is located.An open pit mine of fibrous clays in the vicinity of the lake, as well as groundwater withdrawals to facilitate the mining and supply for urban and agricultural use, produced significant impacts on the natural hydrogeological functioning of the shallow lake. Such impacts where mainly a general lowering of the water table in the area and migration of saline water.The hydrogeological evolution of the area, after the ending of the environmental pressures, shows both a general recovery in all the aquifers of the GWB and a tendency for equilibrium. This recovery, although positive, is still not enough to achieve a complete environmental restoration of the lake,which is the main objective of the project in which this work is framed

Dans les bassins versants méditerranéens où les zones cultivées en vigne occupent une part importante de l'espace, les pratiques culturales sont un facteur important d'apparition de risques de pollution diffuse des eaux par les pesticides. Au cours de la thèse, une démarche de modélisation couplée pression-impact a été développée. La question de recherche a porté sur la prise en compte dans le modèle construit de la dynamique des variables d'état du milieu modifiées par les actions culturales. Deux variables ont été identifiées : l'infiltrabilité de la surface du sol et la concentration en matières actives au sol. A l'échelle du bassin versant, pour réaliser l'évaluation des impacts, on s'est appuyé sur l'utilisation du modèle hydrologique distribué MHYDAS qui permet de simuler les flux d'eau et de polluants selon différents scenarii de pratiques et climatiques. Pour représenter la répartition spatio-temporelle des opérations culturales sur chacune des parcelles du bassin versant, le modèle décisionnel DHIVINE a été construit. Il permet de simuler les itinéraires techniques des viticulteurs. Pour chaque exploitation du bassin versant, le modèle est basé sur une représentation de la conduite technique annuelle du vignoble sous forme de plans d'activités. Ces plans mettent en oeuvre des indicateurs d'états de l'agrosystème et prennent en compte les caractéristiques des ressources productives de l'exploitation ainsi que les arbitrages à réaliser entre opérations culturales et parcelles concurrentes. Des modèles biophysiques ont été développés pour simuler les indicateurs de la décision ainsi que l'impact des différentes pratiques sur les états de surface du sol qui conditionnent l'infiltrabilité du sol en surface. Une typologie fonctionnelle des états de surface basée sur leurs propriétés d'infiltrabilité du sol a été utilisée pour développer une démarche visant une modélisation continue dans le temps de l'infiltration. Elle intègre une modélisation parallèle de la dynamique des états de surface du sol nu et du développement de la couverture herbacée par les adventices. Un couplage des modèles a été réalisé sous la plate-forme OpenFLUID. La démarche adoptée ici permet de représenter les dynamiques différentes des variables d'état du milieu en fonction de différentes pratiques culturales et semble adaptée pour l'évaluation des impacts en terme de pollution de l'eau par les pesticides à l'échelle de bassins versants viticoles méditerranéens., In Mediterranean catchments in which vineyards account for a major share of the area, cropping practices are an important factor with respect to increasing risks of diffuse pesticide pollution of water. This study was about developping an approach for pressure-impact modelling. The research question considered dynamics of agrosystem status variables modified by cropping actions. Two variables were identified : soil surface infiltrability and active material concentration on the soil. On a catchment scale, to assess impacts, we used the distributed hydrological model MHYDAS to simulate water and pollutant flows according to different cropping practice and climatic scenarios. To represent the spatiotemporal distribution of cropping operations on each plot, the decision model DHIVINE was built. It simulates vinegrowers's crop management sequences. For each farm in the catchment, the model is based on a representation of the vineyard annual technical management strategy in the form of activity plans. These plans involve agrosystem status indicators and take into account the characteristics of productive resources on the farm and arbitration between cultivation operations and competing plots. Biophysical models were developped to simulate decision indicators and impacts of cropping practices on soil surface characteristics which are drivers of soil surface infiltrability. A functional typology of soil surface states based on their soil infiltrabilty properties was used to develop an approach for temporally continuous modelling of infiltration. It was based on a parallel modelling of dynamics (i) of soil surface characteristics of bare soil and (ii) of weed cover development. Model coupling was realized with OpenFLUID platform. The approach developped herein allows simulating dynamics of agrosystem status variables as a function of cropping practices. It seems adapted for assessing hydrological impacts at the catchment scale in Mediterranean environments.

International audience

An example of karst water resources exploitation : snow production in Villard-de-Lans-Corrençon-en-Vercors (Isere, France) This article proposes a geographical approach of water resources exploitation on Villard-de-Lans and Correncon-en-Vercors karst (Isere, France). Increasingly employed around the world on skiable fields to make reliable ski lifts exploitation, artificial snow is also largely used on Villard-Corrençon ski resort, in answer to the variability of snow-covered precipitations of Vercors plateau. Winter sports tourism, and particularly downhill skiing, is indeed one of the economic activities of this territory. The snow production requires important water volumes onto a field which, taking into account its karstic characteristics, presents paradoxically a relative surface aridity. To satisfy these needs, the karstic emergence of Goule Blanche is exploited. Since its discharge system, which concentrates the whole of the underground flows, water is conveyed at a long distance towards two artificial storage reservoirs built on the skiable field, via the drinking water network of Villard-de-Lans. The analysis of the interrelationships between the various water uses involved (artificial snow, drinking water, hydroelectricity), and the impacts of artificial snow on the karstic water resources, allow us to question the application of integrated water resources management concept on this territory., Cet article a pour objet l'exploitation des ressources en eau du karst de Villard-de-Lans et de Corrençon-en-Vercors (Isère, France) pour la production de neige. De plus en plus employée sur les domaines skiables pour fiabiliser l'exploitation des remontées mécaniques, la neige de culture l'est aussi largement sur le domaine skiable de Villard-Corrençon. Cette pratique est une réponse à la variabilité des précipitations neigeuses du massif du Vercors. Le tourisme des sports d'hiver, le ski alpin en particulier, est en effet une des activités économiques importantes de ce territoire. La production de neige nécessite la mobilisation d'importants volumes d'eau sur un terrain qui, compte tenu de ses caractéristiques karstiques, présente une relative indigence d'eau en surface. Pour satisfaire ces besoins en eau, l'émergence de Goule Blanche est exploitée. Depuis cet exutoire karstique, l'eau est acheminée vers deux ouvrages artificiels de stockage construits sur le domaine skiable, en passant par le réseau d'eau potable de la commune de Villard-de- Lans. L'analyse des interrelations entre les différents usages de l'eau en présence (neige de culture, eau potable, hydroélectricité), et des impacts de la production de neige sur le karst et ses ressources en eau, nous permet de questionner l'application du concept de gestion durable de la ressource en eau sur ce territoire., Paccard Pierre. Un exemple d'exploitation des ressources en eau du karst : la production de neige à Villard-de-Lans - Corrençon-en-Vercors (Isère, France). In: Karstologia : revue de karstologie et de spéléologie physique, n°53, 1er semestre 2009. Stalagmites et imageries 3D dans l'aven d'Orgnac. pp. 41-52.

Les bassins versants influencés par la présence de barrages-réservoirs constituent les objets d'étude de cette thèse. L'objectif principal est de mettre au point une méthode de prise en compte, au sein d'un modèle pluie-débit global, de l'impact de retenues d'eau artificielles sur le comportement hydrologique du bassin versant. Un tel outil, simple dans sa conception, doit permettre d'améliorer la simulation des débits de bassins versants influencés et d'évaluer l'impact de barrages-réservoirs sur le régime hydrologique des cours d'eau, en particulier lorsque l'on se place loin à l'aval de l'ouvrage. La démarche adoptée est empirique dans le sens où l'on a cherché, sur une base de données de 46 bassins versants situés en France, aux Etats-Unis et au Brésil, à exploiter au mieux, dans la structure du modèle pluie-débit, une information simple sur les ouvrages, à savoir l'évolution temporelle des volumes stockés dans les retenues. La diversité des conditions hydro-climatiques présentes dans la base de données donne aux résultats obtenus un caractère assez général. Au cours de cette thèse, un grand nombre de solutions de prise en compte des barrages-réservoirs a été testé. Les résultats montrent que cette information sur les remplissages des ouvrages peut être utilement exploitée au sein d'une structure de modèle global pour améliorer la simulation des bassins influencés. Les solutions qui se sont révélées être les plus performantes n'engendrent pas de complexification de la structure initiale du modèle puisqu'aucun ajout de paramètre n'a été nécessaire. Des gains de performances significatifs ont été réalisés, en particulier sur la simulation des étiages. Il s'agit d'un résultat important de la thèse car il montre qu'il est possible de prendre explicitement en compte, dans un modèle pluie-débit global, les barrages-réservoirs présents sur le bassin versant. Nous avons ensuite essayé de comprendre le lien entre la méthode de prise en compte des barrages-réservoirs et certaines caractéristiques physiques des bassins versants et des ouvrages de stockage afin de tenter d'adapter la solution au bassin versant considéré. Les résultats de ces tests ont montré que ce lien est difficile à mettre en évidence et qu'à ce stade, une solution générique semble la plus efficace. La solution la plus performante a ensuite été évaluée sur un échantillon complémentaire de 31 bassins versants n'ayant pas servi à son développement. L'évaluation a confirmé l'intérêt de la méthode pour l'amélioration des simulations des débits mais a également montré sa sensibilité à la disponibilité des données de stockages ainsi qu'aux transferts interbassins inconnus.