The Global Groundwater Crisis

Groundwater depletion the world over poses a far greater threat to global water security than is currently acknowledged

From Global to Local and Vice Versa: On the Importance of the 'Globalization' Agenda in Continental Groundwater Research and Policy-Making.

Groundwater is one of the most important environmental resources and its use continuously rises globally for industrial, agricultural, and drinking water supply purposes. Because of its importance, more knowledge about the volume of usable groundwater is necessary to satisfy the global demand. Due to the challenges in quantifying the volume of available global groundwater, studies which aim to assess its magnitude are limited in number. They are further restricted in scope and depth of analysis as, in most cases, they do not explain how the estimates of global groundwater resources have been obtained, what methods have been used to generate the figures and what levels of uncertainty exist. This article reviews the estimates of global groundwater resources. It finds that the level of uncertainty attached to existing numbers often exceeds 100 % and strives to establish the reasons for discrepancy. The outcome of this study outlines the need for a new agenda in water research with a more pronounced focus on groundwater. This new research agenda should aim at enhancing the quality and quantity of data provision on local and regional groundwater stocks and flows. This knowledge enhancement can serve as a basis to improve policy-making on groundwater resources globally. Research-informed policies will facilitate more effective groundwater management practices to ensure a more rapid progress of the global water sector towards the goal of sustainability

Rapport I.10. Les méthodes de prévision en hydrologie souterraine

Forecasting methods which have been widely used for a long time in surface hydrology have only just begun to spread to the field of underground hydrological applications. After discussing the reasons for this delay — and for the new development — an attempt is made to provide a comprehensive list of available methods, for some of which details are given of recent applications for forecasting source flows and water-table levels. Conclusions are then drawn on the specific nature of hydrological forecasting problems and on the need to employ a methodology slightly different from that which has proved itself in surface hydrology. The concepts of probabilistic and deterministic models, in particular, are called into question.Les méthodes de prévision, très employées en hydrologie de surface depuis longtemps, commencent juste à se répandre en hydrologie souterraine. Après avoir analysé les raisons de ce retard — et de ce développement — , on tente un inventaire des méthodes disponibles, dont on présente quelques applications récentes à la prévision de débits de sources et de niveaux de nappes. On en tire les conclusions sur la spécificité des problèmes de prévision en hydrogéologie, et la nécessité d’employer une méthodologie légèrement différente de celle qui a fait ses preuves en hydrologie superficielle ; les notions de modèle probabilistes et déterministes, en particulier, sont remises en question.Canceill M., Margat Jean. Rapport I.10. Les méthodes de prévision en hydrologie souterraine. In: L'hydrotechnique au service d'une politique de l'eau. Évolution des problèmes de l'eau au cours de la dernière décennie. Compte-rendu des XVes journées de l'hydraulique. Toulouse, 5, 6 et 7 septembre 1976. Tome 1, 1979

Quantifying renewable groundwater stress with GRACE

Groundwater is an increasingly important water supply source globally. Understanding the amount of groundwater used versus the volume available is crucial to evaluate future water availability. We present a groundwater stress assessment to quantify the relationship between groundwater use and availability in the world’s 37 largest aquifer systems. We quantify stress according to a ratio of groundwater use to availability, which we call the Renewable Groundwater Stress ratio. The impact of quantifying groundwater use based on nationally reported groundwater withdrawal statistics is compared to a novel approach to quantify use based on remote sensing observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. Four characteristic stress regimes are defined: Overstressed, Variable Stress, Human-dominated Stress, and Unstressed. The regimes are a function of the sign of use (positive or negative) and the sign of groundwater availability, defined as mean annual recharge. The ability to mitigate and adapt to stressed conditions, where use exceeds sustainable water availability, is a function of economic capacity and land use patterns. Therefore, we qualitatively explore the relationship between stress and anthropogenic biomes. We find that estimates of groundwater stress based on withdrawal statistics are unable to capture the range of characteristic stress regimes, especially in regions dominated by sparsely populated biome types with limited cropland. GRACE-based estimates of use and stress can holistically quantify the impact of groundwater use on stress, resulting in both greater magnitudes of stress and more variability of stress between regions

Fertilité du sperme d'étalon conservé de 24 à 72h dans l'INRA96: stratégie d'insémination et température de conservation

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