GIOVANETTI (René), Wittelsheim et ses mines de potasse. Amélie et Joseph-Else

Après l’histoire patrimoniale et sociale des mines de potasse d’Alsace et celle des chevalements dans la plaine d’Alsace, René Giovanetti commence une histoire des villes du bassin potassique et de leurs rapports avec cette industrie minière. En 2011, sa première étude a concerné Staffelfelden. Dans son nouveau livre, sur Wittelsheim, il retrace cent ans de vie commune. L’auteur expose l’histoire de la découverte de la potasse à Wittelsheim et les débuts difficiles de son exploitation. Mélang..

Un bassin d’activité à l’épreuve de la Seconde Guerre mondiale : les mines de potasse d’Alsace (1937-1949)

Le projet qui est à l’origine de nos recherches est d’expliquer la complexité de l’histoire des mines de potasse d’Alsace pendant la Seconde Guerre mondiale, les ruptures et les continuités de l’organisation administrative et de l’exploitation du bassin potassique entre démocratie et dictature. Motivations et cheminements de la recherche Plus grand employeur d’Alsace, dans un bassin d’emploi d’une superficie de 200 km2 situé au nord de la ville de Mulhouse, avec une importante main-d’œuvre ét..

Ecohydrological modeling in three contrasted watersheds from OZCAR research infrastructure

International audienceThe French OZCAR Critical Zone Observatory network offers the opportunity to performmulti-site studies to explore the critical zone functioning under contrasted climate, geology, vegetation and land use. In this study, we investigate how soil-water-vegetation interactions control the hydrologic response of three watersheds, and we present recent results obtained by taking advantage of a large database for critical zone sciences at the French national scale and using the novel fully spatially distributed and physically based ecohydrological model EcH2O-iso (Kuppel et al., 2018). The ecohydrological functioning of three contrasted watersheds was investigated in detail with (1) the Kervidy-Naizin watershed characterized by an oceanic climate (north-west of France), a metamorphic bedrock and an intensive pig and dairy farming; (2) the Aurade watershed, a watershed with a semi-continental oceanic climate (south-west of France), a sedimentary geological substratum and an extensive crop cover with a wheat-sunflower rotation and; (3) the Strengbach watershed characterized by a mountain climate (north-east of France), a granitic bedrock, and a beech-spruce forest cover without agriculture. Results fromecohydrological simulations underline the importance of soil and regolith thicknesses as well as spatial variability of hydrodynamic parameters in the shallow subsurface for controlling stream discharge at watershed outlets. The seasonality of the vegetation cover and evapotranspiration is also a key feature to understand variations of total water storage and water transit time in watersheds. Intercomparison between the three watersheds also shed light on differences in water storage dynamics and allows us to better identify the key soil-water-vegetation interactions controlling storage dynamics. Modeling robustness was evaluated by a large number of variables including stream flow, water level in piezometers, and evapotranspiration fluxes measured from climatological stations and flux-towers located in the watersheds. This study highlights the interest of crossing different critical zone observatories for an integrated understanding of soil-water-vegetation interactions and their control on water storages and water transit times

Exploring the critical zone heterogeneity and the hydrological diversity using an integrated ecohydrological model in three contrasted long-term observatories

<p>These files provide useful data and supplementary material associated with the publication 'Exploring the critical zone heterogeneity and the hydrological diversity using an integrated ecohydrological model in three contrasted long-term observatories' (MNT information, atmospheric forcings, R scripts used to process and draw the graphs from the EcH2O-iso simulations, and observed water discharges).</p&gt

Exploring the landscape heterogeneity and the hydrological diversity in three contrasted observatories of the French critical zone research infrastructure OZCAR

International audienceThe French OZCAR critical zone network offers the opportunity to conduct multi-site studies and to explore the critical zone functioning under contrasted climate, geology, vegetation and land use. In this study, an integrated modeling of the water cycle is performed with the ecohydrological model EcH2O-iso in three long-term observatories: (1) the Naizin watershed characterized by an oceanic climate, a metamorphic bedrock and an intensive agriculture (north-west of France, AgrHyS observatory); (2) the Aurade watershed, a watershed with a warmer semi-continental oceanic climate, a sedimentary geological substratum and a crop cover with a wheat-sunflower rotation (south-west of France, Aurade observatory) and; (3) the Strengbach watershed characterized by a mountain climate, a granitic bedrock, and a beech-spruce forest cover (north-east of France, OHGE observatory).Modeling robustness is evaluated by taking advantage of the large database for critical zone sciences including stream flow, water level in piezometers, and evapotranspiration fluxes measured from climatological stations and flux-towers located in the watersheds. Our comparative study brings these general outcomes: (1) the long term CZ evolution controlling the regolith thickness strongly impacts the total water storage in watersheds; (2) the Quaternary geomorphological evolution influences the current hydrological partitioning and the separation of hydrologically active and inactive water storage; (3) Both internal watershed characteristics and external forcings, such as current atmospheric forcing and recent land use need to be considered to infer stream persistence and to understand hydrological diversity; and (4) the observed hydrological diversity cannot be fully understood without considering a continuum of time scales in CZ evolution. Overall, this work illustrates the strength of critical zone networks, allowing a new level of multi-site and comparative studies that are crossing several observatories and encompassing a wide diversity of geology and climate

Looking for feedback loops in the critical zone

International audienceThe critical zone (CZ) is a complex system, composed of many interacting subsystems over a wide range of space and time scales. These systems are driven by external forcing and internal processes, often non-linear (e.g. rainfall-runoff relationship), and feedback loops. However, due to these interactions and feedbacks, a perturbation in the forcing or in the internal dynamics can lead to regime shifts in some CZ elements. In such a case, they do not always return to their previous state after the perturbation ceases. These behaviours are generally due to the existence of positive feedback loop(s) in the internal dynamics of the system, which may induce instabilities leading to the existence of tipping points, and alternative states. A gradual and reversible response of, e.g. hydro-socio-systems to changes in forcing (e.g. rainfall, land management) is a common view of hydrological change. However, if tipping phenomena exist, this ”linear” vision may lead to incorrect anticipations of the system trajectories, and possibly inadequate adaptation strategies. The possible tipping of key elements of the earth system under climate change is a current concern of the scientific community. Hence, tipping elements may lie in the CZ. This specific scientific issue is being investigated in the framework of a scientific working group within the OZCAR community (French Critical Zone Observatories network). The objective is three-fold :i) identify the main feed-back loops driving the CZ and infer their impact on the functioning of the CZ; ii) evaluate if we use adapted observational setups to monitor them in the field and iii) ; evaluate if and how we should include these feedback processes in CZ models.This talk presents a state-of-the art of the inventory (still in progress) of known or speculative feedback-loops in the CZ, based on the expertise and observations gained at the diverse OZCAR observatories, both in temperate and tropical areas. Reported feedbacks include water, erosion, vegetation and sediment transport; carbon cycle (CC) and alteration (carbonates), CC and forest resilience under warming, CC and fertilizers, CC and humid areas (e.g. peat-lands); land use change (e.g. urbanization), water cycle and hydrological risk; permafrost... A first evaluation of their representation in CZ, hydrological and Earth System models is presented

Looking for feedback loops in the critical zone

International audienceThe critical zone (CZ) is a complex system, composed of many interacting subsystems over a wide range of space and time scales. These systems are driven by external forcing and internal processes, often non-linear (e.g. rainfall-runoff relationship), and feedback loops. However, due to these interactions and feedbacks, a perturbation in the forcing or in the internal dynamics can lead to regime shifts in some CZ elements. In such a case, they do not always return to their previous state after the perturbation ceases. These behaviours are generally due to the existence of positive feedback loop(s) in the internal dynamics of the system, which may induce instabilities leading to the existence of tipping points, and alternative states. A gradual and reversible response of, e.g. hydro-socio-systems to changes in forcing (e.g. rainfall, land management) is a common view of hydrological change. However, if tipping phenomena exist, this ”linear” vision may lead to incorrect anticipations of the system trajectories, and possibly inadequate adaptation strategies. The possible tipping of key elements of the earth system under climate change is a current concern of the scientific community. Hence, tipping elements may lie in the CZ. This specific scientific issue is being investigated in the framework of a scientific working group within the OZCAR community (French Critical Zone Observatories network). The objective is three-fold :i) identify the main feed-back loops driving the CZ and infer their impact on the functioning of the CZ; ii) evaluate if we use adapted observational setups to monitor them in the field and iii) ; evaluate if and how we should include these feedback processes in CZ models.This talk presents a state-of-the art of the inventory (still in progress) of known or speculative feedback-loops in the CZ, based on the expertise and observations gained at the diverse OZCAR observatories, both in temperate and tropical areas. Reported feedbacks include water, erosion, vegetation and sediment transport; carbon cycle (CC) and alteration (carbonates), CC and forest resilience under warming, CC and fertilizers, CC and humid areas (e.g. peat-lands); land use change (e.g. urbanization), water cycle and hydrological risk; permafrost... A first evaluation of their representation in CZ, hydrological and Earth System models is presented