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Changes in groundwater levels associated with hydroclimatic variations and anthropogenic water extraction can deform the solid Earth, both elastically and inelastically. Satellite-based geodetic techniques which measure the Earth’s surface displacements can thus be used to track changing conditions in aquifer systems. However, accurately extracting groundwater-induced deformation signals still poses a challenge as geodetic techniques like GNSS and InSAR also record noise, systematic errors and other sources of deformation. In this study, we take advantage of the relatively dense in situ groundwater monitoring network of the Sacramento Valley aquifer in California to constrain its deformation and hydromechanical properties. We start by characterizing the main seasonal and multiannual fluctuations in groundwater levels with an Independent Component Analysis (ICA) and exploit the resulting temporal signature to extract the associated deformation field from GNSS and InSAR time series. We then develop a poroelastic model of the aquifer to invert for its elastic storage capacity and estimate the respective contributions of elastic and inelastic processes to long-term subsidence. Our modeling also suggests that depth-dependent elastic properties are necessary to explain the spatial distribution of horizontal poroelastic displacements measured by GNSS. This work has important implications for the sustainable management of heavily-stressed Californian aquifers but also serves as a calibration between in situ and remote sensing techniques, which is essential for the successful deployment of satellite-based groundwater monitoring in areas with sparse field-based instrumentation.

On observe actuellement une multiplication des dispositifs participatifs de collecte des données. L’objectif de cet article est d’analyser les enjeux de ces pratiques en interrogeant la capacité d’un dispositif à orienter l’action collective de collecte. Celle-ci est étudiée en fonction des caractéristiques de la structure de gouvernance du dispositif, analysée à travers le protocole de mesure, et ses finalités. Trois dispositifs participatifs reposant sur l’utilisation de microcapteurs sont comparés. Nous montrons que cette capacité de guidage du dispositif est variable selon les situations et s’exprime à travers le processus de validation des données et l’objet de la surveillance réalisée par les volontaires distinguant, en particulier, les dispositifs de production de données de ceux destinés à impliquer des publics. There is currently a proliferation of participatory data collection mechanisms. The objective of this article is to analyze the issues at stake in these practices by examining the capacity of a system to guide collective action in collecting data. This is studied according to the characteristics of the structure of governance of the device, analyzed through the measurement protocol, and its aims. Three participatory devices based on the use of microsensors are compared. We show that the guiding capacity of the device varies according to the situation and is expressed through the data validation process and the purpose of the monitoring carried out by the volunteers, distinguishing, in particular, the data production devices from those intended to involved citizens. Actualmente se observa una multiplicación de los mecanismos participativos de recopilación de datos. El objetivo de este artículo es analizar lo que está en juego en estas prácticas, examinando la capacidad de un sistema para orientar la acción colectiva en la recogida de datos. Esto se estudia en función de las características de la estructura de gobierno del dispositivo, analizadas a través del protocolo de medición, y sus objetivos. Se comparan tres dispositivos participativos basados en el uso de microsensores. Demostramos que esta capacidad de orientación del dispositivo varía según la situación y se expresa a través del proceso de validación de los datos y de la finalidad del seguimiento realizado por los voluntarios, distinguiendo, en particular, los dispositivos de producción de datos de los destinados a crear públicos implicados.

International audience; The Anthropocene, a new geological period when human actions are altering the habitability of the Earth for all forms of life, raises new challenges in terms of knowledge integration that fragmented approaches cannot overtake. Due to complex interactions within geo-eco-socio-systems (GESS), a “whole system” approach is required to answer societal concerns around soil capital, water resources, chemical pressure and biodiversity.To address these challenges, the TERRA FORMA project will design and test in-situ observation plateform coupling sensor viewpoints on human, biotic and abiotic dynamics. This project builds on pioneering and mature technological advances (optical sensors, 3D printing, IoT, AI) to design and probe a scalable network of smart sensors. We will develop a new generation of smart, connected, low-cost, low-impact and socially appropriated environmental sensors, adapted to field conditions, dedicated to capture the behavior, metabolism and trajectory of GESS emerging from states and fluxes of liquid, gas and solid matter and biota. These new technologies will contribute to shed light on “essential variables” for GESS and evaluate the descriptive and predictive potential of models over a wide range of contexts. TERRA FORMA gathers scientists, in an interdisciplinary effort at the crossroad of Earth, environmental, technological, computer and social sciences.In this presentation, we will show how instrumental developments (spectroscopy, lab on a chip, …) and methodological developments (biogeophysics, …) contributes to the construction of the observation plateform.

International audience; The German Research Unit GlobalCDA has the goal to improve the predictive skills of hydrological models by combining remote sensing information using a calibration/data assimilation (C/DA) approach. In order to validate model results and to assess the success of the C/DA efforts, independent data sets are crucially needed, such as in-situ groundwater observations to assess the ability of the model to describe groundwater storage changes. The main challenge arising from such comparisons is to capture basin-scale groundwater storage from a set of in-situ GW observations settled in highly heterogeneous lithologies with irregular & non-homogeneous sampling. Furthermore, the conversion from groundwater (GW) level measurements to storage variations requires information on specific yield, ideally given site-specific for each monitoring well. However, this information is largely not available and difficult to estimate in areas with highly heterogeneous geology.In our study we use a data set of groundwater level observations at about 3000 groundwater monitoring wells in France. Based on a high-resolution hydro-geological information system provided by the French geological survey (BRGM) and water authorities (BDLISA), we assign the borehole data to individual hydro-geological units. For the upscaling to river basin averages, we (i) aggregate the measurements that originate from the same unit and (ii) account for the areal fractions of the hydro-geological units within the river basin. For the interpretation of GW level variations to GW storage changes, we tested several approaches to estimate specific yield values for the individual hydro-geological units. Wherever possible, we use the specific yield values explicitly provided in the BDLISA data base, mostly estimated from pumping test analysis. When not available, we assign literature-based specific yield values based on the detailed lithological information provided for each unit. This method is compared to global porosity information provided by low resolution geological data from GHYLMPS (Gleeson et al., 2014)Besides presenting the methodological approach, this presentation shows the resulting groundwater storage time series, averaged for individual river basins in France and for individual 0.5° grid cells. Additionally, comparisons to simulated groundwater storage variations of the WaterGAP Global Hydrology Model (WGHM) will be presented. We discuss the sensitivity of basin averaged GW storage time series to different choices of specific yield for individual boreholes.How to cite: Hsu, K.-H., Eicker, A., Hasan, M., Güntner, A., and Longuevergne, L.: Estimating groundwater storage changes for major river basins in France using a regional groundwater data set , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7127, https://doi.org/10.5194/egusphere-egu22-7127, 2022.

International audience; There is currently a proliferation of participatory data collection mechanisms. The objective of this article is to analyze the issues at stake in these practices by examining the capacity of a system to guide collective action in collecting data. This is studied according to the characteristics of the structure of governance of the device, analyzed through the measurement protocol, and its aims. Three participatory devices based on the use of microsensors are compared. We show that the guiding capacity of the device varies according to the situation and is expressed through the data validation process and the purpose of the monitoring carried out by the volunteers, distinguishing, in particular, the data production devices from those intended to involved citizens. Actualmente se observa una multiplicacion de los mecanismos participativos de recopilacion de datos. El objetivo de este articulo es analizar lo que esta en juego en estas practicas, examinando la capacidad de un sistema para orientar la accion colectiva en la recogida de datos. Esto se estudia en funcion de las caracteristicas de la estructura de gobierno del dispositivo, analizadas a traves del protocolo de medicion, y sus objetivos. Se comparan tres dispositivos participativos basados en el uso de microsensores. Demostramos que esta capacidad de orientacion del dispositivo varia segun la situacion y se expresa a traves del proceso de validacion de los datos y de la finalidad del seguimiento realizado por los voluntarios, distinguiendo, en particular, los dispositivos de produccion de datos de los destinados a crear publicos implicados.; Actualmente se observa una multiplicación de los mecanismos participativos de recopilación de datos. El objetivo de este artículo es analizar lo que está en juego en estas prácticas, examinando la capacidad de un sistema para orientar la acción colectiva en la recogida de datos. Esto se estudia en función de las características de la estructura de gobierno del dispositivo, analizadas a través del protocolo de medición, y sus objetivos. Se comparan tres dispositivos participativos basados en el uso de microsensores. Demostramos que esta capacidad de orientación del dispositivo varía según la situación y se expresa a través del proceso de validación de los datos y de la finalidad del seguimiento realizado por los voluntarios, distinguiendo, en particular, los dispositivos de producción de datos de los destinados a crear públicos implicados.; On observe actuellement une multiplication des dispositifs participatifs de collecte des données. L’objectif de cet article est d’analyser les enjeux de ces pratiques en interrogeant la capacité d’un dispositif à orienter l’action collective de collecte. Celle-ci est étudiée en fonction des caractéristiques de la structure de gouvernance du dispositif, analysée à travers le protocole de mesure, et ses finalités. Trois dispositifs participatifs reposant sur l’utilisation de microcapteurs sont comparés. Nous montrons que cette capacité de guidage du dispositif est variable selon les situations et s’exprime à travers le processus de validation des données et l’objet de la surveillance réalisée par les volontaires distinguant, en particulier, les dispositifs de production de données de ceux destinés à impliquer des publics.