Modélisation des hydrosystèmes complexes par machine learning : illustrations sur la prévision des extrêmes hydrologiques (crues, étiages)

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ESPADA : un outil pour la gestion en temps réel des crues éclairs urbaines en pleine modernisation

La ville de Nîmes est un territoire particulièrement exposé au risque inondation, et notamment aux crues torrentielles. Si aucun cours d'eau majeur n'est présent dans sa zone urbaine dense, ce sont les cadereaux, fossés de garrigues, qui sont en charge de la collecte du ruissellement et traversent la ville. Les évènements méditerranéens, des bassins versants de taille réduite (au plus 30 km2) et de nature karstique ainsi qu'une configuration en piémont sont autant de facteurs à l'origine de ruissellement potentiellement conséquent avec débordements majeurs sur la ville, de type crues-éclairs. Suite aux inondations du 3 octobre 1988, la ville de Nîmes a lancé une politique ambitieuse de prévention du risque inondation, incluant un aménagement important des cadereaux. Dans cette démarche, elle se dote en 2004 d'un système d'alerte et d'aide à la gestion de crise permettant de prévoir le risque inondation : ESPADA (Evaluation et suivi des précipitations en agglomération pour devancer l'alerte). L'objectif est de prévoir les débits des cadereaux à échéance maximale 1 h 30, en exploitant un modèle hydrologique intégrant une représentation fine du fonctionnement karstique. Dans le cadre de son Programme d'actions de prévention des inondations (PAPI), la ville de Nîmes a débuté en 2014 la modernisation du système ESPADA avec pour objectif d'améliorer la qualité des données d'entrée du système temps réel (pas de temps 5 min). Un réseau radio de collecte fiabilisée des capteurs hydrométéorologiques de la Ville a été mis en place, assurant également la collecte de postes du SPC-GD (Service de prévision des crues du Grand Delta). Parallèlement, un outil radar d'observation et prévision de pluie au pixel 500 m, échelle adaptée aux contraintes hydrologiques locales, a été développé, incluant une calibration de la donnée par exploitation des données des postes pluviographiques disponibles. Dans le cadre de la seconde étape de cette modernisation, le modèle de prévision du système est retravaillé afin de fonctionner en continu au pas de temps 5 min. La propagation est gérée via un modèle hydraulique 1D. Par ailleurs, les données limnigraphiques sont utilisées en temps réel afin de réajuster les valeurs de débits et les niveaux des bassins de rétention. De même, une interface en ligne est en cours de développement, permettant une utilisation efficace des outils par l'ensemble des acteurs de la gestion de crise. À terme, il est prévu de mettre à disposition de la population une partie des informations associées au système ESPADA via une interface de type Vigicrues

Labcom Hydr.IA: a joint Company-Academic laboratory to develop new flood forecasting services. Case Study on the Nîmes Flash-Floods (Southeastern France)

International audienceThe Hydr.IA project involves the SYNAPSE Company and the HydroSciences Montpellier Laboratory. It is based on a specific observation: despite the growing development of AI-related solutions in many complex fields, and the demonstration of their relevance to a number of hydro(geo)logy issues, there is a deficit in the transfer of these technologies to end-users. It would appear that two elements are lacking to ensure a more massive transfer of these solutions to the market. The first is the difficulty for research to be directly confronted with real operational conditions. The second is the limited confidence users have in solutions that are often perceived as opaque, and whose operational implementation is rare, leading to a vicious circle that this project aims to break.The program of work envisaged by this project will meet the following objectives:1) Definition of the range of real-time forecasting services, corresponding to the need for impact reduction and in line with market acceptance,2) Creation of a demonstration platform for these services using digital twins to demonstrate the efficiency of AI to end-users,3) Development of methodologies for the design of AI models adaptable to the range of services defined above,4) Extend the forecasting horizon, currently limited to the response time of the hydrosystem, by coupling AI modeling solutions with meteorological forecasts that can be post-processed.The city of Nîmes, in the South of France, is the first study site chosen. Mediterranean climate combined with small karst catchments can lead to complex flash flood events (concentration time less than 1/2 hour) resulting in large damages. The city shows the particularity to be crossed by different urban rivers. The city also acquired an alert system to support crisis management and better predict floods. This system, named ESPADA, uses a hydrological model including karst components, high-resolution precipitation and hydrometry measurements on the entire catchment, in real time.By reducing costs from field studies and physical model conception, the Hydr.IA approach would allow the application of low cost and effective tools for floods risk management.The poster will present the Hydr.IA project and the first results in comparing and combining both IA and conceptual approaches for Nimes floods forecasting

Labcom Hydr.IA: a joint Company-Academic laboratory to develop new flood forecasting services. Case Study on the Nîmes Flash-Floods (Southeastern France)

International audienceThe Hydr.IA project involves the SYNAPSE Company and the HydroSciences Montpellier Laboratory. It is based on a specific observation: despite the growing development of AI-related solutions in many complex fields, and the demonstration of their relevance to a number of hydro(geo)logy issues, there is a deficit in the transfer of these technologies to end-users. It would appear that two elements are lacking to ensure a more massive transfer of these solutions to the market. The first is the difficulty for research to be directly confronted with real operational conditions. The second is the limited confidence users have in solutions that are often perceived as opaque, and whose operational implementation is rare, leading to a vicious circle that this project aims to break.The program of work envisaged by this project will meet the following objectives:1) Definition of the range of real-time forecasting services, corresponding to the need for impact reduction and in line with market acceptance,2) Creation of a demonstration platform for these services using digital twins to demonstrate the efficiency of AI to end-users,3) Development of methodologies for the design of AI models adaptable to the range of services defined above,4) Extend the forecasting horizon, currently limited to the response time of the hydrosystem, by coupling AI modeling solutions with meteorological forecasts that can be post-processed.The city of Nîmes, in the South of France, is the first study site chosen. Mediterranean climate combined with small karst catchments can lead to complex flash flood events (concentration time less than 1/2 hour) resulting in large damages. The city shows the particularity to be crossed by different urban rivers. The city also acquired an alert system to support crisis management and better predict floods. This system, named ESPADA, uses a hydrological model including karst components, high-resolution precipitation and hydrometry measurements on the entire catchment, in real time.By reducing costs from field studies and physical model conception, the Hydr.IA approach would allow the application of low cost and effective tools for floods risk management.The poster will present the Hydr.IA project and the first results in comparing and combining both IA and conceptual approaches for Nimes floods forecasting

Transdisciplinary characterisation of a complex coastal aquifer, for a sustainable exploitation of its groundwater resources in a Mediterranean context. The DEM'EAUX ROUSSILLON project

International audienceMore than 80 million m3 per year are pumped into the Roussillon plain coastal aquifer, covering 850 km² and located between the Pyrenean massif to the west and the Mediterranean Sea to the east, south of France. This is a multilayer aquifer of more than 350 m thick, made up of sandy layers embedded in low-permeability clayey material from the Pliocene and topped by alluvial formations from the Quaternary. Its groundwater resource is primarily used for the supply of drinking water, but also contributes to the irrigation of some 13,000 hectares. For more than 40 years, this aquifer has been undergoing a general decline in its piezometric level due to pumping and water demand is expected to increase (growing irrigation areas and climatic demand). Moreover, given its flat topography, the Roussillon plain is likely to suffer sea water intrusions and marine submersion, due to the sea level rise, which could reach 1 m by 2100. This context shaped the Dem'Eaux Roussillon project, which brought together nearly ten partners from the Occitanie region (research units, consultancies and local authorities). Its objective was to characterise the behaviour of the groundwater resource in this aquifer, in order to be able to project its future situation, in the context of climate change, rising sea levels (risk of saline intrusion) and changes in water use. A detailed characterisation of the geological reservoir highlighted the need to consider the offshore extension of this coastal aquifer. The analysis of the piezometric evolution at the scale of the Roussillon plain over the last 50 years allowed the spatialized characterization of the hydrodynamic parameters and the understanding of the vertical drainage processes that control the hydraulic equilibrium between the Quaternary and the Pliocene water tables. Two high-resolution hydro-geophysical observatories have been set up to quantify these processes and improve understanding of saline intrusions processes. Finally, a conceptual model presenting the main features of the main processes controlling the groundwater evolution and the sea water intrusion risk was obtained ready to launch a numerical modelling wor

Transdisciplinary characterisation of a complex coastal aquifer, for a sustainable exploitation of its groundwater resources in a Mediterranean context. The DEM'EAUX ROUSSILLON project

International audienceMore than 80 million m3 per year are pumped into the Roussillon plain coastal aquifer, covering 850 km² and located between the Pyrenean massif to the west and the Mediterranean Sea to the east, south of France. This is a multilayer aquifer of more than 350 m thick, made up of sandy layers embedded in low-permeability clayey material from the Pliocene and topped by alluvial formations from the Quaternary. Its groundwater resource is primarily used for the supply of drinking water, but also contributes to the irrigation of some 13,000 hectares. For more than 40 years, this aquifer has been undergoing a general decline in its piezometric level due to pumping and water demand is expected to increase (growing irrigation areas and climatic demand). Moreover, given its flat topography, the Roussillon plain is likely to suffer sea water intrusions and marine submersion, due to the sea level rise, which could reach 1 m by 2100. This context shaped the Dem'Eaux Roussillon project, which brought together nearly ten partners from the Occitanie region (research units, consultancies and local authorities). Its objective was to characterise the behaviour of the groundwater resource in this aquifer, in order to be able to project its future situation, in the context of climate change, rising sea levels (risk of saline intrusion) and changes in water use. A detailed characterisation of the geological reservoir highlighted the need to consider the offshore extension of this coastal aquifer. The analysis of the piezometric evolution at the scale of the Roussillon plain over the last 50 years allowed the spatialized characterization of the hydrodynamic parameters and the understanding of the vertical drainage processes that control the hydraulic equilibrium between the Quaternary and the Pliocene water tables. Two high-resolution hydro-geophysical observatories have been set up to quantify these processes and improve understanding of saline intrusions processes. Finally, a conceptual model presenting the main features of the main processes controlling the groundwater evolution and the sea water intrusion risk was obtained ready to launch a numerical modelling wor

Transdisciplinary characterisation of a complex coastal aquifer, for a sustainable exploitation of its groundwater resources in a Mediterranean context. The DEM'EAUX ROUSSILLON project

International audienceMore than 80 million m3 per year are pumped into the Roussillon plain coastal aquifer, covering 850 km² and located between the Pyrenean massif to the west and the Mediterranean Sea to the east, south of France. This is a multilayer aquifer of more than 350 m thick, made up of sandy layers embedded in low-permeability clayey material from the Pliocene and topped by alluvial formations from the Quaternary. Its groundwater resource is primarily used for the supply of drinking water, but also contributes to the irrigation of some 13,000 hectares. For more than 40 years, this aquifer has been undergoing a general decline in its piezometric level due to pumping and water demand is expected to increase (growing irrigation areas and climatic demand). Moreover, given its flat topography, the Roussillon plain is likely to suffer sea water intrusions and marine submersion, due to the sea level rise, which could reach 1 m by 2100. This context shaped the Dem'Eaux Roussillon project, which brought together nearly ten partners from the Occitanie region (research units, consultancies and local authorities). Its objective was to characterise the behaviour of the groundwater resource in this aquifer, in order to be able to project its future situation, in the context of climate change, rising sea levels (risk of saline intrusion) and changes in water use. A detailed characterisation of the geological reservoir highlighted the need to consider the offshore extension of this coastal aquifer. The analysis of the piezometric evolution at the scale of the Roussillon plain over the last 50 years allowed the spatialized characterization of the hydrodynamic parameters and the understanding of the vertical drainage processes that control the hydraulic equilibrium between the Quaternary and the Pliocene water tables. Two high-resolution hydro-geophysical observatories have been set up to quantify these processes and improve understanding of saline intrusions processes. Finally, a conceptual model presenting the main features of the main processes controlling the groundwater evolution and the sea water intrusion risk was obtained ready to launch a numerical modelling wor

Transdisciplinary characterisation of a complex coastal aquifer, for a sustainable exploitation of its groundwater resources in a Mediterranean context. The DEM'EAUX ROUSSILLON project

International audienceMore than 80 million m3 per year are pumped into the Roussillon plain coastal aquifer, covering 850 km² and located between the Pyrenean massif to the west and the Mediterranean Sea to the east, south of France. This is a multilayer aquifer of more than 350 m thick, made up of sandy layers embedded in low-permeability clayey material from the Pliocene and topped by alluvial formations from the Quaternary. Its groundwater resource is primarily used for the supply of drinking water, but also contributes to the irrigation of some 13,000 hectares. For more than 40 years, this aquifer has been undergoing a general decline in its piezometric level due to pumping and water demand is expected to increase (growing irrigation areas and climatic demand). Moreover, given its flat topography, the Roussillon plain is likely to suffer sea water intrusions and marine submersion, due to the sea level rise, which could reach 1 m by 2100. This context shaped the Dem'Eaux Roussillon project, which brought together nearly ten partners from the Occitanie region (research units, consultancies and local authorities). Its objective was to characterise the behaviour of the groundwater resource in this aquifer, in order to be able to project its future situation, in the context of climate change, rising sea levels (risk of saline intrusion) and changes in water use. A detailed characterisation of the geological reservoir highlighted the need to consider the offshore extension of this coastal aquifer. The analysis of the piezometric evolution at the scale of the Roussillon plain over the last 50 years allowed the spatialized characterization of the hydrodynamic parameters and the understanding of the vertical drainage processes that control the hydraulic equilibrium between the Quaternary and the Pliocene water tables. Two high-resolution hydro-geophysical observatories have been set up to quantify these processes and improve understanding of saline intrusions processes. Finally, a conceptual model presenting the main features of the main processes controlling the groundwater evolution and the sea water intrusion risk was obtained ready to launch a numerical modelling wor

Transdisciplinary characterisation of a complex coastal aquifer, for a sustainable exploitation of its groundwater resources in a Mediterranean context. The DEM'EAUX ROUSSILLON project

International audienceMore than 80 million m3 per year are pumped into the Roussillon plain coastal aquifer, covering 850 km² and located between the Pyrenean massif to the west and the Mediterranean Sea to the east, south of France. This is a multilayer aquifer of more than 350 m thick, made up of sandy layers embedded in low-permeability clayey material from the Pliocene and topped by alluvial formations from the Quaternary. Its groundwater resource is primarily used for the supply of drinking water, but also contributes to the irrigation of some 13,000 hectares. For more than 40 years, this aquifer has been undergoing a general decline in its piezometric level due to pumping and water demand is expected to increase (growing irrigation areas and climatic demand). Moreover, given its flat topography, the Roussillon plain is likely to suffer sea water intrusions and marine submersion, due to the sea level rise, which could reach 1 m by 2100. This context shaped the Dem'Eaux Roussillon project, which brought together nearly ten partners from the Occitanie region (research units, consultancies and local authorities). Its objective was to characterise the behaviour of the groundwater resource in this aquifer, in order to be able to project its future situation, in the context of climate change, rising sea levels (risk of saline intrusion) and changes in water use. A detailed characterisation of the geological reservoir highlighted the need to consider the offshore extension of this coastal aquifer. The analysis of the piezometric evolution at the scale of the Roussillon plain over the last 50 years allowed the spatialized characterization of the hydrodynamic parameters and the understanding of the vertical drainage processes that control the hydraulic equilibrium between the Quaternary and the Pliocene water tables. Two high-resolution hydro-geophysical observatories have been set up to quantify these processes and improve understanding of saline intrusions processes. Finally, a conceptual model presenting the main features of the main processes controlling the groundwater evolution and the sea water intrusion risk was obtained ready to launch a numerical modelling wor

Transdisciplinary characterisation of a complex coastal aquifer, for a sustainable exploitation of its groundwater resources in a Mediterranean context. The DEM'EAUX ROUSSILLON project.

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