Integrated modelling of social-ecological systems: The MAELIA high-resolution multi-agent platform to deal with water scarcity problems

International audienceSustainable water resource management is typical of environmental management problems emerging from complex social-ecological systems. It deeply depends upon water user strategies, land use management and water governance systems. MAELIA, a "policy issue" modelling platform, allows performing integrated assessment at watershed level of a wide range of scenarios regarding water and land use management strategies in combination with global changes. It has been developed through a strong analysis of different French water management situations and an inductive modelling process. It allows representing dynamic interactions between human activities (farming practices), ecological processes (hydrology and crop growth), and governance systems (water regulations and releases from dams) at fine spatiotemporal resolutions in order to handle actual problems of water managers and issues of the main water users (farmers). MAELIA includes original farmer, dam manager and state services (software) agents

The MAELIA multi-agent platform for integrated assessment of low-water management issues

International audienceThe MAELIA project is developing an agent-based modeling and simulation platform to study the environmental, economic and social impacts of various regulations regarding water use and water management in combination with climate change. It is applied to the case of the French Adour-Garonne Basin, which is the most concerned in France by water scarcity during the low-water period. An integrated approach has been chosen to model this social-ecological system: the model combines spatiotemporal models of ecologic (e.g. rainfall and temperature changes, water flow and plant growth) and socio-economic (e.g. farmer decision-making process, management of low-water flow, demography, land use and land cover changes) processes and sub-models of cognitive sharing among agents (e.g. weather forecast, normative constraints on behaviors

Integrated assessment of four strategies for solving water imbalance in an agricultural landscape

International audienceAbstractWater imbalances are an environmental, social, and economic problem in many agricultural watersheds, including those in temperate climates. Structural changes are recommended because crisis management, through water restrictions, is not sustainable. However, the content of these changes is debated, especially because their impacts concern different sectors and stakeholders and are uncertain. MAELIA is an integrated assessment and modeling platform, which combines a multi-agent model with a geographic information system; it represents fine-scale interactions among water, water management, and agricultural systems, accounting for daily irrigation decisions on each field and effects of the corresponding water withdrawals on water flows. In this article, for the first time, we investigated the effectiveness of some of the most popular strategies aimed at solving water imbalances considering environmental, water management, and agricultural indicators calculated with MAELIA. The alternatives we assessed were (i) reducing the irrigated area, (ii) assisting irrigation with decision-support tools, (iii) implementing crop rotations, and (iv) merging water storage into large reservoirs. Simulations were run for the 2001–2013 period on a case-study area, the downstream Aveyron watershed. We show that, in this area, the decision-support tool and crop-rotation alternatives drastically decreased irrigation withdrawals and required fewer restrictions and flow-support releases. However, those two alternatives had different impacts on the environment and farming systems: decision-support tools cost almost nothing for farming systems and improved environmental indicators slightly, while crop rotations had greater potential for long-term environmental preservation but degraded local and farm economies in the current context. The uniqueness of this study comes from using a fine-scale mechanistic model to assess, in an integrated way, the impacts of politically debated water management strategies that were previously only assessed in terms of potential withdrawal reduction

Formal Representation of Water Withdrawal Policies for Integrated Impact Assessment

International audienceThe regulation of water use and water management has evolved considerably in recent years. The evolution of water regulatory systems includes the design of new management policies, which could benefit from ex-ante comparative impact assessments with regard to those of current or past practices. To this aim, the MAELIA project develops an integrated modelling and simulation platform for the assessment of alternative water management policies, especially during low-water crisis in the Adour-Garonne basin (South-West region of France). The development of such an integrated assessment and modelling platform requires the consideration and integration of many entities and processes involved in the system under consideration - water resources and flows, agricultural structures and activities, state and evolution of land cover and land use, etc. This article focuses on the formal representation of two alternative options regarding the choice of water withdrawal policy, which are likely to have considerable impacts on the whole socio-hydro-system s: management by rate of flow (currently applied); and management by volume quotas (alternative to be assessed). Furthermore, the article presents a conceptual framework for the integrated modelling of such social-ecological systems together with graphical notations for models' representation

Simulating Renewable Energy Production Scenarios Under Water and Food Constraints

Energy and agriculture are two big greenhouse gas emitters. Emissions of greenhouse gases lead to rising temperatures and originate long-term shifts in weather patterns, i.e. climate change, causing intense droughts, severe fires, rising sea levels and flooding, together with destructive storms. To reduce emissions, an energy transition from fossil fuels to renewable and low-carbon energy sources is essential, and this cannot be led without considering the deep interlinkages that exist between energy, water and food. Renewable production units can enter into competition with agriculture through land use, and both energy and agriculture are water dependent. Digital tools appear as an efficient and agile way to manage water-energy-food systems. Developing a generic digital tool that contributes to the acceleration of a sustainable energy transition is the aim of this research work. The current work is focused on extending Maelia, a spatially explicit multi-agent simulation platform for integrated assessment and modelling of socio-agro-ecological systems, that enables the simulation of fine-grained spatial and temporal land management scenarios. The platform includes agriculture and hydrology models, considers biomass production and recycling ones, and through this research work, will also integrate solar and windmill models. To make Maelia an innovative digital decision tool that deals with water-energy-food systems, data must be collected, assembled and treated with R, Python and QGIS

Quelles distributions spatiales des systèmes de culture pour limiter l'occurence des crises de gestion quantitative de l'eau ? Une démarche de conception évaluation sur le territoire irrigué de l'Aveyron aval

Dans les territoires irrigués exposés aux crises de gestion quantitative de l’eau, la sévérité des étiages dépend des interactions entre systèmes de culture, situations pédoclimatiques, hydrologie, lâchers d’eau et restriction d’irrigation. Dans de nombreuses situations, l’absence de nouvelles solutions de stockage et les tensions entre gestionnaires et usagers de l’eau rendent nécessaire la planification des étiages. Mes travaux explorent le potentiel de « la gestion spatiale » de l’eau pour mettre en adéquation la dynamique des prélèvements pour l’irrigation avec celle de l’offre en eau disponible (naturelle et stockée). Je propose une méthodologie participative de conception-évaluation d’organisations territoriales des activités agricoles, déployée sur l’aval du bassin versant de l’Aveyron (800 km²), en trois étapes: (1) modéliser le système socio-agro-hydrologique, (2) concevoir des alternatives de distribution spatiale des systèmes de culture, (3) conduire une évaluation intégrée des alternatives face à la variabilité climatique observée. Ces travaux combinent des méthodes, connaissances et outils « hard and soft », et font usage de la plateforme de simulation multi-agent MAELIA. Le processus a permis de formaliser des visions d’acteurs et de poser les bases d’une concertation multi acteur. Cependant la simulation des impacts de ces alternatives a montré leurs limites pour régler le problème de déficit structurel en eau. Cette démarche pourrait être prolongée pour aboutir à des propositions opérationnelles. ABSTRACT : In irrigated landscapes exposed to quantitative water management crisis, the intensity of low flows depends on interactions between cropping systems, pedoclimatic situation hydrology, water releases and withdrawal restrictions. In many situations there are no opportunities for more water storage, thus tensions occur between water managers and users, which makes the planning of water demand dynamics necessary. My work explores the potentials in the “spatial management of water” to align the water demand dynamics with natural and stored water availability. I present a 3 step, participatory method to design and assess agricultural landscapes: (1) model the Social-Agro Hydrological system, (2) design alternative spatial distribution of the cropping systems, (3) carry an integrated assessment of those alternatives based on observed climatic variability. This method combines “hard” and “soft” methods, knowledge and tools, and uses the MAELIA multi-agent simulation platform. I tested the method tested in the downstream area of the Aveyron River (800 km² Southwestern France). It allowed to formalize the actors’ visions on alternative distributions of the cropping systems. However they showed to be limited in solving the water deficit issue. The method could be continued to reach operational proposals

Quelles distributions spatiales des systèmes de culture pour limiter l'occurence des crises de gestion quantitative de l'eau ? Une démarche de conception évaluation sur le territoire irrigué de l'Aveyron aval

Dans les territoires irrigués exposés aux crises de gestion quantitative de l’eau, la sévérité des étiages dépend des interactions entre systèmes de culture, situations pédoclimatiques, hydrologie, lâchers d’eau et restriction d’irrigation. Dans de nombreuses situations, l’absence de nouvelles solutions de stockage et les tensions entre gestionnaires et usagers de l’eau rendent nécessaire la planification des étiages. Mes travaux explorent le potentiel de « la gestion spatiale » de l’eau pour mettre en adéquation la dynamique des prélèvements pour l’irrigation avec celle de l’offre en eau disponible (naturelle et stockée). Je propose une méthodologie participative de conception-évaluation d’organisations territoriales des activités agricoles, déployée sur l’aval du bassin versant de l’Aveyron (800 km²), en trois étapes: (1) modéliser le système socio-agro-hydrologique, (2) concevoir des alternatives de distribution spatiale des systèmes de culture, (3) conduire une évaluation intégrée des alternatives face à la variabilité climatique observée. Ces travaux combinent des méthodes, connaissances et outils « hard and soft », et font usage de la plateforme de simulation multi-agent MAELIA. Le processus a permis de formaliser des visions d’acteurs et de poser les bases d’une concertation multi acteur. Cependant la simulation des impacts de ces alternatives a montré leurs limites pour régler le problème de déficit structurel en eau. Cette démarche pourrait être prolongée pour aboutir à des propositions opérationnelles

An Agent-Based Model for Simulating Irrigated Agriculture in the Samambaia Basin in Goiás

Agriculture is one of the main economic activities in Brazil. The intensive use of water for irrigated agriculture leads to water rise demand contributing to increase water stress. Agent-based models help assess this problem with promising applications entailing an organizing principle to inform us of how to view a real-world system and effectively build a model. In this work, agent-based modeling is applied to simulate water usage for irrigation in agricultural production in the Samambaia river basin in the municipality of Cristalina in the Goias state of Brazil. The use of real data enables analysis of resource availability in a scenario with high demand irrigation, allowing a greater understanding of the needs of the parties involved

Multi-agent modeling for water policy impact assessment : a road map

Politicas públicas de água têm grande influência sobre diferentes tipos de recursos (recursos hídricos, da terra e do solo; infraestrutura e instalações prediais; recursos financeiros; informação e conhecimento ambiental; etc.). Elas atuam sobre agentes individuais ou coletivos (usuários, gestores, empresas públicas ou privadas, associações, etc.), assim como como regras e normas de comportamento que estes atores são os destinatários ou agentes. Sistemas complexos, se for o caso, essas políticas têm vários tipos de efeitos, esperados e inesperados, os efeitos diretos e indiretos, sociais, econômicos, ambientais e ecosistêmica. O atual desenvolvimento de plataformas multi-agente abre uma nova área para a definição, concepção, implementação e monitoramento da gestão da água, produzindo simulações ex ante do impacto das medidas que promovem políticas públicas de água e da evolução provável da situação sócio--HYDROSYSTEM em causa. Aqui vamos dar uma visão geral das novas oportunidades de modelagem de política da água e avaliação de impacto, que resumem as etapas do processo de modelagem e apresentar os principais ingredientes que entram na composição de uma plataforma dedicada a simulações de impacto. Também argumentam que o interesse de construir cenários de água e produção de indicadores úteis para a tomada de decisão sobre o uso, distribuição e gestão dos recursos hídricos à escala da bacia.Water policies have a great impact upon different types of resources (water, land and soil resour-ces; infrastructure and facilities; financial resour-ces; environmental knowledge and information; etc.). They involve many individual or collective actors (users, managers, public or private companies, associations, etc.) as well as rules and norms of behavior that these actors are the reci-pients or agents. Complex systems, if any, these policies have several kinds of effects, expected and unexpected, direct and indirect effects, societal, economic, environmental and eco-systemic. The current development of multi-agent platforms opens up a new area for the definition, design, implementation and monitoring of water management by producing ex ante simulations of the impact of measures that promote water public policies and of the likely evolution of the socio-hydrosystem concerned. Here we give a quick overview of these new opportunities of water policy modeling and impact assessment. We summarize the steps of the modeling process and present the main ingredients entering in the composition of a platform dedicated to impact simulations. We also argue the interest of building water scenarios and producing useful indicators for decision-making regarding the use, distribu-tion and management of water resources at the basin-scale