23 research outputs found
Quelles distributions spatiales des systÚmes 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 irriguĂ©s exposĂ©s aux crises de gestion quantitative de lâeau, la sĂ©vĂ©ritĂ© des Ă©tiages dĂ©pend des interactions entre systĂšmes de culture, situations pĂ©doclimatiques, hydrologie, lĂąchers dâeau et restriction dâirrigation. Dans de nombreuses situations, lâabsence de nouvelles solutions de stockage et les tensions entre gestionnaires et usagers de lâeau rendent nĂ©cessaire la planification des Ă©tiages. Mes travaux explorent le potentiel de « la gestion spatiale » de lâeau pour mettre en adĂ©quation la dynamique des prĂ©lĂšvements pour lâirrigation avec celle de lâoffre en eau disponible (naturelle et stockĂ©e). Je propose une mĂ©thodologie participative de conception-Ă©valuation dâorganisations territoriales des activitĂ©s agricoles, dĂ©ployĂ©e sur lâaval du bassin versant de lâAveyron (800 kmÂČ), en trois Ă©tapes: (1) modĂ©liser le systĂšme socio-agro-hydrologique, (2) concevoir des alternatives de distribution spatiale des systĂšmes de culture, (3) conduire une Ă©valuation intĂ©grĂ©e des alternatives face Ă la variabilitĂ© climatique observĂ©e. Ces travaux combinent des mĂ©thodes, 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 dâacteurs et de poser les bases dâune concertation multi acteur. Cependant la simulation des impacts de ces alternatives a montrĂ© leurs limites pour rĂ©gler le problĂšme de dĂ©ficit structurel en eau. Cette dĂ©marche pourrait ĂȘtre prolongĂ©e pour aboutir Ă des propositions opĂ©rationnelles
Quelles distributions spatiales des systÚmes 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 irriguĂ©s exposĂ©s aux crises de gestion quantitative de lâeau, la sĂ©vĂ©ritĂ© des Ă©tiages dĂ©pend des interactions entre systĂšmes de culture, situations pĂ©doclimatiques, hydrologie, lĂąchers dâeau et restriction dâirrigation. Dans de nombreuses situations, lâabsence de nouvelles solutions de stockage et les tensions entre gestionnaires et usagers de lâeau rendent nĂ©cessaire la planification des Ă©tiages. Mes travaux explorent le potentiel de « la gestion spatiale » de lâeau pour mettre en adĂ©quation la dynamique des prĂ©lĂšvements pour lâirrigation avec celle de lâoffre en eau disponible (naturelle et stockĂ©e). Je propose une mĂ©thodologie participative de conception-Ă©valuation dâorganisations territoriales des activitĂ©s agricoles, dĂ©ployĂ©e sur lâaval du bassin versant de lâAveyron (800 kmÂČ), en trois Ă©tapes: (1) modĂ©liser le systĂšme socio-agro-hydrologique, (2) concevoir des alternatives de distribution spatiale des systĂšmes de culture, (3) conduire une Ă©valuation intĂ©grĂ©e des alternatives face Ă la variabilitĂ© climatique observĂ©e. Ces travaux combinent des mĂ©thodes, 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 dâacteurs et de poser les bases dâune concertation multi acteur. Cependant la simulation des impacts de ces alternatives a montrĂ© leurs limites pour rĂ©gler le problĂšme de dĂ©ficit structurel en eau. Cette dĂ©marche pourrait ĂȘtre prolongĂ©e pour aboutir Ă des propositions opĂ©rationnelles. 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 âspatial management of waterâ 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 âhardâ and âsoftâ 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 kmÂČ Southwestern France). It allowed to formalize the actorsâ 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
Analyse participative des compromis entre les services écosystémiques de la zone humide dans la vallée de GaMampa, Province du Limpopo, Afrique du Sud. Leçons pour la gestion des ressources visant la durabilité de la zone humide
The GaMampa wetland is located in the Olifants River catchment, in the Limpopo province of South Africa. It traditionally supports livelihoods, mainly through natural vegetation collection for food provisioning and raw materials. Since the 1990's, and most intensively from 2000 to 2005, it has been drained and its natural vegetation cut and burnt for subsistence maize cultivation. Its ecological integrity is jeopardized. The sustainability of the biological and geomorphologic features, as well as traditional provisioning and contemporary farming opportunities, are questioned. In a diagnosis of the situation, the research identified the reasons for this sudden change in wetland use. Starting from existing data on the case study, mostly developed under the CPWF and WETwin projects, this study analyzed the possible management responses to the problems of the wetland, emphasizing the need for integration of the wetland to the GaMampa valley resource system and thus the need for a global management of the resources aiming at wetland sustainability. This report provides details on management options and their alternatives for implementation, developed through consultation of stakeholders. It also proposes 4 sets of Management Solutions which can be used both by the WETwin project for future research purposes and the GaMampa valley decision makers to establish a management plan
What alternative cropping systems spatial distributions to limit the risk of quantitative water management crises ? A design and assessment method for an irrigated landscape in the lower reaches of the Aveyron River
Dans les territoires irriguĂ©s exposĂ©s aux crises de gestion quantitative de lâeau, la sĂ©vĂ©ritĂ© des Ă©tiages dĂ©pend des interactions entre systĂšmes de culture, situations pĂ©doclimatiques, hydrologie, lĂąchers dâeau et restriction dâirrigation. Dans de nombreuses situations, lâabsence de nouvelles solutions de stockage et les tensions entre gestionnaires et usagers de lâeau rendent nĂ©cessaire la planification des Ă©tiages. Mes travaux explorent le potentiel de « la gestion spatiale » de lâeau pour mettre en adĂ©quation la dynamique des prĂ©lĂšvements pour lâirrigation avec celle de lâoffre en eau disponible (naturelle et stockĂ©e). Je propose une mĂ©thodologie participative de conception-Ă©valuation dâorganisations territoriales des activitĂ©s agricoles, dĂ©ployĂ©e sur lâaval du bassin versant de lâAveyron (800 kmÂČ), en trois Ă©tapes: (1) modĂ©liser le systĂšme socio-agro-hydrologique, (2) concevoir des alternatives de distribution spatiale des systĂšmes de culture, (3) conduire une Ă©valuation intĂ©grĂ©e des alternatives face Ă la variabilitĂ© climatique observĂ©e. Ces travaux combinent des mĂ©thodes, 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 dâacteurs et de poser les bases dâune concertation multi acteur. Cependant la simulation des impacts de ces alternatives a montrĂ© leurs limites pour rĂ©gler le problĂšme de dĂ©ficit structurel en eau. Cette dĂ©marche pourrait ĂȘtre prolongĂ©e pour aboutir Ă des propositions opĂ©rationnelles.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 âspatial management of waterâ 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 âhardâ and âsoftâ 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 kmÂČ Southwestern France). It allowed to formalize the actorsâ 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
Réconcilier les moyens de subsistance avec l'intégrité des écosystÚmes dans la zone humide de Ga-Mampa, Afrique du Sud
International audienceThe Ga-Mampa wetland is an example of the many small wetlands used for multiple purposes in South Africa. Over the last 15 years it has been progressively converted to subsistence cropping, with negative impacts on its ecosystem integrity. Stakeholders at local and higher scales have different views on the ways to mitigate the impacts of current uses while enhancing local communitiesâ livelihoods. A participatory decision support framework was developed under the WETwin project to assess the trade-offs between wetland ecosystem services provision and ecosystem integrity and to support wetland planning and management. This paper reports its application to the case of Ga-Mampa wetland, where a particular focus was given to stakeholder involvement in the assessment process. The participatory multi-criteria analysis allowed initiating and strengthening dialogue between very diverse stakeholders, from local to national levels. It also provided reflective material for decision makers in the form of a diagnosis of stakes, and documented management options adapted to the situation and validated by stakeholders. The process itself was more useful than its outcome, raising external stakeholdersâ awareness of the complexity of the socio-ecological system and accompanying local farmers in building their own project
Toward integrated water and agricultural land management: participatory design of agricultural landscapes
International audienceOne of the great challenges of developing sustainable water management is to integrate water and land use issues, and to favor stakeholdersâ involvement in the process of designing a solution to the speciïŹc issues of water basins. This study aims to help reach these objectives: we present the outcomes of a methodology that aims to design, with stakeholders of a watershed facing quantitative water manage- ment issues, alternative agricultural landscapes that they each consider as potential solutions. Our design approach combines (1) facilitation of participatory workshops for designing changes in cropping systems and their spatial distributions at the landscape level with (2) formalization of these alternatives in a GIS. The formalized alternatives provide precise information about ïŹelds, farms and areas concerned by the designed changes. We present two sample results of this methodology implemented in a 840 km2 irri- gated landscape located in a water-deïŹcient watershed in southwestern France. We discuss how our design approach may be useful for a wider design-and-assessment methodology involving researchers and stakeholders with conïŹicting interests. We show that our co-design approach provides fertile ground for the emergence of salient, credible and legitimate change options
The soil-crop models STICS and AqYield predict yield and soil water content for irrigated crops equally well with limited data
Climate-change scenarios predict increased scarcity of water available for agriculture in irrigated regions. To design and assess cropping system adaptations to more frequent droughts, soil-crop models are useful and efïŹcient. The variety of models available makes it difïŹcult to select one that is robust under a wide range of agro-pedoclimatic contexts and effective with limited input data and standard values. Here, we compared performances of two soil-crop models of contrasting complexity: STICS, a mechanistic model, and AqYield, which is much simpler and more empirical. For this purpose, predicted soil water contents and yields were compared to independent data acquired for three spring crops (maize, sunïŹower, and sorghum) at four sites in a summer-water-deïŹcient region in southwestern France. Crops were grown under several irrigation strategies, from rainfed to full irrigation conditions. Both models tended to predict yields satisfactorily, but more accurately for maize, intermediate for sorghum and less accurately for sunïŹower. They accurately ranked situations according to crop, soil and irrigation strategy, but failed to rank inter-annual variability. Both AqYield and STICS predicted much of the variability observed in soil available water content (AWC) under maize and sorghum. Predictions were less accurate, although satisfactory, for sunïŹower. STICS underpredicted AWC under sorghum, but was generally more accurate than AqYield in situations with low water stress. AqYield was more accurate for high levels of water stress, but tended to overpredict AWC. Yearly dynamics of AWC were evaluated with a novel expert method. Both models accurately represented these dynamics in more than 60% of cases. Overall, we demonstrated that both models sufïŹciently predicted yield and water balance; however, STICS is more appropriate when other limiting processes need to be simulated
Gestion quantitative de l'eau en territoires irriguĂ©s: intĂ©rĂȘt et contraintes du numĂ©rique aux diffĂ©rentes Ă©chelles de dĂ©cision
La gestion quantitative de lâeau est un enjeu majeur, en particulier dans les territoires ruraux oĂč lâactivitĂ© agricole est soutenue par lâirrigation alors mĂȘme que la ressource en eau est peu abondante. Cet article prĂ©sente, Ă partir de 3 exemples (modĂ©lisation intĂ©grĂ©e, donnĂ©es satellitales, compteurs communicants), tout lâintĂ©rĂȘt du numĂ©rique pour gĂ©rer l'eau et prendre des dĂ©cisions en amont et pendant la campagne dâirrigation. Il illustre Ă©galement les besoins et contraintes techniques associĂ©s Ă l'usage du numĂ©rique. Il conclut sur lâimportance du facteur humain pour rendre effectifs les atouts du numĂ©rique