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

How do multi-criteria assessments address landscape-level problems? A review of studies and practices

Viewing the landscape as a spatialized social-ecological system allows identification of specific management challenges: integration of multiple views, multiple levels of organization, complex spatial-temporal patterns and uncertainties. Multi-criteria assessments (MCAs), which allow the comparison of alternative actions when multiple interests collide, are considered adequate to support landscape management. However, there is no consensus about how they should be applied and can integrate both multiple views and spatial dimension. We conducted an extensive quantitative and qualitative literature review targeting MCAs with a participatory and spatial approach. Our results suggest that (1) for sustainability assessments, participatory and spatial approaches endorse different rationales and hybrid methods are not so common; (2) within those methods, only scenario-selection methods (as opposed to design methods) can integrate spatially-explicit, spatially-implicit, place-specific, and overall values; and (3) current applications, which aggregate values ignoring their spatial and social distribution, do not coincide with the nature of landscape-management challenges. In addition, they give little importance to the structuration of information and to collective deliberation. We conclude that, in the absence of a good match between spatiality and participation, MCAs should, for now, be handled as insightful but distorted tools to explore and structure landscape-level management problems

Analyse frequentielle du climat : resultats preliminaires

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A multicriteria assessment method to compare scenarios of water management in agricultural landscapes

In the Aveyron watershed (South-Western France), where the agricultural economy mainly relies on irrigated productions (maize and fruits), engaging changes in quantitative water management is socially challenging. The watershed suffers from a structural misbalance between the water demand and the water offer, and recurring crises in the low-flow period lead to emergency restrictions of use. This situation tenses competing stakeholder positions and erodes the social-ecological system’s resilience.Characterizing and valuing options for change can support decision-making. Nonetheless, the various expert assessments that flourished as answers to political incentives for a better management of watershed did not succeed in bringing out socially-accepted solutions. We hypothesize that expert judgments (alone) cannot frame problems that also arise from colliding values and interests. Hence we built a spatialized multi-actor multi-criteria assessment method in order to map out matches and mismatches between the people involved and between the stakes relevant to them.This method proceeds through various steps: 1) Problem structuring: relevant stakeholders are identified; criteria and scenarios are defined following a bottom-up approach; 2) Definition and evaluation of a set of indicators for each scenario, using mainly model simulations of water management; 3) Mapping out stakeholder judgments; 4) Collective deliberation over the sociallyrelevant option(s) for change. A specificity of the method lies in the way stakeholder judgments are elicited and represented (step 3). Indicators constitute arguments that stakeholders can combine to express their judgments. Stakeholders map out where one scenario is acceptable to them and where it is not (spatialized judgments). In addition, they can define places of special importance for each criterion (spatialized weights). Integrating those maps would help change the focus from “which scenario is the best” to “where does a scenario bring out conflicts and where is it consensual option”. We expect such a transformation to favour social learning and the design of new technical and organizational solutions for watershed management

Water futures: A review of water scenarios based on an original analytical framework

International audienceWater is being increasingly seen as one of the key resources in the context of climate change. Despite scholarship focusing on water issues can be traced back to long time ago, it has not been until recently that Integrated Assessment (IA) techniques have permeated in this field. Scenario development is a key component of IA, together with computer-aided Integrated Assessment Models, simulation gaming and qualitative Integrated Models. However, we argue that the use of the word scenario has been polysemous and to some extent confusing. In this contribution, we present an extended review of scenario analysis concerning water resources at multiple scales and we build an interpretative framework to analyze them. By doing so we propose some guidelines and areas where research is needed

Partager l'eau d'irrigation dans les bassins versants : usages et intérêts des quotas

International audienceLes quotas sont un outil de gestion de l’eau d’irrigation qui joue sur la demande ; ils répartissent la ressource entre usagers en limitant la quantité prélevable. Cependant, les systèmes de quotas existent dans des contextes divers, sous des formes et dénominations hétérogènes. Afin de comprendre ces systèmes complexes, nous proposons ici une grille d’analyse qui nous permet de 1) déterminer si le système de partage de la ressource rencontré relève de l’utilisation de quotas, 2) comprendre les liens entre ce système et son environnement social et hydrologique, et enfin 3) caractériser la diversité des quotas par quatre angles d’analyse (règles d’attribution, insertion dans une gestion collective de la ressource, transférabilité et adaptation à une pénurie conjoncturelle)

Spatial aggregation of indicators in sustainability assessments: Descriptive and normative claims

International audienceIndicators are widely used in sustainability assessments. They serve both a descriptive function (i.e.., assessing a situation or effects of potential changes) and a normative function (i.e., allowing the expression of value judgments). These functions are usually considered when identifying and using indicators. However, processes such as formalization, estimation, and customization are needed to produce tangible indicators. These processes and their influence on sustainability assessments are studied less often. We focus on spatial aggregation, a specific type of customization commonly used for landscape-scale and regional assessments. Using a database with 146 indicator profiles for water management, we investigated reasons for spatial aggregation choices, i.e. whether indicators based on spatially-explicit data are aggregated while under development or are provided to users in a disaggregated form. Although the literature assigns a descriptive function to spatial aggregation, our database shows that reasons underlying aggregation choices are more diverse. These reasons include highlighting differences, fitting to the scale of a process, fitting to criteria, recognizing a lack of knowledge, expressing social rationality, contextualizing information, and allowing different interpretations of the same indicator. Some of these reasons reflect the choice to expand or reduce the range of potential uses of an indicator, and therefore the potential for different viewpoints to confront each other. Hence, normative claims combine with descriptive claims when aggregating indicators, and even more so when customizing them. In general, the form of indicators merits more attention in the practice and theory of sustainability assessments

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 stakeholders’ involvement in the process of designing a solution to the specific 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 fields, 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-deficient 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 conflicting interests. We show that our co-design approach provides fertile ground for the emergence of salient, credible and legitimate change options

Partager l'eau d'irrigation dans les bassins versants : usages et intérêts des quotas

International audienceLes quotas sont un outil de gestion de l’eau d’irrigation qui joue sur la demande ; ils répartissent la ressource entre usagers en limitant la quantité prélevable. Cependant, les systèmes de quotas existent dans des contextes divers, sous des formes et dénominations hétérogènes. Afin de comprendre ces systèmes complexes, nous proposons ici une grille d’analyse qui nous permet de 1) déterminer si le système de partage de la ressource rencontré relève de l’utilisation de quotas, 2) comprendre les liens entre ce système et son environnement social et hydrologique, et enfin 3) caractériser la diversité des quotas par quatre angles d’analyse (règles d’attribution, insertion dans une gestion collective de la ressource, transférabilité et adaptation à une pénurie conjoncturelle)