Joseph H. A. Guillaume

Integrated assessment and modelling

Integrated assessment and its inherent platform, integrated modelling, present an opportunity to synthesize diverse knowledge, data, methods and perspectives into an overarching framework to address complex environmental problems. However to be successful for assessment or decision making purposes, all salient dimensions of integrated modelling must be addressed with respect to its purpose and context. The key dimensions include: issues of concern; management options and governance arrangements; stakeholders; natural systems; human systems; spatial scales; temporal scales; disciplines; methods, models, tools and data; and sources and types of uncertainty. This paper aims to shed light on these ten dimensions, and how integration of the dimensions fits in the four main phases in the integrated assessment process: scoping, problem framing and formulation, assessing options, and communicating findings. We provide examples of participatory processes and modelling tools that can be used to achieve integration. This is an overview on integrated assessment and modelling (IAM) for environmental problems.We examine the ten key dimensions of integration in IAM including what is being integrated, why and how.We discuss how the integration dimensions fit into the IAM process.

Using a parallelized MCMC algorithm in R to identify appropriate likelihood functions for SWAT

Markov Chain Monte Carlo (MCMC) algorithms allow the analysis of parameter uncertainty. This analysis can inform the choice of appropriate likelihood functions, thereby advancing hydrologic modeling with improved parameter and quantity estimates and more reliable assessment of uncertainty. For long-running models, the Differential Evolution Adaptive Metropolis (DREAM) algorithm offers spectacular reductions in time required for MCMC analysis. This is partly due to multiple parameter sets being evaluated simultaneously. The ability to use this feature is hindered in models that have a large number of input files, such as SWAT. A conceptually simple, robust method for applying DREAM to SWAT in R is provided. The general approach is transferrable to any executable that reads input files. We provide this approach to reduce barriers to the use of MCMC algorithms and to promote the development of appropriate likelihood functions. Bayesian MCMC analysis has yet to be successfully applied to the popular SWAT model.An R implementation of DREAM accommodates SWATs reading of input files.Open source script allows for likelihood function development to advance modeling.

Fit for purpose? Building and evaluating a fast, integrated model for exploring water policy pathways

Exploring adaptation pathways is an emerging approach for supporting decision making under uncertain changing conditions. An adaptation pathway is a sequence of policy actions to reach specified objectives. To develop adaptation pathways, interactions between environment and policy response need to be analysed over time for an ensemble of plausible futures. A fast, integrated model can facilitate this. Here, we describe the development and evaluation of such a model, an Integrated Assessment Metamodel (IAMM), to explore adaptation pathways in the Rhine delta for a decision problem currently faced by the Dutch Government. The theory-motivated metamodel is a simplified physically based model. Closed questions reflecting the required accuracy were used to evaluate the models fitness. The results show that such a model fits the purpose of screening and ranking of policy options and pathways to support the strategic decision making. A complex model can subsequently be used to obtain more detailed information.

A methodology for eliciting, representing, and analysing stakeholder knowledge for decision making on complex socio-ecological systems: From cognitive maps to agent-based models

This paper aims to contribute to developing better ways for incorporating essential human elements in decision making processes for modelling of complex socio-ecological systems. It presents a step-wise methodology for integrating perceptions of stakeholders (qualitative) into formal simulation models (quantitative) with the ultimate goal of improving understanding and communication about decision making in complex socio-ecological systems. The methodology integrates cognitive mapping and agent based modelling. It cascades through a sequence of qualitative/soft and numerical methods comprising: (1) Interviews to elicit mental models; (2) Cognitive maps to represent and analyse individual and group mental models; (3) Time-sequence diagrams to chronologically structure the decision making process; (4) All-encompassing conceptual model of decision making, and (5) computational (in this case agent-based) Model. We apply the proposed methodology (labelled ICTAM) in a case study of viticulture irrigation in South Australia. Finally, we use strengths-weakness-opportunities-threats (SWOT) analysis to reflect on the methodology. Results show that the methodology leverages the use of cognitive mapping to capture the richness of decision making and mental models, and provides a combination of divergent and convergent analysis methods leading to the construction of an Agent Based Model.

The world’s road to water scarcity: shortage and stress in the 20th century and pathways towards sustainability

Water scarcity is a rapidly growing concern around the globe, but little is known about how it has developed over time. This study provides a first assessment of continuous sub-national trajectories of blue water consumption, renewable freshwater availability, and water scarcity for the entire 20th century. Water scarcity is analysed using the fundamental concepts of shortage (impacts due to low availability per capita) and stress (impacts due to high consumption relative to availability) which indicate difficulties in satisfying the needs of a population and overuse of resources respectively. While water consumption increased fourfold within the study period, the population under water scarcity increased from 0.24 billion (14% of global population) in the 1900s to 3.8 billion (58%) in the 2000s. Nearly all sub-national trajectories show an increasing trend in water scarcity. The concept of scarcity trajectory archetypes and shapes is introduced to characterize the historical development of water scarcity and suggest measures for alleviating water scarcity and increasing sustainability. Linking the scarcity trajectories to other datasets may help further deepen understanding of how trajectories relate to historical and future drivers, and hence help tackle these evolving challenges.

Water Stress in Global Transboundary River Basins: Significance of Upstream Water Use on Downstream Stress

Growing population and water demand have increased pressure on water resources in various parts of the globe, including many transboundary river basins. While the impacts of upstream water use on downstream water availability have been analysed in many of these international river basins, this has not been systematically done at the global scale using coherent and comparable datasets. In this study, we aim to assess the change in downstream water stress due to upstream water use in the worlds transboundary river basins. Water stress was first calculated considering only local water use of each sub-basin based on country-basin mesh, then compared with the situation when upstream water use was subtracted from downstream water availability. We found that water stress was generally already high when considering only local water use, affecting 0.95–1.44 billion people or 33%–51% of the population in transboundary river basins. After accounting for upstream water use, stress level increased by at least 1 percentage-point for 30–65 sub-basins, affecting 0.29–1.13 billion people. Altogether 288 out of 298 middle-stream and downstream sub-basin areas experienced some change in stress level. Further, we assessed whether there is a link between increased water stress due to upstream water use and the number of conflictive and cooperative events in the transboundary river basins, as captured by two prominent databases. No direct relationship was found. This supports the argument that conflicts and cooperation events originate from a combination of different drivers, among which upstream-induced water stress may play a role. Our findings contribute to better understanding of upstream–downstream dynamics in water stress to help address water allocation problems.

Diet change and food loss reduction: What is their combined impact on global water use and scarcity?

There is a pressing need to improve food security and reduce environmental impacts of agricultural production globally. Two of the proposed measures are diet change from animal-based to plant-based foodstuffs and reduction of food losses and waste. These two measures are linked, as diet change affects production and consumption of foodstuffs and consequently loss processes through their different water footprints and loss percentages. This paper takes this link into account for the first time and provides an assessment of the combined potential contribution of diet change and food loss reduction for reducing water footprints and water scarcity. We apply scenarios in which we change diets to follow basic dietary recommendations, limit animal-based protein intake to 25% of total protein intake, and halve food losses to study single and combined effects of diet change and loss reduction. Dietary recommendations alone would achieve 6% and 7% reductions of blue and green water consumption, respectively, while changing diets to contain less animal products would result in savings of 11% and 18%, respectively. Halving food loss would alone achieve 12% reductions for both blue and green water. Combining the measures would reduce water consumption by 23% and 28%, respectively, lowering water scarcity in areas with a population of over 600 million. At a global scale, effects of diet change and loss reduction were synergistic with loss reductions being more effective under changed diet. This demonstrates the importance of considering the link between diet change and loss reduction in assessments of food security and resource use.

Aquifer-yield continuum as a guide and typology for science-based groundwater management

Groundwater availability is at the core of hydrogeology as a discipline and, simultaneously, the concept is the source of ambiguity for management and policy. Aquifer yield has undergone multiple definitions resulting in a range of scientific methods to calculate and model availability reflecting the complexity of combined scientific, management, policy, and stakeholder processes. The concept of an aquifer-yield continuum provides an approach to classify groundwater yields along a spectrum, from non-use through permissive sustained, sustainable, maximum sustained, safe, permissive mining to maximum mining yields, that builds on existing literature. Additionally, the aquifer-yield continuum provides a systems view of groundwater availability to integrate physical and social aspects in assessing management options across aquifer settings. Operational yield describes the candidate solutions for operational or technical implementation of policy, often relating to a consensus yield that incorporates human dimensions through participatory or adaptive governance processes. The concepts of operational and consensus yield address both the social and the technical nature of science-based groundwater management and governance.RésuméLa disponibilité de l’eau souterraine est au centre de l’hydrogéologie en tant que discipline, et simultanément le concept est source d’ambiguïté pour les processus de gestion et de police de l’eau. Le terme débit d’un aquifère a connu de multiples définitions résultant de la gamme des méthodes scientifiques de calcul et modèles disponibles, reflétant la difficulté de concilier science, processus de gestion, police de l’eau et dépositaires d’enjeux. Le concept d’un continuum aquifère-débit fournit une approche pour classer les prélèvements d’eau souterraine dans un spectre s’étendant de la non utilisation au débit exploitable assuré, débit exploitable, débit maximum exploitable, débit de sécurité, débit d’exploitation toléré des réserves, jusqu’à l’exploitation des réserves ultimes, spectre à la base de la littérature existante. De plus, le continuum aquifère-débit fournit une vision systémique de la disponibilité de l’eau souterraine pour intégrer des aspects physiques et sociaux dans l’évaluation des options de gestion exploitation selon les catégories d’aquifères. Le débit opérationnel décrit les solutions candidates pour une mise en place opérationnelle ou technique d’une politique de l’eau, souvent en relation avec une production consensuelle incluant des dimensions humaines à travers des processus de gouvernance participative ou adaptative. Les concepts de débit opérationnel et consensuel concernent à la fois la nature sociale et technique de la gestion et la gouvernance scientifique de l’aquifère.ResumenLa disponibilidad del agua subterránea es el centro de la hidrogeología como disciplina y, simultáneamente, el concepto es una fuente de ambigüedad para su gestión y la política. El rendimiento de un acuífero ha sido objeto de múltiples definiciones que derivan en un abanico de métodos científicos para calcular y modelar la disponibilidad reflejando la complejidad de los procesos combinados, científicos, de la gestión, de la política y de las partes interesadas. El concepto de continuidad del rendimiento de un acuífero proporciona una aproximación para clasificar los rendimientos del agua subterránea a lo largo de un espectro, desde el no uso, a través de rendimientos, permisivos sostenidos, sostenibles, máximos sostenidos, seguro, permisivos mineros a máximo minero, que se basan en la literatura existente. Adicionalmente, el rendimiento continuo del acuífero proporciona una visión de los sistemas de la disponibilidad de agua subterránea para integrar aspectos físicos y sociales al evaluar las opciones de gestión a través de la configuración de los acuíferos. El rendimiento operacional describe las soluciones candidatas para la implementación operacional o técnicas de la política, a menudo relacionadas a un rendimiento de consensuado que incorpora dimensiones humanas través de procesos adaptativos y participativos de gobernanza. Los conceptos de rendimiento operacional y de consenso satisfacen la naturaleza social y técnica de la gestión y la gobernanza del agua subterránea basada en la ciencia.摘要地下水可用性是水文地质学科的核心,同时也是管理与政策模糊不清的根源。出水量经历了很多定义,导致一系列计算和模拟可用性的科学方法,表明了联合科学、管理、政策以及涉众过程的复杂性。含水层产量连续的概念为出水量分类提供了一种方法,根据不同范围,基于已有文献,分为不能使用,大致可持续出水量,可持续出水量,最大程度可持续出水量,安全出水量,可出水量到最大程度出水量。另外,含水层产量连续提供了地下水可用性的一个系统视图,可整合含水层设置的管理选项评价中物理和社会方面。运营出水量描述了可操作的或者技术上可行的政策候选方案,通常与包含有可参与的或者可适当控制处理的人文因素的共识出水量相关。运营出水量和共识出水量的概念均记有以科学为基础的地下水管理和调控的社会和技术性质。ResumoA disponibilidade da água subterrânea é nuclear na hidrogeologia como disciplina e, simultaneamente, o conceito é origem de ambiguidade para a gestão e para as políticas da água. A produtividade dos aquíferos teve múltiplas definições, de que resultaram diversos métodos científicos para o cálculo e modelação da disponibilidade, refletindo a complexidade da combinação dos processos científicos, gestionários, políticos e os parceiros envolvidos. O conceito de continuum aquífero-produtividade fornece uma abordagem para classificar as produções de água subterrânea ao longo de todo um espetro, tal como se encontra na literatura, desde o não-uso, passando pelo uso permitido permanente, a produção sustentável, a produção máxima sustentável, a produção segura, o esgotamento permitido e o esgotamento máximo. Adicionalmente, o conceito de continuum aquífero-produção proporciona uma visão em sistema da disponibilidade da água subterrânea para a integração de aspetos físicos e sociais na avaliação de opções de gestão através de cenários no aquífero. A produção operacional descreve as soluções candidatas para implementação técnica e operacional de políticas, frequentemente relacionada com uma produção consensual que incorpora as dimensões humanas através de processos de governância participativa ou adaptativa. Os conceitos de produção operacional e consensual respondem ambos à natureza social e à natureza técnica da gestão e da governância cientificamente fundamentada da água subterrânea.

Role of spatial anisotropy in design storm generation: Experiment and interpretation

Rainfall accumulation depths over a given area are strongly dependent on the shape of the storm together with its direction of advection. A method to produce design storms exhibiting anisotropic spatial scaling is presented by combining a state-of-the-art stochastic rainfall generator STEPS with the linear generalized scale invariance (GSI) notation. The enhanced model is used to create ensembles of design storms based on an extreme storm with a distinct rainband shape observed in Melbourne, Australia. Design storms are generated both with and without accounting for anisotropy. Effect of anisotropy on precipitation characteristics is studied using the entire region covered by the radar (radar scale) and at a significantly smaller catchment scale. A rainfall-runoff model is applied to route the rainfall through the catchment into streamflow. Accounting for anisotropy allows for a more realistic description of precipitation features at the radar scale. At the catchment scale, anisotropy increases the probability of high rainfall accumulations, which translates into greater flood volumes. No discernible difference was observed in streamflow characteristics after controlling for the accumulation over the catchment. This could be explained by a lower importance of anisotropy relative to other factors affecting streamflow generation, and by the difficulties in creating representative rainfall temporal properties at the catchment scale when the radar scale is used for model calibration. The proposed method provides a tool to create ensembles of design storms when the anisotropic shape of the fields is of importance.

Robust discrimination between uncertain management alternatives by iterative reflection on crossover point scenarios

When comparing environmental management alternatives, there is a need to assess the effect of uncertainty in the underlying model(s) and future conditions on robustness of recommendations. At times, it may be difficult or undesirable to specify the uncertainty in inputs and parameters a priori. An alternative approach instead generates crossover points, describing scenarios where the preferred alternative will change (i.e. alternatives are of equal value), and prompts the analyst to assess their plausibility a posteriori. This paper extends previous work by introducing principles, design and implementation of a new method to analyse crossover points. It reduces the complexity of dealing with many variables by identifying single crossover points of greatest concern, and progressively building understanding through three stages of analysis. We present three implementations using R, Excel and a web interface. They use two examples involving cost-benefit analysis of managed aquifer recharge and the water footprint impact of changing diets. Display Omitted Crossover points describe scenarios where recommendations change.Emphasis is on when each alternative is better, not which alternative is better.A multi-stage approach builds understanding of the method and of the problem.All assumptions are considered uncertain; analyst is prompted to review them.Multiple variables are dealt with by identifying crossover points of greatest concern.