Decision-making under uncertainty in model-based water management : The science-practice interface

Balancing the different needs and demands of water users and managing the supply side under temporal and spatial variability and extremes has always been a challenging task for water managers. However, accelerated environmental and societal change aggravates water management as uncertainties increase even further. Decision-making in water management must integrate uncertainty information to base decisions on and be prepared for surprise and ambiguity. While it is often considered that decision-makers do not understand or – at least sometimes – ignore uncertainty analysis, this research shows that uncertainties do in fact matter for water managers and that they already cope with them and acknowledge them as an integral part of their planning. This doctoral research aims at improving the understanding of how scientific uncertainties find better integration into planning and decision-making processes in model-based water management. The thesis hereby follows the hypothesis that understanding and identifying the plurality of practitioners and the diversity of their approaches, perspectives, and reasoning are key aspects to close the science-practice gap. Extensive expert elicitation, a quantitative survey and qualitative system modelling present the applied methods to answer the research questions. The intensive engagement with practitioners plays a crucial role for the thesis to assess uncertainty perception and handling strategies of water managers. Even though the results are mainly demonstrated at the case of reservoir management under changing intra-annual and annual conditions, the findings can easily be transferred to other water-related management objectives. The main finding of this research is that water managers acknowledge uncertainties. However, the degree of acknowledgement and handling capacity varies per level of working experience, educational background, type of employer and affiliation to business unit. In close relation to their background, water managers have developed different strategies to handle uncertainties, approaches which may seem less obvious to scientists. Additionally, tacit knowledge plays a major role in handling uncertainties as well as the implicit handling of process uncertainties. A lack of transparency, regulations and constraints in a highly politicized decision-making environment present limitations of uncertainty integration. Thus, the use of uncertainty strategies and routines applied by the practitioners differs regarding group membership and time-frame of the management objective. In the course of this doctoral thesis, three major tools were developed to increase the transparency and integration of uncertainties: 1) a 2x2 uncertainty matrix, 2) an integration and analytical framework, and 3) a qualitative system model. This compilation has identified criteria, described prerequisites and provided a practical strategy to improve the integration of scientific uncertainties into planning and decision-making processes in model-based water management. It gives implications for increasing usability of uncertainty information and enables second or third loop learning for adaptive or transformative water management by fostering cross-communication within practice and between science and practice. This research also presents a theoretical construct to rethink uncertainty implications and their interrelations with respect to a plurality of perspectives, especially, regarding the diversity of practitioners. Furthermore, this research contributed to the science-practice gap research by emphasising the plurality of practitioners' uncertainty perception and handling. Acknowledging this plurality overcomes the thinking of a linear causal chain of information and makes room for a plurality of knowing and, hence, different ways to cope with and to integrate uncertainties into final decisions.Entscheidung unter Unsicherheit im Modell-basierten Wassermanagement : Die Wissenschaft-Praxis Schnittstelle Eine zentrale Herausforderung für das Wassermanagement ist, den Ausgleich zwischen verschiedenen Wassernutzern und ihren Bedürfnissen herzustellen, bei gleichzeitiger Berücksichtigung zeitlicher und räumlicher Variabilität sowie Extreme des Wasserdargebots. Zunehmende Unsicherheiten aufgrund des Umweltwandels und sozialen Wandels erschweren das Management dieser Ressourcen zusätzlich. Die Integration von Unsicherheiten in Entscheidungsprozesse im Wassermanagement ist daher von besonderer Bedeutung, um auf unerwartete Ereignisse und eine große Bandbreite an möglichen Zukunftsszenarien vorbereitet zu sein. Ziel der Arbeit ist es zum Verständnis beizutragen, wie wissenschaftliche Unsicherheiten besser in Planungs- und Entscheidungsprozesse des modell-basierten Wassermanagements integriert werden und die Qualität des Wassermanagements damit verbessert werden kann. Hierbei wird die Hypothese verfolgt, dass das Verständnis und die Identifikation der Pluralität von Akteuren und ihrer unterschiedlichen Ansätze, Perspektiven und Entscheidungsmuster einen Schlüsselaspekt darstellen, um einen Beitrag zur Überbrückung der Lücke zwischen Forschung und Praxis zu leisten. Hauptmethoden, um die Ziele dieser Arbeit zu erreichen, sind umfangreiche Experteninterviews, Umfragen und qualitative Systemmodellierung. Dabei ist die intensive Auseinandersetzung mit Praxisakteurinnen und -akteuren ein zentrales Element, um die Wahrnehmung und den Umgang mit Unsicherheiten von Wasserressourcenmanagerinnen und -managern einschätzen zu können. Während die Ergebnisse hauptsächlich am Beispiel des Talsperrenmanagements unter sich ändernden intra-annuellen und annuellen Rahmenbedingungen erläutert werden, können sie auch auf alle anderen wasserbezogenen Bereiche übertragen werden. Die zentrale Erkenntnis dieser Arbeit besteht darin, dass Wassermanagerinnen und -manager Unsicherheiten einen hohen Wert beimessen. Die Wahrnehmung und Berücksichtigung von Unsicherheiten und Handlungskapazitäten variieren jedoch in Abhängigkeit von der Erfahrungsstufe der Praxisakteurinnen und -akteure, ihres Bildungshintergrunds, ihres Arbeitgebers, sowie ihrer Zugehörigkeit zu bestimmten Geschäftsbereichen. In Anlehnung an ihr berufliches Umfeld haben diese Akteurinnen und Akteure verschiedene Strategien zum Umgang mit Unsicherheiten entwickelt, die auf den ersten Blick nur schwer von Wissenschaftlerinnen und Wissenschaftlern wahrgenommen werden. Zusätzlich spielt Erfahrungswissen im Umgang mit wissenschaftlichen Unsicherheiten und Prozessunsicherheiten eine große Rolle. Fehlende Transparenz, Normen und Regularien in einem hoch politisierten Umfeld erschweren die Integration von Unsicherheiten. Im Rahmen der Arbeit wurden drei Werkzeuge zur Verbesserung der Transparenz und Integration von Unsicherheiten entwickelt: 1) eine 2x2 Unsicherheitsmatrix, 2) ein Integrations- und Analysekonzept, sowie 3) ein qualitatives Systemmodel. Insgesamt wurden Kriterien identifiziert, Voraussetzungen erläutert sowie eine praktische Strategie entwickelt, wie die Integration von wissenschaftlichen Unsicherheiten in wasserbezogene Planungs- und Entscheidungsprozesse verbessert werden kann. Es werden Ansätze aufgezeigt, mit denen die Nutzbarkeit von Unsicherheitsinformationen erhöht werden kann und die einen vertieften Diskurs zwischen Praxisakteurinnen und -akteuren untereinander sowie zwischen Wissenschaft und Praxis ermöglichen. Der theoretische Beitrag dieser Arbeit hebt die Bedeutung der Interrelationen von Unsicherheiten und der Pluralität an Perspektiven und Strategien hervor. Indem diese Vielfalt hervorgehoben wird, wird die Forschung an der Schnittstelle Wissenschaft-Praxis bereichert, da sie alte Annahmen linear-kausaler Zusammenhänge von Informationen verwirft und Raum für eine Pluralität an Wissen sowie unterschiedliche Herangehensweisen hinsichtlich Unsicherheitsintegration in finale Entscheidungen eröffnet

Lessons Learned from PARADeS Project for Flood Disaster Risk Planning and Management in Ghana

The PARADeS project focused on Ghana’s national flood disaster risk reduction and management strategy by investigating existing flood risk and mechanisms for disaster management, governance-policy, human-water interaction, and development of possible future scenarios and feasible and sustainable measures. Three case study areas with different types of flooding were identified and chosen in a participatory flood risk-based process. These are including the catchments Odaw in Accra (pluvial, fluvial and coastal floods), Aboabo in Kumasi (pluvial and fluvial floods), and the White Volta (fluvial floods). The project used innovative socio-technical and participatory approaches and tools that combines research, development, and institutional strengthening activities. It integrated diverse information, local knowledge and data sources and was developed collaboratively with stakeholder scenarios and socio-technical tools in order to support coherent decision-making processes. A key aspect was analysing different scenarios of flood hazards, investigating and modelling cascading risk effects regarding critical infrastructure, and an assessment tool to identify flood risk at a household level, the FLOODLABEL Ghana. All processes and working steps are realized using interdisciplinary and participatory approaches together with Ghanaian stakeholders. The end products are strengthening institutional and citizens’ capacity through a series of activities on societal awareness and training of specialists, decision, and policymakers. Technologically, the project has produced a set of decision support tools (Flood Information Systems, FLOODLABEL Ghana, etc.) to effectively disseminate vital information to citizens, researchers, and decision makers to respond and mitigate the impact of flooding. In pursuit of sustainable development in FDRM measures, we disseminated the outcomes and products, including technical tools, through reports and scientific publications. Additionally, we developed training materials tailored for students, experts, and decision-makers

The Impact of Land Use/Land Cover Change (LULCC) on Water Resources in a Tropical Catchment in Tanzania under Different Climate Change Scenarios

Many parts of sub-Saharan Africa (SSA) are prone to land use and land cover change (LULCC). In many cases, natural systems are converted into agricultural land to feed the growing population. However, despite climate change being a major focus nowadays, the impacts of these conversions on water resources, which are essential for agricultural production, is still often neglected, jeopardizing the sustainability of the socio-ecological system. This study investigates historic land use/land cover (LULC) patterns as well as potential future LULCC and its effect on water quantities in a complex tropical catchment in Tanzania. It then compares the results using two climate change scenarios. The Land Change Modeler (LCM) is used to analyze and to project LULC patterns until 2030 and the Soil and Water Assessment Tool (SWAT) is utilized to simulate the water balance under various LULC conditions. Results show decreasing low flows by 6–8% for the LULC scenarios, whereas high flows increase by up to 84% for the combined LULC and climate change scenarios. The effect of climate change is stronger compared to the effect of LULCC, but also contains higher uncertainties. The effects of LULCC are more distinct, although crop specific effects show diverging effects on water balance components. This study develops a methodology for quantifying the impact of land use and climate change and therefore contributes to the sustainable management of the investigated catchment, as it shows the impact of environmental change on hydrological extremes (low flow and floods) and determines hot spots, which are critical for environmental development

Dynamics of Human–Water Interactions in the Kilombero Valley, Tanzania: Insights from Farmers’ Aspirations and Decisions in an Uncertain Environment

The Kilombero Valley, one of East Africa's largest seasonal wetlands, is a high-potential agricultural development corridor area in Tanzania. This seasonally flooded wetland is mainly used by smallholder farmers who cultivate during the rainy season, although there are some community-based irrigation systems that reduce hydro-climatic risks. In this study, we aim to understand how farmers' aspirations and visions about the future are related to the current agricultural practices and human–water interaction. We specifically investigate the differences between farmers from rainfed and irrigated agriculture by using focus group discussions. Analysis of the in-depth interviews highlights how farmers' actions both shape and respond to this highly dynamic and uncertain environment. Furthermore, we identify a close link, driven by the farmers' level of agency, between aspirations and expected agro-economic development. The heterogeneity of farmers' agency and hence their ability to cope with change is not only based on the socioeconomic status but also on their perception of the physical environment. We thus recommend that attention is also paid to the capacity for coping with environmental challenges that influences the level of farmers' aspiration

Water and Health Nexus—Land Use Dynamics, Flooding, and Water-Borne Diseases in the Odaw River Basin, Ghana

Water pollution is a major issue in Ghana with direct impacts on human health. However, the underlying drivers of exposure and risks are not comprehensively explored and understood, while the diseases continue posing huge burdens. The key question addressed is: what are the key drivers influencing the water–health nexus, particularly water-borne disease risks in the Odaw River basin, Ghana? Multiple approaches were integrated: qualitative system dynamic modeling and urban land-use change assessment. Multi-level stakeholder participation, including household surveys, focus group discussions, and workshops were employed in developing and identifying indicators and feedback loops. The results revealed that communities have access to water and sanitation, but water-borne diseases are still prevalent. Flooding influenced by poor land use planning and solid waste disposal are key risk factors, contributing to water pollution and disease outbreaks. The major land-use change is the conversion of natural to built-up areas, resulting in decreased urban vegetation cover and increased soil sealing, partly contributing to flood risk. Complex linkages and multiple feedback loops between land use, flooding, water pollution, and water-borne disease risks were identified. In addition to supplying safe drinking water and sanitation, multi-sectoral collaborations are required to co-design and implement integrated interventions, including flood risk reduction, urban land use plans, and improved waste management to reduce disease risks and promote health

Future of Water Supply and Demand in the Middle Drâa Valley, Morocco, under Climate and Land Use Change

Regions of scarce fresh water resources, such as the Middle East and North Africa, are facing great challenges already today, and even more in the future, due to climatic and socioeconomic changes. The Middle Drâa valley in Morocco is one of many semi-arid to arid mountainous areas struggling with increasing water scarcity threatening self-sufficient husbandry. In order to maintain people’s livelihoods water management needs to be adapted. The Water Evaluation And Planning System (WEAP) software has been widely used to examine complex water systems in the water resource planning sector all around the world and proved to be a helpful asset to show the various interactions of water supply and demand. This paper presents the application of WEAP on the Middle Draâ valley’s water demand and supply, including several socioeconomic and land use scenarios under one basic climate change scenario. The climate scenario shows a significant decrease in available water resources up to 2029 while all socioeconomic scenarios show an increase in water demand. In years of droughts groundwater is used for irrigation, leading to increasingly depleted aquifers. The aquifers are recharged by percolation losses from irrigation and by river bed infiltration the latter of which is stronger in the northern oases than in the southern oases due to water withdrawal rules. A drastic reduction of irrigated agricultural area is the only solution to guarantee sustainable water use

The Pluralistic Water Research Concept: A New Human-Water System Research Approach

The use and management of water systems is influenced by a number of factors, such as economic growth, global change (e.g., urbanization, hydrological-climatic changes), politics, history and culture. Despite noteworthy efforts to develop integrative approaches to analyze water-related problems, human-water research remains a major challenge for scholars and decision makers due to the increasing complexity of human and water systems interactions. Although existing concepts try to integrate the social and water dimensions, they usually have a disciplinary starting point and perspective, which can represent an obstacle to true integration in human-water research. Hence, a pluralistic approach is required to better understand the interactions between human and water systems. This paper discusses prominent human-water concepts (Integrated Water Resources Management (IWRM), socio-hydrology, and political ecology/hydrosocial approach) and presents a newly developed concept termed pluralistic water research (PWR). This is not only a pluralistic but also an integrative and interdisciplinary approach which aims to coherently and comprehensively integrate human-water dimensions. The different concepts are illustrated in a synopsis, and diverse framing of research questions are exemplified. The PWR concept integrates physical and social sciences, which enables a comprehensive analysis of human-water interactions and relations. This can lead to a better understanding of water-related issues and potentially sustainable trajectories