Resumen de Water governance in the ebro river basin: construction of a multiregional and multisectoral hydro-economic model
Climate change and food safety are both imminent challenges for social and economic development, despite the differences in their order of magnitude. It is estimated that the global impact of climate change on the availability and quality of water resources, farm output, land productivity and ecosystems could cut world GDP by between 5% and 20% (Stern, 2008). Meanwhile, the intergovernmental panel on climate change (IPCC, 2014) has sounded the alarm over the increase in average global temperatures, a phenomenon associated with rising sea levels, flooding and falling food production. In this context, globalization and the growing interdependence of national economies, which is starkly evident in the internationalization of agri-food production chains, have made food security into a major issue not only locally or nationally but even at the global level. Success will depend to a great extent on the available water resources in each country or region, and on the management of those resources. The importance of these issues is reflected in the Sustainable Development Goals (SDGs) set by the UN in 2015 (United Nations, 2015), which include zero hunger (goal 2); responsible consumption and production (goal 12); and climate action (goal 13).
It becomes clear almost as soon as one begins to think seriously about water that multiple variables affect the quantity and quality of the resource. For example, increased consumption and climate change put pressure on the availability of fresh water (Alcamo et al., 2007; Gerten et al., 2008), but so do bedding and revegetation processes (Bielsa and Cazcarro, 2014), while different water uses and management options may cause contamination, again leading to a reduction in availability. The European Union Water Framework Directive (WFD) (European Communities, 2000) was adopted largely in view of these issues. Specifically, the WFD obliges the Member States of the European Union to take steps to assure the ecological condition of all water bodies and to set environmental flow water requirements. In other words, the volume and distribution of environmental flows over must be defined for all European rivers, together with minimum water quality standards (Acreman and Dunbar, 2004; Acreman and Ferguson, 2010). In general terms, then, the European Union (EU) considers that water governance is a key tool to repair the effects of climate change and to chart paths towards the achievement of the millennium goals.
Water governance is an arduous challenge for all societies, however, given the enormous range of goods and services that make use of water in some way and the sheer diversity of actual and possible uses. The most obvious consumptive uses (drinking water, irrigation and so on) compete not only with each other but sometimes also with non-consumptive uses (hydroelectric generating, power plant cooling, etc.) that require water availability at specific locations and times, thereby conditioning other uses. Such conflicts are common enough in relation to water stored in reservoirs associated with hydroelectric generating and irrigation. Meanwhile, recreational uses like fishing and environmental uses also require minimum water quantity and quality at specific points or reaches along a river, again conditioning other consumptive and non-consumptive uses.
Fresh water is an essential natural resource for life and for almost any kind of economic development, and its value depends on both place and time (Hanemann, 2006). Hence, any analysis of water use and management must inevitably be made in a context of variability in time and space. Furthermore, adaptation to climate change and economic growth in a world where production systems are clearly interdependent at different levels across economic sectors and regions, and are directly influenced by environmental conditions and their impacts, cannot be addressed without close consideration of key issues like the role of technological change, the improvement of governance systems, producer and consumer responsibility in the context of the global production chain, and the links between local and global aspects of production.
Let us not forget, meanwhile, that water is expensive to transport, requiring major capital expenditures to build and maintain infrastructure, not to mention the significant cost of losses along the way. In this light, Gupta and van der Zaag (2008) argue that the costs of long-distance water transportation can only be justified where such transfers are required to guarantee vital supplies.
This thesis treats hydrographic basins as the basic water planning and management units, as seems only logical for all of the above reasons, assuming their physical limits as planning constraints. Meanwhile, rivers often mark borders or run through different countries and regions, obliging governments and other riparian agents representing sometimes very diverse interests to cooperate in governance. Such situations can, on occasion, lead to conflict.
In this light, multisectoral, multiregional models like that developed here to analyse the spatial and temporal dependencies between economic agents in the different regions of a river basin are indispensable for water management. While the methodology described here is applicable to any hydrographic basin, the case study considered in this thesis will be the Ebro River Basin (ERB), perhaps the most representative of the semi-arid Mediterranean basins (Milano et al., 2013), which will provide a framework to distinguish and determine key parameters and productive relationships. The ERB is a highly representative of environmental pressures at the European level, as it suffers from highly unequal distribution of water resources, ever increasing demand and a whole range of serious threats (the Ebro Delta is one of the most ecologically vulnerable areas in Europe). On the plus side, however, it supports highly productive agriculture, while water management experiences have in general been highly successful. Chapter 1 is given over entirely to the case study area, providing more detailed geographical and socio-economic information about the ERB.
Objectives, data sources and methodologies As explained above, this thesis approaches the economic and environmental analysis of the ERB both from a global and local standpoint, examining the consequences of the succession of water uses in the river basin and some of the conflicts between users. The model also integrates different economic activities and water flows, allowing the design of measures to mitigate environmental impacts and foster sustainable regional growth. This allows consideration of a series of geographic and sector-related factors that have traditionally been studied separately at the local (or regional) level, including the environmental impact of economic activities, specialization, sectoral and multi-regional dependencies measured in terms of output and water uses, the role of technological change on production techniques and consumption patterns, and opportunities for local and regional cooperation between different users of water, and the general framework for governance and management of the ERB’s water resources .
The considerable research effort required in terms of data mining and data processing to prepare this thesis study produced important empirical results, allowing, in the first place the construction of a municipal-level database for the ERB, the main characteristics of which are outlined in in the Annex to Chapter 1; in the second, construction of a multiregional and multisector input-output table for the ERB, which is a central contribution to this thesis and, to the best of our knowledge, is the first such MRIO model to be made for any hydrographic basin; and in the third, construction of a hydro-economic model for the ERB which integrates water flows and an input-output structure, another first.
The main methodologies utilized in this thesis are the input-output framework, game theory, hydro-economic models and geographic information systems. These methodologies will allow us to simulate water management alternatives and evaluate socioeconomic and environmental impacts in the multiregional context of the ERB.
The input-output framework reveals the interrelationships between sectors and regions and facilitates assessment of the direct and indirect impacts of possible shocks. For these reasons it has been widely used in economics and has proved a very useful tool to address environmental questions. Game theory has also been taken up enthusiastically by economists, particularly those studying water issues, because it permits analysis of conflict between players from a variety of sometimes very different angles. Among other possibilities, the game theory approach, which is well suited to reflect cooperation and competition in water management processes, can be associated with the institutional conditions under which economic activity takes place allowing researchers to determine the optimal distribution of available water in different scenarios based on a range of criteria and varying assumptions with regard to negotiating power, and to identify both optimal coalitions and optimal distributions within them. Hydro-economic models also take space and time into account, in both hydrological and socioeconomic terms, offering a very handy tool to study and/or evaluate water management capabilities and alternatives.
Meanwhile, geographic information systems (GIS) provide a range of data which we will combine with our findings. We rely on geographic information systems to carry out spatial analysis of the different uses of water and the impacts of the different scenarios that we propose. More detail on the methodologies and tools used is provided in the second chapter.
Thesis structure: The objectives and methodological instruments mentioned above largely define the different sections of this thesis. Chapter 1 offers a socioeconomic and environmental description of the Ebro River Basin, paying special attention to its water flows. In Chapter 2 we review other contributions made in the fields of economics and water management to outline the context of the case study, and we discuss the main characteristics of our base methodologies: (input-output models in section 2.1, game theory in 2.2, hydro-economic models in 2.3 and geographic information systems in 2.4).
Following this methodological review, Chapter 3 examines a specific water management case study involving the conflict between water use in the last stretch of the Ebro and the environmental requirements of the Delta. This chapter introduces and partly justifies what follows. The Ebro is the largest river in Spain, and the sediments it carries downstream from the highlands of the Pyrenees and the Iberian System help to make up and maintain the Delta, at the same time counteracting the growing salt wedge, a problem that has worsened due to upstream regulation (especially at Mequinenza) and climate change, which has raised sea levels in recent decades.
The ERB Authority (Confederación Hidrográfica del Ebro or CHE in the Spanish acronym) is responsible for hydrological planning in the River Basin (CHE, 2014). After initial drafting, these plans are submitted to the ERB’s stakeholders to obtain their opinions and allow them to propose changes. In recent years, certain players, in particular the the Catalan Water Agency (Agència Catalana de l'Aigua or ACA) and the Lower Ebro Sustainability Commission (Comissió per a la sostenibilitat de les Terres de l'Ebre or CSTE) , have branded the minimum environmental flows set for the Delta as insufficient in these rounds of consultations, as reflected in the planning reports, and both . agencies have put forward their own proposals for minimum environmental flows (ACA, 2007; CSTE, 2015). Chapter 3 analyses the options available to increase ecological flows in the Delta in line with these proposals, suggesting various management alternatives for the final stretch of the Ebro. The management of environmental flows into the Delta is currently handled solely from the Mequinenza dam, a solution that has sometimes drained water from the reservoir to environmentally concerning levels, drawing protests from irrigators and other users. The management alternatives that we propose take into account the possibility of using other reservoirs to help achieve the objective of increased environmental flows in the Ebro Delta. A simplified water flow model was built for the purpose of this analysis, simulating possible management alternatives using a real monthly data set spanning 50 years. We analyse the results of this model using game theory.
Interregional and inter-sectoral analysis is key to understanding socio-economic dependencies and environmental conditions in the Ebro Basin, and Chapter 4 is therefore given over to the construction of an input-output table that matches it geographically and to the analysis of interregional and inter-sector trade flows based on the associated implicit virtual flows of value added, jobs and water. This chapter, then, describes the sources used and the main steps in the process followed to construct the multi-regional IO table. In this regard, let us note that our model approach the ERB by the part of five of Spain’s Autonomous Communities (the most representative political regions), namely Aragon, the Basque Country, Catalonia, La Rioja and Navarre; Therefore, the multi-regional input-output table for the ERB considers these regions, as well as the rest of Spain, the rest of the EU and the rest of the world.
Our main sources for the construction of the multi-regional input-output table are the tables provided by regional statistics offices, the Spanish National Statistics Institute, and the World Input-Output Database (WIOD) (Timmer et al., 2015). We rely on the existing satellite accounts at WIOD (Genty et al., 2012), the data reported by Chapagain and Hoekstra (2004) and data from a previous multi-regional model developed for the whole of Spain (Cazcarro et al., 2014) to extend the model environmentally. Given our interest in water governance, the table reflects a high level of primary sector disaggregation, which is the main consumptive user of water. More specifically, the primary sector in the ERB regions, is split between crop cultivation, livestock, and other primary sector activities. Farm output is then further subdivided into 18 groups of irrigated and rainfed crops, which are in turn segmented into, and six livestock groups.
This level of disaggregation not only adds detail to the description of the ERB but means that we can use the IO table as a basis for the construction of a hydro-economic model, which is then used together with GIS data flesh out our portrayal of the ERB by analysing the regional and sectoral interdependencies associated with a range of different variables.
Chapter 5 links the methodologies employed to build the simplified water flow model and multi-regional input-output table for the ERB in Chapters 3 and 4. This is itself a significant scientific contribution, because these approaches have never, to the best of our knowledge, been integrated in this way before.
By linking water flow modelling and IO methodologies, we may establish a set of water availability constraints in our multiregional model (Chapter 4) based on characteristic monthly flows in the ERB, previous uses and environmental needs. Water flow modelling of this kind, respecting the principles of water mass balance and the continuity of river flow, which determine the volume of water availability in the different river sections, is a key feature of hydro-economic models. To this end, we determine a series of nodes where water availability is calculated, formulating equations to describe the relationships between nodes (i.e. the direction of the different water flows). In other words, the hydrological component of the model identifies the water available in each area of the river basin every month, uses of the resource and the destination of unused water.
Agent behaviour equations form the other pillar of hydro-economic models. Water use by the agents in a river basin is associated with a given node, so that withdrawals by each agent are subtracted from a specific node. Hence, the water available for use by a given agent is determined by upstream use by other agents and by hydrological conditions. It is here that multiregional input-output table for the ERB comes in, because the behavioural equations used are based on the underlying inter-sectoral and interregional relationships and on the equilibrium conditions of the input-output framework.
This multi-sectoral and multi-regional hydro-economic model allows a joint, integrated analysis of both productive and consumptive economic activities and of actual water flows taking into consideration successive uses of the resource. Using this model we can, then, propose measures to maximize the benefits obtained from the activities associated with different water uses, but without oversimplifying the economic component, as is all too often the case. The issues that can be addressed with this model include constraints on the use of water resources, technological change, regional trade, imports and exports, changes in demand and so on, and we will look at some of these below. Meanwhile, the environmental impacts of different productive and consumptive water uses can also be quantified in detail by looking at the share accounted for by each activity at each node or for each region. Analysis of different scenarios using GIS data is ideal for these purposes. For this reason, we set out to show the potential of the hydro-economic model of the ERB constructed on the basis described, proposing various scenarios and analysing the results. GIS plays a key role in this analysis, helping locate the areas affected by the impacts observed and identify possible ways to improve outcomes.
This thesis ends with a summary and conclusions section, in which we describe and discuss key findings together with some practical and political conclusions from this research, as well as the future lines of enquiry that it suggests.
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