Water scarcity is a critical environmental issue worldwide, especially in arid and semiarid regions. In those regions, climate change projections suggest further reductions in freshwater supplies and increases of the recurrence, longevity and intensity of drought events. At present, one important question for policy debate is the identification of water policies that could address the mounting water scarcity problems. Suitable policies should improve economic efficiency, achieve environmental sustainability, and meet equity needs. This paper develops and applies an integrated hydro-economic model that links hydrological, economic and environmental elements to such issues. The model is used to conduct a direct comparison of water markets, water pricing and institutional cooperation, based on their economic, environmental and equity outcomes. The analysis is performed in the Jucar Basin of Spain, which is a good natural experiment for studying water scarcity and climate change policies. Results indicate that both institutional and water market policies are high performing instruments to limit the economic damage costs of droughts, achieving almost the same social benefits. However, the environmental effects of water markets are worrying. Another important finding is that water pricing is a poor policy option not only in terms of private and environmental benefits but also in terms of equity.

During the last three decades, like many other Mediterranean states, Spain has intensively promoted the modernization of irrigation, focusing mainly on the introduction of pressurized irrigation systems. Following 30 years of investment, a shift in irrigation policies is needed to solve some of the deficiencies in this modernization process and to incorporate new measures to cope with upcoming challenges generated by international markets, climate change and other social and economic processes. This paper describes and analyses the results of participatory research carried out with the water user associations in the autonomous region of Valencia, in order to define post-modernization irrigation policies. A survey and 24 local workshops involving 304 water user associations were conducted during the irrigation season of 2018 in order to form an assessment of the sector and design new irrigation policies. The results show that after 30 years of important investment, the obsolescence of the infrastructure has become the current main priority, making farmers dependent on public subsidies. New necessities have also emerged, such as renewable energies and nonconventional water resources, which farmers consider indispensable in order to reduce operating costs and guarantee water supply.

Climate change and increased competition for water resources are generating growing concern about how to improve water-use efficiency in agriculture. In turn, this has prompted substantial investments in the installation of water-saving technologies in irrigation systems. The first aim of this research is to use data envelopment analysis to quantify, in terms of gross water savings (GWS), the local-scale efficiency of the irrigation policies adopted in an area of Spain suffering from a structural water deficit. Second, the cross-efficiency method is used to produce a ranking of the irrigation organizations analysed, in order to identify patterns of water-use efficiency performance that can guide future lines of investment. The results reveal that water-use efficiency prior to modernization is a key determinant of the efficiency achieved in terms of GWS at local scale. However, the investments targeted at irrigation modernization often have objectives other than water savings. These and other aspects should be taken into account when allocating public funds to irrigation modernization.

In recent years, co-management has been highlighted in the scientific literature as fundamental strategy for groundwater control. However, the development of this institutional architecture is complex and presents important pitfalls and challenges. In this article we analyse the recent experience of co-management in the Requena-Utiel aquifer (Spain), based on a participatory action research. It aims to advance the co-management of groundwater by facilitating a consensus among users, as a basis on which to support future self-governance measures. We used a cognitive framing approach, developed through interviews with local stakeholders, to analyse the conflicting visions on the aquifer management; and we developed an interactive framing approach, through workshops, to achieve a shared understanding of aquifer co-management. The research demonstrates the usefulness of these approaches to promote collective action and co-management in groundwater. It showed the key role that information and transparency play in gaining shared understanding and improving co-management; but also the difficulties of users in establishing agreements that question the current status quo on the aquifer.