The quality and availability of water are affected by numerous variables, through which the evaluation of water uses from different perspectives, and policy proposals to save water have now become essential. This paper aims to study water use and the water footprint from a river basin perspective, taking into account regions, sectors, and municipalities, while considering the physical frontier along with the administrative sectors. To this end, we have constructed a multi-regional input-output table for the Ebro river basin, disaggregating the primary sector into 18 different crops and 6 livestock groups. We pay special attention to crop production because it is the most water-consuming industry. The construction of the multi-regional input-output model represents an important contribution to the literature, in itself, since, to the best of our knowledge, it is the first to be built for this large basin. We extend this multi-regional input-output model to assess the water footprint by sectors and regions within the basin. We use these data to propose two scenarios: reallocating final demand to reduce the blue water footprint (scenario 1), and increasing value added (scenario 2). These scenarios outline the opportunity costs of saving water in socioeconomic terms in the basin. In another application, we downscale the multi-regional inputoutput model results at the municipal level and depict them using a geographical information system, identifying the hotspots and the areas that would pay for the socioeconomic opportunity costs of saving water. Our results suggest that saving 1 hm 3 of blue water could cost around €41,500 of value added if we consider the entire basin. However, this water reallocation implies losses and gains at the municipal level: some municipalities would reduce value added by more than €30,000, while others would gain more than €85,000 of value added. These tools and results can be useful for policy makers when considering re-allocating water. The contribution and the novelty of this paper is the construction of the multiregional input-output model for the Ebro river basin, and its link with geographical systems analysis at the municipal level.

Environmental flows (EF) define the quantity, timing and quality of river flows needed to preserve freshwater ecosystems while assuring the continuity of human use. Insofar as they reduce water availability and condition agricultural and industrial uses, EF represent a constraint, but they also hold out new opportunities for development. This study focuses on the final stretch of the Ebro River (Spain) and on the competing environmental uses of water (the Ebro Delta is a biosphere reserve) and economic uses (irrigation and electricity generating). Environmental flows in the Ebro Delta are currently managed only from the Mequinenza dam and reservoir in eastern Aragon, and the resulting outflows have more than once driven the level of the reservoir down to critical environmental levels in recent years. In general, this management policy has also caused a range of negative environmental and economic impacts in the area. However, other alternatives exist, which could foster both more cooperative and equitable flow allocations, and the development and sustainability of the Ebro Basin. To this end, we develop a water management model to simulate scarcity scenarios and measure the associated environmental flow default rates assuming current productive uses. Our findings confirm that it is not possible to guarantee EFs in the delta without reservoir-based water management so as to ensure the compatibility of EFs with the irrigation and hydroelectric activities. Moreover, the existence of more equitable and cooperative water management options would reduce water pressures on Mequinenza dam and so help fulfill the subsidized irrigation commitments established in Aragonese Lower Ebro Plan.

Ghana shows remarkable differences in employment and welfare between the southern and northern regions. The promotion of policy focus on the development of the northern regions requires the elaboration of specific databases describing the regional economies. Hence, this work outlines the construction of a Social Accounting Matrix (SAM) for Ghana for the year 2015 with a high disaggregation of sectors, household income groups and education levels across 10 administrative regions. Linear multisectoral models have been applied to this SAM to estimate socio-economic impacts of potential final demand policies down to a regional level in the Ghanaian economy. Further on, the structural path analysis is used to investigate the role played by different agriculture commodities in transmitting income to different types of households. The results allow for an identification of the most suitable sectors to be promoted due to their ability to generate the highest increases in output, employment and value added in the rest of the economy, as well as those with a significant impact on household income generation. As a result, the primary sector will play a key role in the economic and employment growth of the country. Notably, sorghum and millet, pulses, tobacco, cotton and fibres can be considered favourable crops for development in the Northern region.

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