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• This work estimates water and light use efficiency in garlic based on ground data. • The model integrates series of satellite vegetation indices in crop growth models. • The normalization of these efficiencies for the atmospheric conditions is analyzed. • Additional analysis are the use of cold temperature stress on the noted models. • The results are promising for the operative estimation of garlic biomass production. The objective of this paper was to determine the water use efficiency (WUE) and light use efficiency (LUE) values of garlic (Allium sativum L.) and to analyze the normalization of these efficiencies for the atmospheric conditions. We analyzed the use of daily reference evapotranspiration (ETo) and the vapor pressure deficit (VPD) for these purposes. WUE and LUE were valued based on the experimental measurements of dry biomass production and the estimation of transpiration and radiation interception based on time series of Remote Sensing satellite images. The experimental data were obtained in two commercial fields each planted with a different variety of garlic (var. morado and var. spring) growing in different weather conditions in the province of Albacete (in the south-east of Spain). The correlation between the accumulated values of biomass and the estimated values of crop transpiration and radiation absorption resulted in strong linear relationships. The slope of these correlations resulted in values of WUE and LUE, WUE = 5.51 g m−2 mm−1 and LUE = 2.26 g·MJ−1 for both analyzed varieties. The results demonstrated that the inclusion of temperature stress coefficient is required when the WUE and LUE parameters are normalized using the ETo and the VPD variables. However, atmospheric normalization did not conclusively improve results in this study. Results obtained in this paper provided empirical evidence regarding the feasibility of estimating biomass production in garlic based on the same physiological principles used for other crops. [ABSTRACT FROM AUTHOR]

Highlights • Farmers' preferences toward irrigation water supply reliability (WSR) are analyzed. • A discrete choice experiment (DCE) is used with stochastic variables for WSR. • Three classes of farmers are identified according to their WTP for improved WSR. • They show no, low, and high WTP, with several factors explaining class belonging. • The results can assist the design of more efficient water management instruments. Abstract In irrigated agricultural systems, a major source of uncertainty relates to water supply, as it significantly affects farm income. This paper investigates farmers' utility changes associated with shifts in the probability density function of water supply leading to a higher water supply reliability (higher mean and lower variance in annual water allotments). A choice experiment relying on a mean-variance approach is applied to the case study of an irrigation district of the Guadalquivir River Basin (southern Spain). To our knowledge, this is the first study using parameters of these probability density functions of water supply as choice experiment attributes to value water supply reliability. Results show that there are different types of farmers according to their willingness to pay (WTP) for improvements in water supply reliability, with some willing to pay nothing (47.8%) while others have a relatively low (28.0%) or high (24.2%) WTP. A range of factors influencing farmers' preferences toward water supply reliability are revealed, with those related to risk exposure to water availability being of special importance. The results can be used to assist the design of more efficient policy instruments to improve water supply reliability in Mediterranean and semi-arid climate regions. [ABSTRACT FROM AUTHOR]

Highlights • Satellite images have been utilized to estimate crop coefficients. • The estimated and the theoretical crop coefficients have been compared. • The comparison was made among field plots, municipalities and irrigation districts. • A set of water use efficiency indicators have been calculated. Abstract Irrigation in the Duero river basin accounts for 75% of total water resources. Nevertheless, irrigation in this area is paramount to maintain agricultural production. Within this context, this paper is aimed at assessing the water use efficiency (WUE), for the major crop (corn), among four irrigation districts (IDs) from 2014 to 2017. Since the WUE indicators base upon crop water requirements, these were calculated by estimating the reference evapotranspiration and the local crop coefficients Kc. First, they were estimated by satellite images and then, compared with the recommendation from the Regional Irrigation Advisory Service. Finally, the gross irrigation requirements were compared with the irrigation supply. WUE indicators varied among IDs depending upon the hydrologic year, the water available for irrigation (superficial and subsurface water), and the corn sowing date. Usually, the IDs performed deficit irrigation in the dry years, and either full irrigation or over irrigation in the wet years. The rainfall only fulfilled less than 10% of corn requirements. Small differences in Kc were observed within municipalities (in each ID) and/or among IDs. The pattern of the Kc fitted curves varied among IDs and was affected by sowing dates. Although, the local Kc values were close to the general coefficients recommended by the Irrigation Advisory Service, they affected the determination of gross irrigation requirements which were significant different among IDs. Moreover, it was observed that the FAO recommendation for the duration of the corn growth stages fitted better the estimated Kc than the one from the Advisory Center. The gross irrigation requirements were similar among IDs and years, varying between 6476 and 7646 m3/ha. The local Kc estimation could help irrigation managers to adapt the irrigation supply to the actual corn needs. [ABSTRACT FROM AUTHOR]

This paper analyses the impacts and water policy implications of an increase of perennial crops on irrigation water requirements and on the vulnerability of the agricultural system to climatic events in the case of the Guadalquivir River basin. As indicated by the EU Water Framework Directive (WFD), the characterisation of a river basin requires information on the major economic drivers and pressures at river basin scale. Guadalquivir River basin (southern Spain) can be considered a representative Mediterranean case study that has faced basin closure and continues the trend towards increased crop intensification and greater water-use efficiency. Our result shows an increased vulnerability to drought and water scarcity in the basin due to the expansion of irrigated perennial crops and a decrease of RIS (relative irrigation supply) from 0.70 to 0.56 in the period 2000–2021, thereby forcing farmers to adopt deficit irrigation techniques. The potential increase in the frequency of droughts and the growth of irrigation water requirements (IWR) due to higher temperatures, raise the vulnerability of the system to extreme climate events. Such findings can be employed to support the efficient allocation of water resources in order to improve water policy through its adaptation to increasing risks related to droughts and water scarcity. • The evolution of irrigated area in Guadalquivir River basin is characterised by an increasing share of perennial crops. • IWR have increased continuously due to changes in crop patterns (intensification). • Since IWR exceed availability, the irrigation system applies deficit irrigation as a response, with a decreasing RIS. [ABSTRACT FROM AUTHOR]

Over recent decades, groundwater-fed irrigation has sustained the social and economic development of La Mancha, Spain. Without much initial regulation and control, groundwater resources and aquifer levels decreased dramatically, threatening agriculture and also highly valuable groundwater-dependant wetland ecosystems. This paper presents as a historical analysis of the different policy tools used to manage and regulate groundwater abstraction in the Western Mancha Aquifer after Spain approved its 1985 Water Law. It analyses the panoply of control and management instruments laid out by the state to counter the resource depletion trend, demonstrating the necessity by regulatory bodies to complement soft incentives (carrots) with the threat of sanctions and groundwater access limitations (sticks). As this case study shows however, each policy modality has its legal and practical loopholes which can be negotiated and exploited by groundwater users to their own advantage. Improvements in groundwater levels starting in 2010 seem to be linked to aquifer recharge following an unprecedented wet cycle rather than the effectiveness of the policy tools. [ABSTRACT FROM AUTHOR]

The realization of buyback welfare enhancing opportunities is conditioned to the ability of government agencies to place bids consistent with the shadow price of irrigators. However, methods used to inform buyback programmes to date either rely on ex-post trading data that is not readily available in most regions worldwide; or compensate projected foregone income, and thus ignore the effects that buyback may have on other relevant attributes determining utility. This paper uses revealed preference methods to elicit the parameters of a multi-attribute objective function that mimics the observed behavior of irrigators in the overexploited Segura River Basin in SE Spain. Objective functions are used in a series of simulations in which water allocation is progressively constrained to ex-ante reveal the shadow price of water using two alternative compensation measures: i) the foregone income, a proxy of the shadow price typically used in the literature; and ii) the compensating variation that addresses foregone utility. Results show a relevant gap between the two methods For example, restoring the balance in the basin through purchase tenders would demand an investment of million 2400+ EUR (9.6+ EUR m −3 ) attending to the foregone income method, and million 950+ EUR (3.8+ EUR m −3 ) (−60.3%) with the foregone utility method. [ABSTRACT FROM AUTHOR]

Concerns about hydrological drought risk and irrigation water supply reliability have grown in recent years due to the increasing demand for water for irrigation and other uses, and the decline in water availability due to climate change. Hydrological drought insurance hedging against water supply gaps can be a key instrument for adapting irrigated agriculture to this new scenario, since it improves the resilience of the irrigation sector, which is having to cope with increasing uncertainty and vulnerability. The objective of this paper is to assess farmers' willingness to pay (WTP) for index-based hydrological drought insurance under different policy designs, considering several different amounts of insured capital, insurance deductibles, and contract terms. To that end, it uses a discrete choice experiment as the valuation method and the Sector BXII irrigation district (southern Spain) as a case study. The results show that farmers would be willing to pay for the proposed hydrological drought insurance, stating a higher preference for policy designs with lower amounts of insured capital, lower deductibles, and shorter contract terms. Moreover, the results also show the existence of heterogeneity among farmers' preferences, depending on their socio-economic characteristics. Finally, we compare the distribution of farmers' WTP for different policy design options of the proposed insurance with the commercial premium estimated using actuarial analysis. The comparison confirms that only the options with lower levels of insured capital present a mean WTP below the commercial premium, while the rest of the policy design options would need to be subsidized like other agricultural insurance schemes to make them attractive to most farmers. • Farmers are willing to pay for hydrological drought insurance. • Farmers prefer policies with low levels of insured capital, low deductibles, and short contract terms. • WTP is heterogeneous depending on farmers' socio-economic characteristics. • Only policy designs with low levels of insured capital are currently commercially viable. • Once the new drought insurance is implemented, it will become more attractive for farmers. [ABSTRACT FROM AUTHOR]

Generally, in most pressure irrigation systems and particularly in irrigation systems of golf courses, an efficient management of water and energy use is required. Through an efficient management of these resources the excessive consumptions are controlled and a savings in exploitation costs could be achieved. One of the tools that allow controlling and identifying the water and energy consumption is the use of management and automation indicators. With the employ of these tools, several parameters that affect in the efficiency of water and energy use of pumping systems, water network configuration, automation and the associated energy systems could be controlled. In this paper the methodology and implementation of several water, energy and automation indicators and their productivity adapted to four golf courses in south-east Spain are shown. For this purpose, some data of a developed study among 2008 and 2011 in the irrigation systems of these golf courses and their influence in the improvement of the efficiency in the water and energy use are presented. This combined methodology is particularly suitable for comparing the irrigation systems of several golf courses. Moreover, by using these indicators with automation and remote control devices for water and energy management in such irrigation systems, it is possible to reduce and control associated costs. The results demonstrate that automation is a low-cost investment (with a maximum of 2% of the total costs) compared to the large benefits and advantages. For this study, the maximum values of the automation cost per controlled water volume and energy were 0.2007 €·m −3 and 0.2233 €·kWh −1 , respectively. The percentage of automation cost in the total cost is around 1.5 percent. [ABSTRACT FROM AUTHOR]

This paper assesses the feasibility and robustness of an index-based insurance scheme against hydrological droughts under climate change. To this end, we develop a grand ensemble that samples both modeling and scenario uncertainty in the estimation of the insurance risk premium, so to reveal potential unfavorable surprises and minimize regret in the design of the proposed insurance scheme. The grand ensemble combines four microeconomic models and seven GAMLSS models, which are run for three alternative climate change scenarios: stationary climate/no climate change, RCP 2.6, and RCP 8.5. Methods are illustrated with an application to the Cega River Sub-basin (CRS) in central Spain. Results indicate that for a conventional deductible of 30%, the proposed index-based insurance scheme would be actuarially feasible and affordable under all models for the stationary climate scenario (i.e., robust). For climate change scenarios RCP 2.6 and 8.5 and a 30% deductible, the suggested index-based insurance would be actuarially feasible under most models, albeit some outliers point towards potential unfavorable surprises. Lower deductibles decrease feasibility, particularly for deductibles <10%. • For a deductible of 30% and stationary climate, the proposed index-based insurance is actuarially feasible under all models. • Under climate change (RCPs 2.6, 8.5), the insurance is feasible for all deductibles and the median model (except PMAUP WGP). [ABSTRACT FROM AUTHOR]

• New index-based insurance to cover irrigation water supply gaps is proved to be technically feasible. • Although the proposal is tailored to Spain, its main features can also be implemented worldwide. • An innovative actuarial analysis based on a stochastic hydrological model is implemented. • Simulation results show irrigation in southern Spain is expected to become more vulnerable to droughts. • New water management rules mean that the proposed insurance scheme has relatively high premiums. In Mediterranean-climate regions, irrigated agriculture is especially vulnerable to the risk of hydrological drought, and irrigators are particularly concerned about the negative effects of water supply failures. This paper proposes a new index-based drought insurance scheme to cover the risk of water supply failures in irrigated agriculture that overcomes the problems currently hindering the development of this kind of insurance, especially those related to arbitrariness in annual water allotments decision-making. Although the proposal is tailored to Spain, it can be easily adapted to other countries or regions because its main features can also be implemented worldwide. The scheme proposed is a promising instrument to help irrigators manage the risk related to hydrological droughts since it has been proved to be technically feasible. The main contribution of this paper is the innovative actuarial analysis implemented, which is aimed at calculating fair premiums. Considering that recent changes in the institutional framework (new demands, new storage capacity, and revised basin and drought management plans) make historical records unsuitable for this purpose, the actuarial analysis applied is based on a stochastic hydrological model able to simulate future hydrological situations under updated settings. Simulation results have shown that irrigated agriculture in southern Spain is expected to be more vulnerable to hydrological droughts. In fact, incidence rates are likely to increase because of the new institutional framework, leading to relatively high fair premiums. Only by implementing high ordinary deductibles can the hypothetical cost of commercial premiums be affordable for irrigators, accounting for less than 10% of their current variable costs. [ABSTRACT FROM AUTHOR]

Water reuse is a strategic priority for Water Authorities in Europe to reduce the pressure on water resources, although implementation is lagging behind expectations due to financial, administrative and social acceptance concerns. In this context, there is a special interest to identify in which specific Wastewater Treatment Plants it would be interesting to add a Water Regeneration Plant, taking account of potential existing clients in the vicinity and the implied costs and benefits. This paper proposes a method to quantify the infrastructure and operation costs of project implementation and the benefits of the additional water offer. An algorithm designs the distribution network, allowing for a quick cost analysis. The method is applied in the Upper Guadiana in Central Spain, where irrigation led to the overexploitation of the local aquifers and the subsequent restrictions on water use. Taking account of the existing Wastewater Treatment Plants, candidate reuse projects are classified according to their benefit/cost ratio, showing large differences according to the location and potential use of the regenerated water. The analysis allows for a quick assessment of the costs and benefits implied in different reuse projects and scenarios, providing science-based evidence to support water policy decisions. [Display omitted] • A Cost and Benefit Analysis assesses the viability of potential water reuse projects. • An irrigation water distribution network is generated automatically to support cost calculation. • The analysis allows to create multiple scenarios of reuse policies. • Project viability is determined by location and profitability of irrigated crops. [ABSTRACT FROM AUTHOR]

The transfer of successful water market governance between international settings is increasingly attractive to policy makers under globalization. This paper tests lesson-drawing approaches to water market governance transfers using data from Spain and the Murray-Darling Basin, Australia. Spain is the blueprint country for water market adoption in Europe, while Australia is often presented as a world leader in innovative water market arrangements. A preliminary comparative analysis framework linking water market governance principles to observed institutional arrangements and outcomes is provided. Finally, some key lessons, problems and policy transfer potential to stimulate and enhance Spanish water markets from lesson-drawing approaches are drawn, with an emphasis on adaptive capacity as an institutional performance metric. We find that Spain's current water governance institutions and arrangements offer a solid platform for marketing reform, where some key adaptive capacity constraints are able to be addressed. The lessons drawn from this study highlight those areas of change which, while challenging, can be achieved in our view. • Lesson drawing methods offer a novel way to assess adaptive capacity in policy settings. • Australia's water markets provide a case study for comparing Spain's readiness for water market adoption. • Current institutional strengths and weaknesses are identified via the analysis. • Future adaptive capacity evaluation offers useful insights for water governors and policy-makers. [ABSTRACT FROM AUTHOR]

This paper examines the effectiveness of reforming water rights regimes in the agricultural sector by replacing allocation procedures based on the proportional rule with the implementation of a priority rule that establishes security-differentiated water rights. The main objective is to assess whether this change improves the economic efficiency of water allocation at the irrigation district level, particularly during cyclical scarcity events. To this end, a Positive Mathematical Programming model is built to simulate the performance of the proposed reform in an irrigation district in southern Spain. The results show that the efficiency gains brought about by this change are very small, which casts doubt on its ability to improve water-use efficiency in the agricultural sector at the local level (i.e., irrigation district) under current local climate and water availability conditions. In any case, further research is needed to assess the suitability of this change in allocations rules at basin scale with greater farm heterogeneity, especially given the likelihood of more frequent, more intense droughts due to climate change. • A priority-based water rationing system is assessed at the irrigation district level. • The implementation of the new rationing system yields only small efficiency gains. • Efficiency increases could be banished considering actual transaction costs. • Spot water markets are a more suitable policy instrument to cope with droughts. [ABSTRACT FROM AUTHOR]

• A methodology to classify irrigated areas is proposed. • The method permits to identify and map strengths and weaknesses of irrigated areas. • The application of the method to an irrigated area can support decision-making. • The method can be adapted to other areas of the world by adjusting criteria. The large diversity of irrigated agricultural areas hinders the development of social consensus and complicates decision-making about the allocation of investments for irrigation modernization. A classification of irrigated areas permits the identification and mapping of different categories and reveals the strengths and weaknesses of each category regarding specific criteria. This paper proposes a binomial (genus and species) classification methodology of irrigated areas, which was designed based on a participatory approach. Four internal properties determine the genus: type of water source, type of water energy, on-farm irrigation method and water availability. Four external properties classify the variability within each genus into species: land tenure, crop type, existence of an environmental protection figure and socio-economic level. The words used for the genus and specific name arise from the concatenation of syllables representing the state or level of each property. The method was applied to the irrigated area of the Ebro river basin in the Aragón region of Spain (ERB-Aragón). A total of 435,851 ha were classified. A large part of the irrigated land uses surface water (94 %), does not have water availability problems (80 %), is not affected by environmental protection figures (97 %), is devoted to field crops (86 %), and manifests a low (45 %) or moderate (41 %) socio-economic level. A total of 24 genera and 126 species were identified. The two most representative genera are SurGraFloVe (31 %) and SurPumPreVe (27 %), and the two main species are SurGraFloVe DisCeNoLo (19 %) and SurPumPreVe ConCeNoMo (19 %). These species received the local names of " Ribera del Ebro" and " Alto Aragonés" to facilitate policy discussions. The application of the method to the ERB-Aragón provides a privileged insight that can support policy analyses and guide institutional intervention. The proposed methodology can be adapted to other areas of the world by adjusting criteria and categories to local conditions. [ABSTRACT FROM AUTHOR]