Browsing by Author "Rey, Dolores"
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Item Open Access Comparison of different water supply risk management tools for irrigators: option contracts and insurance(Springer, 2015-04-11) Rey, Dolores; Garrido, Alberto; Calatrava, JavierIrrigators must cope with the risk of not having enough water to meet crop demands. There are different tools for managing this risk, including water market mechanisms and insurance. Given the choice, farmers will opt for the tool that offers the greatest positive change in expected utility. This paper presents a theoretical assessment of farmers’ expected utility for two different water option contracts and a drought insurance policy. We analyze the conditions that determine farmers’ preferences for these instruments and perform a numerical application to a water-stressed Spanish region. Results show that farmers’ willingness to pay for the considered risk management tools are greater than the preliminary estimates of these instruments costs. This suggests that option contracts and insurance may help farmers manage water supply availability risks.Item Open Access Developing drought resilience in irrigated agriculture in the face of increasing water scarcity(Springer , 2017-02-08) Rey, Dolores; Holman, Ian P.; Knox, Jerry W.In many countries, drought is the natural hazard that causes the greatest agronomic impacts. After recurrent droughts, farmers typically learn from experience and implement changes in management to reduce their future drought risks and impacts. This paper aims to understand how irrigated agriculture in a humid climate has been affected by past droughts and how different actors have adapted their activities and strategies over time to increase their resilience. After examining recent drought episodes from an agroclimatic perspective, information from an online survey was combined with evidence from semi-structured interviews with farmers to assess: drought risk perceptions, impacts of past drought events, management strategies at different scales (regional to farm level) and responses to future risks. Interviews with the water regulatory agency were also conducted to explore their attitudes and decision-making processes during drought events. The results highlight how agricultural drought management strategies evolve over time, including how specific aspects have helped to reduce future drought risks. The importance of adopting a vertically integrated drought management approach in the farming sector coupled with a better understanding of past drought impacts and management options is shown to be crucial for improving decision-making during future drought events.Item Open Access Essential irrigation and the economics of strawberries in a temperate climate(Elsevier, 2017-09-11) Morris, Joe; Else, M. A.; El Chami, D.; Daccache, Andre; Rey, Dolores; Knox, Jerry W.Strawberries are a high value crop in the UK soft fruit sector, with the majority of production grown at field-scale and under protected (polytunnel) conditions. Despite its importance to the rural economy, there is surprisingly little published scientific evidence on the economics of irrigated strawberry production and the value of water in this horticultural sector. A survey of growers, supplemented by secondary data and industry sources, shows considerable variation in key physical and financial performance indicators, both within and between different strawberry production systems, as well as evidence of good practice. Water application depths ranged widely from 800 to over 2000 m3 ha−1 according to grower and crop variety. Irrigation costs typically range between £1.30 and £2.50 m−3 of water applied, highest where storage reservoirs and public water supplies are used. The average value of irrigation water for strawberry net of costs was about £6 m−3, much higher than for field crops such as potatoes. The importance of a reliable water supply to support irrigated strawberry production is highlighted. Climate change and growing pressures on water resources are likely to force a greater interest in irrigation economics in the soft fruit sector, especially in the face of restrictions on summer abstraction and rising competition and charges for using public water supply.Item Open Access Evaluating the impacts of agricultural development and climate change on the water-energy nexus in Santa Elena (Ecuador)(Elsevier, 2023-12-22) Chengot, Rishma; Zylberman, Raphael; Momblanch, Andrea; Salazar, Oswaldo Viteri; Hess, Tim; Knox, Jerry W.; Rey, DoloresA combination of a changing global climate coupled with rapid socio-economic development is putting unprecedented pressure on water, energy, and food resources. Addressing these issues within a nexus approach can help to identify appropriate management practices and strategic policies to ensure natural resources are used more sustainably thus avoiding exacerbating issues of water scarcity and food insecurity. In this study, we used an integrated water resource planning and irrigation model (WEAP) to assess emerging water-energy nexus issues on the Santa Elena peninsula in Ecuador. Simulated water demands showed that current water resources availability is insufficient to meet full irrigation requirements, especially during the dry season. Annual average energy demand for water conveyance in the SEP was significantly higher than for irrigation with 94.5 GWh and 13.5 GWh being used, respectively. Future challenges associated with changes in agricultural irrigation and urban demands within the SEP were evaluated using scenario analysis. This included considering various scenarios such as agricultural expansion, climate change, population growth, and a shift to export-oriented agriculture. The study underscores the significance of nexus thinking in guiding policy and decision-making in Santa Elena, although the limited data prevents its use in an operational framework. The benefits of adopting an integrated modelling approach to analyse water and energy nexus trade-offs are also discussed.Item Open Access Evaluation of changing surface water abstraction reliability for supplemental irrigation under climate change(Elsevier, 2018-05-28) Rio, M.; Rey, Dolores; Prudhomme, Christel; Holman, Ian P.In many temperate parts of the world, supplemental irrigation is crucial to assure both crop yield and quality. Climate change could increase the risks of irrigation being restricted by increasing crop water requirements and/or decreasing water availability. In England, water abstraction for irrigation is limited by maximum annual volumetric limits, as specified in the abstraction licences, and surface water abstraction restrictions imposed by the regulator during drought. This paper assesses how climate change might impact future irrigation abstraction reliability from surface water in England. Firstly, the probability of annual abstraction being close to the maximum licence limit was estimated for the baseline (1961–1990) and future (2071–2098) periods in each catchment based on observed relationships between annual weather and irrigation abstraction in three licence usage groups. Secondly, the current river discharge triggers for mandatory drought restrictions were used to assess the annual probability of surface water abstraction restrictions being imposed by the regulator in each period. Results indicate significant future increases in irrigated abstraction licence use due to an increase in aridity, particularly in the most productive agricultural areas located in eastern and southern England, assuming no adaptation. The annual probability of having less than 20% licence headroom in the highest usage group is projected to exceed 0.7 in 45% of the management units, mostly in the south and east. In contrast, irrigators in central and western England face an increased risk of drought restrictions due to the lower buffering capacity of groundwater on river flows, with the annual probability of mandatory drought restrictions reaching up to 0.3 in the future. Our results highlight the increasing abstraction reliability risks for irrigators due to climate change, and the need for the farming community and the regulator to adapt and collaborate to mitigate the associated impacts.Item Open Access An innovative option contract for allocating water in Inter-Basin Transfers: the case of the Tagus-Segura Transfer in Spain(Springer, 2015-12-31) Rey, Dolores; Garrido, Alberto; Shafiee, MahmoodThe Tagus-Segura Transfer (TST), the largest water infrastructure in Spain, connects the Tagus basin’s headwaters and the Segura basin, one of the most water-stressed areas in Europe. The need to increase the minimum environmental flows in the Tagus River and to meet new urban demands has lead to the redefinition of the TST’s management rules, what will cause a reduction of transferable volumes to the Segura basin. After evaluating the effects of this change in the whole Tagus-Segura system, focusing on the availability of irrigation water in the Segura, the environmental flows in the Tagus and the economic impacts on both basins; we propose an innovative two-tranche option contract that could reduce the negative impacts of the modification of the Transfer’s management rule, and represents an institutional innovation with respect to previous inter-basin water trading. We evaluate this contract with respect to spot and non-market scenarios. Results show that the proposed contract would reduce the impact of a change in the transfer’s management rule on water availability in the recipient area.Item Open Access Modelling and mapping the economic value of supplemental irrigation in a humid climate, Agricultural Water Management(Elsevier, 2016-04-23) Rey, Dolores; Holman, Ian P.; Daccache, Andre; Morris, Joe; Weatherhead, E. K.; Knox, Jerry W.Irrigation is an essential component of crop production to meet retailer demands for premium quality when rainfall is insufficient. Under drought conditions, irrigation can be constrained by water resources availability, with consequent impacts on yield, quality and revenue. Whilst most agriculture in Europe is rainfed, greater dependence on supplemental irrigation could become more important in humid environments due to a changing climate with greater rainfall uncertainty and higher frequency of droughts. By combining industry and farm level economic data, with geospatial information on agricultural land use, agroclimate, soils and irrigation practices within a GIS, this paper estimates the total financial benefit of outdoor irrigated production in England and Wales assuming no constraints in resource availability and optimal irrigation practices. The analysis suggests that the total net benefits of irrigation in a ‘design’ dry year are around £665 million, with an average irrigation water productivity in excess of £3.3 per m3 (close to £1.1 per m3 excluding soft fruit). Map outputs highlight significant regional differences in water productivity reflecting the composition of land use and the importance of crop mix in determining economic value. A sensitivity analysis to changes in agroclimate, market conditions (crop prices) and water supply (costs) illustrates how the benefits might change under contrasting scenario. The study highlights the importance of supplemental irrigation, even in a humid climate, and the risks that future droughts and/or constraints in water resource availability might have on agricultural systems, livelihoods and the rural economy. The implications for water resources and drought management are discussed.Item Open Access Nature provides valuable sanitation services(Elsevier, 2021-02-19) Willcock, Simon; Parker, Alison; Wilson, Charlotte; Brewer, Timothy R.; Bundhoo, Dilshaad; Cooper, Sarah; Lynch, Kenneth; Mekala, Sneha; Mishra, Prajna Paramita; Rey, Dolores; Welivita, Indunee; Venkatesh, Kongala; Hutchings, PaulMuch previous research shows that safe disposal of human waste has a positive impact on human wellbeing, while preventing the degradation of ecosystems. However, to date, the role that ecosystems themselves play in treating human waste has been largely neglected. We conceptualize the role nature plays in treating human waste—acting as a pipeline and/or treatment plant. We estimate that nature is treating ~41.7 million tons of human waste per year worldwide, a service worth at least 4.4 ± 3.0 billion USD year−1. We demonstrate the opportunities and challenges of quantifying these “sanitation ecosystem services,” using 48 cities across the globe as a worked example. In highlighting this, we are not marginalizing the vital role of engineered infrastructure, but instead are promoting better understanding of how engineered and natural infrastructure interact within a circular economy. This is a promising route for further research and may allow adaptive design and management, reducing costs, and improving effectiveness and sustainability.Item Open Access Reconciling irrigation demands for agricultural expansion with environmental sustainability - a preliminary assessment for the Ica Valley, Peru(Elsevier, 2020-08-15) Salmoral, Gloria; Carbó, Araceli Viñarta; Zegarra, Eduardo; Knox, Jerry W.; Rey, DoloresIrrigation expansion driven by a growing global food demand is threatening the sustainability of scarce water resources. An exemplar is the Ica Valley in Peru which has experienced significant agricultural transformation over the last three decades with uncontrolled abstractions leading to over-exploitation of the Ica-Villacuri aquifer. This paper critically assesses the impacts of agricultural expansion on the long-term sustainability of groundwater resources in the Ica Valley. We apply a combination of spatial analysis and irrigation modelling by farming type (large and small-scale), followed by a multi-criteria assessment on irrigation water use. Historical trends in cropped area were analysed using Landsat satellite imagery to identify agricultural expansion and the changing composition between large and small-scale farms. The blue water footprint (WFblue) for croplands was calculated distinguishing between surface and groundwater abstractions for eight disaggregated geographical zones within the Ica Valley. The economic benefits of water consumption were assessed using the water productivity indicator, and the environmental sustainability of water resources spatially evaluated using a monthly blue water sustainability index and adapted version of the groundwater debt. The analyses showed that the groundwater footprint accounts for 87% of the total WFblue (483 Mm3) with 286 Mm3 groundwater consumed under unsustainable conditions (exceeding groundwater recharge). The highest water productivity (2.4-5.4 sol/ton) occurs in zones with intensive groundwater abstractions and where most large-farms are located, but it is also where the sustainability issue is most acute. Modelling showed that based on existing climate conditions and cropping patterns, irrigated agriculture is locally unsustainable throughout the valley, with the exception of small-scale farming in the peri-urban and middle valley areas. Around 10% of total aquifer recharge results from small-scale irrigated farming, whereas recharge from large scale farming is negligible. The greatest impacts occur in zones dominated by large-scale farms, where a period of 3.7 to 5.9 years is estimated to be needed to replenish water resources consumed by agricultural production. There is thus an urgent need to manage water resources more effectively and promote more sustainable use of water to protect both traditional and agro-export agricultural practices as well as allocations for urban water supply and the environmentItem Open Access Regional variations in the link between drought indices and reported agricultural impacts of drought(Elsevier, 2019-02-26) Parsons, David J.; Rey, Dolores; Tanguy, Maliko; Holman, Ian P.Drought has wide ranging impacts on all sectors. Despite much effort to identify the best drought indicator to represents the occurrence of drought impacts in a particular sector, there is still no consensus among the scientific community on this. Using a more detailed and extensive impact dataset than in previous studies, this paper assesses the regional relationship between drought impacts occurrence in British agriculture and two of the most commonly used drought indices (SPI and SPEI). The largest qualitative dataset on reported drought impacts on British agriculture for the period 1975–2012 spanning all major recent droughts was collated. Logistic regression using generalised additive models was applied to investigate the association between drought indices and reported impacts at the regional level. Results show that SPEI calculated for the preceding six months is the best indicator to predict the probability of drought impacts on agriculture in the UK, although the variation in the response to SPEI6 differed between regions. However, this variation appears to result both from the method by which SPEI is derived, which means that similar values of the index equate to different soil moisture conditions in wet and dry regions, and from the variation in agriculture between regions. The study shows that SPEI alone has limited value as an indicator of agricultural droughts in heterogeneous areas and that such results cannot be usefully extrapolated between regions. However, given the drought sensitivity of agriculture, the integration of regional predictions within drought monitoring and forecasting would help to reduce the large on-farm economic damage of drought and increase the sector's resilience to future drought.Item Open Access Role of economic instruments in water allocation reform: lessons from Europe(Taylor & Francis, 2018-01-19) Rey, Dolores; Pérez-Blanco, Carlos Dionisio; Escriva-Bou, Alvar; Girard, Corentin; Veldkamp, Ted I. E.A growing number of countries are reforming their water allocation regimes through the use of economic instruments. This article analyzes the performance of economic instruments in water allocation reforms compared against their original design objectives in five European countries: England, France, Italy, Spain and the Netherlands. We identify the strengths of, barriers to and unintended consequences of economic instruments in the varying socio-economic, legal, institutional and biophysical context in each case study area, and use this evidence to draw out underlying common guidelines and recommendations. These lessons will help improve the effectiveness of future reforms while supporting more efficient water resources allocation.Item Open Access Which factors determine adaptation to drought amongst farmers in Northern Thailand? Investigating farmers’ appraisals of risk and adaptation and their exposure to drought information communications as determinants of their adaptive responses(Springer, 2024-01-11) Sutcliffe, Chloe; Holman, Ian P.; Goodwin, Daniel; Salmoral, Gloria; Pardthaisong, Liwa; Visessri, Supattra; Ekkawatpanit, Chaiwat; Rey, DoloresDrought communications constitute an important source of learning about climate risks and responses that can assist adaptation decision-making amongst those whose livelihoods are threatened by drought. This paper applies Protection Motivation Theory to explore associations between drought communications and attitudes towards drought risk and adaptation amongst farmers in Northern Thailand. The analysis reveals links between drought communications, farmers’ adaptation appraisal, and their adaptation decisions, whilst links with risk appraisal are minimal. The results highlight positive feedbacks between adaptation experience and appraisal and reveal a weak negative relationship between risk appraisal and adaptation appraisal. The findings imply benefits to framing drought communications in terms of the efficacy and attainability of suitable adaptations, rather than simply highlighting drought risks or providing drought warnings, to best enable farmers to build drought resilience.