Multidisciplinary assessment of the agricultural supply of desalinated seawater in south-eastern Spain

Abstract

Desalinated seawater (DSW) has provided a steady supply of agricultural water for the last decade in south-eastern (SE) Spain, overcoming climatological and hydrological constraints. This article analyses the impacts of the progressive replacement of traditional irrigation water resources with DSW on the main crops of SE Spain, from agronomic, environmental, and economic perspectives, for the first time. The regional magnitude and spatial variability of these impacts have also been evaluated. To that end, six impact indicators were identified and calculated for three water supply scenarios using increasing proportions of DSW, which is representative of the current and possible future situations.The results reflect the high variability of the impact indicators for the different crops. The agronomic impact is favourable but the benefits of reducing water salinity become saturated when DSW exceeds 50 %. The detrimental environmental impact is due to the higher specific energy consumption associated with increased DSW supply, although this is not an intrinsic problem of seawater desalination since it could be mitigated using renewable energies. The economic impact is very sensitive to the cost of DSW and offers heterogeneous results for the different crops. The results show that the combined use of DSW with traditional resources is the most efficient option from the different perspectives of the study, rather than irrigating with DSW alone. The insights from this study could be useful for the assessment of the feasibility of integrating DSW to support agriculture in other regions where desalination plants are being considered to support the water supply.