Maximizing the Benefits of Desalinated Seawater Supply for Agricultural Sustainability

Desalination is increasingly recognised as an essential component of water management in arid and semi-arid coastal regions, including central and northern Chile where conventional freshwater resources are severely constrained. While desalinated water has traditionally served municipal and industrial sectors, its potential role in agriculture remains underexplored. This thesis assesses the feasibility of using desalinated seawater for irrigation through a set of integrated investigations spanning infrastructural, agronomic, economic, and institutional dimensions. A case study of the Copiapó Valley in Chile’s Atacama Region provides an empirical anchor for evaluating both the opportunities and limitations of this emerging practice. The research first reframes desalination within a climate–water–energy–food (CWEF) nexus perspective, developing a multidimensional framework for analysing irrigation with desalinated water as a strategic rather than purely reactive option. Using a water distribution optimization model, the thesis explores how shared desalination infrastructure between the mining and agricultural sectors could reduce costs and environmental impacts. The results indicate that coordinated planning can lower the marginal cost of desalinated water by up to 58%, although practical adoption depends on sectoral incentives and governance capacity. The thesis then introduces a demand-side optimisation framework that leverages desalinated water’s independence from hydro-climatic variability. This framework couples AquaCrop-OSPy with a novel self-tuning multi-layer (STML) algorithm. The method identifies optimal planting windows and deficit irrigation strategies that enhance water use efficiency and crop profitability. Applied to tomato production in the Copiapó Valley, the approach demonstrates that strategically aligning planting schedules with climatic conditions can generate meaningful agronomic gains, and under certain circumstances, approach economic viability. A synthesis chapter integrates these findings to examine the conditions under which desalinated-water irrigation may be feasible in practice. Key considerations include infrastructure constraints, technology adoption, crop selection, coordination between sectors, and institutional readiness. While the Atacama Region provides a highly specific context, several components of the methodology, particularly the optimisation framework, the STML algorithm, and the nexus-based analytical approach, are transferable to other water-stressed regions with appropriate local adaptation. Overall, the thesis positions desalinated seawater as a potentially viable component of climate-resilient agriculture when embedded within coordinated planning, cross-sectoral investment, and adaptive governance. The research contributes methodological innovation, regional insight, and a transferrable analytical foundation for future work at the intersection of water security and agricultural sustainability.<p></p>

Author dc:creator

• Babak Zolghadr-Asli (21058688)

• water resources management
• water-energy-food nexus
• sustainable development
• desalination
• hydroinformatics
• Irrigation

Statement dc:rights

• All rights reserved
• Open Access after 2029-01-26

Identifier

10779/exe.31146613.v1

OAI identifier oai:identifier

oai:figshare.com:article/31146613