Adapting irrigated agriculture to water transfer reductions: Challenges and strategies in southeastern Spain

The projected reduction in the Tagus-Segura water transfer (TST) constitutes a critical factor with significant implications for irrigated agriculture in southeastern Spain. This study analyzes the effects of this reduction and evaluates the feasibility of non-conventional water resources (NCW), such as desalinated and reclaimed water, as potential mitigation strategies. To this end, a Positive Mathematical Programming (PMP) model is applied to the Campo de Cartagena region to simulate various water supply and pricing scenarios, assessing their impacts on farm profit, water consumption, crop distribution, labor, and water costs. The results indicate that a projected 40% reduction in the TST would decrease total water availability by 28% and farm profit by 14%. However, the use of alternative water sources could partially offset these losses, limiting the decline in farm profitability to between 1.5% and 11%. This mitigation, however, would require heavy reliance on NCW, raising concerns about long-term sustainability given their high costs. In this context, supportive policies, particularly subsidies for desalinated water, and stringent limits on groundwater abstraction are essential. This study provides valuable insights into how reductions in conventional water resources affect arid and semi-arid regions, and highlights the growing role of NCW as a key mitigation strategy for more resilient and sustainable agricultural water management.