A system dynamics approach to integrated management of a water, agriculture, and tourism nexus in a Mediterranean coastal region under climate change

Mediterranean coastal regions face complex challenges under climate change, especially in areas where water-dependent ecosystems, agriculture, and tourism sectors (WAT) compete over limited groundwater resources. Multi-purpose resource planning requires integrated tools that mimic systems’ trade-offs, capture feedback and long-term outcomes. This study develops a system dynamics modeling (SDM) framework to analyze WAT interactions in the Torre Guaceto basin (southern Italy), serving as a decision-support tool for decision-makers. Causal loop diagrams, stock-flow simulations, stakeholder knowledge and climate projections were combined to assess system behavior from 2024–2050. Three policy scenarios were evaluated: business-as-usual (BAU), climate change scenarios (RCP4.5 and RCP8.5), and olive crop irrigation (OCI), measured through average groundwater salinity, agricultural yields, and tourism attractiveness, along with their socio-economic impacts. Results show that under RCP4.5 and RCP8.5 scenarios, increasing groundwater salinity is expected to reduce crop yields by 37% and 48%, respectively. This corresponds to a decline in agricultural revenue to 7.77 and 6.1 million dollars annually. Tourism remains economically significant in both scenarios, with revenues averaging 29–36 million dollars per year. Replacing traditional olive groves with disease-resistant or intensive cultivars diminishes tourism revenue by about 15% to 20% per year due to the loss of cultural heritage and landscape value. Still, intensive cultivation achieves more sustainable long-term returns than super-intensive systems by reducing water demand and salinity stress. The study offers also policy recommendations related to the adoption of water conservation practices, stressing the relevance of active stakeholder engagement.