Abstract for: Participatory System Dynamics Modelling of the Water-Energy-Food-Health Nexus in the Inkomati–Usuthu Basin, South Africa

The Inkomati–Usuthu Water Management Area in South Africa faces interconnected challenges of water allocation, agricultural development, and public health, including schistosomiasis and undernutrition. These issues are linked through Water–Energy–Food systems, yet are typically managed in separate sectors. This limits the ability to anticipate cross-sector feedbacks and unintended consequences of resource management decisions. This study applies participatory system dynamics modelling to integrate environmental, socioeconomic, and health processes at basin scale. Stakeholders co-developed causal loop diagrams to identify key feedback mechanisms linking water management, agriculture, and health. These informed the extension of an existing WEF model to include schistosomiasis transmission and undernutrition through environmental and socioeconomic pathways. Preliminary model implementation reproduces plausible seasonal patterns of schistosomiasis transmission by linking hydrological conditions to snail abundance and human water contact. The model incorporates factors such as irrigation-related exposure, migration, and sanitation conditions. Early results demonstrate how environmental variability and human behaviour jointly shape transmission dynamics and highlight critical feedbacks influencing disease risk. The model provides a framework for analysing interactions between resource management and health outcomes within a WEF–Health system. Ongoing work focuses on calibration and scenario analysis. The approach supports the development of integrated decision-support tools to explore cross-sector trade-offs and potential interventions in complex social–ecological systems. AI tools were used for language editing.