SYSTEM DYNAMICS POLICY IMPACT ASSESSMENT OF THE WATER-ENERGY-FOOD-ECOSYSTEM NEXUS IN THE INKOMATI-USUTHU WATER MANAGEMENT AREA, SOUTH AFRICA

Water, energy, food, and ecosystems are linked in a complex system known as the WEFE nexus. Implementing policies in this system affects all other sectors, often in unanticipated ways. Integrated modelling and assessment of the system is necessary to start to understand these complex linkages. In this paper, a system dynamics model of the WEFE nexus in the Inkomati-Usuthu Water Management Area, South Africa, is presented that models the nexus as a complete, coherent system and assesses the impact of policy actions against reference scenarios. Results show that enacting individual policies tend sto have relatively minor impacts confined to one or two WEFE sectors. Implementing many policies in parallel has mich larger system wide impacts, often being detrimental (e.g. negatively affecting the water balance). Such modelling can help policy makers understand this complexity, and can start discussions on to design policies to avoid negative impacts and leverage synergies.