Conceptualizing trade-offs of water conservation strategies and unintended consequences using a system dynamics approach

Improving water use efficiency in agriculture is a key strategy in reducing water scarcity, especially during drought seasons. However, the benefits of these water saving strategies can be reduced if farmers switch to more profitable and water consuming crops or increasing irrigable area, i.e. rebound effects. These feedbacks will likely offset the water savings benefits and subsequently intensify agricultural water use. Here we propose a new system dynamic model that represents the interactions and feedback loops between hydrological and social processes to explore rebound effects by analysing competing water needs for both urban and agricultural allocation. The model is then used to explore the dynamics of different mitigation policy options to alleviate the phenomenon: (i) Restricting water allocation (ii) Limiting size of agricultural land (iii) Changing cropping patterns (iv) Deficit irrigation.