Fig. 2. Conceptual model of Guadiana Estuary System used for designing the simulation analysis of the Policy Issue. The box colors represent the modeled components: environmental (light blue), socioeconomic (yellow), ecological-social-economic (ESE) (green) and linking block (blue). Population block is an input to the environmental component and at the same time itís an output of the socioeconomic component, hence it is highlighted. The Blue Flag block makes the simulation model operational by linking the ecological output to the socioeconomic model.