The recovery of water and other resources from urban water systems (UWSs) has long been practiced in many Mediterranean countries, but remains relatively unexplored in Croatia. In this study, the sustainable circulation processes of water, nutrients, energy, and their components in UWSs in coastal tourist areas are analyzed in order to strengthen urban systems and environmental sustainability. Dissipative structure theory is used to critically analyze the complexity and sustainability of UWSs, urban systems, and circular economy frameworks. This study is based on conceptual analysis and knowledge (experience), and the sustainability of a circular urban water system is assessed based on circular thermodynamics. This study examines the core concepts of circular urban water systems as a local resource for nutrients, water, and energy, integrating approaches that strengthen resource recovery concepts. Systemic urban climate adaptation and circular urban systems have been adopted as interrelated strategies for resilient cities, focusing on closing resource loops while building resilience to climate impacts through whole-system approaches. This framework moves beyond single solutions, connecting urban planning, energy, water, waste, and social factors to incorporate green and low-carbon developments into cities. It was established that the principle of integrated resource management lies at the heart of effective water, energy, and nutrient management in coastal urban areas, which treats entire urban life support systems as an interconnected system. Such systems increase the efficiency percentages of water, nutrient, and energy recovery while minimizing sludge volume and system entropy, thus supporting the tourism economy and low-carbon development.
Jure Margate (Mon,) studied this question.