Water sustainability assessment with integrated water resources management approach under climate change conditions Mehran Gholami mehran.gholami.iut@gmail.com Date of Submission: 16 September 2020 Department of Civil Engineering Isfahan University of Technology, Isfahan 84156-83111, Iran Degree: M.Sc Language: Farsi Supervisor: Dr. Hamid Reza Safavi , hasafavi@cc.iut.ac.ir Advisor: Dr. Sara Nazif , snazif@ut.ac.ir In order to satisfy the significant water demands to support economic growth and enhance social welfare and, on the other hand, preserving freshwater ecosystem services for current and future generations, sustainable water resources management is inevitable. To implement this, adopting an interdisciplinary and integrated approach is indispensable to all environmental, economic, and social dimensions of the water system. Although in recent years, several multi-dimensional methods have been proposed to determine water security and sustainability, these methods are often based on the top-down approach, with a greater emphasis on social or ecological aspects. Additionally, the developed methods are associated with a specific study area. This casts doubt on the salience, credibility, and legitimacy of their application in other areas. In this study, by adopting a bottom-up approach and paying specific attention to stakeholder participation, as well as a fair view of the economic, social, and environmental aspects of sustainable development, the multi-dimensional Zayandehrud Water Sustainability Index (ZRWSI) was developed in a systematic manner. The indicators of ZRWSI were determined based on theoretical principles of sustainability, extensive literature review of existing water sustainability indexes, priorities/requirements of the Zayandehrud basin, with the participation of stakeholders, and on the cause-effect relationships of the Driving force, Pressure, State, Impact, and Response (DPSIR) framework. A comprehensive assessment of changes to the sustainability of the water in the river basin was conducted from the water year 2007 to 2016. The results demonstrated that despite improvement in the overall ZRWSI values, social and economic sustainability was not in line with environmental sustainability. Hence, to prevent the degradation of water resources and ecosystems of the river basin, it is essential to change the status quo, such as changing regional economic development structure and water consumption patterns, enhancing the quality level of wastewater treatment, resolving water conflicts, and so on. The practical application of the ZRWSI in this study (by considering all economic, social, environmental dimensions, and climate variability/change effects in the Zayandehrud river basin) indicated that this index could be used as an appropriate tool to evaluate previous policies, identify unsustainable practices and prioritize future strategies in the river basin. Keywords Sustainable development, Water sustainability, Integrated water resources management (IWRM), Driving force-pressure-state-impact-response (DPSIR) framework, Sustainability index, Stakeholder participation, Zayandehrud river basin