Water resources sustainability assessment through uncertain supply-demand modeling under scarcity conditions.

Interconnected factors, including improper water resource management and climate change, escalated with rapid population growth, are worsening the global water crisis. This study bridges human-environment interactions through water performance indicators to transform complex problems into manageable information if implemented within organized frameworks. The DPSIR framework (Drivers, Pressures, State, Impacts, Responses), coupled with detailed causal relationships, can demonstrate pressures of human activities on ecosystems, impacts of changing state, and prompt responses to restore and enhance sustainability by reducing stressors. The indicators that measure different attributes of water resources systems help in understanding the interactions and their dynamics. This study utilizes key indicators, including water stress, productivity, and efficiency, to assess various aspects of water resource sustainability in the Kor-Sivand River Basin, Iran, as a region facing severe water scarcity challenges. The Principal Component Analysis (PCA) method is utilized to develop a composite indicator, avoiding redundant indicators while reducing complexity. Findings demonstrate growing socioeconomic drivers and pressures; the system state undergoes unstable water demands, and subsequent cascading impacts make the system respond inversely. The system's behavior at a critical tipping point in the year 2008, coinciding with severe drought and dam impoundment, reveals the effects of human-environment interactions. This transferable methodological framework can be readily adapted to other water-stressed regions worldwide, providing a replicable template for informing sustainable water governance and diagnosing human-water interactions. The findings directly inform progress toward Sustainable Development Goals (SDGs), particularly SDG 6, Clean Water and Sanitation, by providing diagnostic tools for water stress assessment and management, supporting targets related to water-use efficiency (Target 6.4), water quality improvement (Target 6.3), and integrated water resources management (Target 6.5). The framework also holds relevance to SDG 14 through the effects of terrestrial water management decisions on downstream marine systems.