Ecological lens on prioritizing water security at sub-watershed level using Pressure-State-Response model and Ordinal Priority

Amid growing water crises, climate change, and intensified human activities, there is an urgent need to assess water conditions from an ecological perspective. This study evaluated Water Security with an Ecological Lens (WSEL) in the Gorganrud watershed using advanced models at a semi-distributed scale. The Gorganrud watershed is a strategic watershed in northeastern Iran facing critical challenges like drought, water scarcity, floods, and sedimentation. After conceptualizing and quantifying WSEL criteria and testing their collinearity through the Variance Inflation Factor (VIF) method, two approaches the Pressure-State-Response (PSR) model and the Ordinal Prioritization Approach (OPA) were employed and compared. The results of the study showed that the WSEL status was unevenly distributed among the sub-watersheds; some areas were in a critical state and required special management, while others showed successful performance despite the pressures to improve the status. Therefore, the adoption of smart management strategies, such as regulating water consumption in agriculture and implementing innovative cultivation techniques, could further enhance water security. The PSR model, aligning closely with field data, estimated the watershed's average WSEL at 0.42, while the OPA model indicated a more critical status with a mean of 0.3. The difference stemmed from the PSR model's integrated analysis of pressure, state, and response factors. Both models identified sub-watershed 6, located in the eastern part of the watershed, as low security (WSEL less than 0.05) and in need of immediate intervention. Overall, the integrated analytical approach provided an effective tool for sustainable water resource management at local and regional levels.