Rapid urbanization, untreated wastewater, and fragmented governance have generated major sustainability challenges in the Río Blanco watershed, located in Zapopan. This study applied the Hydrology¿Environment¿Life¿Policy (HELP) framework integrated with the Watershed Sustainability Index (WSI) to evaluate hydrological conditions, environmental integrity, human wellbeing, and governance performance within the basin. Data were compiled from official governmental reports and statistics, interviews with federal, state, and municipal authorities, and spatial analyses conducted in ArcGIS Pro. Indicators included land-use change, per capita water availability, and Human Development Index (HDI) sub-indicators across multiple periods up to 2020. The watershed obtained a WSI score of 0.33, indicating critically low sustainability. This result was primarily associated with poor water quality, inadequate wastewater treatment infrastructure operating at approximately 5% capacity, alongside weak institutional coordination. Average BOD concentrations reached 156¿mg/L, a level comparable to untreated domestic wastewater. Rapid urbanization was also associated with a 79% increase in BOD5 levels, an 8.84% decrease in per capita water availability, and a 19% reduction in natural vegetation cover. The adapted HELP¿WSI framework proved a useful and replicable decision-support tool for urban watershed assessment. These findings highlight the urgent need for improved governance, stronger stakeholder coordination, and strategic investment in decentralized wastewater treatment infrastructure to support sustainable urban watershed management.
