Evaluation of water resource balance in the Urmia Lake Basin: Integrating carrying capacity and water footprint model for sustainable management

Given the scarcity of water resources and the ever-growing demand, effective water flow management becomes crucial. The Lake Urmia Basin, a critical region in Iran, faces severe water scarcity exacerbated by climatic changes, land use alterations, over-extraction of groundwater, and mismanagement. This study evaluates the water resource balance by integrating carrying capacity and water footprint models to assess sustainable water management practices. Utilizing the InVEST model, water provisioning ecosystem services have been estimated as the supply, while the ecological footprint method quantifies water demand across various sectors. Three scenarios are evaluated: continuation of the current situation, an ideal scenario with substantial reductions in water consumption and pollution, and implementation of operational programs. The findings reveal significant water deficits in certain sub-basins, highlighting the need for a fundamental revision of resource allocation based on each region's ecological capacity. Lake Urmia, the central nucleus of the basin, has experienced a significant size reduction, approximately 10 % of its original size, from the early 1990s to 2018, due to climatic changes, land use alterations, over-extraction of groundwater, and mismanagement. The environmental deficit in some sub-basins raises serious concerns, even in the best scenario where ecological footprint reduction is considered. These results underscore the effectiveness of ecosystem-based comprehensive capacity analysis for sustainable watershed development. This research offers a unified spatial system for quantifying ecological footprints and land resilience, providing critical insights into addressing water scarcity and supporting holistic regional planning.