Saleh Nasiri, Mohammad Zare, Ezzat Raeisi, Zargham Mohammadi, Fereidoun Rezanezhad
In endorheic basins with arid or semi-arid climates, lakebed geometry fundamentally controls water retention and regional atmospheric moisture feedbacks. However, quantifying these hydro-morphometric interactions to define environmental flow requirements remains challenging due to ambiguities in Stage-Area-Volume (S-A-V) relationships caused by spectral confusion between shallow brines and evaporite crusts. We propose a geometry-driven framework that resolves these limitations by integrating high-resolution bathymetric reconstructions with regional atmospheric moisture dynamics. Multi-decadal Landsat imagery (1972-2024) coupled with targeted RTK-GNSS surveys introduced a novel Temporal Stability Ratio (TSR) metric that substantially reduced saline-induced spectral biases. Analysis of the volume-area sensitivity coefficient (β) in a desiccating terminal saline lake delineated hydro-morphological functional zones, identifying key transition thresholds at 268.7 and 411.5 km2 that separate evaporation-dominated from volume-dominated regimes. Time-series analysis revealed a post-2001 surface-dominated state with severely reduced hydrological memory. Variance decomposition of meteorological records demonstrated that each 100-km2 increase in lake surface area elevates regional relative humidity by 1.35 percentage points, an effect that holds across monthly lags at the seasonal scale. The gradual loss of this microclimatic moderation exposes adjacent globally recognized agricultural heritage systems to extreme moisture deficits. These coupled hydro-climatic thresholds support phased filling strategies to reduce evaporative losses, increase storage reliability, and protect regional biodiversity alongside transnational regional economic security. The approach links physical lakebed geometry to atmospheric feedbacks and provides a transferable model for environmental water allocation in complex saline lake systems worldwide.