Budyko Curve Conformance Unravelling Hydrological Change in a Semi‐Arid Mediterranean‐Climate River Basin
Articles > Article · 2026
Authors: Yonca Cavus, Dilek Eren Akyuz, Ebru ERİŞ, Hafzullah Aksoy
Hydrological Processes, Journal Indexed in SCI, International, WoS, 2026, vol 40, pp 1-1
DOI: 10.1002/hyp.70657
Summary
ABSTRACT This study investigates long‐term streamflow changes in the Gediz River Basin, a climatically Mediterranean catchment in western Turkey, by employing a Budyko‐based water balance framework. Using multi‐decadal observations from 18 streamflow gauging stations and four meteorological stations, we analyse basin behaviour through (i) Budyko and Fu curves fitting, (ii) detection of regime shifts using time‐series segmentation and (iii) attribution of streamflow changes via both decomposition and sensitivity methods. A common hydrological regime shift was detected in 1984, after which streamflow consistently declines across most streamflow gauges. Post‐change periods exhibit elevated Fu parameters and increased evaporation ratios, indicating reduced runoff and intensified aridity. A high majority of gauging stations align closely with Budyko expectations, while deviations—particularly in high‐altitude headwaters—are attributed to karst geomorphology, snowmelt processes and data limitations. Attribution analysis reveals that climate variability, especially declining precipitation, accounts for 50%–75% of the total streamflow change, though local anthropogenic drivers also contribute significantly in specific sub‐basins. These findings mirror regional hydroclimatic patterns across the Mediterranean Basin and reinforce the Gediz River Basin's sensitivity to both climate stress and water management practices. The well‐established knowledge that humans are the main factor creating the streamflow decrease has been softened with our data‐limited results showing that the climate‐driven change in Western part of Turkey could be higher than the human effect. The study is a detailed basin‐scale understanding, rather than implying a methodological breakthrough or a definitive proof of persistent Budyko conformance. It emphasises that the hydrological character of Gediz River Basin provides an opportunity to develop Budyko‐based practical methodologies for the river basin‐scale water resources planning and management strategies that could potentially be transferable to data‐scarce, semi‐arid regions facing escalating water insecurity.