An index-based approach for assessment of upstream-downstream flow regime alteration

River regulation is challenging when there diverse upstream and downstream interest, leading to regional international conflict. However, quantifying the upstream-downstream flow regime changes their causes are given less consideration in river basin. In this study, we presented three new ratios for downstream-upstream low contribution (DUL), high ratio (DUH), meteorological-hydrological drought (MHD), an integrated assessment of alteration across To test methods, compared Ceyhan basin central Turkey, which was significantly modified by agriculture between 1984 2018 (the irrigated area increased 2.8-fold, rainfed farming decreased 67.6%). Our analysis revealed a clear change seasons annual last station at Misis after 1984, but no considerable tributaries. decade (2005–2014) second half (1995–2014) frequency hydrological droughts increased, while meteorological followed stationary pattern. Evaluation impact anthropogenic activities on (by comparing characteristics with those from 1975 as post- pre-impact periods) incipient (Hanköy, Karaahmet, Kadirli headwaters), severe below Aslanta? dam center, moderate river. The metrics provide supplementary information can be introduced novel quantitative measure recognize driving factor droughts.