Despite extensive research on meander dynamics, the specific mechanisms driving chute cutoff formation remain underexplored in semi-arid Mediterranean river systems. This study addresses this gap through a diachronic analysis of satellite imagery (2001-2019) combined with field investigations, focusing on the Middle Sebou River within the Sais basin. In this morpho-structural setting, the river is incised into ancient fluvial terraces and Miocene sandstone-marl formations, exhibiting entrenched meanders in the confined reach R1 and freely migrating meanders in the unconfined reach R2. Ten chute cutoff events were identified and analyzed. Each is linked to flood-induced overbank flows and follows one of three recurrent mechanisms: (1) downstream elongation of an erosional embayment; (2) headward incision from the downstream edge of a meander; and (3) widening of a swale aligned with scroll bars or depressions. These mechanisms are influenced by in-channel flow dynamics, the morphosedimentary and ecological structure of point bars and floodplains, bank typology, river morphometry (mean bend radius/width ratio = 3.87), and human pressures such as embankments and cultivation. The results provide an essential basis for both civil engineering interventions and ecological studies. Published by Elsevier B.V. on behalf of COSPAR.