River deltas in arid and semi-arid coastal margins are highly sensitive to concurrent changes in river discharge, sediment supply, flood regime, relative sea level and nearshore hydrodynamics. This study develops an integrated climate-morphodynamic assessment for the Mond River delta, northern Persian Gulf, by combining long-term daily hydro-sediment observations with physically constrained scenario analysis. Daily discharge and sediment-load records for 1940-2024 were processed to define seasonal forcing, calibration and validation datasets, while four modelling strategies were compared: a Hydro-Sediment Balance Model (HSBM), an Eco-Hydrogeomorphic Adjustment Model (EHAM), a Hybrid Data-Physics Model (HDPM) and a Delft3D-SWAN morphodynamic configuration. The HDPM showed the highest validation skill for discharge (NSE = 0.9392 and R² = 0.9499) and log-transformed sediment load (NSE = 0.9153 and R² = 0.9196), whereas Delft3D-SWAN retained the strongest process consistency for interpreting channel change, delta-lobe construction and backwater-scale avulsion. Scenario results indicate that enhanced relative sea-level rise increases avulsion frequency from 0.012 to 0.018 yr⁻¹ and shifts avulsion closer to the shoreline, while increased upstream sediment supply promotes upstream avulsion displacement and higher aggradation. In contrast, more frequent overbank floods reduce net aggradation in the backwater reach and lower avulsion frequency. The combined forcing scenario produced the highest instability, with Af = 0.020 yr⁻¹ and a reduced stability index of 0.32. The results show that the Mond River delta is controlled by a coupled balance between upstream sediment delivery and downstream accommodation, and that avulsion risk should be evaluated using both statistical performance and morphodynamic plausibility.