Ports and Fisheries Division, Ambalapady, Karnataka have a proposal for development of a fisheries harbor at Alvedande situated on the right bank of the Honmov river on the west coast of India. From the debuching point of Honmov river to 1.7 km upstream stretch of river in low tide, considerable sedimentation has occurred. Three jetties are existing in this stretch, which have become non-operational during low tide due to non-availability of required depths. The harbour is facing problem of siltation at the entrance of navigational channel for fishing boats also. The sedimentation in the approach channel is caused due to sediment laden river and long shore littoral drift. The optimum breakwater layout consisting of northern breakwater of length of 105 m and southern training wall of length 575 m with 100 m wide opening was evolved as per the future requirements of having a larger safe area for parking of boats in the embayment and for possible berthing operations there with due consideration to wave tranquility and long shore drift studies. In the present paper, the impact of this optimum layout was assessed from the aspects of hydrodynamics and sedimentation. The model was simulated using MIKE-21 HD module considering both wave and tide induced currents as the site is influenced by both tide and wave. The Model was calibrated for the observed currents. The maximum currents during peak river discharge in monsoon season would be of the order of 0.95 m/s in between the breakwaters for proposed optimum layout, at the inlet these would be of order 1.52 m/s and near jetty the currents would be about 1.21 m/s. During average discharge and in non-monsoon period currents would be within 0.7 m/s and 0.4 m/s respectively. By sediment model, it was observed that during peak river discharge slight deposition can be observed in the approach channel and slight erosion at the river mouth. During average discharge, the sediment pattern remains almost same and in low flows, sedimentation has been observed in approach channel as well as at river mouth. The annual sedimentation in navigational channel would be about 0.12 m. Overall the proposed breakwater would not have any adverse impact on the morphological changes in the harbour. Thus, the mathematical model studies were very useful in taking care of all present problems for this proposed development and in deciding the optimum layout and assessment of the possible morphological effects.