Current movement in Benoa Bay water, Bali, Indonesia: Pattern of tidal current changes simulated for the condition before, during, and after reclamation

Benoa Bay is a reclaimed intertidal region which has become an area of significance. Many problems appeared due to the reclamation such as local people declined (due to fishing activities disruption), social and cultural problems, and environmental degradation as well. This study aimed to determine the hydrodynamic changes which have occurred due to the development of the area. We employed a numerical method (flow model) based on the Navier-Stokes equations. In the 1995 simulation, the flow velocity ranged from 0-1.4 m s−1. In the 2016 simulation, the flow velocity ranged from 0-1.35 m s−1. When the reclamation was implemented, the flow velocity ranged between 0-1.2 m s−1. We found that during low tidal condition, several areas within the bay were not covered by water due to the high rate of sedimentation and unstable sediment distribution which caused by the Benoa Bay development. It is obvious why the area within the bay will be reclaimed. Based on the simulation, the condition will get worse, if the reclamation is applied. The degradation of Benoa Bay has a big impact on the hydrodynamic pattern changes which is resulting in the other effects on circulation and biological aspects. The weakened water flows automatically disrupt the water mass transport mechanism, and if ongoing, it will threaten the marine biota.