Tidal rivers affect groundwater flow and salt levels in coastal aquifers. The study looked at how a tidal river impacts these dynamics. They found that changes in the river's level can reverse groundwater flow. During high tide, seawater intrusion area increases by 5% compared to low tide. The saltwater intrusion region expands towards land from the river. Water exchange between the river and aquifer varies with tidal levels, with the river being recharged by groundwater when the tide is low. A physical river dam can intensify the impact of the tidal river on water exchange and salt flux. These findings help us understand how tidal rivers influence groundwater flow and salt transport in upstream aquifers.