The Lower Neretva is facing the problem of salinity due to the intrusion of seawater into the river flow, which has a negative impact on agricultural land and the biodiversity of the region. This paper summarizes knowledge about the current state of the irrigation system, the amount of salinity in certain areas, the causes and consequences of salt intrusion, and planned measures to improve the irrigation system. A hydrological analysis was made using data from the measuring station Opuzen. It can be seen that the water level drops in the summer months, thus enabling easier intrusion of salt through the Neretva River bed at times when the sea level is higher than the Neretva River water level. The project for the construction of a movable dam with a lock and a siphon under the Mala Neretva is presented, they are envisaged as key measures to combat salt intrusion. The dam will stop the intrusion of seawater, while the lock will ensure the passage of vessels and the migration of fish. The construction of a siphon under the Mala Neretva would enable the evacuation of excess internal saline waters from the Vidrica amelioration system during the summer period (in the irrigation season), using the existing Prag pumping station. After the implementation of the mentioned projects, a significant improvement in the conditions for agricultural production in the Lower Neretva is expected. Maintaining an optimal level of salinity will enable a stable yield, the preservation of the ecosystem, and thus the financial stability of the local population, which is mostly engaged in agriculture.