The Neretva River, which emerges beneath Zelengora mountain in eastern Bosnia and Herzegovina, flows through the Dinaric Arc and finally forms its large delta into the Adriatic Sea. Neretva is the largest river on the eastern side of the Adriatic basin. It has been harnessed and controlled to a large extent by several hydroelectric power plants and their storage lakes, but it still remains unique in its beauty and the diversity of its landscape.

The underground karsts flows of the basin area are another important element of the water system. There is a large number of springs which bring significant quantities of water especially during the winter.

The delta is influenced by the sea water forming brackish water areas. These are also important for biodiversity.