The area of the Nature Park belongs entirely to the Adriatic river basin. Rivers Lika, Gacka and Zrmanja are particularly important for the Park area. Their river basins are on the northeast side of Velebit and the catchment area in the coastal area from Novljanska Žrnovnica on the north to the mouth of the river Zrmanja in the Novigrad Sea on the south. Rivers Lika and Gacka differ significantly in terms of hydrogeological characteristics. Whereas the Gacka river basin shows typical karst features with large karst springs, the largest part of the Lika river basin is related to surface or shallow underground runoff. Lika originates in the area of Medak and Mogorić and sinks into Lipovo polje. Due to its geological structure, Velebit is a hydrogeological barrier so almost a half of the mountain massif is drained into the basin of the Lika river.
Along Velebit’s northeast side there are numerous karst springs, such as for example springs in Počitelj, Divoselo, Barušani and Pazarište where the left tributaries of the Lika river are formed (Počiteljica, Novčica, Otešica). Due to local watertight deposits, smaller amounts of water can be found also in other parts of the massif. The largest one is the spring in Štirovača. In the area of the Park there is a substantial amount of underground drinking water of high-quality so the interest for its utilisation is increasing.
Water supply to the city of Zadar comes from the Zrmanja river and springs in Muškovci. The natural state of the high part of the Zrmanja river basin has been altered: there are now dams on Ričica as well as the retention before the sinking of both rivers into karst underground. The water is used for the hydroelectric power plant Obrovac and led by a tunnel to the level of Zrmanja.
There are two hydropower systems in the area of the Nature Park: hydroelectric power plant Senj and hydroelectric power plant Obrovac. In the case of the hydroelectric power plant Senj, the accumulation and retention system, apart from the inflow tunnel and the engine room in Jurjevo, is located outside the area of the Nature Park.